The EKFC equation outperforms the CKD‐EPI and CKiD equations for GFR estimation in adolescent and young adult kidney transplant patients

Abstract

AbstractAimThis study evaluated the bias and accuracy of the CKD‐EPI/CKiD and EKFC equations compared with the reference exogenous tracer‐based assessment of glomerular filtration rate (GFR) in adult and pediatric patients according to their renal transplant status.MethodsWe assessed the bias and P30 accuracy of the CKD‐EPI/CKiD and EKFC equations compared with iohexol‐based GFR measurement.ResultsIn the overall population (n = 59), the median age was 29 years (IQR, 16.0–46.0) and the median measured GFR was 73.9 mL/min/1.73m2 (IQR, 57.3–84.6). Among non‐kidney transplant patients, the median was 77.7 mL/min/1.73m2 (IQR, 59.3–86.5), while among kidney transplant patients, it was 60.5 mL/min/1.73m2 (IQR, 54.2–66.8). The bias associated with the EKFC and CKD‐EPI/CKiD equations was significantly higher among kidney transplant patients than among non‐kidney transplant patients, with a difference between medians (Hodges–Lehmann) of +10.4 mL/min/1.73m2 (95% CI, 2.2–18.9; p = .02) for the EKFC and +12.1 mL/min/1.73m2 (95% CI, 4.2–21.4; p = .006) for the CKD‐EPI/CKiD equations. In multivariable analysis, kidney transplant status emerged as an independent factor associated with a bias of >3.4 mL/min/1.73m2 (odds ratio, 7.7; 95% CI, 1.4–43.3; p = .02) for the EKFC equation and a bias of >13.4 mL/min/1.73m2 (odds ratio, 15.0; 95% CI, 2.6–85.7; p = .002) for the CKD‐EPI/CKiD equations.ConclusionIn our study, which included adolescent and young adult kidney transplant patients, both the CKD‐EPI/CKiD and EKFC equations tended to overestimate the measured glomerular filtration rate, with the EKFC equation exhibiting less bias. Renal transplant status significantly influenced the degree of estimation bias.image