The CKD-EPI 2021 Equation and Other Creatinine-Based Race-Independent eGFR Equations in Chronic Kidney Disease Diagnosis and Staging

Background: Recent debate on the race correction factor in creatinine-based estimated glomerular filtration rate (eGFR) has led to the development of a new race-independent equation (Chronic Kidney Disease Epidemiology Collaboration, CKD-EPI-2021). Previously, some institutions have already modified the early version of the CKD-EPI or Modification of Diet in Renal Disease (MDRD) equations by removing the race factors (CKD-EPI-2009-non-Black (NB), MDRD-NB) for Black populations although this approach remains controversial. Methods: In this study, the CKD-EPI-2009-NB, MDRD-NB, and European Kidney Function Consortium (EKFC) equations were compared directly with the CKD-EPI-2021 equation in eGFR calculation, chronic kidney disease (CKD) diagnosis, and staging in a local population. Results: These 3 previous methods underestimated eGFR compared to CKD-EPI-2021 for eGFR < 90 mL/min/1.73 m² but overestimated eGFR at the high end (>120 mL/min/1.73 m²). Around the CKD diagnosis cutoff (60 mL/min/1.73 m²), both MDRD-NB and EFKC equations resulted in an increase in CKD cases compared to CKD-EPI-2021. CKD-EPI-2009-NB demonstrated a similar trend although the difference was not statistically significant. In a population with low eGFR (<60 mL/min/1.73 m²), the EKFC equation showed a CKD staging pattern significantly different from that by CKD-EPI-2021, but all 3 previous methods resulted in a similar number of end-stage renal failure cases. In general, the EKFC equation demonstrated a weaker agreement in eGFR calculation and concordance in classification with the CKD-EPI-2021 equation than MDRD-NB and CKD-EPI-2009-NB. Conclusions: Our study provides a direct visual comparison to demonstrate the potential clinical impact between 3 previously used race-independent methods and the CKD-EPI-2021 equation and aids the communication with healthcare providers during the implementation of this new equation.