The relative incidence of the major clinical outcomes of mortality and hospitalization might exclusively determine 5-star ratings for dialysis facilities, but the challenge with estimating relative incidence is design appropriate risk adjustment.
Both the standardized mortality ratio and the standardized hospitalization ratio depend on adjustment for comorbid conditions present at dialysis initiation, as recorded on the Medical Evidence Report, but analyses presented earlier in this report cast considerable doubt on the validity of comorbidity data ascertained from this report.
An alternative approach to rating dialysis facilities is to assign all weight to process outcomes, which facilities might be able to determine more directly.
Here we use public data from the July 2014 release of Dialysis Facility Compare to compile 5-star ratings according to the CMS methodology and, likewise, to an alternative methodology in which the percentage of patients who receive adequate dialysis (as quantified by Kt/V) and the incidence of hypercalcemia are each assigned 50 percent weight.
There is a relationship between the ratings, but there is also considerable discordance. Roughly 44 percent of facilities are assigned equal numbers of stars by the contrasting approaches.
Among facilities assigned one star by the CMS methodology, almost 60 percent are assigned two or more stars by the alternative rating. On the other hand, among facilities assigned five stars by the CMS methodology, more than 56 percent are assigned four or fewer stars by the alternative rating.
Among facilities assigned two, three, or four stars by the CMS methodology, revisions by a margin of either one or two stars with the alternative rating are common.
Comparison of rating from CMS methodology vs. rating based exclusively on Kt/V & hypercalcemia metrics
Number of facilities
(Alternative facility score in rows; CMS rating in columns)
Movement from CMS rating
(Movement in rows; CMS rating in columns)