Patterns of non-prescribed buprenorphine and other opioid use among individuals with opioid use disorder: A latent class analysis

•Nearly 90% of the sample used non-prescribed buprenorphine (NPB) to self-treat withdrawal symptoms.•Latent Class Analysis identified 3 classes of NPB/other opioid use.•Class 1 (Heavy Heroin/Fentanyl Use) included 61%, Class 2 (More Formal Treatment) – 29%, Class 3 (Intense NPB Use) - 10%.•Class 3 had the lowers prevalence of heroin/fentanyl injection, cocaine use, overdose and homelessness. Non-prescribed buprenorphine (NPB) use increased in the US. This study aims to characterize heterogeneity in patterns of NPB and other opioid use among individuals with current opioid use disorder. The study recruited 356 participants in Dayton (Montgomery County), Ohio, area in 2017–2018 using targeted and Respondent Driven Sampling. Participants met the following criteria: 1) 18 years or older, 2) current moderate/severe opioid use disorder (DSM-5), 3) past 6-month NPB use. Latent class analysis (LCA) was conducted to identify subgroups based on past 6-month (days of NPB and heroin/fentanyl use; use of NPB to get high; use of non-prescribed and prescribed pharmaceutical opioids; participation in formal treatment) and lifetime (years since first NPB and other illicit opioid use) characteristics. Selected auxiliary variables were compared across classes using Asparouhov and Muthén's 3-step approach. 49.7% were female, and 88.8% were non-Hispanic whites. 89% used NPB to self-treat withdrawal. LCA resulted in three classes: "Heavy Heroin/Fentanyl Use" (61%), "More Formal Treatment Use" (29%) and "Intense NPB Use" (10%). After adjusting for multiple testing, the following past 6-month variables differed significantly between classes: injection as a primary route of heroin/fentanyl administration (p