A Step Toward Health Equity for Veterans: Evidence Supports Removing Race From Kidney Function Calculations
Background: The practice of race-based medicine fails to recognize that race cannot be used as a proxy for genetic ancestry and that racial and ethnic categories are complex sociopolitical constructs without biological basis. Clinical algorithms and equations that incorporate race modifiers and are currently considered standard for diagnosis and management of disease are appropriately being scrutinized for lack of biological plausibility and their role in exacerbating health inequities. In this paper, we review the history, evidence, and implications of using a Black race coefficient when calculating estimated glomerular filtration rate (eGFR) in the diagnosis and management of kidney disease.
Observations: Currently, the US Department of Veterans Affairs (VA) uses the Modification of Diet in Renal Disease (MDRD) equation for eGFR. This equation includes a Black race coefficient that results in an eGFR that is 21% higher for a Black patient when compared with a patient of any other race. The rationale for the inclusion of this coefficient is based on racist science that incorrectly assumes race as a proxy for genetic ancestry. Multiple studies across diverse Black populations demonstrate that the application of a race coefficient in kidney function estimation equations is inferior when compared with the race-neutral option. Furthermore, the most utilized eGFR equations are biased and imprecise. Because eGFR is the primary diagnostic method for detecting and managing kidney disease, preventing its progression, planning for dialysis, and evaluating for transplantation, it is vital that eGFR be as accurate, precise, and equitable as possible.
Conclusions: The incorporation of a race coefficient in kidney estimation equations lacks biological plausibility and its use exacerbates kidney health disparities. Until a better method to estimate kidney function becomes available, a race-neutral option for current estimation equations should be applied for all patients.
The American Medical Association publicly acknowledged in November 2020 that race is a social construct without biological basis, with many other leading medical organizations following suit.1 Historically, biased science based on observed human physical differences has incorrectly asserted a racial biological hierarchy.2,3 Today, leading health care organizations recognize that the effects of racist policies in housing, education, employment, and the criminal justice system contribute to health disparities and have a disproportionately negative impact on Black, Indigenous, and People of Color.3,4
Racial classification systems are fraught with bias. Trying to classify a complex and nuanced identity such as race into discrete categories does not capture the extensive heterogeneity at the individual level or within the increasingly diverse, multiracial population.5 Racial and ethnic categories used in collecting census data and research, as defined by the US Office of Management and Budget, have evolved over time.6 These changes in classification are a reflection of changes in the political environment, not changes in scientific knowledge of race and ethnicity.6
The Use of Race in Research and Practice
In the United States, racial minorities bear a disproportionate burden of morbidity and mortality across all major disease categories.3 These disparities cannot be explained by genetics.4 The Human Genome Project in 2003 confirmed that racial categories have no biologic or genetic basis and that there is more intraracial than interracial genetic variation.3 Nevertheless, significant misapplication of race in medical research and clinical practice remains. Instead of attributing observed differences in health outcomes between racial groups to innate physiological differences between the groups, clinicians and researchers must carefully consider the impact of racism.7 This includes considering the complex interactions between socioeconomic, political, and environmental factors, and how they affect health.3
While race is not biologic, the effects of racism can have biologic effects, and advocates appropriately cite the need to collect race as an important category in epidemiological analysis. When race and ethnicity are used as a study variable, bioethicists Kaplan and Bennett recommend that researchers: (1) account for limitations due to imprecision of racial categories; (2) avoid attributing causality when there is an association between race/ethnicity and a health outcome; and (3) refrain from exacerbating racial disparities.6
At the bedside, race has become embedded in clinical, seemingly objective, decision-making tools used across medical specialties.8 These algorithms often use observational outcomes data and draw conclusions by explicitly or implicitly assuming biological differences among races. By crudely adjusting for race without identifying the root cause for observed racial differences, these tools can further magnify health inequities.8 With the increased recognition that race cannot be used as a proxy for genetic ancestry, and that racial and ethnic categories are complex sociopolitical constructs that have changed over time, the practice of race-based medicine is increasingly being criticized.8
This article presents a case for the removal of the race coefficient from estimated glomerular filtration rate (eGFR) calculations that exacerbate disparities in kidney health by overestimating kidney function in Black patients.8 The main justification for using the race coefficient stems from the disproven assumption that Black people have more muscle mass compared with non-Black people.9 The questioning of this racist assertion has led to a national movement to reevaluate the use of race in eGFR calculations.
Racial Disparities in Kidney Disease
According to epidemiological data published by the National Kidney Foundation (NKF) and American Society of Nephrology (ASN), 37 million people in the United States have chronic kidney disease (CKD).10 Black Americans make up 13% of the US population yet they account for more than 30% of patients with end-stage kidney disease (ESKD) and 35% of those on dialysis.10,11 There is a 3 times greater risk for progression from early-stage CKD to ESKD in Black Americans when compared to the risk for White Americans.11 Black patients are younger at the time of CKD diagnosis and, once diagnosed, experience a faster progression to ESKD.12 These disparities are partially attributable to delays in diagnosis, preventative measures, and referrals to nephrology care.12
