Abstract
BACKGROUND: Pre-exposure prophylaxis (PrEP) has been effective in reducing HIV transmission in men who have sex with men (MSM). The effectiveness of PrEP is closely related to adherence, whether taken daily or on-demand. In China, there are few studies on PrEP adherence in MSM. METHODS: An online survey was conducted on the Heer Health Platform from July 6 to August 30, 2022. Participants were recruited through private messages sent to users who had purchased PrEP on the platform. The primary outcome was the proportion of daily and on-demand PrEP usage. Secondary outcomes included the proportions of high and low adherence to daily and on-demand PrEP among MSM. Univariate analyses were performed using the chi-square test or fisher's exact test, followed by multivariate logistic regression to identify factors associated with PrEP adherence. RESULTS: Among 384 participants, comprising 321 (83.6%) on-demand and 63 (16.4%) daily PrEP users. High adherence was observed in all daily users (100%) versus 81.9% (263) of on-demand users. During their last on-demand PrEP cycle, 8.7% (28/321) did not take the third pill on time, with 60.7% (17/28) delayed by over 2 h. 10.6% (34/321) missed the fourth pill, with 76.5% (26/34) delayed exceeded 2 h. Primary reasons were forgetting and busy schedules. Multivariable logistic regression identified three independent predictors of high adherence among on-demand PrEP users, including regular follow-up during PrEP use, having an HIV-positive sexual partner not on antiretroviral therapy and PrEP consultation (P < 0.05). Besides, statistically significant differences were found in variables such as sexuality, regular follow-up while taking PrEP, the number of male sexual partners in the last six months, the HIV status of the most recent male sexual partner in the past six months, and perceived HIV infection risk between the high adherence groups of on-demand and daily PrEP (P < 0.05). CONCLUSIONS: Government and health authorities should continue to increase awareness and promotion of PrEP and condoms use among MSM. Emphasizing the importance of non-missing dose resolutions and regular follow-up can help improve PrEP adherence among MSM.