Evidence Updates

Evidence Update: CKD-EPI 2021 vs MDRD GFR Equations

The new race-free CKD-EPI 2021 equation replaces both the CKD-EPI 2009 and MDRD equations. Here's what clinicians need to know about the transition.

Quick Medical Calculator Team · December 11, 2025 · 3 min read

The Shift to Race-Free GFR Equations

In 2021, a joint task force recommended removing race from eGFR calculations. The new CKD-EPI 2021 equation uses only age, sex, and serum creatinine.

Comparing the Equations

MDRD (Modification of Diet in Renal Disease)

  • Developed in 1999/2006
  • Uses: age, sex, race, creatinine
  • Less accurate at GFR >60 mL/min
  • Being phased out

CKD-EPI 2009

  • More accurate than MDRD at higher GFR
  • Still included race adjustment
  • Replaced by 2021 version

CKD-EPI 2021 (Recommended)

  • Race-free equation
  • Similar performance across populations
  • Now recommended by KDIGO, ASN, NKF

Clinical Implications

For Black Patients

Removing race typically lowers estimated GFR by 3-9 mL/min. This may:

  • Earlier CKD diagnosis
  • Earlier nephrology referral
  • Earlier transplant listing

For Non-Black Patients

Minimal change from CKD-EPI 2009.

Key Recommendations

  1. Use CKD-EPI 2021 for all new eGFR calculations
  2. Consider cystatin C for confirmation when:
  • eGFR 45-59 without markers of kidney damage
  • Extremes of muscle mass
  • Medication dosing decisions
  1. Always interpret in clinical context

Drug Dosing Considerations

When adjusting medications for renal function:

  • Use CKD-EPI creatinine equation
  • Consider CKD-EPI creatinine-cystatin C equation for precision
  • Some drugs may need original equations per FDA labeling

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