A mobile application to collect daily data on pre-exposure prophylaxis adherence and sexual behaviour among men who have sex with men: use over time and comparability with conventional data collection.

We studied the use of a mobile application (app) to measure HIV Pre-Exposure Prophylaxis (PrEP) adherence and sexual behaviour, assessed determinants of app use, and we compared data in app and questionnaires. Men who have sex with men (MSM) participating in the Amsterdam PrEP project (AMPrEP) on daily or event-driven PrEP at the Public Health Service of Amsterdam completed data on sexual risk behaviour and PrEP adherence through three-monthly standard questionnaires and on a daily basis using the project's app. Regression analyses were used to assess factors associated with app use. Among those who reported ≥90% of data in the app, the number of PrEP pills taken and number of unknown casual sex partners were compared between the app and the questionnaires by Wilcoxon signed-rank test. Of all participants (n=374), 94% (352/374) reported data in the app at least once; 72% (261/362) reported data ≥90% of the days in the sixth month and 62% (222/359) in the 12th month following PrEP initiation.Factors associated with reporting data in the app were using daily PrEP and recent initiation of PrEP. The reported numbers of pills taken and unknown sexual partners were comparable between app and questionnaires. The AMPrEP app was used frequently, especially by those using a daily PrEP regimen. Data collected by app regarding adherence and sexual risk behaviour were consistent with questionnaire data among those who used the app consistently. An app is a promising tool to measure PrEP adherence and sexual risk behaviour.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.