Understanding the basic case-mix adjustment for the composite rate

Am J Kidney Dis. 2006 Apr;47(4):666-71. doi: 10.1053/j.ajkd.2005.12.037.


In April 2005, Medicare began adjusting payments to dialysis providers for composite-rate services for a limited set of patient characteristics, including age, body surface area, and low body mass index. We present analyses intended to help the end-stage renal disease community understand the empirical reasons behind the new composite-rate basic case-mix adjustment. The U-shaped relationship between age and composite-rate cost that is reflected in the basic case-mix adjustment has generated significant discussion within the end-stage renal disease community. Whereas greater costs among older patients are consistent with conventional wisdom, greater costs among younger patients are caused in part by more skipped sessions and a greater incidence of certain costly comorbidities. Longer treatment times for patients with a greater body surface area combined with the largely fixed cost structure of dialysis facilities explains much of the greater cost for larger patients. The basic case-mix adjustment reflects an initial and partial adjustment for the cost of providing composite-rate services.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Costs and Cost Analysis
  • Female
  • Humans
  • Kidney Failure, Chronic / economics*
  • Kidney Failure, Chronic / therapy*
  • Male
  • Medicare
  • Middle Aged
  • Renal Dialysis / economics*
  • Risk Adjustment*
  • United States