New creatinine- And cystatin C-based equations to estimate GFR without race

the Chronic Kidney Disease Epidemiology Collaboration

Research output: Contribution to journalArticlepeer-review

146 Scopus citations


BACKGROUND Current equations for estimated glomerular filtration rate (eGFR) that use serum creatinine or cystatin C incorporate age, sex, and race to estimate measured GFR. However, race in eGFR equations is a social and not a biologic construct. METHODS We developed new eGFR equations without race using data from two development data sets: 10 studies (8254 participants, 31.5% Black) for serum creatinine and 13 studies (5352 participants, 39.7% Black) for both serum creatinine and cystatin C. In a validation data set of 12 studies (4050 participants, 14.3% Black), we compared the accuracy of new eGFR equations to measured GFR. We projected the prevalence of chronic kidney disease (CKD) and GFR stages in a sample of U.S. adults, using current and new equations. RESULTS In the validation data set, the current creatinine equation that uses age, sex, and race overestimated measured GFR in Blacks (median, 3.7 ml per minute per 1.73 m2 of body-surface area; 95% confidence interval [CI], 1.8 to 5.4) and to a lesser degree in non-Blacks (median, 0.5 ml per minute per 1.73 m2; 95% CI, 0.0 to 0.9). When the adjustment for Black race was omitted from the current eGFR equation, measured GFR in Blacks was underestimated (median, 7.1 ml per minute per 1.73 m2; 95% CI, 5.9 to 8.8). A new equation using age and sex and omitting race underestimated measured GFR in Blacks (median, 3.6 ml per minute per 1.73 m2; 95% CI, 1.8 to 5.5) and overestimated measured GFR in non-Blacks (median, 3.9 ml per minute per 1.73 m2; 95% CI, 3.4 to 4.4). For all equations, 85% or more of the eGFRs for Blacks and non-Blacks were within 30% of measured GFR. New creatinine-cystatin C equations without race were more accurate than new creatinine equations, with smaller differences between race groups. As compared with the current creatinine equation, the new creatinine equations, but not the new creatinine-cystatin C equations, increased population estimates of CKD prevalence among Blacks and yielded similar or lower prevalence among non-Blacks. CONCLUSIONS New eGFR equations that incorporate creatinine and cystatin C but omit race are more accurate and led to smaller differences between Black participants and non-Black participants than new equations without race with either creatinine or cystatin C alone.

Original languageEnglish (US)
Pages (from-to)1737-1749
Number of pages13
JournalNew England Journal of Medicine
Issue number19
StatePublished - Nov 4 2021

Bibliographical note

Funding Information:
The study was conducted by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases, which had no role in the analysis of data, the preparation or approval of the manuscript, or the decision to submit the manuscript for publication. The authors vouch for the completeness and accuracy of the data and for the fidelity of the study to the statistical analysis plan. The institutional review boards at all participating institutions approved each study that was used as a data source, and the institutional review board at Tufts Medical Center approved the overall analyses.

Publisher Copyright:
© 2021 Massachusetts Medical Society.

PubMed: MeSH publication types

  • Journal Article
  • Research Support, N.I.H., Extramural


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