Background

For over a decade, the CKD-EPI 2009 equation included a race coefficient that assigned higher eGFR values to Black patients compared to non-Black patients with identical creatinine levels. In 2021, the National Kidney Foundation and American Society of Nephrology jointly recommended removing race from the equation — a landmark change with significant clinical implications.

Why Was Race Removed?

Race is a social construct, not a biological variable. The original race coefficient was derived from population-level differences in muscle mass and creatinine generation, but:

• →Individual variation within racial groups far exceeds between-group differences
• →Misclassification is common — patients may not identify with the racial categories used
• →Equity concerns — the race coefficient systematically delayed nephrology referral and transplant listing for Black patients
• →Cystatin C data showed the race coefficient was not needed when cystatin C was included

The New 2021 Equation

The 2021 CKD-EPI creatinine equation uses only:

• •Serum creatinine
• •Age
• •Sex (male/female)

It performs comparably to the 2009 equation in most populations and eliminates the racial disparity in eGFR estimation.

Clinical Implications

Drug Dosing

Most pharmacokinetic studies used Cockcroft-Gault (not CKD-EPI) for drug dosing. Continue using Cockcroft-Gault for medication dosing decisions — CKD-EPI is for CKD staging.

CKD Staging

The 2021 equation may reclassify some patients:

• •Black patients previously classified as G2 may now be classified as G3a
• •This may trigger earlier nephrology referral and SGLT2 inhibitor initiation

SGLT2 Inhibitors

DAPA-CKD and EMPA-KIDNEY trials showed benefit down to eGFR 20–25 mL/min/1.73m². With the new equation, more patients may qualify for these kidney-protective agents.

When to Use Cystatin C

The combined CKD-EPI creatinine-cystatin C equation provides the most accurate eGFR estimate, particularly in:

• •Patients with unusual muscle mass (cachexia, amputees, bodybuilders)
• •Elderly patients
• •Patients with liver disease
• •When creatinine-based eGFR seems discordant with clinical picture

Key Takeaway

Switch to the 2021 race-free CKD-EPI equation for all eGFR reporting. This is now the standard recommended by NKF, ASN, KDIGO, and most major nephrology societies worldwide.