The researchers designed the current study to estimate the effect of antiretroviral therapy (ART) on incident TB in a cohort of children with HIV.
Data were analyzed from ART-naïve children without TB who were enrolled in an HIV care program in Kinshasa between December 2004 and April 2008. A Cox proportional hazards marginal structural model was used to estimate the effect of ART on TB incidence while accounting for time-dependent confounders affected by exposure.
The study participants were 364 children, who contributed 596.0 person-years of follow-up. At baseline, the children's median age was 6.9 years, and 163 (44.8 percent) were in HIV clinical stage 3 or 4. A total of 242 children (66.5 percent) initiated ART during follow-up, and 81 (22.3 percent) developed TB.
At the time of TB diagnosis, 41 (50.6 percent) were receiving ART. Among those receiving ART, the TB incidence rate was 10.2 per 100 person-years (95 percent confidence interval [CI] 7.4-13.9). Among those receiving only primary HIV care, the TB incidence rate was 20.4 per 100 person-years (95 percent CI 14.6-27.8).
TB incidence decreased from 18.9 per 100 person-years in the first six months on ART to 5.3 per 100 person-years after 12 months on ART.
"The model-estimated TB hazard ratio for ART was 0.51 (95 percent CI 0.27-0.94). For HIV-infected children in TB-endemic areas, ART reduces the hazard of developing TB by 50 percent," the authors concluded.