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Kidney Experts Say It’s Time to Remove Race From Medical Algorithms–Doing So Is Complicated

By Rae Ellen Bishell and Cara Anthony
Kaiser Health News

Alphonso Harried recently came across a newspaper clipping about his grandfather receiving his 1,000th dialysis treatment. His grandfather later died — at a dialysis center — as did his uncle, both from kidney disease.

“And that comes in my mind, on my weak days: ‘Are you going to pass away just like they did?’” said Harried, 46, who also has the disease.

He doesn’t like to dwell on that. He has gigs to play as a musician, a ministry to run with his wife and kids to protect as a school security guard.

Yet he must juggle all that around three trips each week to a dialysis center in Alton, Illinois, about 20 miles from his home in St. Louis, to clean his blood of the impurities his kidneys can no longer flush out. He’s waiting for a transplant, just as his uncle did before him.

“It’s just frustrating,” Harried said. “I’m stuck in the same pattern.”

Thousands of other Americans with failing kidneys are also stuck, going to dialysis as they await new kidneys that may never come. That’s especially true of Black patients, like Harried, who are about four times as likely to have kidney failure as white Americans, and who make up more than 35% of people on dialysis but just 13% of the U.S. population. They’re also less likely to get on the waitlist for a kidney transplant, and less likely to receive a transplant once on the list.

An algorithm doctors use may help perpetuate such disparities. It uses race as a factor in evaluating all stages of kidney disease care: diagnosis, dialysis and transplantation.

It’s a simple metric that uses a blood test, plus the patient’s age and sex and whether they’re Black. It makes Black patients appear to have healthier kidneys than non-Black patients, even when their blood measurements are identical.

“It is as close to stereotyping a particular group of people as it can be,” said Dr. Rajnish Mehrotra, a nephrologist with the University of Washington School of Medicine.

This race coefficient has recently come under fire for being imprecise, leading to potentially worse outcomes for Black patients and less chance of receiving a new kidney. A national task force of kidney experts and patients is studying how to replace it. Some institutions have already stopped using it.

But how best to assess a patient’s kidney function remains uncertain, and some medical experts say fixing this equation is only one step in creating more equitable care, a process complicated by factors far deeper than a math problem.

“There are so many inequities in kidney disease that stem from broader structural racism,” said Dr. Deidra Crews, a nephrologist and the associate director for research development at the Johns Hopkins Center for Health Equity. “It is just a sliver of what the broader set of issues are when it comes to both disparities and inequities in who gets kidney disease in the first place, and then in the care processes.”

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Alphonso Harried, a school security guard, local musician and minister in St. Louis, spends almost 15 hours each week at a dialysis center about 20 miles from his home in St. Louis. “It’s just frustrating,” says Harried, whose grandfather and uncle also needed dialysis. “I’m stuck in the same pattern.” (Michael B. Thomas for KHN)

Why Race Has Been Part of the Equation

Kidneys filter about 40 gallons of blood a day, like a Brita filter for the body. They keep in the good stuff and send out the bad through urine. But unlike other organs, kidneys don’t easily repair themselves.

“There’s a point of no return,” said Dr. Cynthia Delgado, a University of California-San Francisco nephrologist who is leading the task force working on the national recommendation to ditch the racial part of the equation.

Furthermore, it’s hard to gauge whether kidneys are working properly.  Gold-standard tests involve a chemical infusion and hours of collecting blood and urine to see how quickly the kidneys flush the chemical out. An algorithm is much more efficient.

Buoyed by activism around structural racism, those seeking equity in health care have recently been calling out the algorithm as an example of the racism baked into American medicine. Researchers writing in the New England Journal of Medicine last year included kidney equations in a laundry list of race-adjusted algorithms used to evaluate parts of the body — from heart and lungs to bones and breasts. Such equations, they wrote, can “perpetuate or even amplify race-based health inequities.”

In March, ahead of the national task force’s upcoming formal recommendation, leaders in kidney care said race modifiers should be removed. And Fresenius Medical Care, one of the two largest U.S. dialysis companies, said the race component is “problematic.”

Until the late 1990s, doctors primarily used the Cockcroft-Gault equat- ion. It didn’t ask for race, but used age, weight and the blood level of creatinine — a chemical that’s basically the trash left after muscles move. A high level of creatinine in the blood signals that kidneys are not doing their job of disposing of it. But the equation was based on a study of just 249 white men.

Then, researchers wrapping up a study on how to slow down kidney disease realized they were sitting on a mother lode of data that could rewrite that equation: gold-standard kidney function measurements from about 1,600 patients, 12% of whom were Black. They evaluated 16 variables, including age, sex, diabetes diagnosis and blood pressure.

They landed on something that accurately predicted the kidney function of patients better than the old equation. Except it made the kidneys of Black participants appear to be sicker than the gold-standard test showed they were.

The authors reasoned it might be caused by muscle mass. Participants with more muscle mass would likely have more creatinine in their blood, not because their kidneys were failing to remove it, but because they just had more muscles producing more waste. So they “corrected” Black patients’ results for that difference.

Dr. Andrew S. Levey, a professor at Tufts University School of Medicine who led the study, said it doesn’t make intuitive sense to include race — now widely considered a social construct — in an equation about biology.

Still, in 1999, he and others published the race equation, then updated it a decade later. Though other equations exist that don’t involve race, Levey’s latest version, often referred to as the “CKD-EPI” equation, is recommended for clinical use. It shows a Black patient’s kidneys functioning 16% better than those of a non-Black patient with the same blood work.

Rae Ellen Bichell and Cara Anthony are both correspondents for Kaiser Health News. This story was produced by Kaiser Health News, an editorially independent program of the Kaiser Family Foundation.

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Alphonso Harried keeps a bag packed with supplies he might need if his turn for a kidney transplant comes up. A national group of experts is currently deciding how to alter a medical algorithm that some experts say delays Black patients like Harried from getting a transplant. (Michael B. Thomas for KHN)

KHN (Kaiser Health News) is a national newsroom that produces in-depth journalism about health issues. Together with Policy Analysis and Polling, KHN is one of the three major operating programs at KFF (Kaiser Family Foundation). KFF is an endowed nonprofit organization providing information on health issues to the nation.

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