CMS on Wednesday updated hospital quality star ratings on Medicare's Hospital Compare, marking the final update under the agency's current methodology for rating hospitals.

Cheat sheets: How CMS calculates its quality star ratings

How CMS calculates hospital star ratings

The overall hospital star ratings are based on 57 quality measures across seven categories:

• Effectiveness of care;
• Efficient use of medical imaging;
• Mortality;
• Patient experience;
• Readmissions;
• Safety of care; and
• Timeliness of care.

CMS for the latest ratings used the methodology the agency established in February 2019, though it plans to update the methodology for its next round of ratings in 2021.

CMS for the latest ratings curbed its reliance on patient experience and put more weight on prompt care and readmission rates. To limit "extreme hospital outliers" in the data, CMS used k-means clustering under which the agency repeatedly categorized hospitals into the five star-rating groups until the hospitals in each group were sufficiently similar to each other and distinct from hospitals categorized in other groups.

CMS weighed each hospital's average score for each of the seven quality categories in the same way it has for previous ratings. Mortality, safety of care, readmissions, and patient experience each accounted for 22% of a hospital's overall score, while measures of effectiveness of care, timeliness of care, and efficient use of medical imaging each accounted for 4% of the overall rating.

How hospitals performed

Of the 4,586 hospitals eligible for a star rating:

• 407 hospitals received a five-star rating, compared with 293 hospitals that received a five-star rating in March 2019;
• 1,136 hospitals received a four-star rating, compared with 1,087 hospitals that received a four-star rating in March 2019;
• 1,119 hospitals received a three-star rating, compared with 1,263 hospitals that received a three-star rating in March 2019;
• 710 hospitals received a two-star rating, compared with 799 hospitals that received a two-star rating in March 2019; and
• 228 hospitals received a one-star rating, compared with 282 hospitals that received a one-star rating in March 2019.

CMS did not assign star ratings to 986 hospitals.

Reaction

Hospitals urged CMS to take down the ratings until the agency implements long-term changes to the methodology it uses for the ratings.

"We strongly believe that today's re-publication of the flawed and misleading ratings do not advance the goal of providing the public with accurate, purposeful information about quality of care," Tom Nickels, EVP of the American Hospital Association, said in a statement.

But CMS Administrator Seema Verma in a blog post wrote that the agency decided to publish the ratings using the current methodology because "[t]he American people deserve up-to-date information on how hospitals are performing."

Verma added that CMS is "not done seeking input on the Overall Star Ratings methodology to inform future updates."

CMS in August 2019 announced plans to release a proposed rule in 2020 that would permanently change the methodology. The agency did not provide details on what changes it plans to propose, but said it would use feedback it collected from stakeholders to help guide the proposed rule.

CMS said it plans to include the proposed changes in its Hospital Inpatient Prospective Payment System proposed rule for fiscal year 2021, which it will issue this spring. The agency said it hopes to finalize the changes before issuing new star ratings for hospitals in 2021 (Bean, Becker's Hospital Review, 1/29; Castellucci, Modern Healthcare, 1/29; Verma, CMS blog, 1/29; CMS data, accessed 1/30).