Can a participant-referred ‘study buddy’ increase retention of rural people who use drugs in research? A multi-site, randomized trial

Aims: To test the efficacy of a participant-referred “study buddy” intervention compared with standard retention strategies in retaining rural people who use drugs (PWUD) in longitudinal research. Design: Multi-site, two-arm, randomized controlled trial. Setting: Rural counties in Ohio, Oregon, and Kentucky, USA. Participants: People enrolled in the Peer-based Retention Of people who Use Drugs in Rural Research (PROUD-R²) study who were 18 years or older, resided in the study area, and used opioids or injected any drug to get high in the past 30 days between August 2020 and August 2022. Participants (n = 739) were 42% female, mostly White (89%) and non-Hispanic (96%), unstably housed (57%), and reported lifetime injection drug use (93%). The most common drugs of choice were methamphetamine (42%) and heroin (38%). Intervention and Comparator: Participants were allocated (1:1, stratified by site), to: [1] standard retention approach involving appointment reminders and contact information updates by study staff (n = 365), or [2] the intervention arm, receiving the standard retention approach and asked to recruit a “study buddy” (n = 374). Study buddies were invited to view a training video and instructed to encourage their intervention participant to attend follow-up appointments. Measurements: Intervention, control, and study buddy participants completed interviewer-administered surveys at baseline and at 6 and 12 months. Outcomes included retention at 12 months (primary) and 6 months (secondary). Findings: Retention was 50.3% at 6 months and 46.1% at 12 months. Only 23.5% of intervention participants recruited a study buddy. In intent-to-treat analyses, the intervention did not increase retention at 12 (adjusted odds ratio [AOR] 1.08, 95% confidence interval [CI] 0.79–1.47) or 6 (AOR 0.96, 95% CI 0.69–1.34) months. Conclusions: Recruitment of self-identified “study buddies” did not appear to statistically significantly improve retention of rural people who use drugs in this longitudinal study at 6- and 12-month follow-up relative to standard retention approaches.