PROJECT SUMMARY/ABSTRACT In the United States, declines in cardiovascular mortality have stalled, and there is growing concern that these population-level trends may reflect an increase in the burden of cardiovascular risk factors and disease in low- income working-age adults (18 to 64 years). However, these patterns have not been well characterized on a national scale. The COVID-19 pandemic has only magnified the critical need to track the cardiovascular health of the low-income working-age population. The pandemic has led to substantial disruptions in health care, and created enormous spillover effects, including unemployment and deepening financial hardship, which have fallen more heavily on low-income adults. These changes may widen inequities in health insurance coverage, health care access, and affordability, and ultimately, worsen cardiovascular health for years to come. In the wake of the pandemic, policymakers are now weighing whether to expand the Medicare program to increase access to health care. Understanding the potential effects of this policy change on the cardiovascular health of low-income adults could inform federal strategies to improve health equity nationwide. Building on our team’s expertise in the linkage and analysis of large datasets, the application of epidemiological and econometric methods, and the evaluation of health policies, we will examine changes in cardiovascular risk factors, disease, and outcomes in low-income working-age adults, assess the impact of the pandemic on health care coverage, access, and affordability as well as cardiovascular morbidity and mortality, and determine the potential effects of expanding Medicare on the cardiovascular health of this population. To do so, we will use a unique combination of national survey data, state all-payer and national Medicaid claims, and CDC epidemiological data. In Aim 1, we will perform a national analysis that determines whether the prevalence, treatment, and control of cardiovascular risk factors, incidence of acute cardiovascular events, and cardiovascular mortality were increasing in low-income working-age adults prior to the pandemic. In Aim 2, we will examine whether the pandemic was associated with short- and long-term changes in health care coverage, access, and affordability, cardiovascular morbidity and mortality, and self- reported health in low-income working-age adults using interrupted time series analyses. In Aim 3, we will evaluate the effects of Medicare on health care access and affordability, the screening, treatment and control of cardiovascular risk factors, and self-reported health in low-income adults using quasi-experimental approaches. This research will advance our understanding of changes in cardiovascular morbidity and mortality among low-income working-age adults, before and after the pandemic, and provide critical insights on the implications of expanding Medicare on health care access, affordability, and cardiovascular health for ...