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