Prevalence of HIV Infection and Risk Factors of Tuberculin Skin Test Results among Household Contacts in a HIV Epidemic Area: Chiang Rai

Province, Thailand

byPornnapa Suggaravetsiri, Ph.D.(Epidemiology)

Faculty of Public Health, Khon Kaen University, ThailandJuthatip Putthasorn, M.D.

Chiang Rai Prachanukraow Hospital, Thailand

Rationale of the study

• Both HIV/AIDS and TB are increasing in Thailand especially in the Northern region

•TB sharply increased in Chiang Rai Province

• Knowledge on the extent to which HIV+TB contributes to the transmission of the disease will be useful for further planning for intervention

Objectives1. To determine prevalence of HIV and

TB Infection among household contacts of new TB sputum positive cases

2. To identify risk factors of tuberculosis infection among household contacts of new TB sputum positive cases

Thailand

Chiang-Chiang-RaiRai

MUANG ( 154 )

Area : 11,678 Km2

MAECHAN ( 381 )

MAE SAI ( 229 )

Phan Mae Lao

WiengChai

Setting

Study design

• Cross-sectional study• The study was carried out from

June 2000 and January 2002

Collecting DataFor data collection the

following tools had been used:•Structured interviews•Physical examination•Tuberculin skin test (TST) and

Mumps skin test •Pre-test and post-test

counseling for HIV testing

Inclusion criteria

Index TB cases• Newly TB cases• AFB smear+ • > 15 years old and known HIV status• willing to participant in this project

Household contacts• Stay in the same house with index case > 4 days/week & > 4 weeks before initial TST • Willing to participate and had singed consent to participate

Exclusion Criteria

• Index cases or contacts not willing to participate• Living outside of the study area• Index cases being prisoner• Home visit not possible because of various reasons• Index’s HIV status unknown

Sample Size

•1,211 household contacts participated in this study

TST

Measurement of TB infectionby using tuberculin skin test (TST)

Mumps skin test

TST MST

Data Processing & analysis

• Statistical analysis using STATA v 8.2

• Main results:– prevalence of TST+ using cut-off point of induratio

n size ( >10 mm.)

– Univariate analysis of TST + and each independent variable by OR and 95% CI

– Multivariate analysis and adjustment for confounder

Participate

526 TB cases

Pool of TB index cases 530 cases

Participate and TST1211 contacts

Participation of subjects

Participate and TST1240 contacts – 29 anergy skin test

Prevalence of HIV +ve among household contacts

7.74% (72 / 930 of contacts who did agree for HIV testing)

Results

Prevalence of TST +ve among household contacts

56.98% (690 / 1211 of contacts who did agree for TST)

Table 1 Rate and OR of TST positive and characteristics of household

contactsCharacteristic Number and Prevalence

(%) of TST-positive

Crude OR 95% CI p-value

SexSex

Male 327/528 (61.93) 1.00

Female 363/683 (53.15) 0.51 0.40-0.65 <0.01

Age (years)Age (years)

<10 75/239 (31.38) 1.00

10-19 111/189 (58.73) 3.11 2.09-4.63 <0.01

20-29 107/146 (73.29) 6.00 3.80-9.48 <0.01

30-39 119/171 (69.59) 5.00 3.27-7.66 <0.01

40-49 103/148 (69.59) 5.01 3.21-7.80 <0.01

50-59 82/124 (66.13) 4.27 2.69-6.77 <0.01

≥ 60 93/194 (47.94) 2.01 1.36-2.98 <0.01

Table 1 Rate and OR of TST positive and characteristics of household

contacts (cont.)Characteristic Number and Prevalence (%)

of TST-positiveCrude OR 95% CI p-value

Race / EthnicityRace / Ethnicity

Thai 639/1126 (56.75) 1.00

Hill tribe 51/ 85 (60.00) 1.14 0.73-1.79 0.56

Marital statusMarital status

Single 244/508 (48.03) 1.00

Married 358/558 (64.16) 1.94 1.52-2.48 <0.01

Divorced 88/145 (60.69) 1.67 1.15-2.43 <0.01

Relationship to Index caseRelationship to Index case

Relative 179/366 (48.91) 1.00

Spouse 203/282 (71.99) 2.68 1.93-3.74 <0.01

Children 121/238 (50.84) 1.08 0.78-1.50 0.64

Parent 187/325 (57.54) 1.42 1.05-1.91 0.02

Table 2 Univariate analysis of risk factors associated with TB

infectious among household contacts Variable TST+ TST - OR 95 % CI p-value

Alcohol drinking

No 577 478 1.00

Yes 113 43 2.18 1.50-3.16 <0.01

Cigarette smoking

No 449 380 1.00

Yes 241 141 1.45 1.13-1.85 <0.01

BCG scar present

Positive 411 274 1.00

Negative 279 247 0.75 0.60-0.95 <0.01

HIV status

Positive 22 20 1.00

Negative 539 316 1.55 0.83-2.87 0.17

Table 2 Univariate analysis of risk factors associated with TB

infectious among household contacts (cont.)

Variable TST + TST - OR 95 % CI p-value

Care giver to the TB patient

No 376 406 1.00

Yes 314 115 2.95 2.83-3.81 <0.01

Sleeping in the same bedroom as the TB patient

No 379 362 1.00

Yes 311 159 1.87 1.47-2.37 <0.01

Sleeping in the same bed as the TB patient

No 448 395 1.00

Yes 242 126 1.69 1.31-2.18 <0.01

Table 3 Multivariate analysis of risk factors associated with TB infectious

among hhcVariable in model Adj.OR (95 % CI) p-value

Sex

Male 1.00

Female 0.45 (0.33-0.61) <0.01

Age (years)

<10 1.00

10-19 3.70 (1.89-7.25) <0.01

20-29 6.45 (3.21-12.96) <0.01

30-39 5.34 (2.70-10.57) <0.01

40-49 5.55 (2.79-11.05) <0.01

50-59 6.26 (2.99-12.87) <0.01

≥ 60 2.56 (1.29-5.08) <0.01

Variables entered in the Multiple Logistic Regression Analysis were sex, age, BCG scar present, HIV status, Care giver to the TB patient, and Sleeping in the same bedroom as the TB patient

Table 3 Multivariate analysis of risk factors associated with TB infectious among household contacts (cont)

Variable in model Adj.OR (95 % CI) p-value

BCG scar present

Positive 1.00

Negative 0.74 (0.53-1.04) 0.08

HIV status

Positive 1.00

Negative 3.15 (1.57-6.33) <0.01

Care giver to the TB patient

No 1.00

Yes 2.04 (1.48-2.81) <0.01

Sleeping in the same bedroom as the TB patient

No 1.00

Yes 1.99 (1.44-2.74) <0.01

Conclusion and Suggestions

The results of this study suggest that:• High prevalence of HIV and TB among

HHC

• Screening every 6 months should be provided to TB pt. household members

• To TB pt. VCT should be provided

• To HIV+ anti-TB prophylaxis and treatment should be provided

• Prevention HIV will be decrease TB

Thanks for your attention

Acknowledgement : Staff of TB/HIV Research Project, particularity Sunee,

Saiyood, Mitree, Ratikorn,Uthumporn, Dollaporn and Piyanoot for collection, validation and management.

Doctors and staff of TB clinic and Micro- laboratory, TB patients and Their households of CHR, MH and Phan Hospital

Thailand-Tropical Diseases Research Programme (T-2) and TB/HIV Research Project, Research Institute of Tuberculosis (RIT), Japan for financial supported this study.

Professor Dr. med. Frank Peter Schelp to edit manuscript

Correspondence: porsug@kku.ac.th