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Shannon Shelton Miller

Shannon Shelton Miller is an award-winning writer and journalist who specializes in education, parenting, culture and diversity, sports, and health and beauty articles. She has been published in the New York Times, the Washington Post,, Slate, InStyle and the Huffington Post.

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Racial Bias in Medical Calculations Can Create Healthcare Inequities

Racial Bias in Medical Technology Can Create Health Inequities

Healthcare has long relied on technological devices, mathematical formulas and calculations to treat patients — but that can harm people of color

Your Care

April is National Minority Health Month.

The trusty forehead thermometer and pulse oximeter have long been used to evaluate patient health. But during the earliest days of the Covid-19 pandemic, they took on greater importance.

If a reading from a pulse oximeter — a device placed on a finger to measure blood oxygen levels — was too low, a person might need to go to the hospital. Higher temperatures on a forehead thermometer could indicate a possible Covid infection, and high fevers often warranted a trip to an emergency room.

Few would question the accuracy of either device, and Jayne Morgan, M.D., a cardiologist and clinical director of the Covid task force at Piedmont Healthcare Corp. in Atlanta, took the readings at face value. But that was before she read an article that explained how pulse oximeters passed light through skin to measure blood oxygen levels. Immediately, Morgan thought darker skin would absorb more light and possibly deliver inaccurate results for some patients.

She was correct. Morgan found research that showed how pulse oximeters were underdiagnosing patients of color, and multiple studies found that Black, Hispanic and Asian patients were less likely to get treated for Covid symptoms because of those readings. When she began looking into forehead thermometers, she found evidence that they were less accurate in Black patients as well.

The issue also wasn’t limited to forehead thermometers and pulse oximeters, either. Many medical disciplines have long relied on flawed mathematical formulas, questionnaires, pictures and devices to determine care plans, and this race-based medicine has often been practiced to the detriment of patients of color.

“Disease progresses, you see higher mortality, and nobody can figure it out because everybody's following numbers,” Morgan said. “The bias is inherent in the medical equipment and formulas.

Where racial disparities exist 

During the pandemic, Morgan launched the Stairwell Chronicles, a series of 60-second videos where she delivers medical advice from the stairs of her home. In addition to Covid information, Morgan has addressed women’s health and health equity, including the dangers of relying on race-based medical calculations and formulas.

“Doctors, unbeknownst to them, have been relegating patients to lower levels of care and concern,” she said.

The pandemic also launched Joel Bervell's advocacy. A medical student at Washington State University, Bervell began investigating how common medical formulas and calculators were developed after seeing an Instagram story on racial bias in pulse oximeters. Realizing that he wasn’t learning about these concerns in medical school, he began sharing his findings on social media. Today, he has more than 600,000 followers on TikTok alone.

The formulas, calculations and technology that Morgan, Bervell and other medical professionals have explored include:

Spirometry.Spirometers are handheld devices that measure how much air you inhale and how much and how quickly you exhale. They’re often used to diagnose conditions like chronic obstructive pulmonary disease (COPD) and asthma, and have been used to measure lung function in recovering Covid patients.

To this day, calculations used to evaluate pulmonary function incorrectly assume that Black and Asian patients have smaller lung capacity than white people. These false assumptions date back to Thomas Jefferson’s incorrect observations of people he had enslaved, which were worked into medical guidance in the 1800s.

As late as 1999, this false belief was still being promoted as truth, and healthcare providers were being taught that there were racial differences in lung capacity. Spirometer manufacturers began building their equipment with this racial difference built into the readings. Many doctors don’t even know the software is applying these incorrect formulas.

Why does this matter? Abnormal values on a spirometer are used to determine when a person needs to be seen by a specialist for more highly specialized care. For Black and Asian patients, an abnormal value can be missed because of this incorrect race-based adjustment.

eGFR. The estimated glomerular filtration rate (eGFR) equation measures kidney function. For years, it used a separate calculation for African Americans because some research showed that they had higher levels of creatinine — a waste product made by muscles — than white patients. Researchers then incorrectly assumed the creatinine breakdown was related to higher muscle mass in Black patients.

“They put in a multiplication factor for African Americans that increases their eGFR, which makes their kidney function appear better than it is,” Morgan said. “Because of that, Black patients would get delayed referrals to specialists, delayed onset of medication, late arrival onto kidney transplant lists and fewer chances of receiving a transplant because their disease was so advanced.”

Without the incorrect race-based adjustment, 3.3 million more Black patients would have been classified more accurately as having a higher stage of kidney disease. Add that to the fact that Black patients remain on the kidney transplant list longer than white patients, and the delay caused by the inaccurate eGFR equation was costing people their lives.

Encouraging news: The Chronic Kidney Disease Epidemiology Collaboration eliminated the race adjustment in 2021, and the College of American Pathologists has since instructed members to adopt the new formula.

VBAC calculator. While a cesarean section can be lifesaving for a mother and her infant if complications arise during birth, C-sections still come with risks to mothers and infants, including infection, blood loss, blood clots, the need for a hysterectomy and complications in future pregnancies.

Healthcare providers (HCPs) have been advised to use a formula to predict the odds of a successful birth for a woman wanting a vaginal birth after cesarean (VBAC). While a VBAC can also have risks, such as rupture of the C-section scar on the uterus, it’s generally considered a safer option for many women, and avoids the complications of multiple surgeries.

“The calculator was a formula in which they asked about your height, weight and past deliveries,” Morgan said. “Then there were simple yes/no questions — Are you Black? Are you Hispanic? Yes or no? That answer determines your fate.”

Answering yes to being Black and/or Hispanic lowered your score, making HCPs less likely to offer the possibility of a VBAC.

“What we are really saying is that the Black patient is subject to another surgery,” Morgan said. “Make no mistake, a cesarean is a surgery, so Black mothers have more surgeries than other mothers. We then have the whole issue of poorer maternal health and fetal health outcomes and maternal mortality in the Black community. You can see how it all progresses.”

After Darshali Vyas, a Harvard Medical School student, published a paper challenging the race question in the VBAC calculator, medical bodies moved to remove it.

What healthcare providers can do to reduce racial bias in medical calculations

While some calculators and formulas have already been changed, it will take more time to update others. Researchers are working to improve the way certain devices work on dark skin, and medical organizations continue to push to have more people of color included in studies and trials to make sure technology is accurate for all.

Morgan said that HCPs also need education to make them aware of the limitations of medical technology when it comes to race, and about the changes in formulas like eGFR and the VBAC calculator.

Improving these calculations and devices is one step toward reducing racial disparities in healthcare.

“You can imagine by the time patients get more advanced care and finally meet the metrics for referrals and even transplants, they have more advanced disease,” Morgan said. “They’ve experienced more personal suffering. They know something’s [wrong], but every time they go to the doctor, they hear their values are normal. That’s just not right.”

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