Partner characteristics and undiagnosed HIV seropositivity among men who have sex with men only (MSMO) and men who have sex with men and women (MSMW) in Baltimore.

This study examined the relationship between HIV risk behaviors, partner characteristics, and undiagnosed seropositivity among men who have sex with men and women (MSMW) and men who have sex with men only (MSMO). BESURE-MSM2 is a venue-based cross-sectional HIV surveillance study conducted among MSM in 2008. Stratified log-binomial regression was used to assess adjusted prevalence ratios of undiagnosed seropositivity among 103 MSMW and 296 MSMO (N = 399). Among MSMO, race/ethnicity, age, having had a sexually transmitted infection, concurrency, and having a black/African American male partner were associated with undiagnosed seropositivity. Among MSMW, having five or more male partners, having a main male partner, and having a main female partner were associated with undiagnosed seropositivity. Our findings underscore the importance of partner characteristics in understanding HIV transmission. HIV programs for men with both male and female partners are needed to address the unique partnership dynamics of MSMW.