The Race Coefficient in Glomerular Filtration Rate-estimating Equations and its Removal

Chi-yuan Hsu; Alan S. Go

Disclosures

Curr Opin Nephrol Hypertens. 2022;31(6):527-533. 

In This Article

Abstract and Introduction

Abstract

Purpose of Review: To review new publications about the use of the race coefficient in glomerular filtration rate (GFR)-estimating equations since this topic was last reviewed a year ago in Current Opinion in Nephrology and Hypertension.

Recent Findings: Accounting for race (or genetic ancestry) does improve the performance of GFR-estimating equations when serum creatinine (SCr) is used as the filtration marker but not when cystatin C is used. The National Kidney Foundation (NKF)–American Society of Nephrology (ASN) Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease recommended immediate adoption of a new refitted SCr-based equation without race and increased use of cystatin C. This report has created consensus but the endorsed new SCr equation without race underestimates GFR in Black Americans and overestimates GFR in non-Black Americans, which may result in diminished ability to detect racial disparities.

Summary: The approach recommended by the NKF–ASN Task Force represents a compromise attempting to balance a number of competing values, including racial justice, benefit of classifying more Black Americans as having (more severe) chronic kidney disease, accuracy compared with measured GFR, and financial cost. The full implications of adopting the race-free refitted CKD-EPI SCr equation are yet to be known.

Introduction

The question surrounding the race coefficient in glomerular filtration rate (GFR)-estimating equations was last reviewed in Current Opinion in Nephrology and Hypertension in November 2021.[1] While Delanaye et al.[1] presented a European perspective, the focus of this piece will be American given that both recent data and the social context are almost entirely United States-based. Heretofore, 'Black' refers to 'Black American' and 'non-Black' refers to 'non-Black American'.

A major interim development was the publication of the final report from the National Kidney Foundation (NKF)–American Society of Nephrology (ASN) Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease,[2,3] which was released online the same day as two highly pertinent original articles in the New England Journal of Medicine.[4,5]

One approach to organize the large and complex recent literature[6–26,27] is through the lens of competing values. These values include racial justice, benefit of classifying more Black Americans as having chronic kidney disease (CKD) (or more severe CKD), accuracy compared with measured GFR, and financial cost.

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