Much More Than Revising Estimating Equations
Exploring the journey toward equitable kidney health beyond race-based equations, addressing systemic factors and structural racism.
Imagine a medical calculation that could alter your diagnosis, change your treatment plan, and even determine when you qualify for a life-saving transplant—based not on your biology, but on your race. For decades, this was standard practice in kidney care through the use of race-based equations to estimate kidney function. While recent efforts have eliminated this overtly discriminatory practice, the journey toward truly equitable kidney health reveals a far more complex picture. This article explores how addressing deep-rooted systemic factors—from social determinants of health to structural racism—is proving essential to eliminating the stark racial disparities that persist in kidney disease.
For decades, race-based equations systematically disadvantaged Black patients in kidney care.
For over two decades, healthcare providers worldwide used estimation equations for glomerular filtration rate (eGFR)—a key measure of kidney function—that included a race coefficient2 . These equations, specifically the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, systematically multiplied eGFR results by 1.21 or 1.16 respectively if a patient was identified as "Black"6 .
This adjustment had significant clinical consequences, as eGFR thresholds guide critical decisions in kidney disease management—from diagnosis and specialist referral to qualification for transplant waiting lists6 . The race coefficient meant that Black patients needed to have more advanced kidney damage than non-Black patients to receive the same diagnosis or qualify for the same interventions1 .
The scientific basis for including race in these equations has been widely debunked. Race is a social-political construct, not a biological one1 . The development of the MDRD equation included "Black ethnicity" among initial predictor variables without a functional definition or hypothesis, relying on small, flawed studies that provided no control for social factors6 .
As the medical community has recognized, using race as a biological proxy reinforces flawed assumptions of race essentialism and potentially perpetuates health inequities1 . As one review noted, "Ignoring the biological and social heterogeneity within any racial group and inferring innate individual-level attributes is methodologically flawed"1 .
The race coefficient artificially increased eGFR values for Black patients, delaying diagnosis and treatment.
The medical community has taken significant steps to eliminate race-based calculations.
In response to growing recognition of these problems, the National Kidney Foundation (NKF) and American Society of Nephrology (ASN) convened a Task Force to recommend an evidence-based race-free approach to eGFR2 . After rigorous review of more than 20 approaches, the Task Force recommended immediate implementation of the CKD-EPI 2021 creatinine equation without the race variable2 .
This change, while seemingly technical, represents a significant shift in medical practice toward more equitable care. As one analysis noted, "Removing race from the algorithm used to assess kidney function is most equitable. Since race is a social construct, its use in clinical algorithms has facilitated health disparities"2 .
Research has demonstrated just how significant the race coefficient's impact has been on patient care. One study analyzed population-representative data from the National Health and Nutrition Examination Survey (NHANES) to quantify these effects6 .
| Clinical Action Threshold | Additional Black Americans Who Would Qualify Without Race Coefficient | Percentage Increase |
|---|---|---|
| Diagnosis of Stage 3 Chronic Kidney Disease (eGFR ≤60 mL/min/1.73m²) | 3.3 million | 10.4% |
| Referral to Nephrology Specialist | 300,000 | 0.7% |
| Eligibility for Transplant Evaluation (eGFR ≤20 mL/min/1.73m²) | 31,000 | 0.1% |
This research demonstrated that the race coefficient systematically disadvantaged Black patients by delaying diagnosis and appropriate care. The authors concluded that "abandoning racialized eGFR calculations dismantles discriminatory and unscientific practices and provides opportunity for more accurate and equitable medicine"6 .
While removing race from eGFR equations addresses one form of discrimination, racial disparities in kidney health extend far beyond estimation formulas.
vs. 12% in Non-Hispanic White adults
Compared to White Americans
For African Americans even after adjusting for factors3
Perhaps nowhere are kidney health disparities more evident than in transplantation. One prospective cohort study followed 1,055 patients evaluated for kidney transplantation between 2010-2012, examining whether racial disparities in wait-listing persisted after adjusting for social determinants of health3 .
The research team collected extensive data on demographic characteristics, medical factors, cultural factors (such as medical mistrust and experiences with discrimination), psychosocial characteristics, and transplant knowledge3 . Despite accounting for all these variables, African American patients were still 25% less likely to be placed on transplant waitlists compared to White patients3 .
This finding suggests that novel factors beyond those traditionally measured—potentially including implicit bias and systemic barriers within healthcare systems—continue to perpetuate disparities, highlighting the need for more comprehensive interventions3 .
Achieving equity in kidney health requires addressing the problem at multiple levels.
| Level of Intervention | Key Strategies | Expected Outcomes |
|---|---|---|
| Clinical Tools | Implement race-free eGFR equations; expand use of cystatin C testing2 | More accurate diagnosis; reduced diagnostic delays |
| Healthcare Systems | Increase workforce diversity; use clinical decision aids addressing social determinants9 | More culturally responsive care; reduced bias |
| Policy & Structural | Develop antiracist reimbursement policies; invest in community health9 | Reduced structural barriers; more equitable resource allocation |
As one commentary on navigating to kidney health equity noted, "We need to redirect our science, publications, funding, and other resources from novel discoveries and descriptive epidemiology to implementing evidence-based processes, programs, and policies with explicit and measurable objectives for achieving fair and just opportunities to have equal health outcomes"9 .
Conditions in which people are born, grow, live, work, and age that affect kidney health outcomes8 .
Ways in which societies foster discrimination through mutually reinforcing systems of housing, education, employment, and healthcare1 .
Equity involves providing resources based on need rather than treating everyone the same, which is particularly important in kidney care8 .
Partnering with patients, community members, and other stakeholders to ensure research addresses community priorities9 .
Eliminating the race coefficient from kidney function equations represents an important step toward justice in nephrology, but it is only the beginning. As we've seen, true equity requires confronting structural racism and addressing social determinants of health that create and perpetuate disparities1 9 .
The path forward demands that we look beyond clinical algorithms to consider the full spectrum of factors influencing kidney health—from poverty and pollution to discrimination and limited access to care. It requires diversifying the healthcare workforce, implementing antiracist policies, and most importantly, centering the voices of affected communities in designing solutions9 .
As one analysis aptly stated, "Clinicians have a duty to recognize and elucidate the nuances of racism and its effects on health and disease. Otherwise, we risk perpetuating historical racist concepts in medicine that exacerbate health inequities"1 . The journey to equitable kidney health continues, and it's one we must travel together.