Association of Neighborhood Socioeconomic Disadvantage With Excess Mortality Among Medicare Beneficiaries: Examining an Empirical Basis for Social Risk Adjustment

BACKGROUND: Medicare payment models have adopted social risk adjustment, which adjusts benchmarks based on area-level indices of socioeconomic disadvantage, such as the Area Deprivation Index (ADI). Although the association between ADI and outcomes is well-established, it is unclear whether this association persists after performing clinical risk adjustment. Our objective was to determine whether Medicare beneficiaries living in disadvantaged neighborhoods have higher mortality than expected on the basis of clinical risk adjustment alone. METHODS: We conducted a retrospective, cross-sectional study using a 20% sample of 2018 to 2019 Medicare claims. Exposures included beneficiary-level Hierarchical Condition Category (HCC) score components and ADI decile. The primary outcome was mortality. RESULTS: The study included 4,477,014 Medicare beneficiaries. Excess mortality in the highest ADI decile (most disadvantaged) was significantly higher (0.5 percentage points; 95% CI, 0.4-0.6) compared to the middle decile. CONCLUSION: Socioeconomic disadvantage remained associated with mortality in excess of that expected after clinical risk adjustment.