Eliminating Race as a Variable in Estimating Kidney Function

Eliminating Race as a Variable in Estimating Kidney Function
Trainees lead an effort to end race-based adjustment to eGFR.

In the U.S., Black patients are systematically assigned higher values than non-Black patients in equations for calculating estimated glomerular filtration rate (eGFR), reported in the lab system as eGFR AA. There has been increasing awareness and concern that this systematic practice may be harmful.

“[Race] is included in both the MDRD and CKD-EPI equations, but this variable is not an appropriate proxy for genetics or ancestry, and has never reflected the diversity of individuals with biracial or multiracial identities,” said Sophia Kostelanetz, M.D., an instructor in the Department of Medicine at Vanderbilt University Medical Center. Kostelanetz recently led a group of medical students, residents and faculty to successfully end the use of race as a variable in the calculation of eGFR at Vanderbilt.

The group argued that eliminating the race-based adjustment may offer multiple clinical benefits: more timely management and referral of early kidney disease; earlier transplant listing; and more careful medication decisions for Black patients.

Critically Examining the Use of Race

As a team, the group examined the evidence for and against use of race-based adjustment of eGFR. Collaborators in developing the case against the practice at Vanderbilt included Ali Lutz, Kostelanetz’s co-leader in the Nashville Chapter of the Campaign Against Racism; resident Ndang Azang-Njaah, M.D.; medical students Annie Apple, Karampreet “Peety” Kaur and Tita González Peña; and nephrologists Kahled Abdel-Kader, M.D., an assistant professor of medicine, and Beatrice Concepcion, M.D., associate medical director of the kidney and pancreas transplant program.

After a thorough evaluation of the underlying science, a literature review and discussions with colleagues at other academic medical centers, the group concluded that the race-based adjustment, while initially developed based on a regression model, was inappropriate.

“For all of us, this was an opportunity to investigate medical education’s role in pathologizing race and teaching about racial differences as though race is a biologic phenomenon instead of a measure for sociopolitical, economic, environmental and/or cultural context,” Kostelanetz said.

“This was an opportunity to investigate medical education’s role in pathologizing race.”

Advancing Institutional Change

After presenting a proposal to Alp Ikizler, M.D., director of the Division of Nephrology and Hypertension at Vanderbilt, incorporating input from experts in the field including Vanderbilt professor Julia Breyer Lewis, M.D., and reaching consensus within the Division of Nephrology and Hypertension, the group earned support to advance it to the Department of Medicine. With the department’s approval, race-based eGFR AA is no longer reported at Vanderbilt effective July 8.

When managing patients with chronic kidney disease, the reported eGFR will now be interpreted in the context of the patient’s nutritional status and muscle mass.

“In medicine it is critical that we address issues in societal and health equity,” Concepcion said. “The team that spearheaded the sustained and collaborative engagement needed to bring this change to fruition demonstrated an exemplary level of critical thinking, maturity and awareness.”

Just the Beginning

“This is just the beginning of critical antiracist work that needs to happen across many disciplines in medicine in the United States,” Kostelanetz said. “We must examine the use of race as a biological variable, correct how we teach and apply race and ethnicity in medicine and research, and begin the difficult work of acknowledging the potential harm done to communities of color through our practices.”

Two recent studies published in the Clinical Journal of the American Society of Nephrology and the New England Journal of Medicine affirm race as a social construct and propose a more cautious approach when developing clinical algorithms. Kostelanetz and colleagues hope to further study the effects of this practice change. “We must go beyond only identifying health disparities and strive to implement real change to advance health equity,” she said.

“We must go beyond only identifying health disparities and strive to implement real change to advance health equity.”