Medicine has a long history of erroneous beliefs about biological differences between races. Today this ideology continues in diagnostic algorithms and practice guidelines that are adjusted based on patients’ race—and often lead to further inequities in the health care of nonwhite patients. Now students are working to change these practices, with some successful results. This summer the University of Washington School of Medicine announced that its medical centers would no longer use race in a measure of kidney function called the estimated glomerular filtration rate, or eGFR.
To determine kidney health, doctors first measure factors such as the level of creatinine, a by-product of muscle breakdown, in the blood. (Because failing kidneys have a harder time filtering out creatinine, a high level indicates that the renal system is having problems.) Physicians use an equation to combine this information into an eGFR score. Perfectly healthy kidneys get a score above 60, while failing ones have scores below 15. The first equation to easily calculate eGFR (without the extra step of collecting and analyzing patients’ urine), was developed through a 1999 study with 1,628 participants. Researchers noticed that Black participants had, on average, higher creatinine than white ones. This could be explained by the fact that a higher proportion of Black study participants may have already had end-stage kidney disease. But instead the study assumed that Black individuals had higher muscle mass, and thus higher creatinine, than white ones. To prevent these supposedly elevated creatinine levels from skewing test results, researchers multiplied Black people’s eGFR scores by a factor of 1.2. Ten years later, a larger study led to the development of a more accurate eGFR equation called the chronic kidney disease epidemiology collaboration, or CKD-EPI—but it still contains a correction factor for Black patients.
This could have fatal consequences. In order to qualify for a kidney transplant, a patient’s eGFR score has to be low enough to be considered end-stage kidney disease. Because a Black person’s score is bumped up by the correction factor, they might have to wait until their kidney disease reaches a later, more severe stage before they qualify for treatment.
Aware of this disparity, Naomi Nkinsi, a student of medicine and public health at UW, fought for two years to take race out of the equation—and won. Now the University of Washington system will calculate eGFR using the CKD-EPI equation, but without any race correction. The university also recently established a UW Medicine Office of Healthcare Equity, which it says “provides an opportunity to define short-term and long-term goals.”
In the announcement of its new policy, UW Medicine stated, “This change was made because the use of race in the biomedical environment is an ineffective variable and does not meet the scientific rigor that we expect of our diagnostic tools.” Scientific American spoke with Nkinsi about why this change was necessary, and how she worked to make it happen.
[An edited transcript of the interview follows.]
What was the goal of removing race as a factor in eGFR scores?
One of the bigger issues that we’re trying to bring to light is that Black people in this country are more likely to get diagnosed with kidney disease later and are less likely to have access to treatments like transplants. And one of the reasons for that is because the eGFR measurements are kind of masking disease until the disease becomes later stage. We’re not saying that we want people to practice colorblind medicine; we want them to practice anti-racist medicine. And the reason that having the race variable [in the eGFR] is problematic is because it’s being used as a proxy for muscle mass.
This test is taught in medical schools all over the U.S. How did you end up changing it?
It was really a team effort that started with being outspoken. By this point, I’d already seen so many instances where race, particularly Black race, is brought up as a risk factor—somehow the color of your skin is linked to all of your physiology. I’m sitting there in class [as] one of five Black people, and I remember thinking that this is not just a theoretical discussion: every single person that has kidney function measured is going to have race built into that algorithm. That’s when I started asking more questions. The conversation got pretty heated, and they couldn’t really explain the logic behind using race in these equations. From there, I met with the director of this [course] unit … about why I felt that this was an important topic to review further … within the context of health disparities and race-based medicine. And then all of these different departments came together … and studied whether or not [removing race from the test] could be feasible in our healthcare system—and found that it would be. They specifically credited students for being the ones who actually made this change possible.
I was in complete shock [when I heard], because I went into this fully expecting that nothing would happen. These past two years, that at times felt terrible, it was worth something—and it’s something that could change how we practice medicine forever. The National Kidney Foundation is having a whole task force to discuss whether or not national recommendations should be changed. It’s causing a lot of really good discussions and hopefully causing people to reconsider different algorithms where race is considered.
What made you decide to fight for change?
It’s important because it impacts so many patients. It’s [also] very personal—you’re talking about my body, you’re talking about my family’s bodies. How can I trust that … [we’re] getting the best care, when I know that the way [doctors] treat Black people is so much different than the way we see other people in medicine? If you speak up, you’re an angry Black person who’s unprofessional. If you don’t speak up, you feel like you’re failing the community.
What advice would you give medical students seeking to do what you did at their own schools?
We have to remember that a lot of our educators have been in medicine for so long, and they learned things a certain way, and it gets ingrained over time. Having students come in, you’re able to see things from a different perspective, especially now that we’re so much more aware of health inequities. You should learn about why these disparities exist and about the history of medicine and why we use race in a lot of these algorithms.