RESEARCH ARTICLE High HIV Burden in Men Who Have Sex with Men across Colombia’s Largest Cities: Findings from an Integrated Biological and Behavioral Surveillance Study

Background Among Latin America’s concentrated HIV epidemics, little is known about men who have sex with men (MSM) in Colombia, the region’s third largest country. To date, surveillance studies have been limited to Bogota, while 80 % of HIV cases and deaths originate from Colombia’s other cities and departments. The extent to which interventions should prioritize MSM outside of Bogota is unknown. Methods We recruited 2603 MSM using respondent-driven sampling from seven of Colombia’s larg-est cities. HIV prevalence was estimated by site from dried blood spot samples. Behavioral data were collected through face-to-face interviews and risk factors for HIV infection ana-lyzed using weighted, multi-level logistical regression models accounting for recruitment patterns. Results Across cities, HIV prevalence averaged 15%, varied from 6 % to 24 % and was highest in Cali, Bogota, and Barranquilla. In the past 12 months, 65 % of MSM had 5 casual male partners and 23 % had a female partner. Across partnerships (i.e., casual, stable, and com-mercial), the proportion of MSM engaging in unprotected sex was 52 % with male partners and 66 % with female partners. Self-reported history of STI (24%) and past-year illicit drug use (38%) were also common. In multivariate analysis, age 35 (adjusted odds ratio [AOR], 19.2) and 25–39 (AOR, 5.6) relative to 18–24 years, identifying as homosexual relative to heterosexual (AOR 0.1), meeting casual partners on the Internet (adjusted odd