Vital Statistics Final

8/8/2019 Vital Statistics Final

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Int roduc t io nThese diag n os t ic t ools a n d t ech n iques haveco n sis t ed of t he co mm u n i t ys vi t al s t a t is t ics,

which i n clude t he cou nt s of bir t hs, dea t hs,ill n esses a n d t he various ra t es a n d ra t io t ha t m ay be co m pu t ed fro m t he m .


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WHY VITAL STATISTICS?C o mm u n i t y diag n osis.Heal t h a n d heal t h services pla nn in g.C o m pariso n s over t im e ( t re n ds).

A n esse nt ial co m po n e nt t o a n y surveilla n ce sys t e m .C o m pariso n be t wee n differe nt popula t io n s a n dgeographic regio n s (i n cide n ce a n d prevale n ce).Predic t io n s a n d projec t io n s of heal t h s t a t us, fer t ili t y pa tt er n s, a n d diseases i nt o t he fu t ure.


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INTRODUCTION :

In for m a t io n is a dominant characteristic of globalization process where each people is bo t ha provider and consumer


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Despite of progress made by some countries in

enhancing their NHSIS National Health StatisticalInformation System and its computerization , theFinagles law is still describing the situation of potential users of statistical information


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FINAGLE]S LAW :

The information you have is not what you want ;

The information you want is not what you need ;

The information you need is not what you can get ;

The Information you can get costs more than youwant to pay


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F or those people with a limited information culture ,

the Information ( indicator ) is

like a bikini It shows every things ,

except the essential ones .


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DISRAELI `S JOKE

There are three kinds of lies :

- the ordinary ( white ) lie ,

- the damned lie and

- the sophisticated lie which is statistics


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DATA

specificcontext

INFORM AT ION general context

KNOWLE DG E

D ECISION

Concept; the basic function of data.


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INDICATOR ? D efinitions :

* A variable which helps to measure changes ,directly or indirectly (WHO,1981 ) .

* A statistic of direct normative interest which

facilitates concise, comprehensive, and balanced

judgments about conditions of major aspects of the

society (H.E.W/USA,1969).


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TYPES OF INDICATORS :

FIV E TYPES

* Count / Number Measure without a denominator

* Proportion ( % ) Numerator is part of denominator

.


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* Rate Frequency of occurrence of an event

during a specific time, usually expressed

per k population (k=1000,10000, ).

Rate is used to estimate probability or

risk of occurrence of a disease or to

assess the accessibility or coverage of

health care system .


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* Ratio (per k) Measure for which numerator is not

included in denominator ( e.g. : sex

ratio per 100 ; beds population per

1000 ) .


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.

* Index A ggregation of measurement of

specific indicators . ( e.g. : Health

development index , summary

measures for Health Population )


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RATES AND RATIOS

k ba

a Rate

!

a = t he freque n cy wi t h which a n eve nt has

occurred duri n g so m e specified t im e period.a+b = t he n u m ber of perso n s exposed t o t herisk of t he eve nt duri n g t he sa m e t im e period.

K = so m e n u m ber 10, 100, 10000, or 100,000


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RATE AND RATIO

Usually reserved to refer to those calculationsRATE:

that involve the frequency of the occurrence of someevent.

o Numerator of a rate is a component part of the denominator.o T he multiplier K or the base, used to facilitate calculations

and comprehension of the rate especially if it involves smallnumbers.


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RATES AND RATIOS A ratio is a fraction of :RATIO

the form.

Numerator is not a component partof the denominator (person/doctorratio, person-hospital-bed ratio)

T he values of K most frequentlyused in ratios are 1 and 100.

k d c

K = baseC and d refer tothe frequency

of occurrence ofsome event or item


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HE ALT H INDICATORS |VITAL INDIC E S}

Morbidity

Mortality Fe

rtility


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DE

AT H

RAT E S AND RATIOS

D eath rates express the relative frequency of theoccurrence of death within some specified interval

of time in a specific population.

The de n o m in a t or of dea t h ra t e is referredt o as t he popula t io n a t risk . The n u m era t orreprese nt s o n ly t hose dea t hs t ha t occurredin t he popula t io n specified by t hede n o m in a t or.


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1- ANNUAL CRUDE DE AT H RAT E

t o t al n u m ber of dea t hs duri n g year (Ja n uary 1 t o Dece m ber 31) * K

t o t al popula t io n as of July 1

o The value of K is usually chosen as 1000.o T his indicate the overall health of a community, comparison to other

communities is hazardous unless the many characteristics, other thanhealth conditions, that influence the death rate (age, sex, race,socioeconomic status).

o Adjustment is required for that purpose to control the populationdifference regarding these variables.

o T he same precautions should be exercised when comparing the samecommunity over years.


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CRUDE DE AT H RAT E Community X has a population of 2 millions according to year 2000 census,the number of total deaths were 8000, what is the crude death rate?

= Number of total deaths (8000) * K (1000)Population at risk of death (total population) 2,000,000

T he crude death rate for Community X = 4.T

he death rate in this community is 4 / 1000.


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2 -ANNUAL SP

E CIFIC D

E AT

HRAT

E

It is more meaningful and enlightening to observe the death rates of smallwell defined subgroups of the total population. Rates of this type are calledspecific death rate and are defined as:

T otal number of deaths in a specific subgroup during a year * K T otal population in the specific subgroup as of July1

.1000Where K is usually equal

o Subgroups for which specific death rate can be calculated include thosethat might be distinguished on the basis of sex, race, age.

o Specific rates may be computed for two or more characteristicssimultaneously (white males: race-sex specific, cause specific death rate.


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ANNUAL SPE CIFIC DE AT H RAT E T he registries of D istrict Y revealed a total deaths of 855 persons due toD iabetes Mellitus T ype II and Coronary Heart D isease, knowing that thetotal population at that year was 600,000; compute the cause specific

death rate for this population?

D eaths due to D MII and C.H. D in that year (855 ) * K (1000)

T otal population at risk (600,000)

T he death specific rate for these diseases = 1.425.1.4 for 1000,or 14 / 100,000 (which is more expressive and comprehensive?).


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3 -ADJUST E D OR STANDARDIZ E D DE AT H RAT E

T his method allow to measure the force of mortality in a population whileholding constant one or more of the compositional factors as age, race, orsex through a single figure which is called an adjusted death rate.

For adjustment we can use the direct and the indirect methods of standardization.

specific ratesstandard populationconsists of applying to adirect methodT heobserved in the population of interest.From the resulting expected numbers we may compute an overall rate thattells us what the rate of interest would be if that population had the samecomposition as the standard population.


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A djusted death rate (con.)T his method of adjustment is not restricted to computation of deathrate, we can apply it to other rates (an adjusted birth rate).

If two or more population can be adjusted, the option of comparison isvalid on the basis of the adjustment factors.

T he standard population used for adjustment is the U.S last decennialcensus. For adjustment calculations a population of 1,000,000, reflectingthe composition of the standard population (the standard million) isfrequently used.


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DIR E CT ADJUSTME NT ME T H ODT he 1970 crude death rate for G eorgia (a U.S state) was 9.1deaths/ 1000 population, how to obtain an age adjusted death

rate forG

eorgia by using the 1970 United States census as thestandard population? D ata necessary for calculations:

T he population of G eorgia classified according to age groups.T

he deaths in theG

eorgians by age groups.T he age specific death rates for different age groups.T he standard population by age groups.


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Direc t Adjus tm e nt Me t hod

Age-specificdea t h ra t es

(per 100,000)

Dea t hsPopula t io n Age groups(years)

584.8

47.0158.6223.6442.9952.3

2,072.13,969.19,060.9

2,4834491,3691,3602,2964,632

7,7929,363

12,042

424,600955,000863,000608,100518,400486,400

384,400235,900132,900

0-45-1415-2425-3435-4445-54

55-6465-74

75 a n d over

41,7864,608,700T otal


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ADJUSTMENTT o obtain the standard population based on 1970 census population:

The t o t al for each age group i n t he U.S popula t io n * 1,000,000

The gra n d t o t al popula t io n (U.S popula t io n ).

For t he age group 0-4 : 17,154,337 * 1,000,000 / 203,211,926 = 84,416.

T o obtain the expected number of deaths in the standard population :

Age-specific dea t h ra t e for each age group * S t a n dard popula t io n in t ha t age group / 1,000,000 = 584.8 * 84,416/1000,000 = 49.4


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D ir ec t Adjus tm en t M e thodN o. of expec t ed

dea t hs i n s t a n dard

popula t io n

S t a n dardpopula t io n

B ased o n U.Spopula t io n 1970

Popula t io nU.S popula t io n age groups

(years)

49494

277274503

1,0881,8542,4293,402

84,416200,508174,406122,569113,614114,26591,48061,19537,547

17,145,33740,745,71535,441,36924,907,42923,087,80523,219,95718,589,81212,435,4567,630,046

0-45-14

15-2425-3435-4445-5455-6465-74

75 and over

10,4151,000,000203,211,926T otal

*

z


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ADJUSTMENTThe age adjus t ed dea t h ra t e is co m pu t ed i n t he sa m e m a nn eras a crude dea t h ra t e:

total number of expected deaths * 1000total standard population

10,415 * 1000 / 1,000,000 = 10.4

The death rate in the United States is higher that that found inG eorgia (10.4 9.1 = 1.3)

What that can tell us?


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4 - MAT E RNAL MORTALITY RAT E (RATIO)

D eaths from all puerperal causes during a year * K T otal live births during that year

K taken as 1000,or 100,000.T he preferred denominator for this rate is the number of women whowere pregnant during the year which is impossible to determine.In countries where maternal mortality ascribed to pregnancy, labor, andpuerperium are small so, K taken as 100,000, while in those countries withhigh MMR, taken K as 1000 is more convenient.MMR is a good indicator to assess the qualities of medical care and healthfacilities in any given community.


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Ma t er n al Mor t ali t y ra t e (ra t io) L imitations of MMR

Fe t al dea t hs are n o t in cluded i n t he de n o m in a t or(i n fla t io n of ra t e).

A m a t er n al dea t h ca n be cou nt ed o n ly o n ce, al t hought wi n s a n d m ul t iple bir t hs m ay have occurred. Thede n o m in a t or will be t oo large, he n ce a s m all ra t e.U n der regis t ra t io n of live bir t hs, he n ce s m allde n o m in a t or a n d he n ce t oo large ra t e.

Abor t io n a n d m iscarriage are n o t in cluded a n d m os t of t he t im es t hese eve nt s are n o t regis t ered.


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5- INFANT MORTALIT Y RATEnumber of deaths under 1 year of age during a year * K

total number of live births during that yearWhere K is generally taken as 1000.

L imitations:U n der regis t ra t io n of t he live bir t hs which is t hecase i n m a n y developi n g cou nt ries.Ma n y of t he i n fa nt s who die i n a give n cale n dar

year were bor n duri n g t he previous year.Ma n y childre n bor n in a give n cale n dar year willdie duri n g t he followi n g year.

Infant Mortality rate is a good indictor to valuate the qualities of health careand health facilities.


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6 - MORTALITY RAT E S OF L E SS T H AN ONE

Y E AR

NEONATAL MORTALIT Y RATE:

number of deaths under 28 days of age during a year * K

total number of live births during that yearwhere K =1000

FETAL DEAT H RATE:

total number of fetal deaths during a year * K

total deliveries during that year


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6- Mor t ali t y Ra t es of less t ha n o n e year A fe t al dea t h ra t e is defi n ed as: a produc t of co n cep t io n t ha t shows n o sig n of life af t er co m ple t e bir t h.

P roblems in interpretation: Varia t io n regardi n g t he dura t io n of ges t a t io n in differe nt regio n s.So m e cou nt ries repor t in g o n ly fe t al dea t hs wi t h m in im u m

required gesta

tio

nal period for repor

ti

ng.

It does n o t t ake i nt o accou nt t he ex t e nt t o which a co mm u n i t y is t ryi n g t o reproduce (so we use t he fe t al dea t h ra t io).


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6- Mor t ali t y Ra t es of less t ha n o n e yearFETAL DEAT H RATIO:FETAL DEAT H RATIO:

total number of fetal deaths during a year * K total number of live births during that year

Where K is taken as 100, or 1000.

P ERINATAL MORTALIT Y RATE:(number of fetal deaths of 28 weeks or more) + (infant deaths under 7 days) * K

(number of fetal deaths of 28 weeks or more) + (number of live births)

A ll the previous indicators are important in theevaluation of antenatal care quality.


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7 - CAUSE OF DEAT H RATIO

T his ratio is defined as:

number of deaths due to a specific disease during a year * K

total number of deaths due to all causes during that year .100 K =

o Used t o m easure t he rela t ive i m por t a n ce of a give n cause of dea t h.

o

Should be used with cau

tio

nin

com

parin

g on

eco mm u n i t y wi t h a n o t her.


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8 - P RO P ORTIONAL MORTALIT Y RATIOT his index has been suggested as a single measure for comparing

the overall health conditions of different communities:

n u m ber of dea t hs i n a par t icular subgroup * K t o t al n u m ber of dea t hs

W here K = 100.


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VITAL STATISTICS II

Dr. Tarek Tawfik


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MEASURES OF FERTILIT Y

is the actual bearing of children, whileF ertilityis the capacity to bear children.F ecundity

A knowledge of the rate of childbearingin a community is important to the

health worker in planning servicesand facilities for mothers, infants, and children.


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1 - CRUDE BIRT H RATE

T he most widely used of the fertility measures:

total number of live births during a year*

K total population as of July 1

Where k = 1000.It is a non-specific indicator as the denominator includes all the population,

while those at risk of giving births are females in certain age group (womenof age 15- 49 years).Even in this age group, the risk is confined to those who actually have thecapacity to be pregnant, and in many communities this is restricted withinthe frame of marriage.


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2 - G ENERAL FERTILIT Y RATE

number of live births during a year * K

total number of women of childbearing age at that year

Where K = 1000.The childbearing age is usually defined as ages 15 through 44 or ages 49.

T he limitation of that rate is that the pattern of fertility of women is notconstant, it varies with age, the most fertile period (21-25 years) has thegreatest risk compared to other fertile periods.By including women in the childbearing ages defines and approximates thenumber of person who are actually at risk instead of including the wholepopulation.


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3 - AG E-SP ECIFIC FERTILIT Y RATE

o Since the rate of fertility is not uniform along the whole period of 15-49years, a rate that permits the analysis of fertility rates for shorter maternalage interval is desirable (we classify the childbearing period into intervalsof 5 years duration; 15-19, 20-24, ------, etc.,)

o T his classification will permits to compute the different patterns of fertilityin the different age groups. Specific fertility rates can also be computed forother population subgroup (race, socioeconomic, other demographiccharacteristics).

number of live births to women of a certain age (25-29) in a year * K

total number of women of the specified age (25-29)Where K = 1000.


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4 - TOTAL FERTILIT Y RATEI f t he 7 age-specific fer t ili t y ra t es are addeda n d multiplied by t he i nt erval which t he

ages were grouped (5 years int

erval),theresul t is called t he total fertility rate .

T he resulting figure is an estimate of the number of children a cohort of 1000 women would have if,during their reproductive years, they reproduced atthe rates represented by the age-specific fertilityrates from which the total fertility rate is computed.


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How to calculate fertility measuresCumulative

fertility rate

Expected

Births

Standard

population basedon U.S population1970

A ge-specific

birth rateper 1000women

Number of

births towomen of specified age

Number of

women inpopulation

A ge of

women(years)

495.0

1,379.5

2,030.0

2,362.52,500.52,540.5

19,182

30,707

18,313

7,9673,2271,021

193,762

173,583

140,764

119,804116,925225,162

99.0

176.9

130.1

66.527.64.0

21,790

37,051

22,135

9,2463,7391,044

220,100

209,500

170,100

139,100135,400261,700

15-19

20-24

25-29

30-3435-3940-49

80,4171,000,00095,0051,135,900T otal

Crude birth rate = total births / total population= (95,005 / 4,608,900)(1000) = 21.0

G FR= (95,005/ 1,135,900)(1000) = 84.1A ge specific fertility rate= 99.0(5) + 176.5 (5) + etc= 2,540.5 (total fertility)Cumulative fertility rate= age-specific rate for each group * interval width.Standardized general fertility rate = (80,417/ 1,000,000)(1000)= 80.4


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MEASURES OF MORBIDIT Y

Another area that concerns the health worker who is analyzing thehealth of a community is morbidity.

The word morbidity refers to the communitys status with respectto disease. Data for the study of morbidity of a community arenot, as a rule available and complete as are the data on births anddeaths because of incompleteness of reporting and differencesamong regions, and countries with regard laws that requiring

diseases reporting and notification.The two rates most frequently used in the study of diseases in acommunity are the incidence and the prevalence rates.


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1 - INCIDENCE RATE

D efined as:

total number of NEW cases of a specific disease during a year * K

total population at risk as of July1

T he value of K depends on the magnitude of the numerator. A base of 1000 isused when convenient, but 100 can be used for the more common diseases,and 10,000 or 100,000 for the less common or rare.

T he incidence rate measures the degree to which new cases areoccurring in the community, is useful in helping determine the needfor initiation of preventive measures , the trends of diseases occurrence,the emergence of an epidemic , and the type of diseases that occurringwhether acute or chronic in nature, and the relative weight of each inthe community.


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2 - P REVALENCE RATE

The prevalence rate is really a ratio, since it is computed as:

total number of cases, NEW or OLD

, existing at a point in time*

K

total population at risk at this point in time

Where the value of K is selected by the same criteria as for the incidence rate.

T his rate is specially useful in study of chronic diseasesto study the diseases burden and magnitudes.


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3 - CASE FATALIT Y RATE

T his ratio is useful in determining how well the treatment programs for acertain disease is efficient.

total number of deaths due to a disease * K

total number of cases due to the disease

Where K = 100. the period of time is arbitrary, depending on the nature of the disease,

and it may cover several years for an endemic disease.T his ratio can be interpreted as the probability of dyingfollowing contraction of the disease in question.T his ratio reveals the seriousness of the disease in question.


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4 - IMMATURIT Y RATIO

T his ratio is defined as:

number of live births under 2500 grams during a year * K

total number of live births during that year

Where K = 100.T his ratio measures the magnitude of immaturity and

premature deliveries in the given community and directlyused in the evaluation of the quality of health care providedto women in the childbearing period.


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5- SECONDAR Y ATTACK RATE

T his rate measures the occurrence of an infectious disease among susceptiblepersons who have been exposed to a primary (index) case.

number of additional cases among contacts of aprimary case within the maximum incubation period * K

total number of susceptible contactsWhere K = 100.

T his rate is used to measure the spread of infection and is usuallyapplied to closed groups such as a household, classroom,where it can be assumed that all members were in contact withthe index case.


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TH ANK Y OU

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Vital Statistics Final