Sex differences in comorbid pain and opioid use disorder: A scoping review

Opioid use disorder (OUD) and chronic pain are commonly co-occurring disorders which can exacerbate each other. Sex/gender differences have been shown in aspects of the clinical course and biological underpinnings of both OUD and chronic pain. The purpose of this scoping review is to summarize literature which has addressed sex/gender differences in relation to the confluence of OUD and chronic pain. This review focused on peer-reviewed journal articles with human subjects and addressing (a) opioid misuse, chronic opioid use or opioid use disorder (OUD), (b) chronic or persistent pain and (c) sex/gender differences in relation to OUD and/or chronic pain. Of the 146 papers identified by the search strategy, 30 met the criteria for inclusion. Charting focused on a priori themes of chronic pain, opioid misuse/OUD and sex/gender in sample, predictor and outcome variables, and key study findings. The majority of research identified was cross-sectional in nature, and sex/gender differences and treatment effects were largely included as post-hoc analyses. Together, the results of this early work align with higher prevalence for OUD in men/males and chronic pain in women/females, while adding critical information with respect to potential sex/gender differences in the development and treatment of their co-occurrence across a range of biological and psychosocial factors. Findings underline the importance of considering sex and gender in the intersection of the development and treatment of OUD and chronic pain.