PrEP risk perception and adherence among men who have sex with men: a prospective cohort study based on growth mixture model

Background: It can be considered that pre-exposure prophylaxis (PrEP) risk perception is the negative experiences or concerns about taking PrEP. The aim of this study is to explore the longitudinal trajectory of PrEP risk perception among men who have sex with men (MSM) and its impact on adherence. Methods: : Data related to PrEP risk perception and adherence were derived from a prospective, open-label, cohort study in Western China from 2013 to 2015. Subjects who were divided into the medicine group took oral PrEP daily. The PrEP risk perception scale was constructed, and the growth mixture model (GMM) was used to classify PrEP risk perception. Finally, the effect of different levels of PrEP risk perception on drug adherence was explored using generalized estimating equations (GEE) with relative risk (RR) and 95% confidence interval (CI). Results: : The PrEP risk perception scale consists of 4 dimensions and 16 items with Cronbach's alpha=0.828 and a good model fit. According to the GMM analysis, the subjects' PrEP risk perceptions were separated into two groups: a "high risk perception-declining group" (n=133) and a "low risk perception-smooth group" (n=493), where the proportion of high levels of drug adherence were 57.89% and 68.35%, respectively (p=0.0237). High levels of PrEP risk perception in the MSM population hinder drug adherence (RR=0.6993, 95% CI: 0.4961 to 0.9856, p=0.0411). Conclusion: This study demonstrates that high levels of PrEP risk perception in the MSM population are an obstacle to drug adherence, emphasizing the necessity of focusing on PrEP risk perception in this population.