Impact of antiretroviral therapy on adult HIV prevalence in a low-income rural setting in Uganda: a longitudinal population-based study.

OBJECTIVE: To estimate the contribution to HIV prevalence of lives saved due to the introduction of antiretroviral therapy (ART) in rural Uganda in 2004. DESIGN: Open population-based cohort study. METHODS: An open general population cohort with annual demographic and HIV serostatus data is used to estimate annual HIV prevalence, HIV incidence, and mortality from 2000 to 2010. We calculated standardized mortality rates among HIV-positive adults and the expected number of deaths in the cohort if ART had not been available during 2004-2010, based on the average mortality rate in the 4 years (2000-2003) before ART introduction. RESULTS: During 2004-2010, the estimated prevalence increased by 29% from 6.9% to 8.9%. HIV incidence was 5.6 cases per 1000 person-years in 2004, falling to 3.9 cases per 1000 person-years in 2006, and slightly rising to 5.1 in 2010. There was an increase of 182 in the number of HIV-positive participants during that period, cumulatively 228 lives were saved due to ART. Expected lives saved due to ART accounted for an increasing proportion of the estimated HIV prevalence from 4.0% in 2004 to 29.4% in 2010. CONCLUSIONS: Expected lives saved due to ART largely accounted for the increased estimated HIV prevalence from 2004 to 2010. Because HIV prevalence survey results are important for planning, programming, and policy, their interpretation requires consideration of the increasing impact of ART in decreasing mortality.