title: Performance of the modification of diet in renal disease and Cockcroft-Gault equations in the estimation of GFR in health and in chronic kidney disease.
abstract: The performance of the Modification of Diet in Renal Disease (MDRD) and the Cockcroft-Gault (CG) equations as compared with measured (125)I-iothalamate GFR (iGFR) was analyzed in patients with chronic kidney disease (CKD) and in potential kidney donors. All outpatients (n = 1285) who underwent an iGFR between 1996 and 2003 were considered for analysis. Of these, 828 patients had CKD and 457 were potential kidney donors. Special emphasis was put on the calibration of the serum creatinine measurements. In CKD patients with GFR <60 ml/min per 1.73 m(2), the MDRD equation performed better than the CG formula with respect to bias (-0.5 versus 3.5 ml/min per 1.73 m(2), respectively) and accuracy within 30% (71 versus 60%, respectively) and 50% (89 versus 77%, respectively). Similar results are reported for 249 CKD patients with diabetes. In the kidney donor group, the MDRD equation significantly underestimated the measured GFR when compared with the CG formula, with a bias of -9.0 versus 1.9 ml/min per 1.73 m(2), respectively (P < 0.01), and both the MDRD and CG equations overestimated the strength of the association of GFR with measured serum creatinine. The present data add further validation of the MDRD equation in outpatients with moderate to advanced kidney disease as well as in those with diabetic nephropathy but suggest that its use is problematic in healthy individuals. This study also emphasizes the complexity of laboratory calibration of serum creatinine measurements, a determining factor when estimating GFR in both healthy individuals and CKD patients with preserved GFR.
authors.affiliation: Department of Nephrology and Hypertension, The Cleveland Clinic Foundation, A51, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
authors.forename: Emilio D
authors.initials: ED
authors.lastname: Poggio
authors.forename: Xuelei
authors.initials: X
authors.lastname: Wang
authors.forename: Tom
authors.initials: T
authors.lastname: Greene
authors.forename: Frederik
authors.initials: F
authors.lastname: Van Lente
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Hall
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D016022:Case-Control Studies; D003928:Diabetic Nephropathies / Q000175:diagnosis* / Q000178:diet therapy* / Q000601:surgery; D004032:Diet; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D007677:Kidney Function Tests; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011336:Probability; D012016:Reference Values; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014019:Tissue Donors