national tb prevalence survey cambodia, 2002 · national tb prevalence survey 1st systematic,...

Ikushi Onozaki MD, MPH

Chiba Anti-TB Association/JATAChiba Foundation for Health Promotion and Disease Prevention

National TB Prevalence Survey

Cambodia, 2002

8 years after introduction of DOTS

How much TB in Cambodia? Estimates for 2001

estimate number rate/100,000incidence (all) 75,000 573incidence HIV+ 9,200 70incidence (ss+) 34,000 256prevalence (all) 178,000 1356prevalence (ss+) 72,000 548deaths 16,000 121

From Chris Dye

National TB Prevalence Survey1st Systematic, National Representative and Comprehensive TB Survey in Cambodia

• First population based survey under a typical DOTS program

• 42 clusters of 31,000 people across the country– 30,000, 97%, participated– 22,164, 96%, Age 10 or

more Age <15 y : TuberculinAge 10 or more: X-ray Preparation Meeting with

Local People

Viet Nam

Lao

Thailand

Survey Cluster:★

Basic Operation Schedule: Cluster/Week

Sunday: Arrival & Basic Preparation

Monday: Census/ Informed ConsentArrival of Technical Team

Tuesday/Wednesday: Interview, X-ray, Tu-test, Sputum collection

Thursday: Interview, X-ray, Sputum collection,

Sputum transfer to CENATFriday: Sputum collection, Tu-

readingSaturday: Tu-reading (morning

only) , Departure

Census: Confirming eligible population and asking for participation

People who basically stay in a defined area more than a month are eligible population regardless the possession of their house and their

availability on the survey day

Proper informed consent to avoid creating fears

Survey Days

Collaboration with local community is essential

Family by family interview by a physician from CENAT

• TB related symptoms– Duration of sickness

• TB history– Possible treatment– Consultation Places

1,699 (7.7%) participants who met the TB suspect criteria such as cough more than 3 weeks were asked to submit sputum regardless X-ray findings

Age 10ys or more: Taking X-ray• 22,012 X-ray exams• 2,432 who showed any

kind of abnormality were asked to submit sputum

JICA team is monitoring and ensuring the safety of the survey

Developing Film on the SpotQuality Direct X-ray is Available in Villages

that contributed to high participation rates and 100% sputum collection from suspects

84 showed smear positive slide(s)81 Smear Positive TB1 MOTT2 contamination susp.

81 S(+) TB :(71 New)New: 66on Treatment: 5 New, 2 RetPreviously treated: 8

202 S(-)C(+)190 S(-)C(+) TB Cases12 contamination susp

190 Cases New: 174on Treatment: 3 New, 1 RetPreviously treated: 13

Number of S(+) cases actually detected and Prevalence Rate

0

5

10

15

20

25

10-14 15-24 25-34 35-44 45-54 55-64 65-

0

200

400

600

800

1000

1200

1400

1600

1800

Female

Male

S(+)/100,000

Age Group

No of Detected Cases Prevalence Rate

Table 2-a Results of National TB Prevalence Survey, Cambodia, 2002 -Crude Prevalence 1(/100,000 age 10 or more)

n Point Estimate 95% C.I .Partic ipants age 10 or more 22164

S(+) TB 81 365 286-444S(-)C(+) TB 190 861 740-983S(-)C(-) X-ray ActiveTB 326 1470 1312-1629

Bacteriologically Postive TB 271 1223 1078-1367Active Pulmonary TB 597 2693 2480-2906

Point Estimate 95% C.I . Point Estimate 95% C.I . S+/Bac+Age 10 or more 365 286-444 1223 1078-1367 30%

Male 542 399-685 1508 1271-1745 36%Female 216 133-299 982 805-1157 22%

(Male/Female)

All Age* 270 211-328 902 795-1009Male 387 285-490 1079 909-1249

Female 163 100-226 744 610-877

-5.0Km 255 160-390 1102 873-1331 23%5.1-10.0Km 372 209-534 1004 738-1271 37%

10.1Km- 443 304-582 1467 1216-1719 30%

Table2-b Results of National TB Prevalence Survey, Cambodia, 2002 -Crude Prevalence 2

Smear Positive Bacteriologically Positive

*Assuming that there was no bacterio logically positive case in children age less than 10

2.5 1.5

Distance to DOTS Center

Prevalence of Bacteriologica lly Positive Pulmonary TB by Age GroupNational TB Survey 2002, Cambodia

0

1000

2000

3000

4000

5000

6000

7000

S(+)

Bac(+)

S(+) 66 116 302 469 638 839 1620

Bac(+) 87 314 932 1500 2096 3509 5997

10-14 15-24 25-34 35-44 45-54 55-64 65＋

Prevalence of Bac(+) Pulmonary TBNational TB Survey 2002

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

Smear +(M)

Bac +(M)

Smear + (F)

Bac + (F)

Smear +(M) 44 167 494 652 1264 1299 2954

Bac +(M) 88 469 1297 1739 3218 4453 8439

Smear + (F) 89 65 148 330 226 518 789

Bac + (F) 89 163 641 1319 1358 2850 4474

10-14 15-24 25-34 35-44 45-54 55-64 65-

Relations between prevalence and notificationsmear positive TB

Prevalence Rate /Notification Rate

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

15- 25- 35- 45- 55- 65-

Male

Female

Ａｇｅ

Limitation of Symptom Screening by Interviews to Detect Cases

Smear Positive TBS(+) Non Case Total %

TB Symptomatic 50 1649 1699 2.94%No 31 20434 20465 0.15%

Total 81 22083 22164 0.37%

Specif ic ity 92.5%Sensitivity 61.7%

Bacterio logically Positive TBCases Non Case Total %

TB Symptomatic 108 1591 1699 6.36%No 163 20302 20465 0.80%

Total 271 21893 22164 1.22%

Specif ic ity 92.7%Sensitivity 39.9%

Table3 Patterns of Combined Drug Resistance

Total number of strains tested 245 100.0% 734 100.0%

Susceptible to All 4 Drugs 226 92.2% 651 88.7%

Any Resistance 19 7.8% 83 11.3%Isoniazid(INH) 13 5.3% 57 7.8%

Rifampicin(RMP) 0 0.0% 7 1.0%Ethambutol(EMB) 0 0.0% 1 0.1%Streptomycin(SM) 8 3.3% 39 5.3%

Monoresistance 17 6.9% 64 8.7%Isoniazid(INH) 11 4.5% 39 5.3%

Rifampicin(RMP) 0 0.0% 3 0.4%Ethambutol(EMB) 0 0.0% 0 0.0%Streptomycin(SM) 6 2.4% 22 3.0%

Multidrug Resistance 0 0.0% 3 0.4%INH+RMP 0 0.0% 1 0.1%

INH+RMP+EMB 0 0.0% 0 0.0%INH+RMP+SM 0 0.0% 2 0.3%

INH+RMP+EMB+SM 0 0.0% 0 0.0%

Other Patterns 2 0.8% 16 2.2%INH+EMB 0 0.0% 1 0.1%

INH+SM 2 0.8% 14 1.9%INH+EMB+SM 0 0.0% 0 0.0%

RMP+EMB 0 0.0% 0 0.0%RMP+SM 0 0.0% 1 0.1%

RMP+EMB+SM 0 0.0% 0 0.0%EMB+SM 0 0.0% 0 0.0%

Prevalence Survey 2002 NDRS 2000-2001

DOTS in all MPA Health Centers, primary care level per 10,000 population, by 2005

DOTS Expansion, CambodiaProspect to cover all Health Centers by 2005

3 3 3 3 3 4 5 665 65 65 66 68 68 68 68

76 76 70 70 70 70 70 709 60

252

380

565

750

870

1 11

2

2

4

6

8

0

200

400

600

800

1000

1200

1998 1999 2000 2001 2002 2003 2004 2005

Year (Plan: 2003-)

No. of

Fac

iliti

es

wit

h D

OT

S

Other

MPA-HC

FDH

Referral H

National

Prevalence of TB and Distance to DOTS Service( /100,000 age 10 or more)

276

372

444

827

633

1024

0

200

400

600

800

1000

1200

<5km (15clusters) 5-10Km (10clusters) >10km (17clusters)

/100,0

00 A

ge 1

0 o

r old

er

S(+)

S(-)C(+)

Point Estimates of ARI, 2002 National SurveyChildren with No BCG Scar (RT23:2TU)

3.21%1.62%Age 10-14(N=2,532)

2.10%1.00%Age 5-9(N=2,245)

0.99%0.46%Age 1-4(N=993)

10 mm16 mm mirror

Estimation of Incidence of New S(+)

DOTS CDR=52%, Private Tx=10%, TB/HIV: 15%

P New from the surve 237NTP Notification('02) 139Real Case Detection 104 -10%: Retreatment, -15%: Overdiagnosis, missclassification

Private treatment 8/46 by prevalence surveyNTPx8/(46-8) 22

Undetected Cases (I-NTP-Private)HIV + 1.5% of population=1500/100,000 1500

8% may develop TB/Year and One forth of them is S 30Among NTP 10% From Survey 10Among Private 10% Assumption 2Undetected 17

Incidence PrevalenceDuration of I llness Diag Delay Conversion or Death Total /100,000 /100,000DOTS HIV- 0.58 0.20 0.8 94 73DOTS HIV + 0.58 0.15 0.7 10 8Private HIV- 0.4 0.6 1 .0 20 20Private HIV+ 0.4 0.3 0 .7 2 2Undetected HIV- 2 2.0 59 117Undetected HIV+ 1 1.0 17 17

202 237

Conclusions and Research QuestionsYes, Cambodia has very high TB burden, however,

– S(+) Prevalence, 270, a half of WHO estimate– No more among 22 HBC???, dropping from 18th to 24th?

A large pool of latent infection may be a major source of new cases: Continuous efforts are essential

30/81 S(+) were judged as no-TB suspects by interviews: Limitation of a survey without X-ray and/or CF strategy

S(+) occupied only 30% of Bac (+)Less in groups with better access to DOTS: A transitional phenomenon of short history of DOTS? Or Need of new model?

Bac (+) prevalence of 902: Total TB burden is probably more than the WHO estimate that may make Cambodia still within 22 HBC, even 16th or 17th ?

Efforts on DOTS Expansion, establishing better access to DOTS, are paying off in case detection

NTP TB Case Registration, Cambodia

0

5000

10000

15000

20000

25000

30000

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

CA

SES

S(+)N

Relapse

Pul(-)

Extra-pul

TOTAL

Hospitalized DOTS throughProvincial and DistrictHospitals

DOTS Expansion toHealth Centers andCommunity

JICA Project

Wor ld Bank Support

In troduct ion of DOTSgu ided by WHO

Yes, DOTS is working to reduce S(+) prevalence in Cambodia even with TB/HIV impact. However:

S(+) Prevalence: 50-60% of the WHO estimate and/ or the era before DOTS

Incidence: 80-85% level of thoseDetecting S(+) only: Is it enough in community with

such a high prevalence, where one out of 11 “grandfathers” is C(+)? : Need to assess unknown impact of chronic S(-)C(+) with a large number of close contacts in a large family in Asia

Incidence of S(-)C(+) may be much higher than the WHO estimate with current model. However, majority of them might not come to health facility to seek treatment because many of them are not so sick.

Now, we’ve got a clear view

Thanks for your collaborationin advance!

CENAT/JICA National TB Control ProjectCambodia

Challenge: The next round in 2008?