In this comparative effectiveness study assessing individuals with OUD, more than 50% of individuals with OUD without cooccurring SUD and more 70% of individuals with cooccurring SUD did not receive evidence-based MOUD at time of treatment initiation. This indicates significant treatment gaps in a particularly high-risk population. While clinical studies have revealed similar efficacy of buprenorphine and naltrexone in treatment of OUD in per protocol analyses,18 our analysis found that the distribution of buprenorphine and naltrexone prescriptions in clinical practice varied based on the presence of a cooccurring SUD, such that individuals with cooccurring SUDs may be more likely to receive naltrexone and less likely to receive buprenorphine. Existing research shows polysubstance use is associated with lower likelihood of buprenorphine receipt,3,13 and although the American Society of Addiction Medicine has advised that cooccurring SUDs should not result in suspension of OUD treatment,7 polysubstance use remains associated with stigma, opioid agonist treatment underdosing,19 and exclusion from treatment.1,20 A 2020 analysis of US veterans reported lower likelihood of buprenorphine receipt associated with cooccurring SUDs.3 A 2021 analysis of US insurance claims found
