INH preventive therapy among adult HIV-infected patients in Thailand

SETTING: Two HIV/AIDS clinics in Bangkok. OBJECTIVE: Although isoniazid (INH) preventive therapy (IPT) can reduce the risk of active TB among HIV-infected individuals, preventive therapy is rarely used in developing countries. The WHO recommends INH prophylaxis for tuberculin skin test (TST) positive HIV positives or for all HIV positives in countries with a high prevalence of latent TB if TST is unfeasible. It is not known whether IPT without TST will affect adherence. DESIGN: Prior to receiving IPT, 914 HIV-infected patients in Bangkok were randomized to TST or not. Adherence, measured by self-report and pill counts, and proportion completing therapy were evaluated. RESULTS: Adherence was 84.5% and 79.7%, by self-report, and 81.8% and 73.9% by pill count, respectively, in PPD-positive and non-TST-screened subjects (adjusted OR 1.44, 95% CI 0.79-2.64 and 1.53, 95% CI 0.45-5.26). The drop-out rate before treatment was 6.3% in the TST-screened and 1.7% in the non-TST screened subjects (OR 3.93, 95% CI 1.18-16.04). CONCLUSION: TST screening was not a predictor of adherence to IPT once therapy began, but it was associated with a higher drop-out rate prior to therapy. Acceptable levels of adherence were observed with both regimens.