Given how embedded these equations are in medical software and electronic records, even doctors may not realize how widely they impact care decisions.
“Health equity scholars have been raising alarm bells about the way race has been misused in clinical algorithms for decades,” said Dr. Michelle Morse, New York City’s chief medical officer.
Change is beginning, slowly. No longer are obstetricians supposed to include race in determining the risk of a pregnant woman attempting vaginal birth after a prior C-section. The American Heart Association just removed race from a commonly used calculator of people’s heart disease risk. The American Thoracic Society has urged replacing race-based lung function evaluation.
The kidney saga is unique because of the effort to remedy a past wrong.
“Lots of time when we see health inequities, we just assume there’s nothing we can do about it,” Morse said. “We can make changes to restore faith in the health system and to actually address the unfair and avoidable outcomes that Black people and other people of color face.”
Black Americans are over three times more likely than white people to experience kidney failure. Of the roughly 89,000 people currently on the waiting list for a new kidney, about 30% are Black.
Race isn’t a biological factor like age, sex or weight — it’s a social construct. So how did it make its way into calculations of kidney function?
The eGFR, or estimated glomerular filtration rate, evaluates kidney health based on how quickly a waste compound called creatinine gets filtered from blood. In 1999, an equation used to calculate eGFR was modified to adjust Black people’s results compared to everyone else’s, based on some studies with small numbers of Black patients and a long-ago false theory about differences in creatinine levels. Until recently that meant many lab reports would list two results — one calculated for non-Black patients and another for Black patients that could overestimate kidney function by as much as 16%.
Not every Black kidney candidate was affected. Some may have had kidney failure diagnosed without that test. For others to have a chance at benefitting from UNOS’ mandated lookback, transplant center staff-turned-detectives often worked after hours and weekends, hunting years-old records for a test that, recalculated without the race adjustment, might make the difference.
“You’re reaching out to the nephrologist, their primary care doctors, the dialysis units to get those records,” said Dr. Pooja Singh of Jefferson Health’s transplant institute in Philadelphia, where Evans received her new kidney. “That first patient getting transplanted for us was such a great moment for our program that the work didn’t feel like work after that.”