Effect of HIV-1 infection on antimalarial treatment outcomes in Uganda: a population-based study.

BACKGROUND: Human immunodeficiency virus (HIV) infection may increase the burden of malaria by increasing susceptibility to infection or by decreasing the response to antimalarial treatment. We investigated the seroprevalence rate of HIV-1 infection and its effect on antimalarial treatment outcomes in adults and children with uncomplicated falciparum malaria in Uganda. METHODS: This retrospective study included 1965 patients > or =18 months old who were randomized to receive 1 of 3 antimalarial regimens at 7 sites in Uganda. HIV-1 testing was performed using 2 enzyme-linked immunosorbent assays and Western blot analysis of stored blood spots. The primary study outcome was clinical treatment failure at 28 days after antimalarial treatment. Molecular genotyping was used to distinguish clinical treatment failures due to new infections from those due to recrudescences. RESULTS: The HIV-1 seroprevalence rate was 2.5% in 1802 patients <18 years old and 31% in 163 patients > or =18 years old presenting with malaria. HIV-1 infection was associated with a >3-fold (hazard ratio [HR], 3.28 [95% confidence interval [CI], 1.25-8.59]) increased risk of clinical treatment failure for adults, but there was no increased risk for HIV-1-infected children. Molecular genotyping revealed that clinical treatment failures were due to new infections (HR, 6.35 [95% CI, 1.64-24.5]) rather than to recrudescences (HR, 1.51 [95% CI, 0.27-8.58]). CONCLUSIONS: The HIV-1 seroprevalence rate was surprisingly high in adults presenting with malaria. This finding supports the implementation of routine HIV counseling and testing for adults with uncomplicated falciparum malaria. HIV-1 infection increased the susceptibility to new malarial infections but did not increase the risk of recrudescences in adults.