Comparison of equations to estimate glomerular filtration rate and their impact on frequency of cisplatin-associated acute kidney injury

Abstract

Background: Accurate estimation of kidney function is essential for patient selection and drug dosing in cancer patients. Glomerular filtration rate (GFR) estimating equations are necessary for decision-making and monitoring. Our aim was to identify which of these equations-estimated creatinine clearance (eCrCl) by Cockcroft-Gault (CG), estimated GFR (eGFR) by Modification of Diet in Renal Disease (eGFRMDRD), Chronic Kidney Disease Epidemiology Collaboration (eGFRCKD-EPI) or recently proposed Janowitz-Williams equation (eGFRJ-W)-would be most suitable for GFR estimation among patients with cancer receiving cisplatin. Methods: We assembled a cohort of 5274 cancer patients treated with cisplatin-based chemotherapy at two large cancer centers. We ascertained the frequency of cisplatin-associated acute kidney injury (C-AKI) defined as a ≥0.3mg/dl rise in serum creatinine over baseline. We compared baseline eGFR and eCrCl using Bland-Altman (B-A) plots, coefficients of variation (CV), and concordance correlation coefficients. We calculated positive predictive value (PPV), negative predictive value (PPV), accuracy, and area under the curve (AUC). Results: Patients were predominantly middle-aged (58, IQR 49-66 years), overweight (BMI 26.2, IQR 23.1-29.8 kg/m2), and white (87.6%) with a median baseline creatinine of 0.8 mg/dl and median cisplatin dose of 99 mg. C-AKI developed in 11.5% of the cohort. eGFRCKD-EPI had the highest PPV as well as AUC. eGFRCKD-EPI and eGFRMDRD along with their BSA-modified counterparts had the closest agreement with the lowest CV (7.2, 95% CI 7.0-7.3) and the highest concordance. C-AKI was lowest when using eGFRCKD-EPI to define eGFR ≥60ml/min/1.73 m2. Conclusion: Based on its superior diagnostic performance, eGFRCKD-EPI should be used to estimate GFR in patients being considered for cisplatin-based chemotherapy.