title: Determination of the optimal case definition for the diagnosis of end-stage renal disease from administrative claims data in Manitoba, Canada.
abstract: BACKGROUND
  End-stage renal disease (ESRD) is a major public health problem with increasing prevalence and costs. An understanding of the long-term trends in dialysis rates and outcomes can help inform health policy. We determined the optimal case definition for the diagnosis of ESRD using administrative claims data in the province of Manitoba over a 7-year period.
  
  
  METHODS
  We determined the sensitivity, specificity, predictive value and overall accuracy of 4 administrative case definitions for the diagnosis of ESRD requiring chronic dialysis over different time horizons from Jan. 1, 2004, to Mar. 31, 2011. The Manitoba Renal Program Database served as the gold standard for confirming dialysis status.
  
  
  RESULTS
  During the study period, 2562 patients were registered as recipients of chronic dialysis in the Manitoba Renal Program Database. Over a 1-year period (2010), the optimal case definition was any 2 claims for outpatient dialysis, and it was 74.6% sensitive (95% confidence interval [CI] 72.3%-76.9%) and 94.4% specific (95% CI 93.6%-95.2%) for the diagnosis of ESRD. In contrast, a case definition of at least 2 claims for dialysis treatment more than 90 days apart was 64.8% sensitive (95% CI 62.2%-67.3%) and 97.1% specific (95% CI 96.5%-97.7%). Extending the period to 5 years greatly improved sensitivity for all case definitions, with minimal change to specificity; for example, for the optimal case definition of any 2 claims for dialysis treatment, sensitivity increased to 86.0% (95% CI 84.7%-87.4%) at 5 years.
  
  
  CONCLUSIONS
  Accurate case definitions for the diagnosis of ESRD requiring dialysis can be derived from administrative claims data. The optimal definition required any 2 claims for outpatient dialysis. Extending the claims period to 5 years greatly improved sensitivity with minimal effects on specificity for all case definitions.
authors.affiliation: Section of Nephrology, Department of Medicine, University of Manitoba, Winnipeg, Man. ; Seven Oaks General Hospital, Winnipeg, Man.
authors.forename: Paul
authors.initials: P
authors.lastname: Komenda
authors.affiliation: Department of Community Health Sciences, University of Manitoba, Winnipeg, Man.
authors.forename: Nancy
authors.initials: N
authors.lastname: Yu
authors.affiliation: Department of Community Health Sciences, University of Manitoba, Winnipeg, Man.
authors.forename: Stella
authors.initials: S
authors.lastname: Leung
authors.affiliation: Section of Nephrology, Department of Medicine, University of Manitoba, Winnipeg, Man. ; Health Sciences Centre, Winnipeg, Man.
authors.forename: Keevin
authors.initials: K
authors.lastname: Bernstein
authors.affiliation: Seven Oaks General Hospital, Winnipeg, Man.
authors.forename: James
authors.initials: J
authors.lastname: Blanchard
authors.affiliation: Section of Nephrology, Department of Medicine, University of Manitoba, Winnipeg, Man. ; Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ont.
authors.forename: Manish
authors.initials: M
authors.lastname: Sood
authors.affiliation: Section of Nephrology, Department of Medicine, University of Manitoba, Winnipeg, Man. ; Seven Oaks General Hospital, Winnipeg, Man.
authors.forename: Claudio
authors.initials: C
authors.lastname: Rigatto
authors.affiliation: Section of Nephrology, Department of Medicine, University of Manitoba, Winnipeg, Man. ; Seven Oaks General Hospital, Winnipeg, Man. ; Department of Community Health Sciences, University of Manitoba, Winnipeg, Man.
authors.forename: Navdeep
authors.initials: N
authors.lastname: Tangri