To determine whether attitudes towards highly active antiretroviral therapy (HAART) are associated with unprotected anal sex among sexually active homosexual men. Cross-sectional study nested within an ongoing prospective cohort study. Multicenter AIDS Cohort Study, from April through September 1999. Five-hundred and forty-seven homosexual men reporting anal sex (218 HIV-negative and 329 HIV-positive) during study interviews in 1999, including a 20-item validated scale on attitudes toward HAART and HIV risk behaviors (e.g., 'Because of HAART, I am less concerned about becoming HIV-infected or infecting someone'), and safer sex fatigue (e.g., 'I am tired of always having safer sex'). Self-reported unprotected receptive anal sex (RAS) and insertive anal sex (IAS) in the prior 6 months. More than 50% of HIV-negative and HIV-positive men who reported having anal sex also reported recent unprotected RAS and/or IAS. HIV-negative men who most agreed that HAART reduced concern about becoming infected were more likely to report unprotected RAS compared to other HIV-negative men [adjusted odds ratio (AOR), 3.31; 95% confidence interval (CI), 1.27-8.62]. Moreover, HIV-positive men with greatest reduced concern due to HAART or safer sex fatigue were more likely to report unprotected IAS (AOR, 6.05; 95% CI, 2.24-16.63 and AOR, 4.57; 95% CI, 1.70-12.24, respectively) compared to other HIV-positive men. Among sexually active homosexual men, lessened concern about HIV transmission due to HAART was strongly associated with sexual risk taking, as was safer sex fatigue among HIV-positive men. Prevention programs should take into account underlying attitudes for unprotected sex in the era of HAART among both HIV-infected and uninfected men.
