Social Risk-Weighted Scoring to Improve Medicare Advantage Star Ratings

Medicare Advantage (MA) Star Ratings influence bonus payments and health plan enrollment. Current approaches to accounting for enrollee social risk may not fully capture differences in beneficiary populations. This study assessed how MA contract performance rankings for statin receipt and adherence change under a social risk-weighted scoring approach.

Cross-sectional analysis of 2019 MA encounter, prescription drug, and enrollment data for 165 MA contracts.

Contract-level statin receipt and adherence scores were calculated for disability and dual-eligibility subgroups and aggregated using empirically derived weights from a constrained optimization framework that equalized each subgroup's contribution to overall contract performance. Ordered logistic regression assessed associations between contract characteristics and weighted performance.

Social risk-weighted scoring reclassified 24.2% of contracts for statin receipt and 20.6% for adherence relative to unweighted scoring. For statin receipt, 11.5% of contracts moved up, 12.7% moved down, and 75.8% were unchanged; for adherence, 7.3% moved up, 13.3% moved down, and 79.4% were unchanged. Under the weighted approach, higher disability prevalence remained associated with lower performance ratings even after weighting: Each 1-percentage point (PP) increase in disability prevalence corresponded to a 0.7-PP higher probability of receiving 3 or fewer stars for statin receipt and a 1.3-PP higher probability for adherence. Larger contracts also had lower predicted probabilities of receiving 4 stars, decreasing by 3.4 PPs for receipt and 3.8 PPs for adherence per 1-unit increase in log enrollment.

Social risk weighting rebalanced contract rankings but did not consistently improve ratings for high-risk plans. Remaining variation may reflect differences in quality or unmeasured factors.