Optimizing PrEP Adherence: The Role of User Engagement in a Digital Health Intervention (Preprint)
Authors: HightowWeidman Lisa , Choi Seul-Ki , Yigit Ibrahim , Rainer Crissi , Phillips Victoria , Muessig Kathryn 
Published: October 2024

BACKGROUND

Although highly effective HIV pre-exposure prophylaxis (PrEP) is available, its usage and adherence among young men who have sex with men and young transgender women remain low, reducing its overall effectiveness. While digital tools are promising strategies to impact PrEP adherence, engagement in these interventions is often low, limiting their efficacy at changing health behaviors. We conducted a three-arm randomized clinical trial of Prepared, Protected, emPowered (P3) a comprehensive PrEP adherence digital health intervention compared to an enhanced version, P3+, which incorporates in-app adherence coaching.

OBJECTIVE

This paper seeks to analyze data P3/P3+ study participants to understand how different levels of user engagement with the app's features were associated with adherence to PrEP as well as the costs of each intervention.

METHODS

Descriptive statistics for study variables at baseline were calculated. To examine the differences in intervention engagement and acceptability by arm, independent samples t-tests for continuous variables and a chi-square analysis for categorical variables were conducted. To examine the effect of arm and engagement categories on PrEP adherence at 3-months, three logistic regression analyses were conducted: 1) the effect of arm on PrEP adherence, 2) the effect of engagement categories (high vs. moderate and low) on PrEP adherence, and 3) the interaction effect of arm and engagement categories on PrEP adherence, along with the main effects of arm and engagement categories. We adopted a provider perspective and estimated the costs of P3/P3+ implementation in a community setting using activity-based costing.

RESULTS

A total of 163 participants were randomized to the P3 intervention (82 to the P3 arm and 81 to the P3+ arm). Participants in the P3+ arm earned higher incentives ($90.6 vs. $75.4; p=.038), had more app log-ins (96.6 vs 76.1; p=.013), used the app on more days (63.3 days vs. 53.2 days; p=.037), and spent more time in the intervention (378.8 minutes vs. 186.66 minutes; p<.001) compared to those in the P3 arm. There was no significant association between intervention arm and PrEP adherence at 3-months (p=.989). Engagement category (high vs. mod/low) was significantly associated with PrEP adherence at 3-months (p=.003). The average total monthly cost of P3 was $1118 (305.1). Additional average monthly costs for on-going management of the P3+ coaching intervention were $1200 (60.0).

CONCLUSIONS

This study highlights the critical role of user engagement in enhancing PrEP adherence among young individuals at high risk for HIV. While the P3+ intervention led to increased engagement, this did not translate into significantly better adherence compared to the standard P3 arm. This, coupled with the increased cost and complexity of P3+ delivery, indicates that further studies are necessary to determine whether this intensified intervention is the appropriate fit.

CLINICALTRIAL

NCT03320512

INTERNATIONAL REGISTERED REPORT

RR2-10.2196/10448