Assessing Glomerular Filtration Rate by Estimation Equations in Kidney Transplant Recipients

Abstract

Surveillance of glomerular filtration rate (GFR) is crucial in the management of kidney transplant recipients. With especial emphasis on serum creatinine (SCr) calibration assay, we assessed the performance of estimation equations as compared to iothalamate GFR (iGFR) in 209 patients using the modification of diet in renal disease (MDRD), Nankivell and CockcroftGault methods. Fifty-five percent of patients were treated with a calcineurin inhibitor (CNI) and all were taken trimethroprim-sulfametoxazole at the time of SCr measurement. The mean iGFR was 44 ± 26 mL/min/1.73 m 2 . The MDRD equation showed a median difference of 0.9 mL/min/1.73 m 2 with 53% of estimated GFR within 20% of iGFR. Median differences were 7.5 and 7.0 mL/min/1.73 m 2 for Nankivell and Cockcroft-Gault formulas, respectively. The accuracy of the Nankivell and Cockcroft-Gault formulas was such that only 38% and 37% of estimations, respectively, fell within 20% of iGFR. The performance of all equations was not uniform throughout the whole range of GFR, with some deterioration at the extremes of GFR levels. In addition, good performance of the MDRD equation was seen in subjects taking CNI. In conclusion, the overall performance of the MDRD equation was superior to the Nankivell and CockcroftGault formulas in renal transplant recipients including subjects treated with CNI.

Performance of the Cockcroft-Gault, MDRD, and New CKD-EPI Formulas in Relation to GFR, Age, and Body Size

“…The relation of the absolute bias with body weight and BMI is surprising given their normalization for BSA. In line with our results, others also found the estimation of Cockcroft-Gault to be more dependent on body weight or BMI than MDRD (8,19,20). The influence of BMI on the bias of Cockcroft-Gault has been described before (5,23), although not all studies found this relationship (6,21).…”

“…Most studies showed a larger bias in stage 2 than in stage 3 CKD for Cockcroft-Gault or MDRD (6,7,19,20), which is in contrast to our findings. The relatively small number of patients in the subgroups in our study as well as in some of the aforementioned studies (7,19) could be an explanation for this difference; however, studying the accuracies over the subgroups, all formulas showed a pattern in which the accuracies became smaller per GFR subgroup, which is in line with others (6,20). Furthermore, the regression analysis that was based on the absolute bias per patient did show a linear relation between the GFR and the absolute bias.…”

The MDRD Equation Predicts Peritoneal Dialysis-Delivered Creatinine Clearances from Serum Creatinine

“…Our results suggest that the MDRDEs reliably estimate creatinine clearances in PD patients, and the same MDRDEs also predict GFRs before and after transplantation of hemodialysis and PD patients (7). This suggests that creatinine kinetics are similar in these populations.…”

Five-Year Outcomes in Kidney Transplant Patients Converted From Cyclosporine to Everolimus: The Randomized ZEUS Study

“…At the 5-year study visit, data on donor-specific antibody (DSA) levels and lipid profiles were collected following a protocol amendment. Estimated GFR (eGFR) was calculated according to the Nankivell (23), and MDRD (25) formulae. The primary efficacy end point was eGFR (Nankivell) at month 12, assessed by analysis of covariance (ANCOVA) with treatment, center and donor type as factors, and eGFR at month 4.5 as a covariate, using the last observation carried forward (LOCF) method for missing values (18), that is irrespective of whether one or more components of the calculated GFR were missing, the calculated GFR value of the previous visit was substituted.…”