Abstract Body (Do not enter title and authors here): Introduction
Cardiovascular disease (CVD) is a major cause of morbidity and mortality among older adults in the U.S. The Social Vulnerability Index (SVI), developed by the Centers for Disease Control and Prevention (CDC), is a comprehensive measure aggregating various social determinants of health, including socioeconomic status, household composition, minority status, and housing/transportation factors. Social determinants, measured by the CDC’s Social Vulnerability Index (SVI), affect healthcare access and outcomes. This study examines the link between social vulnerability and CVD-related outcomes among Medicare beneficiaries.

Objectives
To assess the impact of county-level social vulnerability, stratified by SVI quartiles, on total CVD-related hospitalization and mortality rates between 2019 and 2021, with subgroup analyses by gender and race/ethnicity.

Methods
We conducted a retrospective analysis of total CVD-related hospitalizations and mortality rates using ICD-10 codes (I00-I78) among Medicare beneficiaries aged ≥65 years from 2019 to 2021. County-level SVI data from the CDC was categorized into quartiles (Q1: 0–0.25, lowest vulnerability; Q4: 0.75–1.0, highest vulnerability). Age-standardized hospitalization and mortality rates per 100,000 beneficiaries were analyzed across SVI quartiles, gender, and race/ethnicity. Pearson correlation and linear regression models assessed the associations between SVI and outcomes, with rate differences calculated between SVI Q4 and Q1.

Results
The total age-standardized CVD hospitalization rate was 53.61 per 1,000(95% CI: 53.14–54.09), and mortality was 1,526.51 per 100,000 (95% CI: 1,516.57–1,536.45) beneficiaries. Both rose with SVI: hospitalizations from 46.94 (Q1) to 60.08 (Q4), and mortality from 1,376.46 to 1,681.66. Men had higher rates than women (61.52 vs. 47.19 per 1,000; 1,796.07 vs. 1,311.08 per 100,000). Black beneficiaries had the highest rates: hospitalizations at 70.18 per 1,000 and mortality at 1,811.22 per 100,000. SVI correlated with hospitalization (r = 0.363, p = < 0.001 R² = 0.132) and mortality (r = 0.405, p = < 0.001 R²= 0.164). A 0.1 unit increase in SVI was linked to 1.7 more hospitalizations per 1,000 and 39.8 more deaths per 100,000.

Conclusion
Higher social vulnerability is associated with increased rates of CVD-related hospitalizations and mortality among Medicare beneficiaries, with greater disparities by gender and race, underscoring the need for targeted social interventions.