Association Between the Centers for Medicare and Medicaid Service Hospital Star Rating and Patient Outcomes

Abstract

Purpose: The Centers for Medicare and Medicaid Services (CMS) recently introduced a 5-star hospital rating system. This rating depends solely on patient experience based on the Hospital Consumer Assessment of Healthcare Providers and Systems, and currently, it does not include measures of quality of care or patients’ health outcomes. We investigated whether hospitals with more stars have lower risk-adjusted 30-day mortality and readmissions than hospitals with less stars. Methods: We evaluated the characteristics of hospitals by number of stars received. Next, we examined the association between the number of stars hospitals received and patient 30-day mortality and readmission rates. We calculated a composite patient outcome for mortality and readmissions across 3 conditions (acute myocardial infarction, pneumonia, and heart failure) using regression models with indicators for primary condition, patient age, sex, and coexisting conditions. We used multivariable linear regression models to further adjust for hospital characteristics weighted by the number of Medicare hospitalizations for each hospital. Results: Of the 3076 hospitals in our sample, 4.1% received 5 stars, 26.2% received 4 stars, 47.0% received 3 stars, 20.3% received 2 stars, and 2.5% received 1 star. In general, 4- and 5-star hospitals were more likely to be small, nonteaching, and located in small rural towns in the Midwest. We found that the number of stars was inversely associated with risk-adjusted mortality rate. The relationship was monotonic, with 5-star hospitals having the lowest mortality rate of 9.8% (95% CI, 9.7%-9.9%), followed by 4-star hospitals with a rate of 10.4% (95% CI, 10.3%-10.4%), 3-star hospitals with a rate of 10.5% (95% CI, 10.5%-10.5%), 2-star hospitals with a rate of 10.7% (95% CI, 10.7%-10.7%), and 1-star hospitals with a rate of 11.2% (95% CI, 11.2%-11.3%) (P <.001 for trend). Higher CMS star ratings were also associated with lower adjusted readmission rates, with 5-star hospitals having the lowest readmissions rate of 18.7% (95% CI, 18.6%-18.8%), followed by 4-star hospitals with a rate of 20.2 (95% CI, 20.2%-20.2%), 3-star hospitals with a rate of 21.0% (95% CI, 21.0%-21.0%), 2-star hospitals with a rate of 21.8% (95% CI, 21.7%-21.8%), and 1-star hospitals with a rate of 22.9% (95% CI, 22.8%-22.9%) (P <.001 for trend). Conclusion: We found that a higher CMS star rating was associated with lower patient mortality and readmissions. These findings should be encouraging for policymakers and consumers; choosing 5-star hospitals does not seem to lead to worse outcomes and in fact may be driving patients to better institutions.