Comparison of estimating equations for the prediction of glomerular filtration rate in kidney donors before and after kidney donation.

Abstract

The aim of this study is to investigate the usefulness of the GFR-estimating equations to predict renal function in kidney donors before and after transplantation. We compared the performance of 24-hour-urine-based creatinine clearance (24 hr urine-CrCl), the Cockcroft-Gault formula (eGFRCG), the Modification of Diet in Renal Disease equation (eGFRMDRD), and the Chronic Kidney Disease Epidemiology Collaboration equation (eGFRCKD-EPI) with technetium-diethylenetriaminepentaacetic acid ((99m)Tc-DTPA) clearance (mGFR) in 207 potential kidney donors and 108 uninephric donors. Before donation, eGFRCKD-EPI showed minimal bias and did not show a significant difference from mGFR (P = 0.65, respectively) while 24 hr urine-CrCl and eGFRMDRD significantly underestimated mGFR (P<0.001 for each). Precision and accuracy was highest in eGFRCKD-EPI and this better performance was more dominant when renal function is higher than 90 mL·min(-1)·1.73 m(-2). After kidney donation, eGFRMDRD was superior to other equations in precision and accuracy in contrast to before donation. Within individual analysis, eGFRMDRD showed better performance at post-donation compared to pre-donation, but eGFRCKD-EPI and eGFRCG showed inferior performance at post-donation. In conclusion, eGFRCKD-EPI showed better performance compared to other equations before donation. In a uninephric donor, however, eGFRMDRD is more appropriate for the estimation of renal function than eGFRCKD-EPI.