The Centers for Medicare & Medicaid Services Five-Star Quality Rating System, implemented in January 2015, evaluates the quality of care provided by dialysis centers in an effort to provide patients, their families, and their caregivers the ability to easily compare dialysis centers and determine where they would prefer to dialyze. Centers are given a rating between one and five stars; those assigned a rating of five stars are considered to deliver quality care well above the industry average, while those receiving only one star are deemed to deliver care below average quality.

Previously, ratings were assigned using a forced bell curve, and the number of four or five star centers was capped at 30% of the industry. Beginning in calendar year (CY) 2015 (ratings released in October 2016), the evaluation methodology changed. Star ratings are now assigned based on thresholds. Measure scores and ratings are determined by comparing current center performance to industry performance in a baseline year, currently set at 2014. As a result, centers improving performance from one year to the next now have the opportunity to improve their star rating regardless of their performance relative to the industry. Under this new methodology, 41% of centers were rated four or five stars, 11% more than allowed by the previous methodology.1

A framework for understanding dialysis patient quality outcomes

While there have been improvements in mortality over the past few decades, mortality and morbidity remain high among end-stage renal disease patients. A new quality paradigm, a patient-focused quality pyramid, 2 addressed the lack of a unified framework to encourage an approach to improve the lives of patients with kidney disease. To achieve the ultimate goal to improve the lives of patients with kidney disease––the top of the pyramid––it is necessary to improve survival, decrease hospitalizations and optimize the patient’s experience with care. Because these outcomes are evaluated by the CMS Five-Star Quality Rating System, the increase in the proportion of four- and five-star centers across the industry would suggest that the patient is the real winner, assuming these ratings accurately capture excellence in the outcomes on the highest tier of the pyramid.

Given the focus of improving the quality of life for patients with advanced kidney disease, this article will focus on two measures that contribute to quality of life in the Five-Star Quality Rating System—standardized hospitalization ratio (SHR) and standardized mortality ratio (SMR)—to better understand how they are associated with five-star ratings. This article also will assess a measure under consideration for the Five-Star Quality Rating System — the Consumer Assessment of Healthcare Providers and Systems (CAHPS) — designed to measure the experience of patients receiving in-center hemodialysis care, although currently only available for approximately half of the industry.

The association between mortality, hospitalizations, and five-star ratings

The relationship between star ratings, SMR, and SHR was assessed to understand if mortality and hospitalization were lower at centers with higher star ratings. In theory, we would expect to see better performance in the SHR, SMR, and a better reported patient experience associated with higher star ratings. Despite the notable contribution of the SHR and SMR to the star rating score, high performance in the other measures in the Five-Star Quality Rating System could compensate for poorer performance in the SHR and SMR, allowing a center to achieve an average or above-average star rating (three, four, or five stars).

Previous research showed that in CY 2013 and CY 2014, higher star ratings were associated with lower SHR, SMR, and Standardized Readmission Ratio (SRR) (p-trend<0.001 for each). Additionally, centers that improved their star rating from CY 2013 to CY 2014 had a dose dependent association of change in SHR, SMR, and SRR.2  Since the publication of this abstract, CY 2015 star rating and CAHPS data were released. Given the recent methodology change, we sought to understand whether this association would remain in CY 2015.

Using data obtained from the CMS Dialysis Facility Compare website, 6,032 centers received a star rating in CY 2015.3  Of these centers, 6,020 had values for SHR, 5,954 for SMR and 3,349 for CAHPS. Across the industry, the mean SHR was 0.996 and SMR was 1.006, meaning that on average there were as many hospitalizations and as much mortality as expected. However, centers with higher star ratings performed better in the SHR and SMR than those with lower ratings (see Figures 1 & 2). In fact, the median hospitalization and mortality ratios decreased as star ratings increased from one to five-stars, such that for every higher star rating, the hospitalization and mortality ratio was lower (p<0.001).

The association between patient experience and five-star ratings

Turning to patient experience, CAHPS performance is a composite of six measures, which were averaged to obtain an overall score. CY 2015 data suggest that median scores in this overall CAHPS score increase as star ratings increase (see Figure 3). However, while centers assigned a rating of five stars have higher CAHPS scores than one-star centers (p<0.001), there is substantial overlap in the performance ranges at each level of star rating. For example, while the median CAHPS score is higher at a five-star center than a one-star center, many one-star centers had the same CAHPS score as a five-star center. As such, further analyses are required to understand how the patient experience, as defined by CAHPS, may or may not be related to patient quality of life or other clinical outcomes.


To achieve the goal of improving the lives of patients with kidney disease, it is necessary to improve survival, decrease hospitalizations, and optimize the patient’s experience with care. These measures are on the highest tier of the clinical pyramid described by Nissenson.

The analysis outlined here indicates that, in CY 2015, there are more four- and five-star centers across the industry, and, among these centers, there are fewer hospitalizations and lower mortality. Additionally, analysis of the CAHPS results for these centers suggests that patients may have a more positive experience at higher-rated centers, but further analysis of this correlation is needed.


  1. Dialysis Facility Compare datasets. Updated on January 26, 2017.
  2. Besharat AC, Valderrama SA, Krishnan M, Nissenson AR, Brunelli SM. Higher End-Stage Renal Disease (ESRD) Star Ratings Are Associated with Lower Mortality, Hospitalization, and Readmission Ratios. Clinical Journal of the American Society of Nephrology : CJASN. 2016; 27.
  3. Nissenson AR. Improving Outcomes for ESRD Patients: Shifting the Quality Paradigm. Clinical Journal of the American Society of Nephrology : CJASN. 2014;9(2):430-434. doi:10.2215/CJN.05980613.