Evidence of an explosive epidemic of HIV infection in a cohort of men who have sex with men in Thailand

Objective: To assess HIV-prevalence, incidence and risk factors in a cohort of men who have sex with men (MSM) in Bangkok. Design: Cohort study with 4-monthly follow-up visits conducted between April 2006 and July 2012 at a dedicated study clinic in a central Bangkok hospital. Participants were 1744 homosexually active Thai men, at least 18 years old and residents of Bangkok. Methods: Men were tested for HIV-infection at every study visit and for sexually transmitted infections at baseline. Demographic and behavioural data were collected by audio-computer-assisted self-interview. Logistic regression analysis was used to evaluate risk factors for HIV-prevalence and Cox proportional hazard analysis to evaluate risk factors for HIV-incidence. Results: Baseline HIV-prevalence was 21.3% (n = 372) and 60 months cumulative HIV- incidence was 23.9% (n = 222). Overall HIV-incidence density was 5.9 per 100 person-years. Multivariate risk factors for HIV- prevalence were older age, secondary/vocational education (vs. university or higher), employed or unemployed (vs. studying), nitrate inhalation, drug use for sexual pleasure, receptive anal intercourse, history of sexual coercion, no prior HIV- testing, and anti-HSV-1 and 2 and Treponema pallidum positivity at baseline. Multivariate risk factors for HIV- incidence were younger age, living alone or with roommate (vs. with a partner or family), drug use for sexual pleasure, inconsistent condom use, receptive anal intercourse, group sex, and anti-HSV-1 and 2 and T. pallidum positivity at baseline. Having no anal intercourse partners was inversely associated with HIV- incidence. Conclusion: The high HIV prevalence and incidence in this cohort of Bangkok MSM documents an explosive epidemic. Additional preventive interventions for MSM are urgently needed. (C) 2013 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins AIDS 2013, 27:825-832