Background Hospitalizations due to medical and surgical complications of substance use disorder (SUD) are rising. Most hospitals lack systems to treat SUD, and most people with SUD do not engage in treatment after discharge. Objective Determine the effect of a hospital-based addiction medicine consult service, the Improving Addiction Care Team (IMPACT), on post-hospital SUD treatment engagement. Design Cohort study using multivariable analysis of Oregon Medicaid claims comparing IMPACT patients with propensity-matched controls. Participants 18–64-year-old Oregon Medicaid beneficiaries with SUD, hospitalized at an Oregon hospital between July 1, 2015, and September 30, 2016. IMPACT patients (n = 208) were matched to controls (n = 416) using a propensity score that accounted for SUD, gender, age, race, residence region, and diagnoses. Interventions IMPACT included hospital-based consultation care from an interdisciplinary team of addiction medicine physicians, social workers, and peers with lived experience in recovery. IMPACT met patients during hospitalization; offered pharmacotherapy, behavioral treatments, and harm reduction services; and supported linkages to SUD treatment after discharge. Outcomes Healthcare Effectiveness Data and Information Set (HEDIS) measure of SUD treatment engagement, defined as two or more claims on two separate days for SUD care within 34 days of discharge. Results Only 17.2% of all patients were engaged in SUD treatment before hospitalization. IMPACT patients engaged in SUD treatment following discharge more frequently than controls (38.9% vs. 23.3%, p \u3c 0.01; aOR 2.15, 95% confidence interval [CI] 1.29–3.58). IMPACT participation remained associated with SUD treatment engagement when limiting the sample to people who were not engaged in treatment prior to hospitalization (aOR 2.63; 95% CI 1.46–4.72). Conclusions Hospital-based addiction medicine consultation can improve SUD treatment engagement, which is associated with reduced substance use, mortality, and other important clinical outcomes. National expansion of such models represents an opportunity to address an enduring gap in the SUD treatment continuum
