Abstract
BACKGROUND: Medication adherence is the key to success of HIV pre-exposure prophylaxis (PrEP). In China, the majority of real-world users purchase PrEP through e-commerce platforms, yet their adherence remains unaddressed. This cohort study aimed to evaluate PrEP adherence and its associated factors among e-consumers in China. METHODS AND FINDINGS: Eligible participants who had purchased PrEP online in the past 3 months were enrolled in the Real-world E-consumer Cohort of PrEP (RECOPE) in December 2023. Anonymous self-administered e-questionnaires were used at baseline and 1-, 3-, and 6-month follow-ups to collect data on PrEP adherence and potentially associated factors. Optimal adherence was defined as full compliance with the '2-1-1' dosing protocol for event-driven (ED) users and no missed pills in the past month for daily users. Generalized linear mixed-effects models and logistic regression were fitted to identify prognostic factors of PrEP adherence. Of 877 individuals invited, 680 were eligible and 657 completed the baseline survey (response rate 96.6%). The follow-up response rate at the 1-, 3-, and 6-month timepoints was 90.1% (592/657), 82.6% (543/657), and 80.1% (526/657), respectively. Among the 621 participants who had initiated PrEP at baseline, 529 (85.2%) used the ED regimen, and 92 (14.8%) used the daily regimen. Among ED users, the prevalence of optimal adherence at the four timepoints was 41.3% (154/373), 43.1% (146/339), 45.3% (139/307), and 52.6% (160/304), respectively. Among daily users, the prevalence of optimal adherence was 83.7% (77/92), 81.4% (83/102), 87.8% (86/98), 84.3% (75/89) at each survey wave, respectively. Within this group, the mean adherence rates in the past month ranged from 97.1% to 98.7% across waves. Among ED users, older age, receptive or versatile sexual role, and higher self-efficacy were positively associated with optimal adherence, while multiple same-sex partners, chemsex, and PrEP-related stigma were negatively associated factors. Selection bias, recall bias, social desirability bias, confounding bias, and limited representativeness were the main limitations of the study. CONCLUSION: The study found PrEP adherence was low among ED PrEP users who account for the majority of real-world e-consumers in China. Targeted interventions are suggested to prioritize enhancing users' understanding of medication instructions, promoting self-efficacy of maintaining adherence, and alleviating PrEP-related stigma. Additional attention should be given to ED users who have chemsex, insertive anal sex, multiple sexual partners, or a younger age.