Relative risks and population attributable fraction of incident HIV associated with symptoms of sexually transmitted diseases and treatable symptomatic sexually transmitted diseases in Rakai District, Uganda

OBJECTIVES: To assess the linkage of sexually transmitted disease (STD) symptoms and treatable STD to HIV incidence. DESIGN: Analysis of a randomized trial of STD control for HIV prevention, Rakai, Uganda. METHODS: Consenting adults 15-59 years of age were seen at 10-monthly home visits, interviewed regarding STD symptoms, and asked to provide samples for HIV and STD diagnoses. HIV incidence was determined in 8089 HIV-negative subjects over 10 457 person years. Adjusted rate ratios (RR) and 95% confidence intervals (CI) of HIV acquisition associated with genital ulcer disease (GUD) and discharge/dysuria were used to estimate the population attributable fraction (PAF) of HIV acquisition. HIV transmission risks associated with STD symptoms in HIV-positive partners of 167 HIV discordant couples and the numbers of sexual partners reported by HIV-positive subjects were used to estimate the PAF of HIV transmission attributable to STD. RESULTS: HIV prevalence was 16%. The risk of HIV acquisition was increased with GUD (RR 3.14; CI 1.98-4.98) and in males with discharge/dysuria (RR 2.44; CI 1.17-5.12), but not in females with discharge/dysuria. The PAF of HIV acquisition was 9.5% (CI 2.8-15.8%) with any of the three STD symptoms. The PAF for GUD was 8.8% (CI 3.7-13.8), but only 8.2% of reported GUD was caused by treatable syphilis or chancroid . The PAF for discharge/dysuria in males was 6.7% (CI 1.1-13.8), but only 25% of symptomatic males had concurrent gonorrhea or chlamydial infection. No significant differences were seen in PAF between study treatment arms. The PAF of HIV transmission associated with STD symptoms in HIV-positive persons was indirectly estimated to be 10.4%. CONCLUSION: In this mature, generalized HIV epidemic setting, most HIV seroconversion occurs without recognized STD symptoms or curable STD detected by screening. Therefore, syndromic management or other strategies of STD treatment are unlikely to substantially reduce HIV incidence in this population. However, STD is associated with significant HIV risk at the individual level, and STD management is needed to protect individuals.