A study of more than 3,000 hospitals found patient ratings, based on quality scores from the Centers for Medicare and Medicaid Services (CMS) 5-star hospital rating system, had an association with the rate of patient mortality and readmissions.

The study, conducted by researchers at Harvard Medical School and the Harvard T. H. Chan School of Public Health, evaluated the characteristics of hospitals by number of stars received. The sample was restricted to acute care hospitals with 25 or more hospitalizations. The study then examined the association between the number of stars hospitals received and patient 30-day mortality and readmission rates.

Using 100 percent Medicare Inpatient File 2013, composite patient outcomes were calculated for mortality and readmissions across three conditions (acute myocardial infarction, pneumonia, and heart failure) using regression models with indicators for primary condition, patient age, sex, and coexisting conditions. Findings were adjusted for hospital characteristics (hospital size, ownership, teaching status, rurality, ICU, and hospital referral region indicators), and weighted by the number of Medicare hospitalizations for each hospital.

Of the 3,076 hospitals surveyed, 4.1 percent received 5 stars, 26.2 percent received 4 stars, 47 percent received 3 stars, 20.3 percent received 2 stars, and 2.5 percent 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. The study revealed the number of stars was inversely associated with risk-adjusted mortality rate. The relationship showed that as the rating increased the rate of mortality decreased, with 5-star hospitals having the lowest mortality rate of 9.8 percent, followed by 4-star hospitals with a rate of 10.4 percent, 3-star hospitals with a rate of 10.5 percent, 2-star hospitals with a rate of 10.7 percent, and 1-star hospitals with a rate of 11.2 percent.

Higher CMS star ratings were also associated with lower readmission rates, with 5-star hospitals having the lowest readmissions rate at 18.7 percent, followed by 4-star hospitals with a rate of 20.2 percent, 3-star hospitals with a rate of 21 percent, 2-star hospitals with a rate of 21.8 percent, and 1-star hospitals with a rate of 22.9 percent.

It was concluded that a higher CMS star rating was associated with lower patient mortality and readmissions. "Patients are able to use the star ratings in guiding their health care seeking decisions given that hospitals with more stars not only offer a better experience of care, but also have lower mortality and readmissions", wrote lead author David E. Wang and colleagues.