The domains of process outcomes and vascular access technique represent different dimensions of quality, but one might anticipate that facilities that deliver high-quality care tend to perform well in all dimensions.
If facilities tend to perform very differently across multiple dimensions, then composite ratings may be mathematical abstractions, not useful indications of quality.
Here we use public data from the July 2014 release of Dialysis Facility Compare to compile 5-star ratings in which all weight is assigned to process outcomes and alternative ratings in which all weight is assigned to vascular access technique.
Ratings assigned by the contrasting approaches are very often discordant. Only 29 percent of facilities are assigned equal numbers of stars by the contrasting approaches.
Numerous facilities assigned only one star with exclusive consideration of process outcomes are assigned either four or five stars with exclusive consideration of vascular access technique. Likewise, numerous facilities assigned five stars with exclusive consideration of process outcomes are assigned either one or two stars with exclusive consideration of vascular access technique.
Between the ratings, discrepancies by a margin of two or more stars are common.
Ultimately, these data suggest that composite ratings for dialysis facilities are not particularly useful, as they often blur very different levels of achievement in disparate domains.
Comparison of rating based exclusively on Kt/V & hypercalcemia metrics vs. rating based exclusively on fistula & catheter metrics
Number of facilities
(Alternative facility score in rows; CMS rating in columns)
Movement from rating based on Kt/V & hypercalcemia metrics
(Movement in rows; rating based on Kt/V & hypercalcemia metrics in columns)