Impact of Social Determinants of Health on Engagement in Medication for Opioid Use Disorder Treatment: Development and Validation of a Clinical Vignette-based Study - Project Summary Medications for opioid use disorder (MOUD) are the gold standard treatment for opioid use disorder (OUD) but are underutilized particularly among the most marginalized in the United States. To move towards greater health equity, attention to social determinants of health (SDOH) can help improve engagement and success in MOUD treatment for underserved populations. To date, key SDOH with demonstrated impact on MOUD treatment include socioeconomic status, educational attainment, employment status, and health insurance coverage, among others. However, less is known about whether and how opioid treatment providers attend to SDOH in the context of the MOUD clinical encounter. Identifying and developing implementation strategies to increase MOUD treatment engagement and success requires a focus on opioid treatment providers perspectives of SDOH and how SDOH informs their clinical decision-making. Such a focus can inform approaches to person-centered care that directly attend to SDOH in the context of MOUD. The proposed study will employ an exploratory sequential design to examine the extent to which SDOH may influence clinical decision-making among opioid treatment providers who prescribe MOUD. Additionally, a mixed-methods design will be used to evaluate provider perspectives on the facilitators and barriers of MOUD treatment engagement and success. First, a nation-wide sample of opioid treatment providers (N=30) will be recruited to participate in an individual interview to learn their perspectives on the context-specific clinical and social determinants of clinical decision-making and identify the patient, provider, organizational, and policy determinants of MOUD treatment engagement and outcomes (Aim 1). In line with rigorous implementation science research, the interview will be based on a theoretical model (i.e., Health Equity Implementation Framework) and the conceptual model of SDOH (i.e., Healthy People 2030). The Health Equity Implementation Framework was developed to explicitly attend to health equity in healthcare settings and emphasizes the clinical encounter as an important facilitator of both successful implementation and health equity. Second, we will develop a clinical vignette-based survey, based on the findings from individual interviews, existing literature and expert feedback, and then pilot test the clinical vignette survey with a distinct sample of opioid treatment providers (N=20; Aim 2). For the pilot trial, participants will participate in a cognitive interview while completing the vignette-based survey, which will help identify areas of refinement and prepare materials for a future, large- scale factorial vignette experiment. The proposed study represents a critical step in detecting MOUD implementation disparities relevant to SDOH that occur during clinical encounters throughout treatment. Results from this study will inform our understanding of how to adapt MOUD service delivery, develop implementation strategies to improve MOUD outcomes and better attend to the needs of individuals disproportionately impacted by effects of social determinants on OUD treatment.