Within-center correlation in dialysis adequacy

J Clin Epidemiol. 2000 Jan;53(1):79-85. doi: 10.1016/s0895-4356(99)00129-8.


The purpose of this study was to determine whether patients with end stage renal disease treated with hemodialysis were correlated in dialysis adequacy within facilities. This was a retrospective analysis of dialysis adequacy based on urea reduction ratio (URR) values from 6969 patients dialyzed at 154 facilities. The within-center correlation was quantified using the between-center variation and the parameter p that was derived using ANOVA tables and mixed effects models. The variation in center means for URR was wider than expected for independent observations (52.9-76.1 versus 60.7-73.8, respectively). Furthermore, there was a significant within-center correlation in URR values across all facilities (p = 0.136, P<0.0001), which persisted after adjusting for patient specific covariates, facility characteristics, and state. In conclusion, there was a substantial within-center correlation in dialysis adequacy that reflected important center effects on the outcome of ESRD patients.

Publication types

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

MeSH terms

  • Blood Urea Nitrogen*
  • Female
  • Hemodialysis Units, Hospital / standards*
  • Humans
  • Kidney Failure, Chronic / therapy*
  • Male
  • Mid-Atlantic Region
  • Middle Aged
  • Outcome Assessment, Health Care*
  • Retrospective Studies