Comparative performances of the new chronic kidney disease epidemiology equations incorporating cystatin C for use in cancer patients

Aim In cancer patients receiving chemotherapy treatment, accurate assessment of kidney function is required. The aim of our study was to investigate whether the inclusion of cystatin C together with creatinine in prediction equations would improve the prediction of glomerular filtration rate (GFR). Methods Plasma creatinine and cystatin C were analyzed in 155 patients (cancer, n = 80, kidney donors, n = 75) undergoing 99mTechnetium diethylenepentaacetic (Tc‐DTPA) GFR clearance. Equations by the CKD‐EPI (chronic kidney disease epidemiology) group (creatinine‐, creatinine + cystatin C‐, cystatin C‐based, respectively) and Cockcroft–Gault were compared with Tc‐DTPA GFR by difference plots, receiver operator characteristics curve analysis, root mean square error, chi‐squared analysis and percentage concordance according to carboplatin dosage. Comparisons between two creatinine methodologies (enzymatic vs Jaffe) were also performed. Results In the overall group, the combination creatinine and cystatin C equation had 69% of results within 20% of GFR (P20), a sensitivity of 86.3% and a specificity of 73.1% to detect reduced GFR at