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

Aim: 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. Methods: 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. Results: 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 < 0.001), cocaine use (p = 0.044), unintentional drug overdose (p = 0.023), and homelessness (p = 0.044), with the “Intense NPB Use” class having the lowest prevalences. Conclusion: Predominance of self-treatment goals and the association between more intense NPB use and lower risks of adverse consequences suggest potential harm minimization benefits of NPB use. More research is needed to understand consequences of NPB use over time.