Multicentre validation of the CamGFR model for estimated glomerular filtration rate

Important oncological management decisions rely on kidney function assessed by serum creatinine-based estimated glomerular filtration rate (eGFR). However, no large-scale multicentre comparison of methods to determine eGFR in patients with cancer are available.\ud \ud To compare the performance of formulas for eGFR based on routine clinical parameters and serum creatinine not calibrated with isotope dilution mass spectrometry (non-IDMS), we studied 3,620 patients with cancer and 166 without cancer who had their GFR measured with an exogenous nuclear tracer at one of seven clinical centres. The mean measured GFR was 86 ml/min. Accuracy of all models was centre-dependent, reflecting inter-centre variability of non-IDMS creatinine measurements. CamGFR was the most accurate model for eGFR (root-mean-squared-error (RMSE) 17.3 ml/min) followed by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) model (RMSE 18.2 ml/min).