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- Inker, Lesley A., et al.
(author)
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New creatinine- and cystatin C-based equations to estimate GFR without race
- 2021
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In: New England Journal of Medicine. - 0028-4793. ; 385:19, s. 1737-1749
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Journal article (peer-reviewed)abstract
- 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.
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- Inker, Lesley A., et al.
(author)
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CKD-EPI and EKFC GFR Estimating Equations: Performance and Other Considerations for Selecting Equations for Implementation in Adults
- 2023
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In: Journal of the American Society of Nephrology. - 1046-6673. ; 34:12, s. 1953-1964
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Journal article (peer-reviewed)abstract
- Background: New CKD-EPI and EKFC estimated GFR (eGFR) equations usingcreatinine (eGFRcr), cystatin C (eGFRcys) and both (eGFRcr-cys) have sufficientaccuracy for use in clinical practice. A better understanding of the equations, includingtheir performance in race, sex and age subgroups, is important for selection of eGFRequations for global implementation.Methods: We evaluated performance (bias and P30) of equations and methods usedfor equation development in an independent study population comprising 4050participants pooled from 12 studies. The mean (SD) mGFR was 76.4 (29.6)ml/min/1.73 m2, age 57.0 (17.4) years, with 1557 (38%) women and 579 (14%) Blackparticipants.Results: Coefficients for creatinine, cystatin C, age and sex in the CKD-EPI and EKFCequations are similar. Performance of the eGFRcr-cys equations in the overallpopulation (bias 90%) was better than the eGFRcr oreGFRcys equations, with fewer differences among race, sex and age subgroups.Differences in performance across subgroups reflected differences in diversity ofsource populations and use of variables for race and sex for equation development.Larger differences among eGFRcr equations reflected regional population differencesin non-GFR determinants of creatinine.Conclusion: CKD-EPI and EKFC equations are approaching convergence. It is notpossible to maximize both accuracy and uniformity in selecting one of the currentlyavailable eGFRcr equations for implementation across regions. Decisions shouldconsider methods for equation development in addition to performance. Wider use ofcystatin C with creatinine could maximize both accuracy and uniformity of GFRestimation using currently available equations.
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