PROJECT ABSTRACT Medications for opioid use disorder (MOUD) are a key tool in reducing harms of the opioid epidemic. Yet only a minority of those with OUD initiate treatment, early discontinuation is typical, and disparities are endemic. People with disabilities are at especially high risk and epitomize the challenges of OUD with multimorbidity. Preliminary analyses identified 45,035 fatal opioid overdoses among Medicare disability beneficiaries (MDBs) from 2008-2016, and continuing under-utilization and disparities in MOUD, including among overdose survivors. With its wide influence in the health care system, Medicare's role is vital; it is essential to examine the Medicare system's successes and failures in engaging and retaining MDBs in treatment. Several recent policy changes are promising, with important implications for other payers, but their impact across beneficiary subgroups, time and communities needs to be better understood to inform action to improve uptake and reduce disparities. This study, responding to RFA-DA-22-037, will use national Medicare data linked with the National Death Index, Medicaid claims, community resources, prescription drug plan (PDP) formulary policies, and other data sources to assess how policy, community, provider and patient factors interact to shape MOUD initiation and retention, and in turn overdose and other clinical outcomes. With annual updates through 2025, the project will provide a powerful framework for assessing evolving treatment patterns and outcomes in a rapidly evolving environment, as well as potential changes in policy impacts over time. We will assess the drivers of racial/ethnic and other disparities in access; MOUD changes following policy and formulary changes by Medicare and its PDPs; and how these policies interact with the evolving MOUD provider system, community resources and patient characteristics. We will analyze trends and disparities in MOUD treatment and overdoses among MDBs. In cohorts of beneficiaries with new OUD diagnoses or non-fatal overdoses, we will assess factors associated with treatment initiation and retention, and association of treatment with clinical outcomes including non-fatal and fatal overdose. We will assess MOUD uptake across community, provider, and patient subgroups; changes in MOUD treatment patterns associated with the shift to tele-health; and associated changes in the MOUD treatment network serving MDBs. We will examine the sequelae of changes in formulary policies across Medicare's more than 6000 PDPs, including prior authorization requirements for MOUD, across beneficiary subgroups. Expanded reimbursement for tele-MOUD and elimination of prior authorization have the potential to save many lives, but it is critical to better understand their impact on access and disparities. An active dissemination strategy supported by a Stakeholder Advisory Board, complementing peer-reviewed publication, will support translation into evidence-informed policy. Results of this innovative and comprehensive assessment of the multi-level factors shaping MOUD uptake and outcomes among MDBs will have important implications for policy and practice across patient subgroups, payers and health care systems.

PROJECT NARRATIVE This application addresses the critical challenge of uptake, retention and equity in medications for opioid use disorder among adults with disabilities, assessing the factors associated with treatment patterns; impact on clinical outcomes including overdoses; and strategies for reducing disparities. We will utilize national Medicare data for 2008-2025 linked with the National Death Index, Medicaid claims, formulary policies, and other data sources to assess how policy, community, provider and patient factors interact to shape MOUD initiation and retention, and in turn overdose and other clinical outcomes, including differential uptake and outcomes associated with Medicare policy changes affecting tele-health reimbursement and formulary policies for MOUD. Results of this innovative and comprehensive assessment of the multi-level factors shaping MOUD uptake and outcomes among MDBs will have important implications for policy and practice across payers and health care systems.