Prevalence of Chronic Kidney Disease Among Black Individuals in the US After Removal of the Black Race Coefficient From a Glomerular Filtration Rate Estimating Equation

This cross-sectional study examines whether removal of the Black race coefficient from a glomerular filtration rate (GFR) estimating equation is associated with a change in the estimated prevalence of chronic kidney disease (CKD) in the general Black population and among Black veterans in the US.


Introduction
The use of a correction for Black race in glomerular filtration rate (GFR) estimating equations for Black adults has recently been challenged on the basis of race being a social construct, 1 with potential for race-based equations to perpetuate disparities between Black individuals and non-Black individuals. 2-4 Current GFR estimating equations were developed and validated in cohort studies 4 that included voluntarily participating, representative populations of Black individuals in the US. The coefficient for Black race is an attempt to correct for non-GFR factors associated with serum creatinine concentration. Deleting the coefficient for Black race is associated with an approximately 14% lower estimated GFR (eGFR) among Black patients. 5 Removal of the coefficient would increase the number of Black individuals being classified as having CKD or reclassified as having a more advanced stage of the disease if they already had the condition. The aim of our study was to assess how much this change at the patient level would affect the distribution of eGFR categories below eGFR of 60 mL/min/1.73 m 2 (ie, CKD stage 3 or higher, not including dialysis or transplantation) in both the US general population and the population of US veterans who use the Veterans Affairs (VA) Health System.

Methods
In this cross-sectional study, we analyzed data on 9682 Black adults from nationally representative samples of the US general population from the National Health and Nutrition Examination Surveys Sample weights used in analyses of NHANES data allowed application of the estimates to the US general population. We estimated a prevalence of an eGFR less than 60 mL/min/1.73 m 2 among individuals who self-identified as Black in both data sets using the Chronic Kidney Disease Epidemiology Collaboration CKD-EPI equation 5 with and without the coefficient for Black race. We used SAS, version 9.4 (SAS Institute) for analysis of NHANES data and R, version 3.62 (R Project for Statistical Computing) for VA data.

Results
The mean eGFR decreased from 102.  Figure). Elimination of the coefficient for Black race would result in 981 038 (overall prevalence change of 5.8% to 10.4%) more Black individuals being classified as having CKD (eGFR <60 mL/min/ 1.73 m 2 ; ie, CKD stage 3 or higher) in the US adult population (Table). An additional 84 988 (overall prevalence change of 15.5% to 26.3%) Black adults would potentially be classified as having CKD among those using the VA Health System (Table).

Discussion
In this cross-sectional study, removal of the coefficient for Black race from the CKD-EPI equation was associated with a substantial increase in the estimated prevalence of CKD among the US Black population and among US Black veterans who use a large nationally integrated health system. The main limitation of this study is the inconsistency in the reporting of race across all study participants.
In addition, the potential implications of our findings for the outcomes of Black individuals in the US (eg, use of health care services) were beyond the scope of this research letter. A rigorous examination

JAMA Network Open | Nephrology
Removal of Black Race Coefficient From a GFR Equation and Prevalence of CKD