Excluding race in GFR equations leads to ‘substantial’ rise in estimated CKD prevalence
After assessing kidney function in a sample of self-identified Black adults, researchers found excluding race from the calculations led to a “substantial increase” in estimated prevalence of chronic kidney disease.
Healio Nephrology previously reported on this issue, which has been garnering attention from organizations like the National Kidney Foundation and the American Society of Nephrology. These organizations launched a joint task force to reassess the use of race in kidney disease diagnoses in August 2020 with the aim of “ensuring that eGFR provides an unbiased assessment of kidney function.”
“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, with potential for race-based equations to perpetuate disparities between Black individuals and non-Black individuals,” Jennifer Bragg-Gresham, PhD, of the University of Michigan, and colleagues wrote in a research letter. “ ... Deleting the coefficient for Black race is associated with an approximately 14% lower estimated GFR (eGFR) among Black patients. 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.”
To further evaluate the specific impact removing race from eGFR equations might have, researchers included 9,682 Black adults from “nationally representative samples of the U.S. general population” from the National Health and Nutrition Examination Surveys (NHANES) and 786,718 Black veterans from the national VA Health System. Investigators measured eGFR in both cohorts using the Chronic Kidney Disease Epidemiology Collaboration CKD-EPI equation with and without the coefficient for Black race.
For the U.S. adult Black population identified through NHANES, results showed mean eGFR decreased from 102.8 mL/min/1.73m2 using the CKD-EPI equation with the race coefficient to 88.1 mL/min/1.73 m2 using the equation without the race coefficient. Mean eGFR was also seen to decrease in the cohort of Black veterans (from 82.9 mL/min/1.73m2 including race to 71.6 mL/min/1.73m2 without race).
With the decreases seen after eliminating the coefficient for Black race, the overall prevalence of Black individuals classified as having CKD (defined as eGFR <60 mL/min/1.73m2) would increase from 5.8% to 10.4% in the U.S. population and from 15.5% to 26.3% in the veteran population.
“The potential implications of our findings for the outcomes of Black individuals in the U.S. (eg, use of health care services) were beyond the scope of this research letter,” Bragg-Gresham and colleagues concluded of the findings. “A rigorous examination of the consequences of this large, expected shift in the estimated burden of CKD is required, with sensitivity to individual patient perspectives and public health considerations to minimize the possibility of unintended harm. Our findings suggest that continuing research to improve current GFR estimating equations using race-neutral biomarkers should be given high priority.”