Abstract
Emergency departments (EDs) represent a critical point of contact for individuals with opioid use disorder (OUD). Initiation of buprenorphine, a medication for OUD, in the ED has been proposed as a strategy to improve engagement in ongoing treatment and reduce recurrent emergency care utilization; however, evidence across these outcomes has not been comprehensively synthesized. This systematic review aimed to qualitatively summarize the effectiveness of ED-initiated buprenorphine in improving treatment engagement and reducing subsequent ED utilization among adults with OUD. A systematic search of major biomedical databases identified randomized and observational studies evaluating buprenorphine initiation in the ED and reporting outcomes related to treatment engagement or return ED visits. Data were extracted using a standardized approach, and methodological quality was assessed using a validated appraisal tool. Due to heterogeneity in study designs and outcome measures, findings were synthesized qualitatively. Across included studies, ED-initiated buprenorphine was consistently associated with higher rates of engagement in OUD treatment within 30 days compared with referral or brief intervention alone. Evidence regarding reductions in subsequent ED utilization was mixed, with some studies demonstrating fewer opioid-related or all-cause ED return visits and others showing no significant differences, particularly over shorter follow-up periods. Social determinants of health, including housing stability, insurance status, and race, appeared to modify outcomes, and the presence of adjunctive ED-based services such as behavioral counseling and naloxone distribution was variably associated with improved engagement and reduced ED use. Overall, ED-initiated buprenorphine is an effective intervention for improving early treatment engagement among patients with OUD, while its impact on subsequent ED utilization appears context-dependent and influenced by social factors and the availability of supportive follow-up care.