title: Variation in fistula use across dialysis facilities: is it explained by case-mix?
abstract: OBJECTIVE
  Arteriovenous fistulas (AVFs) remain the preferred vascular access for hemodialysis patients. Dialysis facilities that fail to meet Centers for Medicare & Medicaid Services goals cite patient case-mix as a reason for low AVF prevalence. This study aimed to determine the magnitude of the variability in AVF usage across dialysis facilities and the extent to which patient case-mix explains it.
  
  
  METHODS
  The vascular access used in 10,112 patients dialyzed at 173 Dialysis Clinic Inc. facilities from October 1 to December 31, 2004, was evaluated. The access in use was considered to be an AVF if it was used for >70% of hemodialysis treatments. Mixed-effects models with a random intercept for dialysis facilities evaluated the effect of facilities on AVF usage. Sequentially adjusted multivariate models measured the extent to which patient factors (case-mix) explain variation across facilities in AVF rates.
  
  
  RESULTS
  3787 patients (38%) were dialyzed using AVFs. There was a significant facility effect: 7.6% of variation in AVF use was attributable to facility. This was reduced to 7.1% after case-mix adjustment. There were no identified specific facility-level factors that explained the interfacility variation.
  
  
  CONCLUSIONS
  AVF usage varies across dialysis facilities, and patient case-mix did not reduce this variation. In this study, 92% of the total variation in AVF usage was due to patient factors, but most were not measurable. A combination of patient factors and process indicators should be considered in adjudicating facility performance for this quality indicator.
authors.affiliation: Division of Nephrology, Tufts Medical Center, Boston, Massachusetts, USA.
authors.forename: Navdeep
authors.initials: N
authors.lastname: Tangri
authors.forename: Ranjani
authors.initials: R
authors.lastname: Moorthi
authors.forename: Hocine
authors.initials: H
authors.lastname: Tighiouhart
authors.forename: Klemens B
authors.initials: KB
authors.lastname: Meyer
authors.forename: Dana C
authors.initials: DC
authors.lastname: Miskulin
mesh_terms: D000367:Age Factors; D000368:Aged; D000554:Ambulatory Care Facilities / Q000706:statistics & numerical data*; D001166:Arteriovenous Shunt, Surgical / Q000706:statistics & numerical data*; D016009:Chi-Square Distribution; D005006:Ethnicity; D005260:Female; D019983:Guideline Adherence; D054625:Healthcare Disparities / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D019984:Quality Indicators, Health Care / Q000706:statistics & numerical data*; D006435:Renal Dialysis / Q000706:statistics & numerical data*; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D014481:United States