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Study supports removing race from estimate of kidney function

Nov. 17, 2022, 9:53 AM


by Leigh MacMillan

An in-depth analysis of published research studies supports removing race from the calculation of estimated glomerular filtration rate (eGFR) — an assessment of kidney function.

Although measured GFR (mGFR) is the gold standard for evaluating kidney function, it requires infusing chemicals into the blood and quantifying them in urine. Estimated GFR is calculated from the value of a blood marker such as creatinine and other variables including sex, age and race.

Ebele Umeukeje, MD, MPH

“Including race in the equation has systematically increased eGFR for Black patients, which could delay clinical care that depends on eGFR thresholds, such as specialist referrals or transplantation, and increase health inequities,” said Ebele Umeukeje, MD, MPH, assistant professor of Medicine in the Division of Nephrology and Hypertension at Vanderbilt University Medical Center.

In an effort led by medical students, residents and faculty, VUMC was one of the first institutions in the United States to remove race from eGFR calculations. VUMC stopped reporting the race-based “eGFR AA” as of July 8, 2020. The same month, the National Kidney Foundation and the American Society of Nephrology (NKF-ASN) created a task force to evaluate the inclusion of race in eGFR equations, and the task force recommended a new creatinine equation without the race variable in September 2021.

Nunzia Bettinsoli Giuse, MD

Now, the Center for Knowledge Management at VUMC, led by Nunzia Bettinsoli Giuse, MD, vice president of Knowledge Management, in partnership with Umeukeje, has conducted a systematic review of articles published from January 1999 to May 2021 that compared eGFR and mGFR and reported outcomes by Black race. The researchers aimed to answer the question: How well does eGFR, with and without race adjustment, predict mGFR in Black adults?

Of 13,167 citations the team identified, 12 met the criteria of having unique patient cohorts in which eGFR was compared to mGFR with and without race adjustment. The studies included patients with and without kidney disease from Africa, the United States, Europe and Brazil.

“Conducting a robust worldwide systematic review is a painstaking process,” Giuse said. “Our expertise, infrastructure and resources in the Center for Knowledge Management enable such reviews and have put VUMC ahead of the curve in terms of health equity-focused efforts in this area.”

The researchers found that removal of race adjustment improved bias, accuracy and precision of eGFR equations for Black adults. Their report was published recently in the journal PLOS ONE.

“Our study provides the first systematic-level evidence to confirm that removing race from eGFR is indeed the right thing to do,” Umeukeje said. “It strengthens the argument for adoption of the NKF-ASN task force recommendations.

“Race is an inappropriate proxy for genetics all over the world, and efforts to eliminate its use in estimating GFR should be global.”

Umeukeje and Taneya Koonce, MSLS, MPH, deputy director of the Center for Knowledge Management, are co-first authors of the systematic review study. Additional collaborators include Sheila Kusnoor, PhD, Ifeoma Ulasi, MBBS, Sophia Kostelanetz, MD, MPH, Annette Williams, MLS, Mallory Blasingame, MA, MSIS, Marcia Epelbaum, MA, Dario Giuse, Dr. Ing, MS, Annie Apple, MD, Karampreet Kaur, MD, Tavia González Peña, MD, MPH, Danika Barry, MD, Leo Eisenstein, MD, Cameron Nutt, MD, and the study’s senior author, Nunzia Giuse, MD.

The research was supported in part by the National Institutes of Health (grants DK114566 and DK129626) and the Agency for Healthcare Research and Quality (grant HS026122). The study used the REDCap database, supported by a Clinical and Translational Science Award (grant TR000445), for data entry and collection.

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