Prevalence of comorbid substance use disorders among people with opioid use disorder: A systematic review & meta-analysis

Background Comorbid substance use disorders (SUDs) among people with opioid use disorder (OUD) contribute to poor clinical outcomes, including overdose and mortality. We present the first systematic review and meta-analysis to estimate the prevalence of specific non-opioid SUDs among people with OUD. Methods We searched Embase, PsycINFO, and MEDLINE from 1990 to 2022 for studies that used Diagnostic and Statistical Manual of Mental Disorders (DSM) or International Classification of Diseases (ICD) criteria to assess the prevalence of non-opioid SUDs among individuals with OUD. We used random-effects meta-analyses with 95% Confidence Intervals (CIs) to pool current and lifetime prevalence estimates separately. Meta-regressions and stratified meta-analyses were used to examine differences in prevalence estimates by sample characteristics and methodological factors. Results Of the 36,971 publications identified, we included data from 194 studies and 77,212 participants with OUD. The prevalence of any comorbid SUD among people with OUD was 59.5% (95%CI 49.1-69.5%) for current non-opioid SUDs, with 72.0% (95%CI 52.5-87.9%) experiencing a comorbid SUD in their lifetime. Of the studies that examined current comorbid SUDs, cocaine use disorder (30.5%, 95%CI 23.0-38.7%) was most common, followed by alcohol (27.1%, 95%CI 24.4– 30.0%), cannabis (22.7%, 95%CI 19.0-26.6%), sedative (16.1%, 95%CI 13.1-19.3%), and methamphetamine (11.4%, 95%CI 6.8-17.1%) use disorders. Substantial heterogeneity (I2>90%) across estimates was observed. Substantial heterogeneity (I2>90%) was observed across estimates, with significant variations in prevalence identified across geographic locations, recruitment settings, and other study-level factors. Conclusion Findings from this study emphasize the importance of comorbid SUD treatment access for people with OUD. Our estimates can inform the provision of treatment and harm reduction strategies for people with OUD and specific subpopulations.