Project Summary/Abstract Stroke is a major public health problem in the United States. It is the fifth leading cause of death and a leading cause of serious disability in adults. There are an estimated 800,000 strokes in the United States each year, with more than 7.6 million stroke survivors. Twenty percent of stroke survivors require institutional care after 3 months and 15%-30% are permanently disabled. Stroke in adults is strongly age dependent, and the rate of adverse outcomes and complications associated with stroke increases with advanced age. Because the United States population is aging, the population at risk for stroke, recurrent stroke events, and other post-stroke outcomes will increase over the coming decades. Its high prevalence, associated deficits, and adverse outcomes impose a large burden on patients, their families, and the healthcare system. Stroke survivors are at high risk of new diseases due to their functional disability, neurological deficits, and pre-existing cardiovascular risk factors and comorbidities. The proposed renewal application builds on the Original R01 (Disparities in Patterns of Recurrent Stroke in the Elderly study) to expand our extensive patient-linked surveillance database to provide invaluable information on patterns and trends of 1-, 5-, and 10-year outcomes after ischemic stroke. We will combine Medicare fee-for-service and Medicare Advantage administrative data for 2017 to 2024 to accomplish the following specific aims: 1) to assess national and county-level rates and trends in 1-year outcomes for Medicare Advantage and fee-for-service beneficiaries with ischemic stroke and describe disparities by sociodemographic factors from 2017 to 2024; 2) to assess 5-year outcomes for Medicare Advantage and fee-for-service beneficiaries with ischemic stroke and describe disparities by sociodemographic factors, clinical characteristics, and geographic location from 2017 to 2024; and 3) to assess 5-year and 10- year outcomes for Medicare fee-for-service beneficiaries with ischemic stroke and describe disparities by sociodemographic factors and region from 2001 to 2024. Clinical practice, public policy, and reimbursement decisions are increasingly informed by data obtained from administrative datasets. The proposed study will be the largest contemporary investigation of recurrent stroke rates, post-stroke events, and long-term follow-up of Medicare beneficiaries hospitalized with ischemic stroke in the United States. Results from this project will identify geographic areas and subgroups that have distinctive health profiles that put them at high risk for adverse outcomes after stroke. Such information will inform care providers, insurers, public health agencies, and policy makers about communities that may derive the greatest benefit from targeted programs and community-based interventions.