title: Derivation and validation of a clinical index for prediction of rapid progression of kidney dysfunction.
abstract: BACKGROUND
  Chronic kidney disease is common among the elderly, and these patients are at risk of progressive kidney dysfunction.
  
  
  OBJECTIVE
  To develop an index to predict rapid progression of kidney dysfunction.
  
  
  METHODS
  Community-based cohort divided into derivation (n = 6789) and validation (n = 3395) subsets.
  
  
  METHODS
  We identified 10 184 subjects aged >/=66 years from computerized laboratory data. Prescription drug data was used to define disease categories and medication exposure, and an index for predicting rapid progression of kidney dysfunction (> or =25% decline in glomerular filtration rate over a 2-year period) was obtained from a logistic regression model in the derivation cohort. The risk score for each subject was calculated by summing the component variables together, which were subsequently categorized into five risk classes.
  
  
  RESULTS
  Five predictors of rapid progression were identified: age >75 years, cardiac disease, diabetes mellitus, gout, and use of anti-emetic medications. Rates of rapid progression for risk classes I through V were 8.6%, 10.9%, 13.9%, 15.6%, and 24.1%, respectively, for the derivation cohort, and 8.4%, 11.6%, 15.5%, 17.3%, 21.9%, respectively, for the validation cohort. The risk index distinguished between low and high risk of rapid progression, with a 2.5-fold greater risk for the highest, compared to the lowest, risk decile.
  
  
  CONCLUSIONS
  Readily available clinical data can be used to identify most elderly at risk of rapid progression of kidney dysfunction. This simple index could help clinicians to identify patients at risk, and implement strategies to slow the progression of kidney dysfunction.
authors.affiliation: Division of Nephrology, Foothills Medical Center, 1403 29th Street NW, Calgary, Alberta T2N 2T9, Canada. brenda.hemmelgarn@calgaryhealthregion.ca
authors.forename: B R
authors.initials: BR
authors.lastname: Hemmelgarn
authors.forename: B F
authors.initials: BF
authors.lastname: Culleton
authors.forename: W A
authors.initials: WA
authors.lastname: Ghali
mesh_terms: D000368:Aged; D015331:Cohort Studies; D018450:Disease Progression; D006801:Humans; D008297:Male; D051437:Renal Insufficiency / Q000503:physiopathology*; D018570:Risk Assessment / Q000592:standards; D012307:Risk Factors; D012720:Severity of Illness Index