Association Between Hospital-Based Addiction Consult Service Implementation and Hospital Length-of-Stay and 30-Day Readmission Rates for Patients with Opioid Use Disorder

BACKGROUND: Addiction consult services (ACSs) are a growing hospital-based care model that increases quality of care for patients with substance use disorders (SUDs). One implementation barrier has been concern about negative financial impacts for health systems. OBJECTIVE: To examine whether starting an ACS changes hospital length-of-stay and 30-day readmissions for patients with opioid use disorder (OUD) served in a large academic health system. DESIGN: Quasi-experimental difference-in-differences study of opioid-related hospital admissions from January 2018 to December 2024, comparing one hospital that implemented an ACS to three hospitals in the same urban, academic system in Philadelphia, PA without ACSs. PARTICIPANTS: Adults (≥ 18 years) with opioid-related hospitalizations. INTERVENTION: A fully staffed, hospital-based, multidisciplinary ACS launched in July 2023. MAIN MEASURES: Primary outcomes were hospital length-of-stay and 30-day readmissions. Secondary outcomes were receipt of any medication for opioid use disorder (MOUD) during hospitalization, discharge on a therapeutic MOUD dose, emergency department visits within 6 months of discharge, and discharges before medically advised. KEY RESULTS: In unadjusted analyses, ACS implementation was associated with a 5 percentage point increase in MOUD receipt (95% CI 0-10) and a 9 percentage point increase in discharge on therapeutic MOUD (95% CI 5-13), without significant changes in length-of-stay or 30-day readmissions. In adjusted analyses, therapeutic MOUD at discharge increased by 8 percentage points (95% CI 4-12), with no significant differences in length-of-stay or 30-day readmission. Results were robust to sensitivity analyses with alternative comparison groups and after accounting for the COVID-19 pandemic. CONCLUSIONS: Implementation of an ACS improved evidence-based care for hospitalized patients with OUD without prolonging length-of-stay or increasing readmissions.