Factors associated with discontinuation rate in clinical follow-up among men who have sex with men (MSM) using pre-exposure prophylaxis (PrEP) in Taiwan: A prospective cohort study

Abstract

Introduction

Event-driven dosing is the preferred option for oral PrEP among MSM in Taiwan. Lost to follow-up and discontinuation can be barriers to PrEP upscale in real life, yet most studies included daily users only. This study aimed to investigate the discontinuation of PrEP in clinical follow-up and associated factors among different PrEP dosing regimen users.

Material and Methods

Adult MSM receiving PrEP service at a medical center in southern Taiwan were enrolled prospectively in 2018-2023. Questionnaires were completed at each clinical visit. Participants were categorized into three groups based on the overall percentage of self-reported daily PrEP use during all visits for each person: “majorly daily” (≥75% of daily use), “switch”, and “majorly event-driven” (≤25%). PrEP discontinuation, defined as having no clinical visit for over 6 months, was analyzed using the Kaplan-Meier method and log-rank test comparing differences among dosing regimen groups. Cox proportional hazards models identified associations between PrEP users' characteristics and the first PrEP discontinuation.

Results

A total of 301 MSM were included (median age: 29 years), and 66.1% majorly used event-driven PrEP. The median time to first discontinuation for all participants was 209 days. In the PrEP discontinuation multivariable model, the “majorly event-driven” users were more likely to be lost to follow-up than “majorly daily” users (hazard ratio [HR]=1.77, 95% CI=1.08-2.90), and the “switch” group is less likely to discontinue than the “majorly daily” group (HR=0.22, 95% CI=0.06-0.73). PrEP users self-reporting sexually transmitted infections and self-paid for PrEP were also more likely to discontinue.

Discussion

Event-driven PrEP users demonstrate lower clinical follow-up rate in Taiwan. Differentiated service delivery better-tailoring resources to users’ demand should be developed. Clinicians should also be cautioned for PrEP users with higher HIV risk yet discontinuing PrEP clinical follow-up regardless of the dosing regimen.