State-Level Hospital Quality in the United States: Analyzing Variation and Trends From 2013 to 2021

This study develops a hospital quality index to analyze state-level variations in hospital quality in the United States from 2013 to 2021, using data from 3,000 hospitals from the Centers for Medicare & Medicaid Services (CMS) Hospital Compare data set.

The quality index combines three risk-adjusted measures from the CMS Hospital Compare: 30-day readmission rate, 30-day mortality rate, and patient experience. Each measure is converted into a z-score, weighted by hospital beds, and averaged to form the final index, which has a mean of 0 and a standard deviation of 1.

In 2021, the average U.S. hospital quality measures were 15.1% for readmissions, 11.2% for mortality, and 69.7% for patient experience. There was significant state-level heterogeneity. The quality index ranged from -0.54 to 0.57. Eight states notably outperformed the U.S. average, with Utah leading. Conversely, 14 states underperformed. From 2013 to 2021, there was an average annual improvement in readmissions (0.08pp) and mortality (0.12pp), but a decline in patient experience (0.27pp).

The study highlights improvements in hospital quality over time but underscores disparities at the state level. The quality index provides a valuable tool for understanding and addressing these variations in hospital care quality.