title: Evaluation of the Cockroft-Gault, Jelliffe and Wright formulae in estimating renal function in elderly cancer patients.
abstract: BACKGROUND
  More elderly patients are being treated with chemotherapy. Reliable and accurate measures of renal function are needed to obtain predictable, safe and effective exposure to renally excreted drugs. The Jelliffe, Cockroft-Gault and Wright formulae have been used to evaluate renal function, although they have not been validated in elderly oncology patients. We performed a retrospective evaluation of these formulae using the [51Cr]-ethylenediamine tetraacetic acid ([51Cr]-EDTA) method of measuring glomerular filtration rate (GFR) as the 'gold standard'.
  
  
  METHODS
  Inclusion criteria were age > or = 70 years and serum creatinine <250 micromol/l, performed within 4 weeks of glomerular filtration rate (GFR) measurement. Creatinine clearance was calculated using the Cockroft-Gault, Jelliffe and Wright formulae. The precision and accuracy of the three formulae were compared with the gold standard.
  
  
  RESULTS
  Two hundred and twenty-five patients were evaluated: median age, 74 years (range 70-89); males, 108; females, 117; median creatinine, 84 micromol/l (range 44-186). Correlation coefficients of the Jelliffe, Cockroft-Gault and Wright formulae were similar. In the specific GFR ranges of 50-70, 70-90 and 90-120 ml/min, the bias [mean percentage error (MPE)] was +8%, -4% and -13%, respectively. The degree of bias was greater with the Cockroft-Gault and Jelliffe formulae across the same range of GFR with the MPE being -15%, -25%, -32% and -12%, -19% and -23%, respectively. All three formulae have reduced precision and greater bias at the extremes of GFR.
  
  
  CONCLUSIONS
  The Wright formula is the most accurate, precise and least biased formula for the calculation of GFR in elderly patients with a GFR >50 ml/min. These results allow the physician to make a decision regarding the use of the formula based on an expected degree of bias.
authors.affiliation: Guys and St Thomas' Hospitals, Medical Oncology Department, Guy's Hospital, London SE19RT, UK. gmarx@shoc.com.au
authors.forename: G M
authors.initials: GM
authors.lastname: Marx
authors.forename: G M
authors.initials: GM
authors.lastname: Blake
authors.forename: E
authors.initials: E
authors.lastname: Galani
authors.forename: C B
authors.initials: CB
authors.lastname: Steer
authors.forename: S E
authors.initials: SE
authors.lastname: Harper
authors.forename: K L
authors.initials: KL
authors.lastname: Adamson
authors.forename: D L
authors.initials: DL
authors.lastname: Bailey
authors.forename: P G
authors.initials: PG
authors.lastname: Harper
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use; D003404:Creatinine / Q000652:urine; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000502:physiology*; D007674:Kidney Diseases / Q000150:complications* / Q000175:diagnosis*; D008297:Male; D008962:Models, Theoretical; D009369:Neoplasms / Q000150:complications / Q000188:drug therapy; D011379:Prognosis; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D003404:Creatinine