Comparison of Equations To Estimate Glomerular Filtration Rate and Their Impact on Frequency of Cisplatin-associated Acute Kidney Injury.

Background: Accurate estimation of kidney function is essential for patient selection and drug dosing in patients with cancer. eGFR 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), eGFR by Modification of Diet in Renal Disease (eGFR), CKD Epidemiology Collaboration (eGFR) or the recently proposed Janowitz-Williams equation (eGFR)-would be most suitable for GFR estimation among patients with cancer receiving cisplatin.

Methods: We assembled a cohort of 5274 patients with cancer treated with cisplatin-based chemotherapy at two large cancer centers. We ascertained the frequency of cisplatin-associated AKI (C-AKI) defined as a ≥0.3 mg/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 the positive predictive value (PPV), negative predictive value (PPV), accuracy, and area under the curve (AUC).

Results: Patients were predominantly middle aged (median 58 years, IQR 49-66 years), overweight (median BMI 26.2, IQR 23.1-29.8 kg/m), and White (88%), with a median baseline creatinine of 0.8 mg/dl and median cisplatin dose of 99 mg. C-AKI developed in 12% of the cohort. eGFR had the highest PPV and AUC. eGFR and eGFR, along with their BSA-modified counterparts, had the closest agreement with the lowest CV (7.2, 95% CI, 7.0 to 7.3) and the highest concordance. C-AKI was lowest when using eGFR to define eGFR ≥60 ml/min per 1.73 m.

Conclusions: On the basis of its superior diagnostic performance, eGFR should be used to estimate GFR in patients being considered for cisplatin-based chemotherapy.