Emergency Department Access to Buprenorphine for Opioid Use Disorder.

Importance: Although substantial evidence supports buprenorphine for treatment of opioid use disorder (OUD) in controlled trials, prospective study of patient outcomes in clinical implementation of emergency department (ED) buprenorphine treatment is lacking. Objective: To examine the association between buprenorphine treatment in the ED and follow-up engagement in OUD treatment 1 month later. Design, Setting, and Participants: This multisite cohort study was conducted in 7 California EDs participating in a statewide implementation project to improve access to buprenorphine treatment. The study population included ED patients aged at least 18 years identified with OUD between April 1, 2021, and June 30, 2022. Data analysis was performed in October 2023. Exposure: All participants were offered buprenorphine treatment for OUD (either in ED administration, prescription, or both), the uptake of which was examined as the exposure of interest. Main Outcomes and Measures: The primary outcome was engagement in OUD treatment 30 days after the ED visit, determined by patient report or clinical documentation. The association of ED buprenorphine treatment with subsequent OUD treatment engagement was estimated using hierarchical generalized linear models. Results: This analysis included 464 ED patients with OUD. Their median age was 36.0 (IQR, 29.0-38.7) years, and most were men (343 [73.9%]). With regard to race and ethnicity, 64 patients (13.8%) self-identified as non-Hispanic Black, 183 (39.4%) as Hispanic, and 185 as non-Hispanic White (39.9%). Most patients (396 [85.3%]) had Medicaid insurance, and more than half (262 [57.8%]) had unstable housing. Self-reported fentanyl use (242 [52.2%]) and a comorbid mental health condition (328 [71.5%]) were common. Interest in buprenorphine treatment was high: 398 patients (85.8%) received buprenorphine treatment; 269 (58.0%) were administered buprenorphine in the ED and 339 (73.1%) were prescribed buprenorphine. With regard to OUD treatment engagement at 30 days after the ED visit, 198 participants (49.7%) who received ED buprenorphine treatment remained engaged compared with 15 participants (22.7%) who did not receive ED buprenorphine treatment. An association of ED buprenorphine treatment with subsequent OUD treatment engagement at 30 days was observed (adjusted risk ratio, 1.97 [95% CI, 1.27-3.07]). Conclusions and Relevance: The findings of this cohort study suggest that among patients with OUD presenting to EDs implementing low-threshold access to medications for OUD, buprenorphine treatment was associated with a substantially higher likelihood of follow-up treatment engagement 1 month later. Future research should investigate techniques to optimize both the uptake and effectiveness of buprenorphine initiation in low-threshold settings such as the ED.