The tuberculin skin test (TST) can be used to identify HIV-infected people who would benefit the most from long-term isoniazid preventive therapy (IPT). However, in resource-constrained settings, implementation of the TST can be challenging. The objectives of this study were to assess the feasibility of implementing the TST for IPT initiation and to estimate the proportion of TST-positive incidence among HIV-positive patients in 2 high tuberculosis and HIV burden settings.
Two prospective observational cohort studies were conducted under programmatic conditions in Mathare, an urban slum of Nairobi, Kenya, and in rural Shiselweni, Swaziland. HIV-positive adults with negative tuberculosis symptomatic screening underwent the TST. Those testing positive were started on 36-month IPT.
Of 897 and 1021 patients screened in Mathare and Shiselweni, 550 and 696, respectively, were included. Median age was 38 years, 67.7% were female, and 86.8% were on antiretroviral therapy. Among TST-eligible participants, 88.0% (491/558) and 81.8% (694/848) accepted TST and 74.2% (414/558) and 77.1% (654/858) returned for test reading in Mathare and Shiselweni, respectively. The TST was positive in 49.8% (95% confidence interval: 44.9 to 54.6) in Mathare and 33.2% (95% confidence interval: 29.6 to 36.8) in Shiselweni. The 36-month IPT was accepted by 96.1% (198/206) patients in Mathare and 99.5% (216/217) in Shiselweni. IPT implementation at the clinics was managed with no additional staff or extra space.
Implementing the TST for IPT initiation was feasible and acceptable in both urban and rural resource-constrained settings. This strategy allows patients who can benefit the most to receive long-term IPT and avoids unnecessarily treating a significant number of patients who do not stand to benefit.