Objective: To examine the predictors of transmission risk among HIV-infected men who have sex with men (MSM) in 4 US cities.
Method: Individual computer-assisted interviews assessing psychologic measures and sexual behavior with the 5 most recent male and female partners were conducted with a diverse sample of 1910 HIV-infected MSM recruited from community and clinic settings in San Francisco, New York, Los Angeles, and Milwaukee. Transmission-risk events were defined as unprotected vaginal or anal sex with a partner who was HIV negative or of unknown status.
Results: A small but not insignificant proportion of MSM (12.7%) reported at least 1 transmission-risk event in the previous 3 months, with 57% of those events taking place with casual as opposed to steady partners. Multivariate predictors of transmission risk with casual partners were stimulant (eg, crystal methamphetamine) and other drug use, having low coping self-efficacy, and not having disclosed one's HIV serostatus to all partners. Stimulant use and failing to disclosing one's serostatus to all partners were associated with risk in primary relationships.
Conclusions: Responding to HIV transmission risk in MSM requires different strategies for primary and casual partners.