Leveraging A Digital Pill System to Understand Prevention-Effective Adherence to Oral Hiv Pre-Exposure Prophylaxis Among Men Who Have Sex with Men with Substance Use.

Daily oral pre-exposure prophylaxis (PrEP) is highly effective for HIV prevention, though efficacy depends on adherence. Digital pill systems (DPS) can enable direct, real-time adherence measurement. HIV-negative men who have sex with men (MSM) with substance use (excluding alcohol) utilized a DPS over 90 days and completed weekly surveys reporting sexual activity, condom use, and substance use. Responses indicating (1) any sexual activity and substance use or (2) condomless anal intercourse (CAI) in the prior week were categorized as high risk for HIV acquisition. PrEP adherence data for the 7-day period preceding each response was dichotomized as ≤ 3 and ≥ 4 doses/week, indicating prevention-effective adherence, and compared by HIV risk level. Thirteen MSM were analyzed (median age: 32). Of 113 surveys, 48.7% indicated high HIV risk, with 12.4% reporting CAI alone, 16.8% any sexual activity and substance use, and 19.5% both CAI and substance use. Weekly mean PrEP adherence was 90.3% (6.3 of 7 doses/week), with ≥ 4 doses/week recorded during 92.0% of weeks. The proportion of participants with ≥ 4 recorded doses/week was 88.9% during weeks with CAI alone, 89.5% during weeks with any sexual activity and substance use, 92.0% during weeks with both CAI and substance use, and 92.8% during lower risk weeks. Participants ingested ≥ 4 doses/week during 89.1% of all high-risk weeks and 94.8% of low-risk weeks. Overall, participants maintained high levels of PrEP adherence while engaging in HIV risk behaviors. DPS can be deployed concurrently with data collection tools to assess ingestion patterns during periods of elevated risk.

Real-World Implementation Challenges Associated with a Digital Pill System to Measure Adherence to HIV Pre-Exposure Prophylaxis from Two Studies of Men Who Have Sex With Men.

Once-daily oral pre-exposure prophylaxis (PrEP) is highly effective for HIV prevention, but its efficacy is dependent on adherence, which can be challenging for men who have sex with men (MSM) with substance use. Digital pill systems (DPS) represent a novel tool for directly measuring adherence through ingestible radiofrequency sensors that confirm ingestions in real-time. We examined operational challenges across two studies involving DPS to measure PrEP adherence. While most participants successfully operated the system, a number of technological and sociobehavioral challenges requiring intervention were identified across both studies. Technological issues were both system- and participant-related, and were primarily addressed with technical updates and participant re-education, while sociobehavioral issues, including health and housing changes and issues with technology access, warranted innovative solutions. Future research leveraging DPS technology should develop robust supportive infrastructure and mitigation procedures to promptly identify and resolve operational issues to optimize the potential benefits of DPS use.