Substance use and sexual transmission risk behavior of HIV-positive men who have sex with men.

We examined substance use in relationship to transmission risk behavior (unprotected insertive, UIAI, or receptive anal intercourse, URAI) between HIV-positive men who have sex with men (MSM) and their HIV-negative or unknown serostatus partners. Men who engaged in transmission risk behavior with casual partners were more likely than men who did not engage in such behavior to have used various substances. Users of certain drugs were specifically less likely to use condoms with HIV-negative or unknown status partners than users. Of men who drank alcohol, those who drank more frequently before or during sex engaged in significantly more UIAI with casual partners. Of men who used drugs, those who used more frequently before or during sex were more likely to engage in URAI with casual partners. In multivariate analyses, use of inhalants as well as drinking before or during sex predicted UIAI, while use of inhalants as well as noninjection drug use before or during sex predicted URAI. HIV prevention programs for HIV-positive MSM should focus on decreasing substance use and use specifically before or during sex. Developing prevention programs for substance-using MSM is critical to improve community health and decrease HIV transmissions.