Development and Usability Testing of a Mobile Phone Based Intervention to Increase Knowledge and Uptake of PrEP Among Persons with Substance Use Disorders

Introduction: Pre-exposure prophylaxis (PrEP) has been shown to be an effective strategy to prevent HIV in people with substance use disorders. However, substance users tend to have limited knowledge about PrEP, and therefore, low rates of PrEP uptake. Mobile health (mHealth) applications (apps) have recently emerged as a promising platform for communicating health information and promoting positive changes in health behaviors. The purpose of this study is to develop and test the usability of a mobile phone based tool at increasing substance users’ knowledge about PrEP and self-efficacy to initiate PrEP.

Methods: Using the CommCare platform, we developed a user-centered app that features seven modules with information on: the basics of PrEP, considerations before starting PrEP, initiating PrEP, adhering to PrEP, reducing HIV risks, general health management, and PrEP-specific resources. The app underwent a first round of usability testing with substance users receiving services at a syringe exchange program. Findings informed revisions to the design and contents of the app, which underwent a second round of usability testing with substance users receiving services at an outpatient substance use disorder treatment program. Participants’ completed a post-study system usability questionnaire (PSSUQ).

Results: Participants in the first round of usability testing (n=5) were all male, 60% were over 50 years-old, and 60% identified as Black/African American. All participants had a lot of experience using mobile phones and 80% had heard of PrEP prior to this study. Participants found the content of the app informative and easy to understand, but most had issues with navigating the app. Mean PSSUQ score for overall satisfaction was 6.8 out of 7.0 (SD=0.45). Participants in the second round of usability testing (n=7) were mostly male, 43% identified as Hispanic, and the median age was 46 years-old. More than half of the participants had a lot of experience using mobile phones and 71% had heard of PrEP prior to the study. Participants found the content of the app to be informative and relevant, and previous problems with app navigation were resolved. Mean PSSUQ score for overall satisfaction was 6.7 (SD=0.52).

Conclusion: Our mHealth tool for PrEP was usable, and can be a viable strategy to addressing substance users’ barriers to knowledge about PrEP and PrEP initiation. mHealth tools should focus on having user interfaces that are easy to navigate by target populations while maintaining the integrity of content.