title: The Cockcroft-Gault: a better predictor of renal function in an overweight and obese diabetic population.
abstract: BACKGROUND
  The performance of the Cockcroft-Gault (CG) equation, the Modification of Diet in Renal Disease (MDRD) formula, and the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) was evaluated in body mass index (BMI) categories.
  
  
  METHODS
  In this retrospective cohort study in diabetic patients, creatinine clearance was measured by collecting 24-hour urines. Renal function was estimated using the CG, MDRD, and CKD-EPI. The performance of the equations was evaluated using correlation, Krippendorff's coefficient, bias, precision, and accuracy.
  
  
  RESULTS
  The bias of the MDRD and CKD-EPI increased from -13.9 ml/min/1.73 m(2) and -14.0 ml/min/1.73 m(2) (BMI < 25 kg/m(2)), respectively, to -31.7 ml/min/1.73 m(2) and -29.6 ml/min/1.73 m(2) (BMI > 30 kg/m(2)), respectively. Bias of the CG decreased from -13.4 ml/min (BMI < 25 kg/m(2)) to -3.2 ml/min (BMI > 30 kg/m(2)). With an accepted 30% dispersion, CG had the largest accuracy in the overweight and obese group (76.9 and 76.8%, respectively). The MDRD and CKD-EPI had an accuracy of 45.8 and 34.0% (overweight group), respectively,and 51.9 and 37.3% (obese group), respectively.
  
  
  CONCLUSIONS
  All renal function prediction equations are biased when used in overweight or obese diabetic populations with preserved renal function. The CG provides the best estimate of kidney function. The limitations of renal function prediction equations should be kept in mind when making clinical decisions.
authors.affiliation: Diabetes Centre, Isala Clinics, Zwolle, the Netherlands. i.drion@isala.nl
authors.forename: Iefke
authors.initials: I
authors.lastname: Drion
authors.forename: Hanneke
authors.initials: H
authors.lastname: Joosten
authors.forename: Liane
authors.initials: L
authors.lastname: Santing
authors.forename: Susan J J
authors.initials: SJ
authors.lastname: Logtenberg
authors.forename: Klaas H
authors.initials: KH
authors.lastname: Groenier
authors.forename: Aloysius G
authors.initials: AG
authors.lastname: Lieverse
authors.forename: Nanne
authors.initials: N
authors.lastname: Kleefstra
authors.forename: Henk J G
authors.initials: HJ
authors.lastname: Bilo
mesh_terms: D000368:Aged; D015982:Bias; D015992:Body Mass Index; D003404:Creatinine / Q000652:urine; D003920:Diabetes Mellitus / Q000503:physiopathology*; D003928:Diabetic Nephropathies / Q000150:complications / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D050177:Overweight; D015203:Reproducibility of Results; D012189:Retrospective Studies
chemical_list: D003404:Creatinine