Factors associated with unprotected anal intercourse between HIV-positive men and regular male partners in a Sydney cohort.

Blood plasma HIV-RNA load (BPVL) is the strongest predictor of HIV-1 transmission during sex. Unprotected anal intercourse (UAI) is the highest risk activity for transmission among men who have sex with men (MSM). Awareness of BPVL may influence rates of UAI. We assessed whether optimism towards antiretroviral therapy (ART) and/or biomedical factors influenced sexual activities with regular partners. Questionnaires were administered to 109 HIV-positive MSM participating in a cross-sectional study of BPVL and seminal viral load. The survey assessed HIV transmission beliefs and sexual practices with regular male partners in the past three months. Sixty-nine of 109 (63.3%) had been in a regular relationship and 42 reported having had anal sex. Unprotected receptive anal intercourse without ejaculation (URAI - e) was associated with awareness that their most recent BPVL was detectable (>50 RNA copies/mL) and not taking ART. Receptive UAI with ejaculation (URAI + e) was associated with not taking ART, having a sexually transmissible infection and having an HIV-positive partner; the latter was also associated with insertive UAI with ejaculation (UIAI + e). Treatment optimism was not associated with UAI. In this cohort, sexual practices were based more upon knowledge of biomedical factors rather than attitudes regarding transmission risks.