Tuberculosis after one year of combination antiretroviral therapy in Nigeria: a retrospective cohort study.

Our objective was to determine tuberculosis (TB) incidence and evaluate TB risk in adults after one or more years of use of combination antiretroviral therapy (cART) through a retrospective cohort study in Jos, Nigeria. We studied a cohort of HIV-infected adults treated with ART for at least 1 year. Based on immunologic and virologic responses to ART, patients were categorized into four groups: CD4 T cell count ≥350 cells/mm(3) and HIV-1 RNA level ≤400 copies/ml (group 1), CD4 T cell count ≥350 cells/mm(3) and HIV-1 RNA level >400 copies/ml (group 2), CD4 T cell count <350 cells/mm(3) and HIV-1 RNA level ≤400 copies/ml (group 3), and CD4 T cell count <350 cells/mm(3) and HIV-1 RNA level >400 copies/ml (group 4). Time to incident TB for the four groups was analyzed using the Kaplan-Meier method. Cox regression models were used to evaluate predictors of incident TB. In this cohort of 5,093 HIV-infected adults, of which 68.4% were female, with a mean age 35.1 years (standard deviation 9.1 years), we observed 98 cases of incident TB during 4 years and 3 months of follow-up. The overall TB incidence rate was 8.7 cases/1,000 patient-years of follow-up. Adjusted hazards for incident TB were 2.11 (95% CI 0.97-4.61), 2.05 (95% CI 1.10-3.79), and 3.65 (95% CI 1.15-5.06) in group 2, 3, and 4 patients, respectively, compared to group 1. Tuberculosis incidence in patients on ART is driven by poor immunologic and/or virologic response. Optimization of HIV treatment should be prioritized to reduce the burden of TB in this high-risk population.