Abstract
OBJECTIVES: To examine associations between Social Vulnerability Index (SVI), Social Deprivation Index (SDI), and median household income, and rates of hospitalizations for atrial fibrillation (AF) among Medicare beneficiaries. METHODS: We analyzed hospitalizations with AF as the principal diagnosis among Medicare beneficiaries (aged ≥65) across 3,116 US counties (2019-2021). Age-standardized hospitalization rates were obtained from the CDC's Atlas of Heart Disease and Stroke. We examined associations between social determinants and hospitalization rates overall and stratified by sex and race/ethnicity using correlation and linear regression analyses. RESULTS: The overall rate of hospitalization among patients with AF was 575 per 100,000 beneficiaries. Each 0.01-point increase in SVI and 1-point increase in SDI was associated with 1.6 and 1.7 additional hospitalizations per 100,000, respectively (p < 0.001). Each $1,000 increase in median household income was associated with 1.8 fewer hospitalizations (p < 0.001). Income effects were strongest among women (-2.3 per $1,000) and persisted across all racial/ethnic groups. SDI demonstrated superior model fit (AIC: 12,967) compared to SVI (AIC: 13,000) and income (AIC: 13,069), explaining 6.2% of variance in hospitalization rates. CONCLUSIONS: Neighborhood social determinants are strongly associated with AF hospitalization rates among Medicare beneficiaries despite near-universal coverage, with pronounced sex disparities. These findings support the use of county-level socioeconomic indices for geographic surveillance, while underscoring that patient-level longitudinal studies are needed to identify the specific drivers of these associations before clinical or policy interventions can be recommended.