Building evidence for effective extended-release buprenorphine treatment for opioid use disorder - There are an estimated 6-7 million people with opioid use disorder (OUD) in the United States (US). Medications for OUD is the gold standard treatment, but the full benefits of these medications remain unrealized, due to several factors, including inadequate access and poor retention. Extended-release buprenorphine (XR) injection for OUD became available in the US in 2018, offering additional choice and flexibility. XR has the potential to improve access and retention for some patients because of advantageous characteristics (e.g., no burden of daily dosing, no risk of diversion or misuse, less fluctuation in daily drug levels). However, compared to daily sublingual buprenorphine (SL), XR costs more and has more restrictive insurance coverage, which may exacerbate persistent patterns of medication access and retention. There is currently little guidance informing treatment decisions between XR and SL buprenorphine. A better understanding of which patient subgroups benefit most from XR is critical to inform optimal treatment for each person and motivate efforts to address barriers to access. The goal of this K99/R00 is to address these gaps and to support Dr. Ross’s career goal of becoming an independent investigator whose research advances evidence-based treatment of OUD through cross-disciplinary collaboration and application of novel quantitative methods. Through the award, Dr. Ross will build on her training as an epidemiologist with experience in pharmacoepidemiology and causal inference to develop competency in 1) OUD and its treatment, 2) conceptualization and quantification of population subgroup differences in health services, 3) statistical methods for precision medicine, and 4) professional skills to be a responsible and independent investigator. The proposed research will use recent Medicaid data from 50 states and data from the large multi-site Optimizing Retention, Duration, and Discontinuation Strategies for OUD Pharmacotherapy trial (RDD). The research aims are to: 1) assess current demographic differences in real-world XR treatment for OUD among Medicaid patients, 2) identify the patient subgroups expected to have the greatest improvement in treatment retention from XR relative to SL using the RDD trial data, and 3) predict the effect of personally tailoring buprenorphine formulation decisions on real-world treatment retention and demographic differences in retention among Medicaid patients. This work is aligned with NIDA’s strategic priorities to support personalized addiction medicine and leverage data science tools for clinical decision making. This grant will support Dr. Ross’s transition to an independent investigator in OUD treatment through salary support, focused training, and a dedicated mentorship team.