Patterns of mHealth Engagement and Identification of Facilitators and Barriers to Mobile Health Applications for People Who Use Opioids.

Mobile health (mHealth) applications represent low-cost, scalable interventions with broad reach and are valuable for people who use opioids (PWUO), a population that often experiences low retention in traditional research studies. This study examines engagement patterns with the OASIS app, an mHealth app prompting PWUO in Baltimore, Maryland, to report daily on substance use locations and overdose prevention behaviors over 14 days. Between December 2022 and September 2023, 210 PWUO participated. Engagement was measured by survey completion, with high engagement defined as completing at least 75% of surveys. The median number of surveys completed was 9.0 (mean: 7.57), and 29.4% of participants demonstrated high engagement. Logistic regression models showed that residential stability was significantly associated with higher engagement (adjusted odds ratio [aOR]: 4.90; 95% CI: 1.35, 17.84), while weekly or more frequent injection drug use was associated with lower engagement (aOR: 0.31; 95% CI: 0.11, 0.89). Mobile device proficiency and other demographics were not significantly associated with engagement, likely due to mandatory in-person training reducing tech barriers. Results indicate that PWUO can meaningfully engage with mHealth apps, especially when supported by structural factors, such as stable housing.