Variation in Postoperative Outcomes Across Centers for Medicare and Medicaid Services Hospital Star Ratings

Abstract

INTRODUCTION: To provide a single public measure of hospital quality, the Centers for Medicare and Medicaid Services (CMS) introduced the Overall Hospital Quality Star Rating program. However, whether CMS hospital star ratings are associated with postoperative outcomes and a reliable measure of hospital quality for the public remains unknown. METHODS: We performed a cross-sectional review of 1,953,057 Medicare beneficiaries undergoing 1 of 5 common surgical procedures (colon resection, coronary artery bypass, cholecystectomy, appendectomy, and incisional hernia repair) between 2014 and 2018. Hospitals were stratified by their CMS Star Rating. We then calculated risk- and reliability adjusted hospital mortality rate. Finally, we analyzed the variation in mortality within and across CMS Star Ratings. RESULTS: Overall, risk- and reliability adjusted hospital mortality was 5.7% (95% CI: 5.7 to 5.8) and ranged from 2.4% to 16.2%. Hospital mortality decreased in a stepwise fashion from 6.5% (95% CI: 6.3 to 6.6) at 1-star hospitals to 6.1% (95% CI: 6.0 to 6.2) at 2-star hospitals, 5.8% (95% CI: 5.8 to 5.9) at 3-star hospitals, 5.5% (95% CI: 5.5 to 5.6) at 4-star hospitals, and 5.1% (95% CI: 5.0 to 5.2) at 5-star hospitals (odds ratio [OR]: 0.53, 95% CI 0.49 to 0.57). There was wide variation in mortality withing CMS star ratings (Figure). Specifically, 1-star hospital mortality varied by 3.4×, 2-star hospitals varied 5.8×, 3-star hospitals varied 4.2×, 4-star hospitals varied 4.0×, and 5-star hospitals varied 3.8×.FigureCONCLUSION: Although CMS hospital star rating was associated with postoperative mortality, there was wide variation in mortality within each star rating group. These findings highlight the limitations of CMS’s star rating system and should be a call for continued improvement of publicly reports hospital grade measures.