The excerpt below is from the 2022 issue of Brigham magazine.


In July 2012, Audrey* logged into her patient portal following her annual physical, as she had done for years.

A middle-aged white woman in good health, Audrey was pleased by the array of test results confirming her well-being. But then, in small print under one result, she noticed something strange related to an eFGR test: “If patient is black, multiply by 1.21.”

Audrey wondered, “What is eGFR? Why would it be different only for Black people? Who decides who’s Black?”

*Patient’s name has been changed to protect privacy.

Separate and Unequal Kidney Medicine

The eGFR is a blood test result estimating the glomerular filtration rate (GFR), which shows how well kidneys are filtering our blood. Because kidney function is difficult to evaluate with precision, accuracy, and speed, eGFR is a fast, inexpensive way for doctors to assess the health of these vital organs and determine if additional testing is needed.

The first method for estimating GFR through a blood test was developed in the 1970s but created from a study of 249 white men. In 1999, a new method for estimating GFR was introduced from a study of 1,628 participants, 12% of whom were Black. This method included a race adjustment, partly justified by a theory that Black people have more muscle mass than white people. This new approach to estimating GFR became a widely used standard of care in the U.S, even though it increased Black people’s GFR values by 21% (higher values indicate better kidney function).

“It’s interesting because these two studies introducing race adjustments in estimates of kidney function [the first in 1999 and a revision in 2009] were considered landmark, gold-standard studies at the time,” says Mallika Mendu, MD, MBA, nephrologist and executive medical director of clinical operations at Brigham and Women’s Hospital. “Both attempted to be inclusive of patients from different racial backgrounds, which was a huge improvement over prior studies that had been more homogeneous.”

Mendu adds, “I was taught the race adjustment in medical school in 2004, and then as a resident, and then as a fellow. And, to be frank, I didn’t question it.”

But Mendu’s perspective changed when she began practicing.

“I thought I needed to be transparent with my patients about the race adjustment,” she says. “And when I met with my patients and said it out loud, I found it confusing and hard to explain. So I stopped using it for my patients.”

Mallika Mendu, MD, MBA (Photo by Stu Rosner)

Questions Can Change Patient Care

A decade after Mendu began medical school, racial justice and health equity movements began to take hold in academic medical centers across the U.S.

In 2016, Cameron Nutt, MD, was in his first year at Harvard Medical School (HMS) when he learned about the race adjustment for eGFR from his professor, Melanie Hoenig, MD, a nephrologist at Beth Israel Deaconess Medical Center (BI). Nutt and other students in the HMS Racial Justice Coalition asked Hoenig why the formula inflates Black people’s kidney function when they are at the greatest risk for kidney disease of any racial group.

“Even though racialized eGFR reporting was standard practice in nephrology, Dr. Hoenig never got defensive with students asking questions,” says Nutt. “She listened thoughtfully to our concerns. Then she set up meetings for us with other nephrologists at the BI and with pathologists who ran their lab. And after a long process and many conversations led by Dr. Hoenig, the BI changed their policy in March 2017 to stop reporting inflated eGFR values for Black patients.”

When Nutt joined the Brigham as an internal medicine resident in 2019, he wanted to learn more about the possible contribution of racialized eGFR reporting to racial disparities in the treatment of chronic kidney disease (CKD). Nutt joined a research team led by Mendu and her colleague, Salman Ahmed, MD, MPH, to analyze the records of more than 56,000 patients with CKD across Partners HealthCare (now Mass General Brigham).

When the researchers removed the race adjustment and reclassified the severity of CKD for the 2,225 who self-identified as Black or African American, 743 people (33%) met the criteria for a more severe stage of CKD. Of those, 64 met the criteria to be referred for kidney transplant—but because their scores had been adjusted for race, none of them had been waitlisted, evaluated, or even referred for a kidney transplant.

“Our research countered current practice by putting the facts out there, and this was only for our system,” says Mendu. “Across the country, Black patients are three times more likely to progress from chronic kidney disease to kidney failure. And they are less likely to be seen by a nephrologist, receive home dialysis, or receive a transplant, which makes the upward adjustment in kidney function more concerning as it can delay delivery of care. So when you think about this race adjustment happening for two decades in the U.S., the number of people potentially affected is huge. What happens to all these patients and their care?”

Based on the study’s preliminary findings, the MGB hospital system eliminated the use of race adjusted eGFR in June 2020. At the time, only a few other health systems in the U.S. had taken this action.

Read the full story and more in Brigham magazine here.