Project Summary Rates of alcohol use and misuse are increasing faster among older adults than among any other age group. Simultaneously, the prevalence of heart failure (HF), a major cause of reduced lifespan and health span among older adults, has also been increasing. It is possible that alcohol use and misuse exacerbate and accelerate HF, both directly via biological mechanisms and indirectly by hindering the ability to engage in the rigorous self-management required to avoid adverse health outcomes. If so, addressing alcohol use and misuse among older adults with HF has the potential to substantially improve morbidity, mortality, and quality of life for this population. Yet, despite these hypotheses, little is known about the effects of alcohol use and misuse among older adults with HF nor about the alcohol-related care received by this population. The specific aims of this application are to use rigorous causal inference and machine learning methods to 1) estimate the relationships of alcohol use and misuse with HF self-management behaviors for the first time and 2) produce less biased and more generalizable estimates of the relationships between alcohol use and misuse and adverse HF outcomes, which are currently poorly understood. In addition, we will 3) characterize the quantity and sources (venue, provider specialty, length of patient-provider relationship, provider participation in Accountable Care Organizations) of documented alcohol-related care currently received by older adults with HF. To accomplish these aims, we will utilize a linkage of two existing data sources: Medicare fee-for-service claims and the Health and Retirement Study (HRS), a nationally representative longitudinal panel of 22,000+ older adults. The research will be accomplished by a strong team of experts in alcohol use and misuse, cardiovascular conditions, aging populations, mental health care coordination, and analyses of Medicare claims and HRS. This research has the potential to inform critically needed evidence-based guidelines for clinical management of HF patients as well as future research developing interventions and policies that will improve the delivery of alcohol-related care and overall health outcomes among this population. As such, it helps advance NIAAA’s strategic goal of identifying and reducing alcohol’s influence on health and disease throughout the lifespan. It also responds directly to NIAAA Notice of Special Interest NOT-AA-20-018 “Secondary Analyses of Existing Alcohol Research Data.”