Comparison of different equations for estimated glomerular filtration rate in Han Chinese patients with chronic kidney disease.

AIM

To understand the agreement, precision, and accuracy between other estimated glomerular filtration rate (eGFR) equations and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine-cystatin C equation (EPI_Cr_CysC).

MATERIALS AND METHODS

We conducted a cross-sectional study of 1,913 CKD patients. The eGFRs were calculated separately by creatinine clearance rate and Cockcroft-Gault equation corrected for standard body surface area (Ccr_BSA and eCcr_BSA); CKD-EPI creatinine equation (EPI_Cr); CKD-EPI cystatin C equation (EPI_CysC); EPI_Cr_CysC equation; Modification of Diet in Renal Disease (MDRD) Study equation with standardized serum creatinine; and full-age spectrum creatinine equation (FAS). The EPI_Cr_CysC equation was used as the reference.

RESULTS

When compared with the EPI_Cr_CysC equation, the EPI_Cr equation achieved the highest agreement in eGFRs (Lin's concordance correlation coefficient = 0.936, 95% confidence interval (CI) = 0.930, 0.941). eCcr_BSA and EPI_Cr equations achieved the first and second highest percentage agreement in the accurate classification of CKD stage (72.55 vs. 71.25%). The MDRD equation had minimal bias and was closely followed by the EPI_Cr equation (median difference = -1.3, 95% CI = -2.0, -0.8 vs. median difference = 2.5, 95% CI = 1.7, 3.3 mL/min/1.73m). The EPI_CysC and EPI_Cr equations achieved the first and second highest precision (interquartile range (IQR) of the difference = 12.2, 95% CI = 11.6, 12.9 vs. IQR of the difference = 15.5, 95% CI = 14.7, 16.3 mL/min/1.73m). The EPI_Cr and MDRD equations performed similarly and both had the highest accuracy at 30% (1 - P = 18.6, 95% CI = 16.9, 20.4 vs. 1 - P = 18.6, 95% CI = 16.8, 20.3%).

CONCLUSION: For assessment of renal function, the EPI_Cr equation performed the best and remained an acceptable alternative to the EPI_Cr_CysC equation in the absence of cystatin C.
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