Objectives: The Medicare End-Stage Renal Disease Prospective Payment System (PPS) used data from 2006-08 to set weights for each case-mix adjuster that is part of the bundled payment formula. The details of the population case-mix were not made public, and little is known about consistency of case-mix over time. This study estimated the prevalence of case-mix adjusters during 2006-2008 and analyzed changes in case-mix prevalence from 2000-2008.
Methods: Cross-sectional cohort study using United States Renal Data System data for Medicare dialysis patients. Three 3-year cohorts (2000-02, 2003-05, 2006-08) were analyzed for changes over time in case-mix prevalence.
Results: Double-digit trends were observed in many case-mix categories between 2000-02 and 2006-08. Large declines were observed in prevalence of patients with low BMI, pericarditis, new to dialysis, and ages 18-44. Large increases were observed in chronic co-morbidities, pneumonia and age cohort 80+.
Conclusions: Substantial changes in case-mix adjuster prevalence suggest the PPS payment formula should be regularly updated.