Outpatient-Based Opioid Treatment Engagement and Attendance: A Prospective Cohort Study of Homeless-Experienced Adults.

Abstract

The opioid overdose epidemic disproportionately impacts people experiencing homelessness. Outpatient-based opioid treatment (OBOT) programs have been established in homeless health care settings across the USA, but little is known about the success of these programs in engaging and retaining this highly marginalized patient population in addiction care. To evaluate predictors of initial engagement and subsequent attendance in a homeless-tailored OBOT program. Prospective cohort study with 4months of follow-up. A total of 148 homeless-experienced adults (≥18years) who newly enrolled in the Boston Healthcare for the Homeless Program (BHCHP) OBOT program over a 1-year period (1/6/2022-1/5/2023). The primary outcomes were (1) initial OBOT program engagement, defined as having ≥2 additional OBOT visits within 1month of OBOT enrollment, and (2) subsequent OBOT program attendance, measured monthly from months 2 to 4 of follow-up. The average age was 41.7years (SD 10.2); 23.6% were female, 35.8% were Hispanic, 12.8% were non-Hispanic Black, and 43.9% were non-Hispanic White. Over one-half (57.4%) were initially engaged. OBOT program attendances during months 2, 3, and 4 were 60.8%, 50.0%, and 41.2%, respectively. One-quarter (24.3%) were initially engaged and then attended the OBOT program every month during the follow-up period. Participants in housing or residential treatment programs (vs. unhoused; adjusted odds ratios (aORs) = 2.52; 95% CI = 1.17-5.44) and those who were already on or initiated a medication for opioid use disorder (OUD) (aOR = 6.53; 95% CI = 1.62-26.25) at the time of OBOT enrollment had higher odds of engagement. Older age (aOR = 1.74 per 10-year increment; 95% CI = 1.28-2.38) and initial engagement (aOR = 3.50; 95% CI = 1.86-6.59) conferred higher odds of attendance. In this study, over half initially engaged with the OBOT program, with initial engagement emerging as a strong predictor of subsequent OBOT program attendance. Interventions aimed at enhancing initial OBOT program engagement, including those focused on housing and buprenorphine initiation, may improve longer-term outcomes in this marginalized population.