1

Identifying all tuberculosis cases detected in Identifying all tuberculosis cases detected in the health system: A new approach to revisit the health system: A new approach to revisit

the case detection ratethe case detection rate

Task force on impact measurementTask force on impact measurementGeneva, 23Geneva, 23--25 September25 September

Dr Dr AmalAmal BassiliBassiliStop TB, WHO, Regional Office of the Eastern Stop TB, WHO, Regional Office of the Eastern

Mediterranean Mediterranean

On behalf of:On behalf of:NTP research teams in Syria, Egypt, Pakistan, NTP research teams in Syria, Egypt, Pakistan,

Djibouti and Yemen Djibouti and Yemen

2

• Reports from the Region showed that the delay in treatment reached up to 4 months in some countries and the patient or health system contribution varied from one country to another

• In spite of that reported delay, almost all cases reached health care providers, private or public at different stages during their care seeking

• In view of the above, it could be deduced that the great majority of cases are missed within the health system. The latter consists of NTP and Non-NTP providers.

RationaleRationale

3

Cases notified to NTPNTP

TB suspects/cases undetected by either either sectorsector

TB cases detected by nonnon--NTP NTP

Hypothetical model showing that the majority of delayed detectedcases are finally diagnosed at NTP or Non-NTP facilities (Based on Chris Dye’s Onion Model)

Negligible proportion remains undetected in the community

ES

TIMA

TED

4

ObjectivesObjectives• General objective • To determine the case detection rate (CDR) based

on the extent of reporting/under-reporting rate of non-NTP providers

• Specific objectives• To evaluate a new methodology for estimation of

TB incidence based on determining the extent of reporting/underreporting of other providers within the health system;

• To compare between the estimated incidence using the study results and other evidence collected from the countries;

• To evaluate the case management of TB by non-NTP providers including their notification/referral of cases to NTP.

5

MethodsMethodsDurationDuration SettingSetting

SyriaSyria Q4, 2006 Private laboratories

EgyptEgypt Q4, 2007

Non-NTP laboratories and facilities

PakistanPakistan Q4, 2007

DjiboutiDjibouti Q1, 2008

YemenYemen Q1, 2008

6

Sampling techniqueSampling techniqueSyria and DjiboutiSyria and Djibouti No sampling-comprehensive

survey

EgyptEgypt Stratified cluster, with second stage sampling of districts in 2 governorates

(4 out of 27 governorates )

PakistanPakistan Stratified cluster, with second stage sampling of private clinics

(13 out of 130 districts)YemenYemen Stratified cluster

(4 out of 17 governorates)

7

Study subjectsStudy subjects

Consented laboratory staff and physicians delivering care to TB patients in the following non-NTP sectors (whenever applicable) were enrolled in the study:

Public: Public hospitals; Health Insurance facilities; Medical organizations; Ministry of Interior (prisons); Ministry of Defence,etc.

Private: Private hospitals; Private clinics; NGOs

8

Study design and tools Study design and tools •Modified laboratory and suspect registersintroduced in the non-NTP facilities

•Added columns:•Nationality•Basis of diagnosis•Source of referral•Action taken when suspecting or diagnosing TB •Reasons of referral•Date of onset of symptoms•Status of registration at NTP

•Weekly visits to collect forms and check the status of registration of cases at NTP

9

Data Cleaning Data Cleaning

• Data cleaning for each non-NTP source (lab and clinics)

•Merging the 2 files and cleaning the merged file. Arabic names were used as unique identifier supported by other variables

•Adding a column on the status of registration of NTP cases at non-NTP

•Cross-checking the status of registration of non-NTP cases in NTP using e-surveillance data for the whole year

10

duplication

Compare with another variable (age)

11

CrossCross--checking with surveillance datachecking with surveillance data

12

Data analysisData analysis

I- Description of the case management practices of non-NTP

II-Inventory method: Number of cases detected at NTP only Total number of cases detected in both sectors

III-Capture re-capture method

13

Suspects identified in the Non-NTP facilities during the study quarter

398287

90 140191 132203

0100200300400500

Syria Egypt Pakistan Djibouti Yemen

Num

ber

Laboratories Non-NTP clinics/hospitals

ResultsResults

14

Investigations requested in the different countries

56

13.2

18.1

54.2

41.5

54.3

0.5 1.129.6

17.2

28.519.6 16.6

42

80

25.30.35

8.3

2.1

0%

20%

40%

60%

80%

100%

Syria Egypt Pakistan Djibouti Yemen

%

Sputum Sputum and X-Ray X-Ray Culture Other

NB. Syria figures are reported from an earlier EMRO supported study on the case management practices of the non-NTP sector

15

Action taken by the Non-NTP providers upon suspecting or diagnosing TB (among detected cases)

0

4232

5

68

92.7

0

15.9

95

18

5852

13

0102030405060708090

100

Syria Egypt Pakistan Djibouti Yemen

%

Referral of suspects for diagnosis Referral after diagnosis for treatment Diagnosis, treatment +/- notification

16

Characteristics of cases in both sectors• There was no significant difference between Non-

NTP and NTP regarding the age distribution of their cases in all the studied countries

• In Egypt, Pakistan and Djibouti there was no significant difference between both sectors regarding the gender distribution of their cases, while in Syria and Yemen, males were significantly higher than females in the non-NTP

• There was no significant difference between both sectors regarding the proportion of pulmonary TB out of all forms in all studied countries

17

SYR SYR EGYEGY PAK PAK DJIDJI YEMYEMNo. detected in No. detected in nonnon--NTP only NTP only

6 46 1,541 6 37

No. detected in No. detected in both sectors both sectors

41 115 336 18 76

No. detected in No. detected in NTP only NTP only

291 249 6,057 778 358

88.8(85.7-91.8)

72(68-75)

54(all

forms)

% detected% detected(inventory) (inventory)

98.2(96.8-99.6)

81(79.7-81.4)

99.3(98.7-99.8)

92.1(89.6-94.7)

CDR (%) CDR (%) (cap re(cap re--cap)cap)

87.5(84.1-90.8)

18(17.5-18.3)

*further data cleaning

76(74-78)

67.5(64.0-71.1)

WHO WHO estimated CDR estimated CDR (%) in 2006(%) in 2006

48 (smear

positive)

59(all forms)

43(all forms)

48 (all

forms)

18

FUNDSFUNDS• Budget: ≤ US$ 10,000 each + Capital cost +

routine programme contribution mainly from PPM

• Source of funds:– Syria, Djibouti, Pakistan: EMRO/TDR small

grants scheme

– Egypt, Yemen: Global Funds

19

Methodological issues Methodological issues

• The tool was validated by the Syrian scenario

• The reported results are consistent with other evidence in Syria :– Ban of selling Anti-TB drugs in the private sector – Previous study: 93% of private providers refer

their suspects/diagnosed cases to be treated at NTP; and 99% rely on sputum smear examination for diagnosis

– In depth-review mission report 2006 using Onion model (Syria cannot be missing 60% of cases)

20

The assumptions Syria Yemen Pakistan Egypt Djibouti

1.Closed 1.Closed populationpopulation

Most likely Less likely

2. All cases have 2. All cases have equal chances to equal chances to be captured by be captured by either sourceeither source

Most likely Less likely: informal providers, and quacks

Most likely

3. Extent of use 3. Extent of use of health of health services in the services in the country country

≈100% ≈90% <50% (self medication+ drug stores in 40-50% of patients)

≈100% >95%

Methodological issuesMethodological issues:

capture re-capture assumptions

21

The assumptions

Syria Yemen Pakistan Egypt Djibouti

4.Validation of 4.Validation of NonNon--NTP NTP diagnosisdiagnosis

In 41 out of 47

For cases detected in both sectors

For cases detected in both sectors

Yes Mainly for cases detected in both sectors

5.Perfect linkage 5.Perfect linkage Yes, using Arabic names: first/middle/lastand e-surveillance

Problem of English names

Yes, using Arabic names: first/middle/lastAnd e-surveillance

6.Independence 6.Independence of sourcesof sources

PPM not yet HIO notify to NTP

PPM not yet

Methodological issuesMethodological issues:

capture re-capture assumptions

22

Methodological issuesMethodological issues• The study produced reliable results when the assumptions were

almost fulfilled (Syria, Yemen, and Djibouti)

• Over or underestimation:– When cases are not recognized as having been captured in both

systems, the estimated number is too high (Pakistan)– If there is some dependence between the two systems, the

number may be underestimated (Egypt). Need to adjust.

• Record linkage:– The use of original language for patients’ names (Arabic, Urdu)

– To add the personal IDNO to the form

– All surveillance data of the year and one quarter following the study should be cross-checked

23

Methodological issuesMethodological issues

• To validate diagnosis:

– to add one column “diagnosis made by non-NTP providers” to compare it with the “final diagnosis” made by NTP

– to strengthen the follow-up on the cases that were not registered by NTP to confirm their diagnosis and add them to the total notified cases

24

Methodological issuesMethodological issues

• Sampling of governorates allows better coverage of non-NTP facilities as cases tend to use services within their governorate rather than other governorates

• If a second stage sampling has to be done, the secondary sampling units should be districts (Egypt) rather than facilities (Pakistan), as the inventory method cannot be applied in the latter

• More financial resources

25

Methodological issues Methodological issues Decision tree to select the appropriate methods

Use of Microscopy by non-NTP

1st Scenario (Syria)

3rd Scenario (One stage sampling-

Yemen)Non-NTP labs in country

Non-NTP clinics/hospitalsin country

Limited

Limited

2nd Scenario (Djibouti)

<95% or unknown

LargeLarge

LargeLarge

<95% or <95% or unknownunknown

Very LargeVery Large

4th Scenario (2 stage sampling-

Egy/Pak)

≥95%

26

Questions to the task forceQuestions to the task force

•• Do you agree on using this protocol to estimate Do you agree on using this protocol to estimate the incidence and to provide evidence for the the incidence and to provide evidence for the certification process?certification process?

•• Criteria to recommend conducting the survey:Criteria to recommend conducting the survey:

–– Prior assessment of the 6 assumptions for capture rePrior assessment of the 6 assumptions for capture re--capturecapture

–– Low prevalence <100/100,000 population where Low prevalence <100/100,000 population where disease prevalence survey is not recommendeddisease prevalence survey is not recommended

27

Questions to the task forceQuestions to the task force• The majority of countries have 2 main

sources of data: NTP and Non-NTP. Though there are legislations on the notification of TB cases from non-NTP providers, they do no comply with the law and there are no penalties if they do not.

Based on that, can we assume that these Based on that, can we assume that these 2 sources are independent sources?2 sources are independent sources?