Skip to content

Inker et al. New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race. N Engl J Med. 2021;385(19):1737-1749. PMID 34554658

One-paragraph summary

The CKD-EPI collaboration developed race-free creatinine and creatinine–cystatin C equations in 8,254 and 5,352 participants, then validated them against measured GFR in 4,050 participants.

Key findings

  • At least 85% of estimates from all equations were within 30% of measured GFR. (Inker 2021, PMID 34554658)
  • The new creatinine-only equation underestimated measured GFR in Black participants by median 3.6 and overestimated it in non-Black participants by 3.9 mL/min/1.73 m². (Inker 2021, PMID 34554658)
  • Race-free creatinine–cystatin C equations were more accurate and had smaller between-group differences. (Inker 2021, PMID 34554658)

Limitations

  • Race categories and source cohorts do not represent biological ancestry.
  • Cystatin C access, cost and standardization constrain implementation.
  • Equation performance does not itself measure downstream access or outcomes.

Why it matters

It enabled removal of race from routine US eGFR reporting while making the remaining accuracy and implementation trade-offs measurable.

Cited by wiki pages

  • race and the egfr equation
  • definition staging and measurement
  • overview