Concordance of estimated glomerular filtration rates using Cockcroft-Gault modification of diet in renal disease, and chronic kidney disease epidemiology in renal transplant recipients

Abstract

Introduction: Various equations have been used to estimate the glomerular filtration rate (GFR) in renal patients, including kidney transplant recipients. Controversy exists concerning which equation is more precise to determine kidney failure.

Aim: The aim of this study was to analyze the concordance (bias, variability, and exactness) of GFR estimated by the Modification of Diet in Renal Disease (MDRD4) and the Chronic Kidney Disease Epidemiology (CKD-EPI) equations using the Cockcroft-Gault (CG) method as the reference.

Material and methods: This observational, cross-sectional study included 153 clinically stable patients who underwent kidney transplantation between 2007 and 2009. The GFR was estimated at 12 months after the transplantation using the MDRD and CKP-EPI formula, using CG as the reference.

Results: The mean GFR for the various methods was as follows: CG = 65.6 ± 23.3 mL/min/1.73 m(2), MDRD4 = 54.9 ± 19.3 mL/min/1.73 m(2), and CKD-EPI = 55.8 ± 19.6 mL/min/1.73 m(2). Good correlations were found between CG-MDRD4 (r = 0.84; P < .001), CG-CKD-EPI (r = 0.87; P < .001), and MDRD4-CKD-EPI (r = 0.98; P < .001). The analysis of concordance detected a bias (normal difference) of -10.6 ± 12.7 versus -9.8 ± 11.3 mL/min/1.73 m(2) (P = .006), a variability (percent difference) of 14.5 ± 15.4% versus 13.6 ± 14.5% (P = .031), and an exactness (P30) of 81.7% versus 86.9% (P < .001) of CG-MDRD4 versus CG-CKD-EPI, respectively. For a GFR >60 mL/min/1.73 m(2) the exactness was 75.3% versus 83.5% (P < .001) for CG-MDRD4 versus CG-CKD-EPI, and for a GFR ≤ 60 mL/min/1.73 m(2) it was 89.7% versus 91.2% (P < .001).

Conclusions: In our population the CKD-EPI method most approached the CG values, particularly when the GFR was >60 mL/min/1.73 m(2).