Accuracy assessment of five equations used for estimating the glomerular filtration rate in Korean adults

Background: We aimed to assess the performance of the five creatinine-based equations commonly used for estimates of the glomerular filtration rate (EGFR), namely, the creatinine-based Chronic Kidney Disease Epidemiology Collaboration (CKD-EPIcr), Asian CKD-EPI, revised Lund-Malmö (revised LM), full age spectrum (FAS), and Korean FAS equations, in the Korean population. Methods: A total of 1, 312 patients, aged 20 yr and above who underwent ⁵¹Cr-EDTA GFR measurements (mGFR), were enrolled. The bias (EGFR-mGFR) and precision (root mean square error [RMSE]) were calculated. The accuracy (P30) of four EGFR equations was compared to that of the CKD-EPIcr equation. P30 was defined as the percentage of patients whose EGFR was within±30% of the mGFR. Results: The mean bias (mL·min^-1·1.73 m^-2) of the five EGFR equation was as follows: CKD-EPIcr, -0.6; Asian CKD-EPI, 2.7; revised LM, -6.5; FAS, -2.5; and Korean FAS, -0.2. The bias of the Asian CKD-EPI, revised LM, and FAS equations showed a significant difference from zero (P<0.001). The RMSE values were as follows: CKD-EPIcr, 15.6; Asian CKD-EPI, 15.6; revised LM, 17.9; FAS, 16.3; and Korean FAS, 15.8. There were no significant differences in the P30 except for the Asian CKD-EPI equation: CKD-EPIcr, 76.6%; Asian CKD-EPI, 74.7%; revised LM, 75.8%; FAS, 76.0%; and Korean FAS, 75.8%. Conclusions: The CKD-EPIcr and Korean FAS equations showed equivalent analytical and clinical performances in the Korean adult population.