When doctors want to know how well your kidneys are doing, they measure something called your GFR, or glomerular filtration rate.
To do that, doctors measure waste products in your bloodstream, among other factors.
Dr. Stephen Seliger, a nephrologist at the University of Maryland Medical Center, says the amount of waste product in your blood tends to reflect how much muscle you have.
So when calculating your GFR, doctors also take your age and sex into account.
“On average, younger people have more muscle for the same body weight. On average, men have more muscle for the same age and body weight than women,” Seliger said.
But in addition to age and sex, doctors also used race – that is, whether you are African American or not – to calculate your GFR.
“It was long assumed…that people whose ancestry derived from Africa also had more muscle than people whose ancestry derived, say, from Europe,” Seliger said.
For decades, hospitals factored in a patient’s race – specifically, whether or not they were Black – to calculate a patient’s kidney health.
Doctors at the University of Maryland Medical System (UMMS) recently stopped this practice, saying it has no scientific basis. It was one of the earliest health systems to do so. In the past several weeks, more health systems, including Johns Hopkins, have done the same.
Dr. Joseph Wright, the chief health equity officer at UMMS, said doctors cannot rely on race, a social construct, to accurately calculate a biological function.
“How someone looks does not really ascribe to a biologic proxy of what's going on in the person's body,” he said.
Seliger said the race-based algorithm tended to overestimate how well Black patients’ kidneys were working.
“It might lead to delayed recognition in them having advanced or more end-stage kidney disease, the kind of severity of kidney disease that, for example, would otherwise trigger consideration of kidney transplantation,” Seliger said.
He said changing the race-based algorithm, which went into effect earlier this year, did not happen overnight.
Shortly before UMMS announced the change last year, a task force formed by the National Kidney Foundation and the American Society of Nephrology recommended that doctors stop including race when estimating kidney function.
Seliger said along with this national push was a cultural shift at UMMS.
“You have a new generation of physicians, physicians-in-training, who are increasingly part of a clearly multiethnic society,” he said.
He said that helped UMMS change its practices more quickly than many other health systems.
Wright said this algorithm is just a first step for him and his colleagues in reexamining the role of race in medicine.
“We are a generation of physicians and health professionals who have grown up with these assumptions baked into our training and education,” he said.
It’s these assumptions that affect Black patients like Uchenna Ndubisi from Prince George’s County.
She got on the kidney transplant waitlist while at the University of Maryland Medical Center, when the race-based algorithm was still in use.
“I was lucky to have a really great nephrologist,” Ndubisi said. “But not everybody is able to have… the access to healthcare that I was able to get.
If she had a different nephrologist who only considered her GFR, she said things could have been very different.
“If I didn't get the good care in time, I could have ended up being really sick, sent to the hospital and then put on hemodialysis which would completely change my day to day life,” she said.
Ndubisi said because she is a physical therapist and has doctors in her family, it was easier for her to advocate for her needs as a patient.
“Being the best patient advocate that you can for yourself is super important,” she said. “And I don't know if a lot of patients know that.”
And Ndubisi added that bridging health inequities means having more doctors who look like her, and who can listen to patients of all backgrounds.
