Access to Medications to Treat Opioid Use Disorder in the Medicare Population - Summary/Abstract: Access to effective treatment for opioid use disorder (OUD) continues to be an important public health problem two decades after the start of the opioid crisis. Patients diagnosed with OUD may receive one of three Food and Drug Administration-approved medications to treat OUD (MOUD): methadone, buprenorphine, and naltrexone. Yet, only 16% of Medicare beneficiaries diagnosed with OUD received a MOUD in 2020. In the absence of MOUD, Medicare beneficiaries with OUD are at greater risk of morbidity and mortality. The little MOUD that is dispensed to Medicare beneficiaries does not accrue evenly to different patient groups. Medicare beneficiaries have reported that a lack of insurance coverage for OUD treatment was a barrier to treatment. Prior to 2020, Medicare did not cover methadone for OUD treatment. Even if a Medicare beneficiary has coverage for MOUD, they may not live near a provider who prescribes it. For example, Medicare beneficiaries living in rural areas have less access to MOUD compared to those in urban areas. Similarly, nonwhite Medicare beneficiaries are less likely to have access to and receive MOUD than White beneficiaries. The quality of individual providers and their contributions to disparities in MOUD use has remained unstudied. Disparities in MOUD use can occur due to disadvantaged patients receiving care at lower quality providers or because they receive worse care at the same providers as more advantaged patients. Policy prescriptions for increasing access and closing disparities will depend on the pathways determining disparities in access to care. Finally, a host of state and federal policies have aimed to increase access to MOUD. In the proposed study we will conduct analyses designed to assess beneficiary access to MOUD and health outcomes and assess the impacts of state and federal policies. We plan to calculate facility-level quality measures of MOUD and health outcomes for Medicare beneficiaries with OUD. Finally, we assess how federal- and state-level policies impact MOUD access and health outcomes. We propose to study the following aims: Aim 1: Quantify and compare access to MOUD and health outcomes for Medicare beneficiaries, stratifying by beneficiary (race/ethnicity, sex, and geography), provider (specialty, geography, waiver status during our study period), and facility characteristics (ownership, OTP status, service setting). Aim 2: Construct facility-level quality measures reflecting access to MOUD and health outcomes for Medicare beneficiaries diagnosed with OUD and stratify facilities based on their relative performance. Aim 3: Evaluate the effect of federal- and state-level policies on access to MOUD and on health outcomes for Medicare beneficiaries diagnosed with OUD. MOUD is an effective form of treatment that few Medicare beneficiaries diagnosed with OUD receive. A range of state and federal policies have been enacted to increase MOUD access. The proposed team for this R01 will track providers offering and use of MOUD treatment over time and assess how policies impact their use.