Pre-Exposure Prophylaxis Adherence and HIV Self-Testing App Among Women in the South Bronx: 12-Month Usability, Acceptability, and Feasibility Study.

Background: HIV pre-exposure prophylaxis (PrEP) is underused by cis- and transgender women despite a significant HIV burden. Smartphone technologies are promising tools to support HIV prevention but have yet to be assessed in women. Objective: We conducted a 12-month feasibility study to assess the use and acceptability of a mobile phone app, SmartPrEP, designed to support PrEP adherence and HIV self- and partner-testing among women living in an area of elevated HIV burden in New York City. Methods: Nonpregnant adult cisgender and transgender women who met US PrEP eligibility criteria and were PrEP naïve, reported PrEP use for <3 months, or had inconsistent PrEP use were eligible. Participants received oral PrEP and HIV self-testing kits and downloaded the SmartPrEP app, which sent daily reminders to take PrEP and record adherence through the app. PrEP adherence was assessed based on participants' self-recorded average doses per week as entered in the app. Sexual behaviors and app acceptability were evaluated quarterly by interviewer-administered questionnaires. Results: From February 2022 to August 2023, 40 participants were enrolled in the study. Median age was 30 (IQR 24-35) years, 70% (28/40) identified as cisgender women, 30% (12/40) as transgender women, 48% (19/40) as Hispanic, and 35% (14/40) as Black. At baseline, the majority, 80% (32/40), had no history of PrEP use, and 65% (26/40) reported that they did not believe they were at risk of HIV. However, 90% (36/40) reported ≥1 and 25% (10/40) reported >4 HIV risk behaviors in the past 6 months, with 58% (23/40) reporting anal or vaginal sex with more than 1 partner. Over the course of the study, although 8 participants withdrew early, and 14 were lost to follow-up, there were 2 pregnancies and 1 HIV seroconversion. PrEP adherence was low, with 80% (32/40) recording <3 doses per week, 17% (7/40) recording 3-5 doses, and 3% (1/40) recording ≥6 doses per week. PrEP adherence averaged over the second half of study participation was lower than adherence in the first half, with only 10% (4/40) recording >3 doses per week compared to 20% (8/40). In total, 4 participants conducted HIV self- or partner-testing using SmartPrEP during study follow-up. App acceptability assessed at month 12 was moderate to high (median score 3.71 of max 5, IQR 3.47-4.16). Conclusions: Despite consistently rating the app as acceptable and receiving quarterly HIV testing and counseling, most participants did not achieve optimal PrEP adherence, demonstrating the limitations of this mobile health app among women at elevated risk of HIV. Active navigation and strategies to address gaps in risk perception among women will remain critical, as new, long-acting formulations of PrEP become available.