Perceived HIV risk, actual sexual HIV risk and willingness to take pre-exposure prophylaxis among men who have sex with men in Toronto, Canada.

Pre-exposure prophylaxis (PrEP) reduces HIV acquisition. Our goal was to determine the willingness of men who have sex with men (MSM) to take PrEP given perceived and actual HIV risk. HIV-negative MSM were recruited from September 2010 to June 2012 and asked about PrEP willingness and perceived HIV risk. Actual sexual HIV risk was measured by three condom-use components generated through principal components analysis. General HIV risk was measured using the HIV Incidence Risk Index for MSM (HIRI-MSM). Model 1 measured PrEP willingness given perceived and actual sexual HIV risk. Model 2 included actual HIV sexual risk, perceived HIV risk and general HIV risk. Model 3 removed actual sexual HIV risk. We recruited 150 HIV-negative MSM. About 55% were willing to take PrEP. Reasons for PrEP unwillingness were: low perceived risk (64%), side-effect concerns (44%), daily pill burden (16%) and efficacy concerns (4%). Model 1: MSM with high compared to low actual sexual HIV risk were more willing to use PrEP (OR 27.11, 95% CI 1.33-554.43) after adjusting for perceived risk, which was not significantly associated with PrEP willingness (OR 4.79, 95% CI 0.72-31.96). Model 2: MSM with high compared to low actual sexual HIV risk were more willing to use PrEP (OR 29.85, 95% CI 1.39-640.53) after adjusting for perceived and general HIV risk, neither of which was significantly associated with PrEP willingness (OR 5.07, 95% CI 0.73-35.09) and (OR 1.58, 95% CI 0.37-6.79), respectively. Model 3: After removing actual sexual HIV risk, MSM with high compared to low perceived risk were more willing to use PrEP (OR 6.85, 95% CI 1.23-38.05), and the HIRI-MSM general risk index was not associated with PrEP willingness (OR 1.87, 95% CI 0.54-6.54). Therefore, actual sexual HIV risk was the best predictor of PrEP willingness and general HIV risk did not inform PrEP willingness.