MORTALITY OF IMPAIRED LIVES 1964-73

BY R. D. CLARKE, F.I.A.

[Submitted to the Institute. 27 November 1978]

1. INTRODUCTION

1.1. In 1965 Dr T. W. Preston and I submitted a paper to the Institute (J.I.A. 92, 27) which gave the results for the period 1947-63 from an investigation into impaired lives mortality undertaken by the office with which we have been associated. The purpose of the present paper is to report on the experience over a further period of ten years, viz. 1964-73.

1.2. It is not intended to reproduce here the full coding system which was devised by Dr Preston and which may be found in the 1965 paper. One result of the previous investigation was that certain impairments such as hernia, varicose veins, otitis media and family history of tuberculosis produced no significant extra mortality and it has seemed pointless to pursue the investigation of these categories. Furthermore it was decided to restrict publication in the main to codes for which there were sufficient deaths to yield significant results. This means inevitably that a number of codes are missing from the accompanying table.

1.3. For calculating expected deaths, the A1967–70 table, with a two-year select period, has been employed. The period 1967–70 is nearly equivalent to the middle four years of the decade 1964-73. The table is based on the experience of male lives accepted at standard rates of premium by offices transacting ordinary life assurance in the United Kingdom. It so happens that the experience of standard lives of the office concerned in the present investigation lies very close to the combined experience of all offices and consequently the A1967–70 table is appropriate as a basis for calculating expected deaths.

1.4. The accompanying table of results (pp. 23–25), showing the number of deaths and the percentage of actual to expected deaths, relates to the experience at duration 2 and over, the data at durations 0 and 1 being of negligible proportions. However, for code 18—coronary artery impairment-the data for all durations are of interest and this code has been excluded from the table and dealt with fully in the text. The same applies to codes 520–522, diabetes for entry ages under 30, where the smallness of the experience rendered any subdivision impracticable.

1.5. For female lives the amount of data in almost all codes is inadequate to derive much useful information. A final section of the text deals with the few codes for which results may be regarded as significant. In calculating expected deaths for female lives, a special table was constructed by applying the ratios of female to male mortality in English Life Table No. 12 to the Al967–70 rates referred to above.

15

16 Mortality of Impaired Lives 1964–73

1.6. Causes of death for some of the major impairments are analysed in an Appendix.

2. ANALYSIS OF RESULTS

Hypertension 2.1.1. The results obtained for the hypertension codes show a fairly modest

extra mortality for moderate hypertension, but a marked increase in risk for high-blood-pressure readings whether systolic or diastolic or both. The largest quantity of data relates to entry ages 40–59 and it is apparent that as soon as the systolic reading exceeds 170 or the diastolic exceeds 95, there is an appreciable increase in the extra mortality. Re-arranging the order of the results shown in the table on page 23 we obtain:

Systolic (SAP) Diastolic (DAP) Extra Mortality Under 95 +26%

155–170 95–105 +60% Over 105 +103% Under 95 +106%

Over 170 95–105 +136% Over 105 +193%

For entry ages 60 or over, the extra mortality percentages are, as would be expected, considerably less. However, even here a SAP reading of ‘over 175’ and a DAP of ‘100–110’ gives an extra mortality of +69%

2.1.2. The presence of overweight in conjunction with hypertension has, on the whole, yielded results suggesting that overweight does not add materially to the risk. An exception to this, however, is the group for entry ages over 60, SAP 160–175, DAP under 100, where standard weight cases have shown an extra mortality of +7% against +43% for overweight cases.

Impairment of the Coronary Arteries (Code 180) 2.2. The experience for lives with a history of coronary artery disease has been

very unfavourable, as the following table illustrates:

Attained Actual Duration Ages Deaths 100 A/E

0 All 11 297 1 All 12 346

Under 50 14 1,146 2 and over 50 and over 44 388

All 58 462 (These statistics are not given in the table at the end of this paper).

The conclusion to be drawn is that overall extra mortality is of the order of +400%, but that it is substantially higher at young ages. For practical underwrit-

Mortality of Impaired Lives 1964–73 17

ing purposes a descending scale of extra mortality might be reasonable varying from, say, +800% at age 40 to +300% at age 60.

Peptic Ulcer 2.3.1. The extra mortality exhibited by the peptic ulcer codes over the period

1964–73 showed a different pattern from that revealed by the earlier experience of 1947–63. Thus in the earlier period, the category ‘short history, no operation’ showed no extra mortality, being actually lighter than normal but in the later period, extra mortality of +22% is found for the ‘no complication’ cases and +30% for cases ‘with history of haematemesis’. On the other hand the category ‘short history, with operation’ has shown the reverse trend, an overall extra mortality of +65% having fallen to +7% for ‘no complication’ cases and +49% for cases ‘with history of perforation’.

2.3.2. For the category ‘long history, no operation, no complication’ (code 210) the extra mortality for 1964–73 was actually negative, even though the number of deaths was 274—enough to guarantee statistical significance. Oddly enough a similar result emerged for ‘long history, no operation, history of haematemesis’. For 1947–63 the corresponding extra mortality percentages were +23% for ‘no complication’ and +38% for ‘with complication’.

2.3.3. For ‘long history, with operation, no complication’ the extra mortality for 1964–73 was +14% against +24% for 1947–63. With complications the percentages were somewhat higher: +18% for haematemesis, +34% for per- foration and +23% for other complications. In 1947-63, all complications combined showed +62%.

2.3.4. These somewhat paradoxical results are not easy to interpret. Clearly the most substantial risk attaches to operated cases with history of perforation. A practical way of cutting through the difficulties is to suggest +25% for uncompli- cated cases and +50% for others without differentiation between operated and non-operated cases.

Cholecystitis 2.4. The only code in the cholecystitis group which produced sufficient data to

yield significant results was 233, viz. cholecystitis with cholecystectomy. With 58 deaths, the percentage of actual to expected deaths was only 94%, i.e. a negative extra mortality as against +39% for 1947–63. It would appear, therefore, that this particular impairment has ceased to present any extra hazard---at any rate so long as it is not accompanied by any other form of medical complication.

Epilepsy 2.5. In the epilepsy group, petit mal with 14 deaths showed an extra mortality

of +46%; while grand mal, with 57 deaths, showed an extra mortality of +113%. In the 1947–63 experience there were not enough data to yield any significant result for petit mal; grand mal however, showed +192%, so there would appear to have been some improvement in mortality between the two periods.

18 Mortality of Impaired Lives 1964–73

Head Injuries 2.6. Only two codes in this category provided sufficient data to yield significant

results, viz. 310 (cerebral concussion, without fracture, mild) which showed extra mortality of +12%; and 312 (fracture of skull, no operation, no sequelae) which showed + 21%. Comparable percentages for 1947–63 were +18% and +53% respectively.

Psychoneuroses 2.7. The experience for psychoneuroses was surprisingly light for 1964–73.

Code 320 (‘mild’) showed below standard mortality and code 321 (‘moderate’) showed +16%. Code 322 (‘severe’) yielded no extra mortality, but code 323 (‘with features suggestive of psychosis’) yielded extra mortality of +39%. which was similar to the 1947–63 experience.

Migraine 2.8. The 1947–63 investigation contained insufficient data to give any statisti-

cal results for migraine. In 1964–73, however, code 330 (‘mild’) gave extra mortality of +23%, and code 331 (‘severe’) produced +39%. It would thus appear that migraine is definitely a rateable impairment and that the severity of attacks is a relevant factor.

Non- Pulmonary Tuberculosis 2.9. Extra mortality for non-pulmonary tuberculosis codes over the period

1964–73 seems to have been around +50%. Thus code 400 (spine) showed +57%; code 401 (hip) showed +44% code 402 (other bones or joints) showed +63%; code 407 (kidney) showed +64%. The exception was code 403 (glands) which produced a negative extra mortality. In general, however it can be said that non-pulmonary tuberculosis was atypical of the impairments in the investigation in showing a substantial increase in extra mortality in the period 1964-73 as compared with the experience of 1947–63.

By contrast fistula in ano gave negative extra mortality for 1964–73, as against +43% in 1947–63. No obvious explanation presents itself for this anomaly.

Pleurisy and Spontaneous Pneumothorax 2.10. The only code calling for comment in this group is No. 434 (pleurisy, dry

or indeterminate, not associated with pneumonia), for which the extra mortality was +10%.

Pulmonary Tuberculosis 2.11. Mild cases (codes 440-443) produced no significant extra mortality.

Moderate or severe cases, not treated by special methods, produced +33% for code 444 and +44% for code 445. Cases treated by special methods produced +21 % for code 450 and +28% for code 454. The conclusion from these results would seem to be that mild cases can be accepted at standard rates, cases treated

Mortality of Impaired Lives 1964–73 19

by special methods can be accepted with +25%. while moderate or severe cases not treated by special methods call for an extra mortality loading in the neigh- bourhood of +40% or +50%. It is, of course, assumed here that the disease has been arrested and the proposer is otherwise in good health.

Glycosuria 2.12. No significant extra mortality was found for glycosuria (codes 500–519).

Diabetes 2.13.1. After impairment of the coronary arteries, diabetes is probably the

most serious risk included in the investigation. (It is possible that more serious risks may exist among the tumours in the 90–990 range, but sufficient data have not yet accumulated for these to provide any useful results). As is generally known, diabetes occurring at a young age is more serious than when it first appears later in life. In the 1947-63 investigation, actual deaths among cases with entry ages under 30 were 833% of expectation—although this was based upon only 10 deaths. For 1964–73, actual deaths for these entry ages were 420% of expectation, this result being based upon 19 deaths. It is difftcult to be dogmatic on such scanty data; one can only suggest that some improvement in the experience may be inferred. Even so, the risk is clearly substantial and extra mortality of probably +400% should be assumed for underwriting purposes. (Note: For those cases with entry ages under 30, all durations have been combined in order to maximize the data and the results are not given in. the table.)

2.13.2. Turning now to codes 523-525 (entry ages 30–50), code 523 (standard weight) showed extra mortality of +190%, code 524 (underweight) gave +128% and code 525 (overweight) +253%. For the three codes combined the percentage extra mortality was +184% as compared with +252% in 1947-63. For the 1947-63 investigation, a breakdown by weight was not practicable and it is interesting now to note that weight may be a relevant factor in assessing the risk.

2.13.3. For entry ages over 50 (codes 526–528) the percentage extra mortality, as would be expected, was lower. For standard weight cases (526) with 28 deaths, it was +46%. Underweight cases (527) showed +112%. but this was based on only 8 deaths. Overweight cases (528) also had only 8 deaths and gave +59%. The high extra mortality for the underweight cases would appear to contradict the relatively favourable experience for entry ages 30–50, but the small quantity of data makes positive conclusions difficult. If all three weight categories for entry ages over 50 are combined, the resultant extra mortality percentage was +57% (based on 44 deaths), compared with +74% in 1947–63 (based on 24 deaths). Some improvement between the two periods therefore may be inferred.

2.13.4. To sum up, the results for diabetes show: (a) a sharp decline in percentage extra mortality with age at entry varying from,

say, +400% at entry age 20 to +50% at entry age 60. (b) an improvement in prognosis since the period covered by the 1965 paper. (c) a probability that overweight constitutes an additional hazard.

20

Goitre

Mortality of Impaired Lives 1964–73

2.14. The data for goitre are not very substantial. For what the results are worth, there appears to have been no significant extra mortality in the ‘simple or unclassified’ category. For exophthalmic goitre. code 550 (untreated) yielded

+66% extra mortality (based on 9 deaths) but code 551 (surgical treatment) gave negative extra mortality (14 deaths).

Underweight 2.15. Data for entry ages under 30 in the underweight class are too scanty to

yield results of any value. For entry ages 30–50, code 610 showed extra mortality of +15% and code 611 (chest expansion unsatisfactory) showed +52%. Code 612 (not medically examined) showed nil extra mortality. For entry ages over 50, code 620 showed +12% extra mortality and code 622 (not medically examined) showed +35%. Other codes had insufficient data to give useful results.

Overweight 2.16.1. For entry ages under 30, code 650 (20-30% over standard) showed

extra mortality of +25%; code 653 (30–40% over standard) showed +69%; and code 656 (more than 40% over standard) showed +92%. These results exhibit a predictable gradation of the extra risk with increasing weight.

2.16.2. For ages 30–50, the pattern is more complicated. The significant data cover a larger number of categories and the extra mortality percentages are best set out in tabular form as follows:

Weight category 20–30% 30–40% More than

over standard

over standard

40% over standard

% % % Girth satisfactory 9 31 6 Girth unsatisfactory 46 20 54 Not medically examined (NME) 36 33 *

* insufficient data to produce a result

2.16.3. These results are not easy to interpret. However the bulk of the data came in the first column (20–30% over standard) with 225 deaths at code 660, 82 at code 661 and 189 at code 662. It would seem, therefore, that for medically examined lives at entry ages 30-50, appropriate loadings are +10% for ‘girth satisfactory’ and +150% for ‘girth unsatisfactory’; while for lives not medically examined a loading of +40% may be appropriate.

2.16.4. Turning to entry ages over 50, other anomalies arise. Most categories showed no significant extra mortality. There was, however, an exception: code 672(20–30% over standard, not medically examined) where extra mortality was

Mortality of Impaired Lives 1964–73 21

+40%. It should be noted that the other NME codes (675 and 678) in this age group did not provide sufficient data to give useful results.

Respiratory Diseases 2.17.1. The three codes for bronchial asthma produced substantially lower

mortality than in 1947–63. This may well be due to the changes in treatment that have taken place in the last two decades. Code 701 (entry ages under 30) produced extra mortality of +14%; code 711 (entry ages 30–49) produced +38%; and code 721 (entry ages 50 and over) produced +36%. These results suggest that an extra mortality percentage of, say, +40 may be adequate for bronchial asthma without further complications.

2.17.2. Turning to chronic bronchitis without emphysema, code 712 (entry ages 30–49) showed an extra mortality percentage of +28 and code 722 (entry ages 50 and over) showed +70%. These percentages are again lower than in 1947–63.

2.17.3. Chronic bronchitis with emphysema exhibited appreciably heavier extra mortality. Code 713 (entry ages 30–49) gave +223% and code 723 (entry age 50 and over) gave +96%.

2.17.4. Overall, the results for bronchitis are anomalous in so far as for cases without emphysema the percentage risk appears to increase with age at entry, while for cases with emphysema it appears to decrease. In 1947–63, the extra mortality for cases without emphysema was roughly constant with age at entry; cases with emphysema followed the same pattern as 1964–73, i.e. the extra mortality decreased with entry age. A tentative suggestion for practical under- writing is 75% for chronic bronchitis without emphysema at all entry ages, with a further addition for emphysema of +150% at entry age 30 running down to +25% at, say, entry age 60.

2.17.5. For code 724, emphysema without bronchitis, entry age 50 and over, only 11 deaths were recorded, representing an extra mortality percentage of +18. In 1947–63 there were also 11 deaths with corresponding extra mortality of +23%. Thus there is virtually no change in this category.

Urinary Impairments 2.18. Code 802, urinary calculus removed by nephrotomy, gave extra mor-

tality of +70%. Code 803 urinary calculus removed by nephrectomy, gave +55%. Code 842, albuminuria (other than orthostatic) showed +83% but code 843, albuminuria with history of nephritis, gave only +15%.

Tumours 2.19. Only three codes in this group produced sufficient data to yield results of

any value: code 960, innocent tumours (confirmed), showed extra mortality of +19%; and code 962 malignant tumours, showed +108%. Code 963, enlarge- ment of the prostate, showed negative extra mortality (–16%). based on 23 deaths.

22 Mortality of Impaired Lives 1964–73

Osteomyelitis 2.20. Code 990, with 23 deaths, showed negative extra mortality (–24%). It is

interesting that in his recent work Medical Selection of Life Risks, Dr Bracken- ridge states that extra mortality in cases with a history of acute osteomyelitis has been reduced to negligible levels. He is more cautious, however in regard to chronic cases.

3. FEMALE LIVES

As indicated earlier, for most impairment codes the female data are not sufficient to yield useful results. There are, however, a few exceptions.

Code 612, 20–30% underweight, entry ages 30–50 not medically examined, showed 62 deaths with extra mortality of + 22%. The corresponding male group showed no extra mortality.

Code 711, bronchial asthma entry ages 30–49, produced only 10 deaths, but the extra mortality was + 143%.

Code 932, non-malignant tumours of the breast, produced 14 deaths with an extra mortality of + 133%. Code 940, uterine fibroids (confirmed), produced 47 deaths and an extra mortality of + 26%.

4. CONCLUSION

In conclusion I should like once again to pay tribute to Dr T. W. Preston, who was responsible for planning the investigation and devising the coding system and also to acknowledge the work done by Mr G. V. Barker M.A., F.I.A., in producing the computer data on which the present report has been based.

Mortality of Impaired Lives 1964–73

MEDICAL BUREAU 1964–73 MALE LIVES Percentages of Actual to Expected Deaths

(Duration 2 and over)

Code Description Hypertension

Entry Age Weight SAP under 40 150–165

155–170

Exposed Actual to risk deaths 100 A/E

110 130 131 132 133 134 135 138 140 142 144/5 148 150 151 152 153 158 160

standard

over 170 155–170 over 170

40–59 155–170 over 170 under 155 155–170

20% overweight 155–170 over 154

60 or over

under 155 160–175 over 175

standard 160–175 over 175 under 160

20% overweight 160–175

DAP under 95 under 95 under 95 95–105 95–105 over 105 over 105 95 or over under 95 95–105 over 105 over 94 under 100 under 100 100–100 100–110 100 or over under 100

11,361 8,226

891 7,889 1,751 1,454 1,707 7,261 1,706 2,117

984 2,268 2,514

424 816 522 374 289

48 162

21 170 53 31 53

136 25 44 20 33

142 22 42 34 24 20

152 126 206 160 160 203 293 143 120 187 196 133 107 108 117 169 141 143

Peptic ulcer 200 Short history, no operation. no complication 11,284 201 Short history, no operation, history of haematemesis 5,592 204 Short history, with operation, no complication 3,293 206 Short history, with operation, history of perforation 4,837 210 Long history, no opration, no complication 43,302 211 Long history, no operation, history of haematemesis 5,310 214 Long history. with operation, no complication 21,280 215 Long history, with operation, history of haematemesis 2,859 216 Long history, with operation, history of perforation 5,957 217 Long history, with operation, other complications 1,057

59 43 23 53

274 36

229 27 63 11

122 130 107 149 90 90

114 118 134 123

230 233

Cholecystitis Without stones, no operation With stones, cholecystectomy

1,155 10 123 5,599 58 94

300 301

Epilepsy Petit mal Grand mal

3,527 14 146 9,886 57 213

Head Injuries 310 Cerebral concussion without fracture or operation, mild 21,555 76 112 312 Fracture of skull, no operation, no sequelae 9,937 48 121

320 321 322 323

Psychoneuroses mild moderate severe with features suggestive of psychosis

39,869 155 94 24,965 142 116 4,466 21 101 3,873 24 139

23

24 Mortality of Impaired Lives 1964–73

Code Description Exposed Actual to risk deaths

330 331

Migraine mild severe

15,802 63 123 2,919 15 139

400 401 402 403 407 420

Non-pulmonary tuberculosis of spine of hip of other bones or joints of glands of kidney Fistula in ano

2,288 15 157 1,834 11 144 2,265 16 163

10,936 33 89 1,036 8 164 4,977 28 71

430 434 435 438

Pleurisy and spontaneous pneumothorax Pleurisy with effusion Pleurisy, dry or indeterminate, standard weight Pleurisy, dry or indeterminate, underweight Spontaneous pneumothorax

10,594 19,934 5,251 7,166

440 441 444 445 450 454

Pulmonary tuberculosis Mild cases weight standard or over standard Mild cases underweight Moderate or severe cases, weight standard or over standard Moderate or severe cases, underweight Treated by artificial pneumothorax Treated by major surgical procedures

13,543 40 95 2,640 13 106

18,881 95 133 3,728 24 144 7,604 40 121 9,239 43 128

Glycosuria 503 513

Inconstant, two or more tests, standard weight, no BSTT Inconstant, two or more tests, standard weight, BSTT

Diabetes Entry Ages

1,651 19 111 1,260 10 94

523 524 525 526 527 528

30–50

over 50

standard weight underweight overweight standard weight underweight overweight

4,695 1,705

755 952 228 267

Goitre 541 543

Simple or unclassified with operation

550 Thyroid adenoma etc. with operation Exophthalmic, no special treatment

551 Exophthalmic, with surgical treatment

1,202 10 103 1,085 8 125

910 9 166 2,776 14 85

Underweight Entry Ages

610 611 612

30–50 chest satisfactory chest unsatisfactory

I not medically examined 20–30% under- weight

over 50 chest satisfactory not medically examined

13,988 99 950 10

12,627 70

620 622

3,263 98 1,689 38

100A/E

29 75 33 24

75 110 77

108

63 290 17 228 14 353

28 146 8 212 8 159

115 152 100

112 135

Code Description

650 652 653 656 660 661 662 663 664 665 666 667 670 671 672 673 614 677

Overweight Entry Ages Overweight

20–30%

under 30 20–302 30–40% over 40%

20–30%

Girth satisfactory not medically examined satisfactory satisfactory satisfactorv

30–50 30–40%

over 40%

20–30%

over 50 30–40%

over 40%

unsatisfactory not medically examined satisfactory unsatisfactory not medically examined satisfactory unsatisfactory satisfactory unsatisfactory not medically examined satisfactory unsatisfactory unsatisfactory

701 710 711 712 713 721 722 723 724

Respiratory impairments Entry Ages under 30 bronchial asthma

hay fever

30–49

over 49

bronchial asthma chronic bronchitis without emphysema chronic bronchitis with emphysema bronchial asthma chronic bronchitis without emphysema chronic bronchitis with emphysema emphysema without bronchitis

800 801 802 803 804 820 821 842 843

Urinary impairments no operation

Urinary calculus voided or removed nephrotomy

nephrotomy Renal colic Cystitis without calculus Pyelitis without calculus Albuminuria, not orthostatic History of nephritis

960 962 963

Tumours (Miscellaneous) Innocent tumours (confirmed) Malignant tumours Enlargement of the prostate

990 Osteomyelitis Osteomyelitis

Mortality of Impaired Lives 1964–73

Exposed Actual to risk deaths

21,524 28 125 34,701 30 88 11,606 19 169 6,486 11 192

39,373 225 109 8,158 82 146

30,092 189 136 13,607 81 131 5,408 39 120 2,360 15 133 4.181 19 106 3,077 24 154 3,532 88 103 2,448 69 97 1,220 31 140

575 12 97 984 21 87 403 12 117

31,780 31 114 15,900 22 51 23,565 113 138 4,383 30 128 1.788 35 323 1,708 41 136 1,278 44 170

1,084 45 196 240 11 118

2,760 7,867 4,671 1,233 8,599

12,704 4,314 1,874 6,330

16 29 58 15 33 52 16 23 27

97 71

170 155 88 98 87

183 115

3,574 22 119 1,111 17 208

864 23 84

8,320 23 76

25

100 A/E

26 Mortality of Impaired Lives 1964–73

APPENDIX

Causes of Death

A1.1. For impairment groups where excess mortality was significant and the data was sufficient, an analysis of deaths by cause has been made. Inevitably for most categories, only broad groups of causes could be considered because of the smallness of numbers.

A1.2. For a basis of comparison, the results obtained from the report on causes of death among assured lives 1967–70 published by the Institute and Faculty of Actuaries (CMIR 1,49) have been employed. These are based on the experience of male assured lives accepted at standard rates of premium, i.e. the same group of lives as provided the basis for calculating the ratios of actual to expected deaths from all causes.

Al.3. In the statistics which follow, only cause-groups where extra mortality was significant have been segregated. Thus, other causes of death where the mortality was not significant are grouped under ‘other causes’. These ‘other causes’ include a residual group for which no further analysis is possible.

A1.4. Except for the final impairment group in this Appendix (uterine fibroids), all the information relates to male lives.

Hypertension A2.1. Deaths among the hypertension impairment groups have been analysed

into circulatory causes and other causes. A further analysis of the ‘other causes’ group showed no significant excess from any particular cause and it can therefore be stated categorically that the whole of the excess mortality can be attributed to circulatory causes. For ages at death under 45, there were only 31 deaths during the period for all the relevant impairment groups combined. The analysis into cause groups is as follows:

Circulatory Other All causes causes causes

Expected deaths 6·7 14·4 21·1 Actual deaths 16 15 31

A2.2. This illustrates clearly that the whole of the extra mortality was due to circulatory causes. For ages at death 45–59 a more detailed analysis by impair- ment group was possible. Codes 130, 132 and 138 are shown individually and other codes have been arranged in three groups as indicated in the following table. Codes for which data were trivial have not been included.

Mortality of Impaired Lives 1964–73 27

Circulatory causes Other causes All causes

Impairment Expected Actual 100 Expected Actual 100 Expected Actual 100 code deaths deaths A/E deaths deaths A/E deaths deaths A/E

110/2/8 17·2 37 215 14·6 11 75 31·8 48 151 130 20·1 34 169 17·0 22 123 37·1 56 151

131/3/4/5 15·1 65 430 12·9 18 140 28·0 83 296 132 20·4 45 221 17·3 19 110 37·7 64 170 138 18·0 37 206 15·4 14 91 33·4 51 153

140–148 20·8 40 192 17·6 17 97 38·4 57 148

A2.3. The most noteworthy feature of this table is to be found in the group of codes 131/3/4/5, where either the systolic pressure exceeds 170, or the diastolic pressure exceeds 105, or both. In this group the extra mortality from all causes was + 200%, or four times that of almost all the other groups shown in the table. Extra mortality from circulatory causes only was +330% or approximately three times that of all the other groups. To express the outcome in another form, of the 55 ‘extra deaths’ in this group, no less than 50 were due to circulatory causes and only five to other causes. There could scarcely be a more striking illustration of the importance of hypertension and its close connection with death from diseases of the circulatory system.

A2.4. For ages at death 60 and over, the percentages of actual to expected deaths were, naturally, considerably less than at the younger age groups. The results in the same groupings as for ages 45–59 (excluding the group 110/2/8) are given below.

Circulatory causes Other causes All causes

Impairment Expected Actual 100 Expected Actual 100 Expected Actual 100 code deaths deaths A/E deaths deaths A/E deaths deaths A/E

130 50·2 65 129 41·7 39 94 91·9 104 113 131/3/4/5 20·6 56 272 17·2 17 99 37·8 73 193

132 37·5 79 211 31·2 27 87 68·7 106 154 138 33·3 66 198 27·7 18 65 61·0 84 138

140–148 24·7 46 186 20·6 21 102 45·3 67 148

Once again it is the group 131/3/4/5 which stands out above all other groups and all of the 35 ‘extra deaths’ are due to circulatory causes. Systolic pressures of over 170 and diastolic pressures of over 105 are clearly features of which we must beware.

Impairment of the Coronary Arteries (Code 180) A3.1. Mortality from this impairment has already been discussed at length in the main part of the paper. Here it is sufficient to record that of the 81 deaths for

28 Mortality of Impaired Lives 1964–73

this code, no fewer than 64 were attributed to coronary artery disease. Only one death was attributed to other circulatory causes and no other cause of death was noteworthy in any way.

Psychoneuroses (Codes 321–323) A4. As demonstrated in the first part of the paper, total extra mortality in these

codes was not remarkable. However, out of a total of 187 deaths in codes 321–323 there were 15 suicides against an expectation of three, so that for this cause of death actual mortality was about five times expectation. Deaths from accident numbered 16 against an expectation of ten, so there was some excess from this cause also. No other cause of death showed significant extra mortality.

Diabetes (Codes 520–528) A5. Owing to the small number of deaths at individual impairment codes, all

codes in the group have been combined for the purpose of analysing the causes of the death. The results are as follows:

Cause of

Death

Cancer Diabetes Circulatory

causes All other

causes

Total

Age at death

0–44 45–59 60 and over 100 100 100

E A A/E E A A/E E A A/E

3·1 6 194 8·6 11 128 9·0 7 78 — 9 — 0·1 4 4,000 0·2 4 2,000

3·8 10 263 16·6 49 295 17·7 35 198

4·8 15 313 5·3 13 245 5·5 5 91

11.7 40 342 30·6 77 252 51 32·4 157

This analysis, apart from revealing the foregone conclusion that diabetics tend to die from diabetes, also shows a noteworthy excess mortality from circulatory causes. One might wish for more information about the deaths from other causes. All that can be said is that the extra deaths in this category were due neither to accident, nor to suicide. This may be of some interest because of the view sometimes expressed that diabetics are accident prone.

Overweight (Codes 660–665) A6. Four code groups had sufficient data to justify analysis by cause of death.

Although there was some excess in the residual group included in ‘other causes’, most of the excess mortality was due to circulatory diseases. The results are as follows:

Mortality of Impaired Lives 1964–73 29

Age at death

Under 60 60 and over Impairment 100 100

code E A A/E E A A/E

Circulatory causes 660 86·4 105 122 259 31 120 661 19·5 29 149 11·1 14 126 662 62·5 91 146 12·8 25 195 663–5 46·1 61 132 11·2 14 125 Total 214·5 286 133 61·0 84 138

660 661 662 663–5

Total

Other causes 73·3 61 91 21·5 22 102 16·5 22 133 9·3 17 183 52·9 63 119 10·7 10 93 39·1 52 133 9·3 8 86

181·8 204 112 50·8 57 112

No individual cause can be identified as responsible for the excess mortality from ‘other causes’. The main inference from these results is clear, i.e. that circulatory disease is the primary risk for overweight lives.

Bronchial Asthma (Code 711) A7. Code 711 (entry ages 30–49) was the only code for bronchial asthma to

yield results of statistical value. Unfortunately, most of the extra mortality occurred in the residual group included in ‘other causes’, for which, as already indicated, no analysis is possible. Cancer deaths were only 70% of expectation and deaths from circulatory causes only 95% of expectation. Deaths from accident and suicide were 13 compared with an expectation of five; while there were four deaths from bronchitis compared with an expectation of three. Of the remainder there were 30 deaths in the residual group of unclassified causes, compared with an expectation of six. The cause of death classification was drawn up in 1947, when it was felt that all the important causes had been segregated. It is now easy, with hindsight, to wish that the classification had been further extended so that one might know the specific causes from which these 30 bronchial asthma sufferers actually died. As it is, this information is regrettably not available.

Urinary Calculus removed by nephrotomy or nephrectomy (Codes 802/3) A8. The analysis by cause of death for all ages combined was as follows:

30 Mortality of Impaired Lives 1964–73

Cause of Expected Actual death deaths deaths 100 A/E

Cancer 12·0 15 125 Circulatory

causes 23·8 46 193 All other

causes 8·0 12 150

Total 43·8 73 167

Female lives Uterine fibroids (Code 940) A9. Of the 47 deaths recorded, 23 were due to cancer, compared with an

expectation of 11. This constituted the whole of the additional mortality in the group and deaths from all other causes followed the standard pattern of distribu- tion.

ABSTRACT OF THE DISCUSSION

The Author: The paper before you this evening is in the nature of a progress report on an investigation which is still continuing. The basic planning of the investigation was fully described in the paper which Dr Preston and I presented to the Institute in 1965 (J.I.A. 92, 27), and I accordingly see no reason to reproduce material which has already been recorded.

Considering the contents of this paper, it is clear that excess mortality among impaired lives proved in general to have been less in the period 1964–73 than in the earlier period 1947–63.1 believe this to be a reflection of the advances made in medical science in the meantime. It will be observed that there are a number of inconsistencies and anomalies. These are particularly noticeable in the peptic ulcer group, and Mr Lew has written to point out that the results shown in the paper run contrary to the trends which he has discerned in investigations carried out by him on North American data. I cannot, therefore, exclude the possibility that chance has led to a freak result, or some freak results, in the experience of this group of lives during 1964–73. I shall await with interest the report on the investigation for the decade 1974–83 to see whether the observed trends continue or whether they are reversed.

I have been asked about the absence from the table of results of a column showing standard deviations. These were, in fact, calculated, but as you are aware, the perennial problem of duplicate policies can make a standard deviation virtually meaningless when small numbers are involved. After due consideration it seemed preferable to omit them, rather than to suggest a spurious accuracy. I may, or may not, have been right in reaching this decision; I can only say that I have an easier conscience as a result.

Mr R. Bellinger (opening the discussion): This paper is the third of a series of which Mr Clarke has been the producer, or the co-producer, and in publishing these results he and his office have provided a tremendous service to the rest of the insurance industry. As in the discussion of the two previous papers the question of extending the investigation from merely the author’s office to ‘all offices’ must be seriously considered, particularly in the light of changes in disease and underwriting since the papers were presented. The advantages of such an investigation are firstly that more ‘accurate’ statistics will be achieved upon which our future underwriting decisions will be based, and secondly that, by increasing the data by a considerable amount, we will achieve our statistics much more quickly, and thus be able to reflect the results in our decisions whilst those statistics are still relevant.

Another major advantage of an all-British investigation is the check that it will provide upon the voluminous American statistics which we use as the cornerstone of our life underwriting today. In recent years the Americans have continued to provide us with the results of their investigations, and the recent book Medical Risks: Patterns of Mortality and Survival, by Singer and Levinson has been of great interest, and has resulted in at least one of our major reassurers using the statistics contained therein as the basis of a new underwriting manual. A new Medical Impairment Study is being prepared in North America based upon policies issued between 1952 and 1976, and this should be available within the next few years. Undoubtedly we will use the results of this new study to underwrite our own risks in the future.

Why we are content to use American statistics relating to impaired lives for our own underwriting is difficult to understand: the two races are of separate ethnic origin, have different physical make-up and their diseases follow a different history and, moreover, often are differently defined. Medicine and surgery in the two countries follow a different pattern, not least because of our National Health Service and the differing methods of remuneration of doctors and surgeons. Could the American and British experiences be moving further apart and how much financial loss is necessary before we have regard to the statistics?

Earlier I referred to the production of more ‘accurate’ statistics, but unfortunately the word is largely meaningless when dealing with statistics based upon sub-standard lives mortality. The result of any investigation is a function of the experience of a particular group of lives relative to a control group, which may not be directly comparable. Add to this the effect of using the result to assess a further non-comparable group at a point many years in the future, and it is clear why, at previous

31

32 Mortality of Impaired Lives 1964–73

Institute meetings on this subject, the profession found itself divided over whether such an investiga- tion was worthwhile.

The speed with which disease has changed since the author’s first codings were made in 1947 has been astonishing. Diseases of importance then have today been all but eradicated, while new diseases have appeared to take their place.

In earlier discussions concerning the problem of achieving consistency in the coding of the impairments, it was suggested that by widening the investigation the lack of consistency would increase so much that the results would become increasingly suspect. The extensive use of the numerical rating system and the general acceptance by offices of reinsurers underwriting manuals has resulted in this problem fading into relative insignificance, as it is clear that, since the two previous papers were written, underwriting practice has become far more consistent throughout the market.

Whilst the argument against an ‘all-offices investigation’ on grounds of inconsistent coding now carries less weight, an additional objection to such an investigation has now arisen. In recent years many offices have begun to collect information about impaired lives, and though still well behind the author’s office they are gradually building up their own statistics. These offices will surely be reluctant to alter their list of impairment codings to fall into line with the general consensus, or alternatively to carry out two parallel investigations. Inevitably, however, I feel it will be on the grounds of the lack of time available that the all-offices investigation will once again be deferred. Existing commitments to the continuous Mortality Investigation are considerable, and some offices are not yet sufficiently computerized to be able to handle an increase in this commitment with ease.

If we must look for alternative means of obtaining statistics for the underwriting of sub-standard lives, this may necessitate making use of non-insured lives investigations. Many such investigations have been published, and indeed the volume by Singer and Levinson I mentioned incorporated a considerable number of medical studies by hospitals and clinics. The major problems associated with such studies concern the suitability of the control populations, and the appropriateness of applying the results to groups of sub-standard lives presenting themselves for insurance in the United Kingdom. The difficulties can readily be appreciated if we consider a simple example. In the United States many thousands of operations are carried out to relieve coronary artery disease by means of a surgical bypass, whilst in the United Kingdom this operation is carried out selectively and normally only where a serious deficiency of blood supply to the heart is involved. Thus, statistics from America will, in this case, be totally inappropriate to apply to insured lives mortality here.

Studies from sources other than insurance data are of course essential in certain instances, for example where lives with a particular disease or other impairment have previously been considered totally uninsurable. In this case no information will be available from life office records, and the underwriter must either continue to decline to offer terms, or else must use the statistics from an outside source after careful consideration of the suitability or otherwise of the control population. Equally no statistical investigation will be available in respect of certain other impairments which are only of interest to life insurance offices. An example of such a finding at examination is albuminuria which cannot be regarded as a disease, yet which is regarded as significant in terms of extra mortality. Thus this type of impairment must be studied by life offices if we are to have any useful information by which to make our future assessments,

I will now comment on some of the impairments studied in the Analysis of Results. While it is interesting to compare the results of the current study for hypertension with those of the 1965 paper and show that in some cases the mortality rates have reduced by a substantial amount, a comparison with the American 1959 Build and Blood Pressure Study is not particularly easy on the limited data published, and I presume that the information for the codes not published is insufficient to yield significant results. It will be particularly interesting to compare the full results with the new American study which is expected to be published in 1979. Preliminary information from the committee handling the results indicates that blood pressure figures for moderate elevation are in line with the 1959 study. In addition the mortality ratio shows a rising trend with advance in blood pressure which flattens out somewhat for marked elevation, probably reflecting the increased use of medication for severe hypertension in recent years. This brings to the fore the most important feature which underwriters await from the new Build and Blood Pressure Study: the effect upon mortality of the new

Mortality of Impaired Lives 1964–73 33

hypotensive drugs. We know that the drugs reduce blood pressure but have not yet established what effect they have on mortality.

The result of the section ‘Impairment of the Coronary Arteries’ is of particular interest, because in 1965 there were insufficient data available to produce meaningful results. The statistics show that extreme caution must be exercised by underwriters accepting these cases.

In § 2.3.1. I am more inclined to believe the pattern of results of mild cases of peptic ulcer in the current paper than those given in 1965. The resulting + 25% or so extra mortality ties up very closely with the extras being charged by most offices for uncomplicated cases. The extra mortality for the operated cases is less easy to understand. Most offices charge extra premiums assuming that extra mortality is of a reducing nature and that, subject to no recurrence, ordinary rates can be granted after as little as two years. Perhaps this confirms the low overall mortality obtained by the author for duration 2 and over.

The results in §§ 2.7 and A4 concerning psychoneurosis are interesting, particularly when con- trasted with those given in 1965. At that time the combined mild/moderate/severe group produced only 133% expected mortality, whereas the analysis of deaths showed 17 suicides compared with 2.4 expected plus 12 accidents compared with 6.5 expected. The 1978 experience shows 94%, 116%, 101% for the three groups respectively, but once again 15 suicides compared with 3 expected and 16 accidents compared with 10 expected. Could it be that those prone to psychoneurosis are also so concerned about their general health that other diseases are promptly dealt with, thus reducing mortality from these causes? Or is it that offices underwrite these lives in a comparatively severe way, particularly when the mental problem is associated with a physical impairment?

The results for migraine are astonishing, and I would appreciate the author’s comments upon the underwriting policy of his office for this impairment. Normally migraine is totally ignored by underwriters except where a recent onset occurs which may indicate a slow-growing brain tumour. Does the author’s office inquire about recent onset? The results he has obtained, however, are supported by a small investigation in America over the period 1954-70 when on a small sample a mortality of 179% of normal was obtained.

The mortality ratios for diabetes do appear to be high at entry ages under 30 and for the 30–50 group. The investigation by Dr Goodkin of the Equitable Life Assurance Society, which was reported at the Mexico Congress of Life Assurance Medicine, gave ratios of 309% for entry ages under 30 compared with 420% obtained by the author; for the 30–50 age group the comparative figures were 166 and 290%. At ages over 50, however, Dr Goodkin’s result was higher at 197% compared with 146%. Dr Goodkin’s investigation was of particular importance, however, as it drew attention to the main risk features associated with the disease. These were age at diagnosis, duration of diabetes, method of treatment, control of the disease and concurrent existence of any other disease. The author’s results show that overweight or underweight may also be of importance: overweight must certainly be added to the list.

The results for respiratory disease are interesting, in particular with bronchial asthma mortality presumably having been reduced by the armoury of modern drugs. Perhaps we should not be misled into ignoring this disease, particularly the more severe cases where treatment may have been given with steroid drugs, or where the disease has commenced in middle life, as these two groups still produce extra deaths. In addition American mortality studies have not shown such satisfactory experience, the extra deaths being caused largely by diseases of the heart and circulatory system.

From § 2.19 it is apparent that innocent tumours produced extra mortality of + 19% and in the final references to the mortality of female lives non-malignant tumours of the breast produced an extra mortality of + 133% and uterine fibroids + 26%. These results probably indicate the immense difficulty in diagnosing certain malignant tumours even after full microscopic analysis. This is confirmed for at least one of these groups by the comment in the Appendix that for the analysis of uterine fibroids group the ratio of actual to expected mortality for cancer was over 200%.

Mr H. A. R. Barnett: The paper is based on the experience of just one office. This is by no means intended as a criticism: no data are available summarizing the impaired lives’ experiences of all offices. The reflection is, indeed, on the other offices who have, in my opinion, basked too long in the sunshine of the results of the author’s office.

34 Mortality of Impaired Lives 1964–73

I have now been connected with the C.M.I. Committee. in one capacity or another. for a quarter of a century, and over the whole of this period an unfulfilled but regular item on the Committee’s agenda has been ‘The Mortality of Impaired Lives’. This unfulfilment in no way reflects on the Committee who over the years have attempted to find a basis, acceptable to the offices, for collecting the data; in the meanwhile they have regarded the author’s office as the ‘pilot office’ for such an investigation, but what a long ‘meanwhile’ it has been! Would the collection of data be so difficult? Need we cavil at the possibility of heterogeneity? We have accepted a degree of heterogeneity in other investigations, as the mere fact that the main assured lives’ investigations are based on lives accepted at standard rates means that unless all offices employ identical standards of acceptance the data must be heterogeneous in at least one respect Is there really any reason why an investigation, similar to the author’s should not be undertaken, and subdivided according to type of impairment? It may be possible to abridge the impairment code, but in this we should seek the author’s advice. Any attempt to subdivide according to the amount of extra charged would beg many of the questions, and could over-fragment the data. The investigation would need to be on a select basis, and we would hope for adequate data in the select period, and those charged temporary extras (or subject to a temporary debt) should be divided between those where the extra is still current and those where it has expired. Otherwise subdivision should be kept to a minimum.

It is comforting to learn that the excess mortality has declined from 1947–63 to 1964–73, and this presumably indicates a more stringent, or at least a more successful, standard of underwriting. At least, it is comforting to the pilot office, but is it necessarily comforting to other offices, whose standards of underwriting may not have been quite so successful? If they have not made their own investigations, they just do not know, but they ought to know; I would suggest that it is not sufficient just to include the permanent extra cases in the valuation as though they were lives subject to a certain number of years added to the real age, and then hope that they are sufficiently insignificant to be swamped by the normal risk cases. If, on the other hand, other offices have made their own investigations, cannot they be as public-spirited as the pilot office and permit their data to be collated and analysed by the Committee? Maybe for all offices combined the female data may be sufficient to enable some useful results to be published.

The C.M.I. Committee could attempt this not inconsiderable task if they were given the data, and now seems to be an opportune time. From 1979–86 it is proposed to collect cause-of-death informa- tion for annuitants and life office pensioners; during this time it will be necessary also to continue collecting cause-of-death data for assured lives, as these will form a control group for the annuitants. What happens after 1986 will depend upon the results, but the cause-of-death investigation for assured lives shows the effects of selection. Surely it is while this investigation is taking place that we ought also to investigate the effects of partial rejection. We would not, of course, be able to complete the picture by investigating the subsequent experience of those who were totally rejected for life cover.

Mr S. Haberman: Concerning the author’s results, the 100A/Es for codes 11–160 relating to hypertension and overweight seem to suggest that overweight has little effect on the mortality of hypertensive policyholders. This result contradicts the findings of the North American impairment studies, which have viewed the combination of these two impairments very seriously, but it is in keeping with findings mentioned in the author’s earlier paper (J.I.A. 92,27). A natural question to ask then is, does overweight have a non-significant effect on the 100A/E ratio if age and hypertension are held constant?

An estimate of the standard error of the 100A/E ratio is needed to answer it. If it is assumed that the number of actual deaths for any impairment follows a binomial or Poisson distribution (not unreasonable assumptions) then expressions for the standard error can be derived. Such an exercise neglects the presence of duplicate policies—the fact that the whole investigation is based on policies rather than lives. The ratio of the variance when there are duplicates present, to a straightforward binomial variance is called the variance ratio. Theoretical expressions for the variance ratio have been provided by Daw (J.I.A. 77,261) and by Beard and Perks (J.I.A. 75,75), and a study carried out by the Continuous Mortality Investigation Bureau into the distribution of duplicate policies (J.I.A. 83, 34) showed that the variance ratio exceeded I for all ages, and averaged between 1.4 and 1.6. If we ignore the presence of duplicates, and so understate the variance, we can use some simple statistical

Mortality of Impaired Lives 1964–73 35

tests, and useful results may emerge. A further point on variances concerns the use to which they are put. For example, let us assume that a Poisson distribution is appropriate. If we propose to compare two impairments then an estimate of the standard error of 100A/E is 100 A/E. However, if we propose to test the difference between a mortality ratio and the normal value 100, we should use 100/ E as an estimate of the standard error. As an example of the use of these understated standard errors, it can be shown that of the 18 hypertension mortality ratios quoted, at least 7 are not significantly different from 100 (using a significance level of 5%), and that of the ten peptic ulcer mortality ratios at least seven are not significantly different from 100. Random fluctuations may thus explain the freak results which the author mentioned for peptic ulcer. The importance of the effect of overweight on the hypertension mortality ratios can be assessed. From the statistics quoted in the paper mortality ratios for persons with hypertension who are of standard weight can be compared with those for persons who are 20% overweight, and the differences tested. Four such comparisons are possible—none of them is significant, at the 5% level.

I should like to draw attention to the index used for measuring the intensity of risk, namely the mortality ratio (or MR) given by the formula 100A/E. Such an index has well established foundations in actuarial science and in underwriting. However, I would contend that, for reasons which I will state later, there is a more suitable index—the excess death rate (EDR) calculated as the difference between actual deaths and expected deaths expressed per unit exposed to risk, measured in person- years. EDR is less sensitive to age and more sensitive to the extra risk than the MR. Also it is more suitable for risks that are constant or decrease in absolute terms over time. For example, consider a life aged 30 proposing for assurance, who has a level EDR of 5‰, p.a., that is, his q exceeds the standard by •055. Then the mortality ratio varies from 1242% at entry, through 142% at age 50 to 105% at age 70, although the EDR is constant throughout. Now consider other disadvantages of using the mortality ratio; when comparing mortality for all ages combined, the MR usually falls with increasing age, so that, for all ages combined, it may be materially affected by the age composition of the lives with a particular impairment.

When comparing mortality by sex, the very low standard female death rates at ages under 50 may give rise to moderately high MR although the absolute departures from expected mortality, as measured by EDR, are small. For elderly groups, because normal mortality is itself very high, MR may be fairly small compared with the MR for the same impairments at younger ages, despite the fact that the number of deaths may be very large. When dealing with such groups, the use of EDR is preferable. Some of these points were raised in 1976 in an address by Lew (J.I.A. 104, 221). The importance of the EDR at the expense of MR has been recognized by the Society of Actuaries.

In Singer and Levinson’s book, EDR is used as the most important index for analysing results, which include those published in the author’s earlier papers.

My own research has concentrated on a single impairment, namely strokes. For measuring the intensity and incidence of extra mortality, I have used the EDR extensively: this index is certainly preferable to the MR for strokes, since they primarily affect older lives, say over 50. I have attempted to draw together all that the medical, actuarial and underwriting literature has to say about the survival of such impaired lives. The actuarial and underwriting literature are of little help: what they say tends to be inaccurate—for example, ratings that refer to all strokes, when there are five well-defined pathological types, each with its different natural history. Over the last 20 years there have been over 150 medical studies published that consider the survivorship after a stroke. These studies are based on either hospital populations or on naturally occurring communities. About 50 of these studies have been carried out sufficiently rigorously and sufficiently detailed data have been published to enable the results to be actuarially analysed. I have used multiple decrement methods (or the theory of competing risks, as the statisticians call it) together with some statistical estimation to analyse the results, For each study, the end product is a set of EDRs that vary with duration since the stroke, and according to certain risk factors, for example, age, sex, type of stroke. I am now collating these results with the aim of deriving a summary set of EDRs that vary according to the principal risk factors. This information will be of value, I hope, to the medical profession. For the EDRs to be of use to actuaries and underwriters, the expected deaths must be calculated using a suitable select assured lives’ mortality table. One difficulty that has arisen is that the published studies I have discussed tend to use population life tables, for example, E.L.T. 12, for calculating expected deaths. There are good

36 Mortality of Impaired Lives 1964–73

reasons for using such tables. So a way of moving from EDRs based on population life tables to EDRs based on assured lives’ tables is needed—I have used linear regression to construct a formula that works reasonably well for ages over about 50. This research is in the nature of a pilot study to test the viability of using an actuarial approach to calculating ratings. It is hoped to extend the project to cover other impairments.

Dr R. D. C. Brackenridge (a visitor): Last month I attended the annual meeting of the Association of Life Insurance Medical Directors of America in San Francisco and listened to Mr Edward Lew, Dr Joseph Wilbur and Dr Howard M. McCue present papers on the preliminary results of the new Build and Blood Pressure Study. I will attempt to make some comparison of the data which were given at that meeting with that in this paper.

I was encouraged to see a decrease in mortality associated with many of the impairments studied by the author, particularly asthma, where mortality ratios are consistently lower in each age group, compared with the previous investigation. Epilepsy and most peptic ulcer classifications have also produced improved mortality figures. Mild pulmonary tuberculosis, is still associated with very low mortality in the present study, but I wonder why pulmonary tuberculosis, moderate or severe, should produce a mortality ratio much the same as it was in the previous study? I would be interested to know from what these people died.

Lew emphasized that the figures he was quoting were provisional and could be revised slightly before the manuscript is finalized.

As regards build, the first thing that was noticed was that the average weight for men has increased significantly since the 1959 Build and Blood Pressure Study. In the 3–39 age groups these range from + two pounds at the shorter heights, 5’ 3” and below, up to +eight pounds for the tallest men, 6’ 3” and above. Even at 6’ the increase has been in the region of five pounds. In the 50–59 age group the increases have been smaller and range from no change for the shortest men up to + 5 pounds for the tallest men.

Women have fared very much better than the men. For women in the 30–39 age group there has been a decrease of weight of two pounds at the shortest statures, to one pound at the tallest statures, that is 5’ 10” and over. In the age group 50–59 the decrease in weight has been even more marked: four pounds for those of short stature to seven pounds for tall women.

One surprising finding in the new North American study is the quite significant increase in mortality for those who are markedly underweight. In the 1959 study, underweights were producing very favourable mortality ratios compared with the experience during the first half of this century. No rational explanation has been offered for this change. I have tried to compare some mortality ratios in this paper with those in the new Build and Blood Pressure Study. If we consider moderate overweights, i.e. 20–30% over average weight, the mortality ratio in the new North American study is 127% as against 134% in the 1959 study. For comparable overweights in the original study by Preston and Clarke the mortality ratio was 153%. whereas in the present study the results are divided according to: girth satisfactory, 109%; girth unsatisfactory, 146%; and non-medically examined cases, 136%. Thus the British figures tend to be somewhat higher than the North American ones.

I would like to turn to the question of blood pressure. This is the most interesting and revealing part of the new North American study. It has been found that, at the highest levels of blood pressure, mortality ratios have consistently decreased compared with the 1959 study, whereas there has been little change in mortality associated with moderate or mild hypertension. Unfortunately I can find no exactly comparable categories to compare with in the paper. At ages 40–49 in this study, with blood pressure over 170 mm Hg systolic and 105 mm Hg diastolic the mortality ratio is 293%. In the new Build and Blood Pressure Study at all ages combined, taking the systolic pressure alone, 178 to 192 mm Hg the mortality ratio is 232%. But, as I say, these categories are not truly comparable.

It is a great pity that some division into treated and untreated hypertension could not have been made in the paper, although I realize that no code existed for this. Something very significant regarding the mortality of treated hypertensives has been found in the new North American study. A relatively small sub-group of several thousand lives with about a hundred deaths were studied. Those on antihypertensive treatment whose blood pressure at issue was less than 150 mm Hg systolic and

Mortality of Impaired Lives 1964–73 37

100 mm Hg diastolic, approached standard mortality irrespective of the pre-treatment blood pressure.

Treated hypertensives whose blood pressure at issue was 150 mm Hg systolic or 100 mm Hg diastolic or greater produced higher mortality ratios, but still significantly less, group for group, than those of hypertensives not under treatment or whose treatment status was unknown. Lew was of the opinion that these findings may turn out to be the most significant of the whole study, and I am sure that they have important implications for the future underwriting of treated hypertension. Lew told me afterwards that the mortality for cardiovascular diseases among insured lives in North America had fallen around 30% from about 1963 to the present, which is much greater than for the general population, He posed the question: why is mortality from cardiovascular diseases falling so? In my opinion the most important factor was the introduction of efficient antihypertensive drugs in the last 20 years, Lew did not wholly agree and thought that possibly only 6% of the improved mortality could be ascribed to the treatment of hypertension. However I noticed during the subsequent papers that his medical colleagues did not agree with him; they were in no doubt at all that the medical treatment of arterial hypertension is one of major breakthroughs in public health of the present day.

Mr P. J. Turvey: I should like to discuss the problem of assessing appropriate premium ratings for sub-standard lives in the context of the actuary’s commercial and statutory responsibilities for the mortality experience of the whole portfolio of his office The ratings quoted in the paper are not in a form which could be used directly by a practising underwriter responsible for quoting appropriate extra premiums. The impairment analysis groups which he uses are generally too wide, and within any one class there would, in practice, be a wide range of individual cases calling for ratings considerably higher—or considerably lower—than those stated in the paper. In the absence of any other form of rating guide, the best that the underwriter could do would be to use his intuition and experience to modify the ratios quoted in the paper.

Fortunately, there are other guides for rating impaired lives; I refer to the rating manuals which have been produced by a number of larger offices. These manuals are generally based on the hypothesis that appropriate multiplicative ratings for given impairments are relatively constant world-wide, and by bringing together such data as are available from world-wide sources, a sound and consistent basis for the underwriting of impaired lives can be produced. I take the opener’s point about possible differences between North America and the United Kingdom, but I understand that the case for world-wide aggregation of ratings has much more in its favour than it has against it. There are, of course, certain exceptions. The ratings in these published manuals are drawn from statistics published, wherever these can be found, and are based not only upon studies of assured lives, like the author’s, but also upon hospital and other follow-up studies. In the last resort, the editors of these manuals rely upon the intuition and general knowledge of experienced doctors and of lay under- writers As a result, it cannot be claimed that the ratings are always right, but experience has demonstrated that the overall results of such a practice are adequate.

The figures given in this paper are a useful additional source of data, and it can only be regretted that more offices are not in a position to analyse and publish their own experience on impaired lives. One factor which perhaps influences these offices is the relatively small amount of data that they would expect to accumulate. I believe that only an industry-wide study could hope to improve significantly upon the efforts of one rather large office. However desirable such a study might be, we are likely to continue to encounter problems relating to both the expense and practical difficulties of carrying out such an investigation, and the availability of professional resources to design the study and follow the analysis through subsequently, but, like both Messrs Bellinger and Barnett, I hope that it may be possible to make some progress in this direction. Mr Haberman put forward the EDR as an appropriate measure for analysis of mortality. It may be appropriate for the study of strokes, but I do not believe that it is the best measure of extra mortality. I would put forward the case for the mortality ratio, which a number of other studies have found to be consistent with duration since issue.

Consider hypertension: the groups used for the investigation are too broad for direct use in day-to-day underwriting, but they give a good indication of general levels. For practical underwrit- ing, the scale would need to be. refined for different degrees of observed hypertension, and there are other factors which should also be taken into account to modify the tabular rating, including family

38 Mortality of Impaired Lives 1964–73

history, smoking, drinking and build, which could result in a credit of up to 50% if favourable, or a debit, if unfavourable, of almost any size. It would be useful to split the investigation of coronary artery disease between angina and a history of coronary thrombosis. Whereas angina probably has a relatively constant extra mortality ratio by duration, there is a decreasing extra mortality from coronary thrombosis, depending upon the time elapsed since the last attack, Ideally, therefore, the experience should be split between these two impairments and, in the case of coronary thrombosis, analysed by duration since the last attack.

In epilepsy the degree of control is a very important rating factor, which is more important than the distinction between petit mal and grand mal. Education and socio-economic class do seem to affect the degree of control which can be achieved, and the prognosis in this and certain other diseases is affected by this degree of education much more so than for other impairments.

For diabetes I agree with the broad conclusions in § 2.13.4. but consider. with Dr Goodwin as quoted, that the most important rating factors for diabetes are the age at onset, the degree of control, and I would add another: whether or not the disease is insulin-dependent. Perhaps we should add to this list the duration since onset of diabetes. There does seem to be a wide degree of divergence of opinion regarding the ratings for diabetics, particularly in the case of juvenile onset. This difference is much more so than in most other areas of rating. Our own experience corresponds with the author’s findings.

Dr T. W. Preston (a visitor): That there is no increased mortality when overweight is associated with hypertension seems surprising on the face of it, but I should like to suggest an explanation on purely clinical grounds. It is generally agreed that overweight people are more likely to develop hypertension than lightweights. If an underweight person or a standardweight person has hypertension it seems likely that there is some other factor, for example, serious disease of the cardiovascular system or the kidneys.

Considering the question of migraine, it is generally accepted that it has no extra mortality. There is no reason why it should not be taken at standard rate if it were certain that it was migraine. Unfortunately, the underwriter has to accept the information before him. A case of migraine which had been adequately investigated and was proved to be migraine would be a first class life, but people with severe headaches are likely to be labelled as suffering from migraine. Many have not been adequately investigated and most of the extra mortality probably comes from people who really had severe cardiovascular disease or perhaps cerebral tumours in the first instance.

Petit mal has no appreciable extra mortality, but some people use the term petit mal because it sounds rather less serious than grand mal, epilepsy. I very much doubt whether they have petit mal, but probably epilepsy. There should be no extra mortality with petit mal: again, the underwriter has to accept the information before him.

Mr A. J. Steeds: This paper is a progress report, and if it contains little that is startling, that is because on the whole the results do not conflict with earlier findings. I hope that there will be a series of reports in the future because continuity is most important. The maximum duration for an entrant in 1947 is still only 26 years, and as most entrants are at the younger ages this means that we do not yet know much about extra mortality in middle and older life, which is a pity. For many impairments, such as hypertension and diabetes, we expect the extra risk to increase with duration; and it will be interesting to see how in later years the extra risk is related to basic rates of mortality. Although I sympathize with what Mr Haberman and Mr Turvey have said on the subject, I hope that we shall not confuse our study of mortality according to impairment by getting into too actuarial a discussion on problems relating to the incidence of the extra risk.

An interesting and novel section is devoted to coronary artery disease, and further reports as the experience builds up will be most welcome. The results so far, though necessarily based on compara- tively few deaths, are in line with the results of the coronary pool. There continues to be a considerable variation from the results of the diabetic pool, where the extra mortality seems to be a good deal lighter, though the heavy extra mortality at the younger ages is clear from both experiences.

There have been many changes since 1947, the year when this investigation started, both to underwriting itself and to the allocation of responsibilities for underwriting. Today there are few

Mortality of Impaired Lives 1964–73 39

actuaries for whom underwriting is part of their regular work: so far in the discussion at least two of the actuaries who have made useful contributions would not call themselves underwriters. Several reasons can be given, but I believe that the decision not to expand the pilot investigation into an inter-office study, taken in effect by default after the author’s paper of 1961, may have resulted in the disillusionment of younger actuaries about future research into an analysis of mortality by impair- ment, and consequently about the actuary’s role in underwriting. Probably the other main reason is that, although an actuary can soon become a most competent underwriter, so also can an intelligent man or woman who is not an actuary. This does not matter in practice, provided the actuary in the life office continues to give to underwriting the importance it deserves. There have been big developments in non-medical business and indeed in a variety of free-cover schemes, many associated with pension schemes. We expect to increase the proportion of lives accepted at standard rates, but in all these developments the actuary should be playing his part, and to do so requires an understanding of what underwriting is all about.

Do actuaries reading C.M.I. reports reflect that a study of the mortality of standard lives ought to involve some knowledge of how a life comes to be classified as standard, and therefore also some idea of what sub-standard means?

There are new challenges in this field of underwriting. Permanent health insurance is becoming increasingly important, and its underwriting is different from that of life assurance and by no means easy. There are other non-life branches of insurance which are surely going to involve actuaries more and more; these actuaries will have to try to understand what the extremely complicated underwriting problems are. If they have failed to grasp the basic principle of life assurance underwriting, which is the formation of groups of risks as homogeneous as possible, how will they fare in these other fields?

Mr L V. Martin: I wonder whether it is as valuable as some people have suggested to want this study to be extended into an all-office one. I cannot forbear to repeat some words which Perks expressed with his customary trenchancy (J.I.A. 78,216): “The vast numbers of different causes of rating, the various degrees of severity, the varying periods for which an impairment may have existed or since it apparently cleared up, the varying treatments and the unlimited combinations of impairment that arise, would make an investigation of the combined experience of the offices difficult enough and of doubtful utility, even if the mortality of the first-class standard and of the substandard groups were not changing all the time. But this continual flux, together with the need to subdivide at least by age and duration, seems to make an investigation by cause of rating, even on the largest scale, a futile proceeding so fat as life assurance underwriting is concerned”. I would add that I wonder whether a trained doctor’s impression of an individual’s general state of health and well-being is not mote valuable than the presence or absence of specific abnormalities.

All an investigation of the type the author has carried out can do is to show whether lives accepted for insurance despite certain impairments, whether rated-up or not, do in fact experience, as would be expected, heavier mortality than assured lives without those impairments. The main interest, therefore, should perhaps be in those ‘impairments’ that seem to pose no substantial extra risk--like mild pulmonary tuberculosis or pleurisy or goitre or cholecystitis.

For many contracts, but not for term assurances, ratios of 100A/E of up to 130 or 140, which still means mortality less than the population mortality of England and Wales, will have much less effect on the premium than will possible future fluctuations in interest rates. Indeed, are the life offices’ medical officers, despite their invaluable and essential work in excluding quite unacceptable cases of serious illness, not dealing with the wrong contracts? Is it wholly ridiculous to suggest that they might be more profitably employed in deciding which annuitants ought to pay an extra consideration because of their above-average vitality? Nowadays it is often annuitants’ mortality, or lack of it, that is potentially more dangerous than excess mortality among assured lives.

The author’s results on bronchial asthma ate rather surprising in view of concern that has been expressed in the medical press about apparent recent increases in the mortality of asthmatics, particularly among the young. There is a tendency nowadays to regard diabetes as a relatively minor but tiresome illness that, if properly treated, presents no real threat. The figures the author has produced, which presumably cover mainly the milder, controlled cases do not support this optimistic view and show how valuable it would be if some method of preventing the onset of the disease could

40 Mortality of Impaired Lives 1964–73

be found, since it does not appear likely that the steady improvement in methods of treatment will eliminate the very substantial excess mortality experienced by those in whom diabetes develops.

Mr P. N. Downing: I welcome this paper on the ground that some information is better than none, but I think that it requires care in interpretation. As practical business managers, possibly two questions are uppermost in our minds: How well have we done? How should we do it today?

The experience covers the period 1964–3. Although it relates to the deaths during that period, it relates to a much longer underwriting period, that is from the year of acceptance. So how do we then interpret this data for today’s or tomorrow’s underwriting? There are two variables lying behind it which we should not overlook. One is the possibility of a relaxation of underwriting standards, although I suspect that that is of minor importance compared with a willingness to offer a wider range of coverage–that is, to accept lives on a more highly rated basis. The latter could have interesting implications for the interpretation of some of these results. This information is helpful, but judgment is required for tomorrow’s underwriting: a joint assessment by the actuary and by the chief medical officer, the actuary relying very heavily on the knowledge and advice of the latter on the current changes and developments and expected future developments in the medical field, This relates especially to new treatments, the probable, possible, likely, predictable and unpredictable effects of new drugs and, more particularly, how to extend life insurance coverage to new impairments. So, how well have we done and how well will we do? The control population for expected deaths consists of standard lives, a very sound control population, but surely of interest to an individual office is to weight the expected deaths by the underwriting assessment at the time the policy was issued,

I realize that this can nose difficulties when the extra risk is assessed as a temporary extra premium. because we have not clearly stated the period over which we expect that extra risk to run, nor the precise way in which it runs off. Nevertheless, we should try, and that will help us when we come to the style of statement in § 2.2: “The experience for lives with a history of coronary artery disease has been very unfavourable, as the following table illustrates”. Maybe the author will enlighten me as to whether an A/E of 297% is unfavourable if expected deaths are weighted by the assessment at the date of underwriting.

In § 2.2 duration is clearly that since the issue of the policy. Duration since the onset of impairment is, of course, vital for many conditions. This is an area where over the past 15 years or so offices have been more encouraging and experimenting in offering wider coverage. However, I am fortified by the concluding sentence in this section ‘for practical, underwriting purposes’, and that is one of the problems in interpreting these figures: we have to adopt a practical underwriting approach.

This leads me to the concept of the mortality ratios and it is tempting to consider from these ratios something intrinsic about the numerical rating system, but before we jump too fast in that direction we ought to reconsider the underlying philosophy of that numerical rating system. If a case is assessed at + 100% the system assumes that a group of such lives will experience each year, on average, twice the mortality of a control group of standard lives. The assumption is a constant relative extra risk, which because qx is an increasing function, assumes an increasing extra risk.

However, certain impairments are likely to exhibit very different extra risk characteristics, and the data presented do not help us in this regard. Possibly this is due to the data developed to date being insignificant, or insufficient for the essential sub-division to generate significant results.

In considering diabetes, § 2.13.4 says that a sharp decline in percentage extra mortality with age at entry varies from say, + 400% at entry age 20, to + 50% at entry age 60. Is there an overlap in the exposure of these two categories? Is this a difference by characteristic age at entry, or a difference by characteristic attained age at death, or are we being more generous in offering terms to more severely impaired, younger diabetics. Maybe the sheer cost of +400% to a 60-year-old is prohibitive and therefore the potential assured selects himself out of the particular sample?

Concerning the analysis of causes of death, in the Appendix, when we assess a blood pressure case at + 150%, I wonder what we are assuming. Surely we are not assuming that the whole of the extra mortality will arise from circulatory causes? Maybe for that impairment we are—at least that is the author’s conclusion in § A2. 1. However, 1 suggest that in general we are assuming that the mortality of a group of such lives will exhibit mortality from all causes of death of 2•5 times that of deaths from

Mortality of Impaired Lives 1964–73 41

all causes of a group of standard lives. The opener referred to excess deaths from suicide in respect of certain impairments, but maybe that is part of our assessment of the extra overall mortality.

Mr R. W. A. Howe: This paper will not by itself tell us what ratings to impose for any given impairment, but will help us to build up a picture of the additional mortality associated with various impairments. We are seeking to assess the extra mortality for a specific sub-group of impaired lives, those applying for and accepted for life assurance. Statistics for this sub-group are very limited and are generally restricted in the sub-divisions adopted, but by comparing these limited statistics with those from hospital and other studies in the United Kingdom, and with the detailed statistics available from American studies, a much more useful picture emerges. The author has added greatly to our knowledge because this is virtually the only study available in the United Kingdom.

My own office has collected detailed statistics for a number of years, but for a limited number of impairments, restricting itself to diabetes, blood pressure and coronary episodes. Three pools have been established and fairly stringent underwriting criteria have been adopted. Each proposal is underwritten by my office on behalf of the pool, although the contracts are issued by many different offices in the United Kingdom. A good spread of risks is thus obtained with clearly defined impairments. For inclusion in the diabetic pool, for example, the policyholder must have no impairment other than diabetes, thus excluding even moderately overweight or underweight pro- posers and those with hypertension. I have some figures for the diabetic pool over the period 1965–72, which is fairly close to the period adopted in the paper, comparing actual with expected mortality according to the A67/70 select table. All durations have been combined and the percentages apply to attained age rather than age at entry.

Diabetic Pool Experience 1965/72 Age Actual deaths 100A/E

under 50 41 227 50–59 40 172 60 and over 26 88 All ages combined 107 151

Since these figures relate to attained age, comparison with the author’s figures is difficult, but the variation with age is similar although the absolute level is lower. Both sets of figures are very different from those of Equitable Life Assurance Society of America which were quoted by the opener, and this demonstrates clearly the danger of using figures from America without first testing them against U.K. experience. The reasons for the differences are not obvious but are probably related to our very effective diabetic clinics available free of charge under the National Health Service.

The blood pressure pool was established to deal with essential and uncomplicated hypertension only, and again the underwriting criteria were very strict. Probably the most important restriction was that the life assured should not be receiving treatment by drugs for blood pressure; this was introduced to ensure that the statistics were not distorted. The growth of the pool has been very disappointing in recent years, but this is not surprising now that the use of antihypertension drugs has become more wide spread. A number of lives included in the study have almost certainly received drug treatment since becoming members of the pool, and this has probably distorted these statistics. The experience has been split into five groups, depending upon a combination of diastolic and systolic readings. Again the figures are not directly comparable with those given by the author.

Blood Pressure Pool Experience 1965–72 Age 50 59 Age 60 and over

Actual Actual Group Blood pressure reading deaths 100A/E deaths 100A/E

160/100 to 164/102 5 98 4 43 1 165/103 to 174/107 22 183 16 83 3 175/108 to 184/112 23 165 20 78 4 185/113 to 199/117 17 233 25 167 5 200/118 and over 36 367 39 153

1

42 Mortality of Impaired Lives 1964–73

The extra mortality appears to be appreciably lower than in Mr R. D. Clarke’s study, and this is probably due to the underwriting criteria adopted.

The third pool established was the coronary pool. Having perhaps been unduly selective in respect of associated impairments when underwriting both diabetes and hypertension, the requirements for proposers with coronary disease were relaxed somewhat and minor impairments, such as modest overweight and slightly increased blood pressure were acceptable. The most important restriction imposed was that the coronary attack should have occurred at least one year previously and that the proposer should have been actively at work, following his episode, for a minimum of six months. Again, we have a very select portfolio. A number of significant underwriting changes were made in 1965 and the experience statistics were split with effect from that date.

Coronary Pool Experience 1965–72 Old pool, closed to new

business in 1965 New pool Age Actual deaths 100A/E Actual deaths 100A/E

Under 50 20 1111 35 795 50–59 46 341 74 474 60 and over 31 133 17 129 all ages combined 97 252 126 380

The mortality for people who have experienced a coronary varies very significantly with age, being virtually + 1,000% under age 50 and only a little over + 100% for ages above 60; a very sensitive rating structure is therefore indicated.

Dr Walwyn Jones (a visitor): I can see no useful purpose in trying to separate angina pectoris and cardiac infarction because the basic pathology is just the same. In the majority of cases of angina there probably already has been occlusion of the major part of the coronary artery system. The only difference would be whether the left ventricle was involved. As one now considers by-pass surgery in many of these cases, there would be a lot of people who had by-pass surgery with what would have been an infarction otherwise.

I was also interested in what Dr Brackenridge had to say about the reduction in mortality of 30% in cardiovascular disease in the United States from 1963 onwards. This occurred in just one particular group of individuals, mostly executives; whether it was due to treating hypertension or reducing cigarette smoking or alcohol intake is a moot point.

It illustrates the fact that for the major impairments under consideration, when it comes to underwriting there is evolving a select group among these people which is not readily identifiable. Consider diabetes: there is now a very simple laboratory test which can detect the amount of glycolized haemoglobin. This also was mentioned at the San Francisco conference which Dr Brackenridge referred to. This indicates quite clearly whether people are well-controlled diabetics or not. It will help to isolate a group of diabetics that would represent therefore a very select risk. You can apply the same argument to coronary artery disease and also to respiratory disorders. If you can identify the people whose respiratory function is diminishing then you can pick out the ones which are especially at risk from respiratory diseases. Much depends on whether these people are prepared to undergo a complete change in their way of life. This is where the difference in some people’s mortality figures arises. This question of picking out the select groups will have to be faced more frequently in the future.

Mr H. J. Jarvis (closing, the discussion): Much of the discussion, inevitably, centred round the need for, or the desirability of, an all-offices investigation. This was not popular when it was mooted on either of the previous occasions when Mr Clarke and Dr Preston spoke and presented their papers, Indeed, it was Mr Martin who quoted Perks, whom he rightly said spoke extremely trenchantly at the time, and that was probably the largest single factor why nothing-transpired. Of course these large investigations change over the years. With many of the impairments no longer being serious, or having ceased to be a problem as an under writing risk, the need for the codings which have been set up has fallen away. Perhaps, therefore, the best case that can be made for continuing such an investiga-

Mortality of Impaired Lives 1964–73 43

tion is for those conditions which occur most frequently and which are underwritten by the offices themselves.

In this context the opener mentioned albuminuria to which I think could be added hypertension and build, These are topics which are not adequately investigated by the medical profession and are not generally of interest to them in their hospital studies. Another problem we have is the effect of improved treatment. Out-of-date statistics quickly become irrelevant if there are major changes in the treatment of the impairments under consideration.

The opener also made a plea for more statistics sooner. If they can be obtained more quickly they are more likely to be relevant. Reference was also made to the address which Mr Lew gave here in 1976 (J.I.A. 104, 221). He said that we might well be coming to the end of the road for the big medico-actuarial investigations which have been effected in the past. It may be that even in America the insurance industry is not prepared to sustain these investigations on a major scale. That brings us to Mr Barnett who severely took us to task for relying on one office for statistics of this type. He questioned whether we need to be so concerned about heterogeneity. I would agree with him, so long as we are investigating impairments where we can produce some sort of factual, or better still numerical classification. For investigations covering more than one office the very real difficulties occur in dealing with classifications such as ‘moderate’ or ‘severe’.

One or two speakers have referred to the difficulty of getting an exact diagnosis of the impairment. Statistics will show some variation according to which diagnosis is used. So often the problem is that we have to make use of such information as we have. Mr Haberman has mentioned strokes, but another impairment which comes particularly to mind is mental illness. We rely very heavily upon what we are told in the medical report and more particularly, what we are told in the medical attendant’s report.

Mr Barnett appealed for other offices to become involved in this type of investigation via the C.M.I., and many others spoke along the same lines, including Dr Reynolds and Mr Steeds. Mr Turvey also made this plea and perhaps I could join him in saying that as reassurers we are in a weaker position in advocating this sort of exercise, because inevitably the work has to be done by the direct offices who are generating the data. Mr Steeds questioned whether actuaries are being put off from taking a greater interest in underwriting because these investigations are not being made. It is possible. He also went on to discuss the relationship between non-actuarial underwriters and actuaries. There is a very real need for this liaison to continue, and I think that in those offices where it is practised to its greatest extent the most intelligent, detailed underwriting approach is being obtained.

The opener also referred to the data in this country now becoming more consistent. He felt that the use of the numerical rating system itself is leading to a more careful classification of the various risks; I would agree with him. We should remember that in underwriting we are looking for practical results. Although the art of life assurance underwriting is well advanced, we seldom underwrite to intervals of less than 50% additional mortality. So considerable refinements as to control populations and the accuracy of the data, while important in themselves, should not impede us from getting some of the answers that we are looking for.

Mr Haberman talked about the calculation of variance for the mortality ratios of some of these impairments. The author said in his introductory remarks that he had considered putting in figures for variance, but in the end had decided against it. I thought Mr Turvey also made an interesting comment when he talked about the use of life assurance underwriting manuals. Their great attribute is not that they are accurate, but that they are consistent. They produce a consistent basis within impairments and when proceeding from one impairment to another.

Several references were made to Singer and Levinson’s book, which was reviewed in J.I.A. 104,257. Mr Haberman commented on the relative virtues of the excess death rate as against mortality

ratios. He rightly pointed out the problems which occur with younger ages and with all-age comparisons: I agree with him entirely. Singer and Levinson tabulated the results in both these styles wherever possible. However, for practical underwriting the problem always is to interpret the statistics and to produce an arithmetical answer. More often than not we find the numerical rating system produces the simpler approach and it also has a built-in safeguard in that a percentage addition to the mortality throughout the duration of the policy provides a contingency margin.

44 Mortality of Impaired Lives 1964-73

Mr Turvey also favoured the mortality ratio and Mr Steeds urged us not to make it too complicated. I agree with that, as well. Mr Downing also made some comments about why we should make these investigations at all. He rightly divided the reasons into two categories: the first is to produce the correct ratings to be used tomorrow; while the second is to check the actual underwriting results that have been achieved to date.

He also referred to the problem of different age distributions and different durations in force in interpreting these statistics as well as to the problem of self-selection. Do people select themselves for life assurance? Are we underwriting or are we just guarding against anti-selection?

Hospital data can be very valuable at times. Usually the problem is that the follow-up is short. Hospitals tend to lose interest in a particular topic just about the time it starts to become interesting to life assurance. Also it is often only the more severe cases which are included in hospital data, whereas for life assurance purposes we are looking at those who are more modestly impaired.

The comments which were made about specific impairments were legion. Perhaps I could discuss a few. Hypertension was the one which probably attracted most attention. The overriding effect that we have seen in recent years has been the use of hypotensive drugs. The opener referred to this and one or two others also asked whether they actually reduce mortality. Dr Brackenridge was able to bring us some news in this regard from Mr Lew. He said that for blood pressures of up to l50/100, close to standard mortality is being obtained, and a significant mortality rating thereafter, but both these figures were independent of whether the man was receiving treatment or not. and certainly indepen- dent of the blood pressure reading taken before treatment commenced. Taken with other details which he had, the Americans obviously feel that this is a major breakthrough. It may be the first real evidence we have that hypotensive drugs not only reduce hypertension, but also reduce mortality.

We had several sets of diabetes statistics which illustrate again the practicalities with which we have to wrestle. Four investigations were mentioned. We have the author’s figures taken from the current paper and his earlier investigations. The opener mentioned the figures from the Equitable Life Assurance Society in New York. Mr Howe mentioned the figures from the diabetic pool in this country. Mr Turvey also quoted some figures which came to agree quite closely with those of the paper itself. They all point in the same direction without perhaps ascribing a great deal of precision. It is when they point in different directions that the problems really start. I feel reassured that the figures are all pointing in the same way.

I have already made one reference to psychoneurosis concerning the difficulty of getting an adequate description of the condition. The opener drew attention to the fact that there were concealed in the mortality ratio for this impairment increased suicides and therefore lower deaths from all other causes. He asked whether the lives assured were looking after themselves rather better than the average. Perhaps this is also true for other impairments where we often see what appear to be surprising results, and those who have an impairment tend to look after themselves, certainly if they are proposing for life assurance.

Coronary artery disease is another major problem. Two or three speakers made a plea for sub-dividing the data into those lives who had had a full heart attack and those who were suffering only from angina. Again, problems of age at entry and duration in force were mentioned. In other words, can we get inside the mortality ratios which decrease so sharply with the age and the duration in force? Dr Walwyn Jones disagreed with us here. He felt the distinction between full heart attacks and angina was not of sufficient significance to warrant separate investigation,

Referring to a comment relating to migraine which illustrates so many of our problems, the opener professed himself astonished at the additional mortality which was produced for people subject to migraine. It was Dr Preston who pointed out that the problem of inadequate investigation and the lack of adequate information as to whether what we were considering was really significant.

Mr Turvey referred to the problem of added impairments. One of the problems which runs through this sort of work is how do we obtain statistics relating to one impairment only? The temptation is to make the data so homogeneous that you finish up with no data. The ideal must lie somewhere between the two extremes.

The President (Mr P. E. Moody), in proposing a vote of thanks: We have had a number of examples in recent years of co-operation between the actuarial profession and other professions or disciplines: I

Mortality of Impaired Lives 1964–73 45

hope that we shall see more. In particular we have the example of the co-operation between the actuarial and medical professions which gave rise to the 1965 paper, which continues to bear fruit in the further paper that we have been discussing this evening. We shall be looking forward to the promise of further results in due course.

We have heard a considerable amount this evening about what other people are doing, both on this side of the Atlantic and on the other. We have heard a fairly loud call for further consideration of the possibility of an all-office investigation, Whether this turns out to be possible or not, I hope that those concerned will at least take out the files and reconsider the question again.

I realize with an investigation extending over such a long period of years what a great volume of work has gone into Mr Clarke’s paper. There is not a great deal that I wish to add to what other speakers have already said almost unanimously and universally, how much they appreciated the subject matter and quality of this particular paper.

Mr R. D. Clarke (in reply). The opener asked whether, in underwriting, we asked the proposer a specific question about migraine and I discovered that we do not. The information comes in three possible ways: in some cases the proposer mentions it on the original proposal form; in others it may come to light in the private medical attendant’s report as an illness for which the proposer has consulted his doctor; or alternatively the medical referee may extract the information when asking questions about mental illness or disorders. From all this it follows that it is possible for a migraine sufferer to obtain life assurance without mentioning the complaint. A further deduction would appear to be that the cases reported, and therefore coded, are likely to be those sufficiently severe to cause the proposer to seek. medical treatment, Thus, there may be bias in the data towards a preponderance of the more severe cases. Dr Preston has dealt with the real nub of the question why migraine may have given rise to such an adverse experience and so I will not add anything further.

I do not know whether Mr Haberman was present when Dr Brackenridge gave his presidential address to the Assurance Medical Society. If so, he will have found a soulmate in advocating the excess death rate as a measure of extra mortality. I am very much drawn to it myself, and I should like to hear much more discussion on this point in the future. There is undoubtedly much to be said in its favour, but I think that a more detailed analysis of the relative merits of the two measures is desirable before changing established practice.

I am very grateful to Dr Brackenridge for all the points which he made. I was particularly interested in the suggestion that hypertension might be divided into treated and untreated cases. That is something might well consider for the future. Mr Turvey’s suggestion about angina and a history of coronary thrombosis has already been answered by Dr Walwyn Jones. I was very interested in Mr Martin’s quotation from Perks, which recalls a powerful personality whom many of us in this hall will vividly remember.

Mr Downing referred to the remarks about coronary disease and he realized that the 297% occurs at duration 0, where the mortality would be expected to be not so heavy as elsewhere.

Considering the table in § 2.2, the thing that really frightens me is the mortality under age 50 where 100A/E is 1,146, in other words 14 deaths where one would expect about 1. That is where the word ‘unfavourable’ comes in.

It is an old subject why our experience has been higher than that of the diabetic pool, and I think Mr Howe really has put his finger on the answer, that the people included in the diabetic pool have no other impairment whatsoever.

The author subsequently wrote as follows: Much was said by various speakers about the possibility of an all-offices investigation. While I would welcome such a development. I do not feel that it is appropriate for me to add any further comment on this subject. It is a matter for the life offices, in conjunction with the two actuarial professional bodies, to decide. Like Mr Bellinger I keenly await the publication of the new American study and shall be interested to see both what changes have occurred in comparison with the previous American study on impaired lives and also how its results compare with those derived from United Kingdom data. I agree with Mr Turvey that statistical studies provide guidelines rather than precise ratings and that in practice each case must be dealt with on the basis of its own individual features. On the subject of coronary artery disease we have found in

46 Mortality of Impaired Lives 1964–73

practice that it is not easy to sub-divide this category. In theory this ought to be possible if we had a full report on the medical history from a specialist physician; in practice this is often not available. I agree that duration since last attack is a relevant feature. Unfortunately we do not have enough data to render such an analysis possible. The same comment applies to the duration since onset of diabetes. I have made it clear in the paper that the age at onset is a vital element in assessing the risk, but once again scarcity of data limits the degree of analysis that is possible.

I was interested in Mr Martin’s suggestion that annuitants with supernormal vitality might be charged a higher purchase money! Actually I feel that there is a great deal of self-selection among annuitants, and the fact that the Continuous Mortality Investigation Bureau already studies and publishes the experience under purchased life annuities should take care of any such self-selection. With regard to Mr Martin’s suggestion that a trained doctor’s impression of an individual’s health may be more important than the presence or absence of specific impairments, I can only state that, while the medical referee’s report is undoubtedly invaluable to the underwriter, I have on innumer- able occasions been approached by members of the medical profession who have asked me why more statistics are not produced by life assurance offices and who have assured me that such statistics would be of unquestionable value to medical research. I agree with Mr Downing that we cannot anticipate the future and the possible effects of new forms of treatment. To use the experience of the recent past is the best that we can do in estimating the unpredictable future. I also agree with Mr Downing that statistical results must be used with care and with judgment. In conclusion, I should like to express my gratitude to all the contributors to the discussion, not only for their kind remarks on the paper but also for the many constructive ideas and suggestions which have been made and for the information imparted about other research projects being undertaken both in this country and elsewhere.

Mr R. H. Daw wrote as follows:- I have used the crude test of saying that the difference A-E is non-significant unless it is greater than 2 E. The results of this test must be looked upon as giving a broad indication and as a help in putting the figures into some proper perspective. There are 8 groups of type of impairment in the table showing significant above-average mortality out of the 19 impairments given, namely hypertension, epilepsy, pulmonary tuberculosis, diabetes, overweight and (just significant) peptic ulcer, migraine and underweight. The table gives results for 113 individual impairment codes. Of these 23 have values of A/E of less than one, and one of these (hay fever, code 710) shows mortality significantly below average. Of the 90 codes with A/E greater than one, only 33 show significant extra mortality.

However, where there are results for a number of codes in respect of the same impairment, even non-significant results may be regarded as giving useful information if they show some coherent or expected pattern related to, say, the severity of the impairment or to some measurable character like blood pressure or degree of overweight. Thus all the percentages given for hypertension (entry ages 40–59) are significant and, as the author points out, there is also a consistent pattern of increasing risk with increase in both systolic and diastolic blood pressure. Although not set out in the text, entry ages 60 and over show a similar pattern although none of the individual codes give significant extra mortality. In the case of epilepsy, the extra risk for grand mal is significant but that for petit mal is not. However the observed percentage of extra risk is greater for grand mal than for petit mal. Migraine is similar, with a higher A/E ratio for severe cases than for mild, although neither is significant. All the individual codes for diabetes are significant except code 528, but the pattern for entry ages 30–50 and over 50 are somewhat different.

The Appendix to the paper gives valuable information on how some of the impairments operate and so supplements the patterns to which I have referred. My test showed all the percentages for circulatory causes to be significant and all those for other causes non-signiticant of extra risk.