Assessment of the 2023 European Kidney Function Consortium (EKFC) equations in a Chinese adult population

Abstract Objectives The European Kidney Function Consortium (EKFC) developed two novel equations in 2023 for estimating glomerular filtration rate (GFR): one sex-free cystatin C-based equation (EKFC Cys ) and one creatinine-cystatin C combined equation (EKFC Cr-Cys ). This study compared their performance with the previous creatinine-based EKFC equation (EKFC Cr ) and commonly used Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Berlin Initiative Study (BIS) equations in Chinese adults. Methods A total of 2,438 Chinese adults (mean age=53.04 years) who underwent the 99mTc-DTPA renal dynamic imaging for reference GFR (rGFR) were included. Diagnostic value was evaluated using correlation coefficients, sensitivity, specificity, and area under the receiver operating characteristic curve (ROC AUC ). Performance was assessed in terms of bias, precision (interquartile range of the median difference [IQR]), accuracy (percentage of estimates ±30 % of rGFR [P30], and root-mean-square error [RMSE]) across age, sex, and rGFR subgroups. Gender differences in bias and P30 were also analyzed. Results Average rGFR was 73.37 mL/min/1.73 m 2 . EKFC equations showed stronger correlations and larger AUCs compared to the parallel CKD-EPI equations, with EKFC Cr-Cys demonstrating the greatest improvement (R=0.771, ROC AUC =0.913). Concerning bias, precision, and accuracy, EKFC equations consistently outperformed CKD-EPI equations. EKFC Cr-Cys and EKFC Cr performed acceptably well in the entire population and were equivalent to BIS equations in the elderly. All equations, including EKFC Cys , showed similar P30 accuracy across sexes. Conclusions EKFC equations provided a reasonable alternative for estimating GFR in the Chinese adult population. While EKFC Cys did not outperform EKFC Cr , EKFC Cr-Cys improved the accuracy of single-marker equations.