The addiction consultation service for hospitalized patients with substance use disorder: An integrative review of the evidence

Introduction The Addiction Consultation Service has emerged as a model of care for hospitalized patients with substance use disorder. The aim of this integrative review is to characterize the Addiction Consultation Service in general hospital settings, assess its impact on clinical outcomes, identify knowledge gaps, and offer guidance for implementation. Methods We conducted an integrative review of studies from January 2002 to August 2023, applying specific inclusion criteria to collect study design, service characteristics, staffing models, utilization, and health outcomes. Additionally, a comprehensive quality appraisal was conducted for all studies considered for inclusion. Results Findings from 41 studies meeting inclusion criteria were synthesized and tabulated. Study designs included six reports from three randomized controlled trials, five descriptive studies, and 30 observational studies. The most common study setting was the urban academic medical center. Studies evaluated the structure, process, and outcomes of the Addiction Consultation Service. A majority of studies, particularly those utilizing more rigorous designs, reported positive outcomes involving medication initiation, linkage to post-discharge care, and utilization outcomes. Conclusions The Addiction Consultation Service care model improves quality of care for hospitalized patients with substance use disorder. Additional research is needed to assess its effectiveness across diverse medical settings, determine the effectiveness of varying staffing models, demonstrate impactful outcomes, and establish funding mechanisms to support sustainability.