THE assumption that Black people have a lower level of cognitive function than white people was, until recently, built into a formula used by the US National Football League to settle head injury lawsuits. The NFL has now , but race-based adjustments in routine diagnostic tests remain pervasive in mainstream medicine. Although some scientific organisations are working to remove such adjustments, many contacted by New Scientist declined to take a stance on the issue, which is growing in prominence.
Race-norming was by psychiatrist at the University of California, San Diego, as a way to try to account for the way African American people tended to score lower than white people on cognitive tests, which are commonly used to diagnose conditions such as dementia.
Subsequent research has shown that adjusting cognitive test performance to take social factors – such as education quality- into account . Despite this, at the University of California, San Francisco, says that race-norming of cognitive tests is still widely practised by doctors in the US today, something she says is extremely problematic.
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Heaton says that although observed differences in test performance between subgroups of the US population may be explained by racial discrimination, stressful life experiences, a lack of consistent access to good nutrition and healthcare, and limited educational opportunities, measuring these directly is too hard.
“These are extremely difficult to measure, quantify and ‘correct for’ in interpreting test results,” said Heaton in a written statement to New Scientist. “The fact remains, that a very substantial amount of variability in the test performance of normal adults can be ‘explained’ (accounted for) by the demographic variables of age, education, sex, and race/ethnicity (together), so our best available norms ‘correct’ for these characteristics.”
Crude proxy
Possin disagrees with using race in this way. “Race is a crude proxy for lifelong social experience,” she says. “Genetic differences in cognition do not follow these race lines. So correcting for lifelong social experience with something very crude, like race, is not precise medicine,” she says. It also perpetuates the false idea that Black people are less intelligent than white people, she says. “That’s a big problem.”
“1990s
Decade the practice of race-norming was established”
Race-norming could even be exacerbating health issues experienced by people as a result of social factors. “We’re using race as a proxy for other things, instead of measuring those things directly,” says at the University of Washington School of Medicine in Seattle. For example, the assumption embedded into race-norming that Black people start out at a lower level of cognitive function than white people could make it more difficult for Black people to get diagnosed with diseases associated with cognitive decline, such as dementia, when race-norms are applied.
Possin says that to eliminate race-norming in cognitive testing, it would be helpful if prominent organisations, such as the International Neuropsychological Society (INS) and the American Psychological Association (APA), took a stance on the issue. However, both declined to do so when asked by New Scientist.
“Correcting for lifelong social experience with something crude, like race, is not precise medicine”
“The INS does not have guidelines nor take a stance [on] race norming,” said the INS. “We are a global organization and focus on topics that are applicable around the world.”
The APA said: “The APA has no official position… on race-based norming and cognitive testing.”
Race adjustments aren’t just an issue for cognitive tests. If your doctor wants to measure your kidney function, they will probably start with a test that measures the levels of a waste product called creatinine in your blood, then plug the result into an equation that calculates your estimated glomerular filtration rate (eGFR), which is the rate at which your kidneys filter waste.
The most widely used eGFR equations include adjustment for race in accordance with guidance from international non-profit organisation Kidney Disease Improving Global Outcomes (KDIGO), which suggests that laboratories should .
Similarly, (NICE) recommend applying “a correction factor to GFR values… for people of African-Caribbean or African family origin”.
No evidence
The use of race or ethnicity adjustments in calculating eGFR stems from an assumption that Black people have higher average blood creatinine concentrations than white people, because they have more muscle mass on average. But race and ethnicity are social rather than biological constructs, leading .
“There is no evidence that race is related to muscle mass,” says Nkinsi. The origin of this idea can be traced back to a , she says. It found that study participants who self-identified as African American had higher serum creatinine levels on average than those who identified as white. “From this they said, ‘Oh, well if they have a higher creatinine, it must mean that Black people have a higher muscle mass’,” she says.
But that study included just 1628 participants, only 197 of whom identified as African American. “It’s based on this one observation that they found out of a very, very small population,” says Nkinsi. An updated eGFR equation was developed in 2009, , however the assumption that there was a need to adjust for race was carried through from the earlier study, she says. “So now, we have all of these aspects of medicine that are all dependent on these equations that now are being recognised to be built on faulty science.”
Not just faulty, but potentially harmful. A preliminary study in the UK led by Rouvick Gama and Kate Bramham at King’s College London found that eGFR equations with race adjustments , as measured using a more invasive but more accurate method. This overestimation may have serious consequences for Black patients, says Gama. “It could lead to delay in diagnosis of chronic kidney disease,” he says, and thus delays in treatment – something borne out by UK health statistics.
“If you’re of Black ethnicity, you’re three to fivefold more likely to end up with end-stage kidney disease,” says Bramham. “Almost certainly we’re not recognising it enough.” The picture is similar in the US, where, according to the National Kidney Foundation, Black and African American people experience kidney failure at .
When asked about the scientific rationale behind its recommendation to adjust eGFR for race, a KDIGO spokesperson said: “KDIGO is not in a position to comment on the rationale used to determine the adjustment in eGFR calculations.”
NICE told New Scientist that it is reviewing its guidelines on calculating eGFR and plans to publish updated guidance in August 2021. However, a published in January still contained a recommendation to adjust eGFR “for adults of African-Caribbean or African family origin”. The draft guidance suggested that future research should explore the use of “factors other than ethnicity” as biological markers.
In the US, the National Kidney Foundation and the American Society of Nephrology established a task force in 2020 to “reassess the inclusion of race in the estimation of GFR”. Several medical institutions across the country, including Massachusetts General Brigham and Beth Israel Deaconess Medical Center in Massachusetts as well as the University of Washington School of Medicine, have abolished the use of race adjustment in eGFR calculations over the past four years.
“Medicine dependent on these equations is being recognised as built on faulty science”
Race-based diagnosis continues in other areas of medicine, however. A of about 14,000 lung function tests, led by at the University of Pennsylvania, found that removing racial adjustments from the interpretation of the tests saw the number of people correctly diagnosed with a lung defect jump from 59.5 to 81.7 per cent.
The results suggest that adjusting for race in lung function tests may underestimate the severity of lung disease in Black patients, says Moffett. “We’re assuming that their lung function should be worse and using that as a way to approach the diagnosis,” he says.
The use of race adjustment in lung function tests can be traced back to the suggestion by US physician and slaveholder Samuel Cartwright in the 1850s that . “Everything we’ve learned about race in the last 50 years has invalidated this,” says Moffett.
Joint European Respiratory Society and American Thoracic Society (ATS) guidelines recommend the use of . “Ingrained in lung function interpretation is the long-standing assumption that the observed differences across racial and ethnic populations is biologically based,” the ATS told New Scientist.
“There is increasing recognition that race and ethnicity are sociopolitical constructs which are more reflective of the differing social and environmental conditions across populations than representative of true biologic differences,” said the ATS, adding that it is “committed to leading action to address racism in medicine and eliminate the misuse of race and ethnicity in clinical decision making” and that it has “convened a workshop to critically evaluate current guidelines”.
Changing times
Moffett thinks race-norming adjustments should be stopped. He and his colleagues are currently developing a “race-free equation” for interpreting lung function tests, he says.
“Race adjustment can be traced back to the idea that Black people are only healthy when enslaved”
“14%
Overestimation of kidney function using a race-based assessment”
There are also to the most widely used eGFR equations. And, in the US, the Vaginal Birth After Cesarean (VBAC) calculator – a commonly used medical tool for second births – was .
Previously, the use of race and ethnicity adjustments in the VBAC calculator meant that women identified as African American or Hispanic were systematically assigned a lower chance of a successful VBAC than white women.
This may have , because a successful vaginal birth after caesarean is associated with reduced health risks than a repeat caesarean delivery. In the US, Black women have higher rates of caesarean deliveries than white women and are also .
Despite many of the organisations contacted by New Scientist not taking a stance on the issue, overall opinions on racial-adjustments appear to be shifting. “It seems to be like a period of reckoning in medicine,” says Nkinsi. “A lot of it is being pushed back on, of course, because people are resistant to change, but I think we’re moving down a path where it’s no longer excusable to have these racist algorithms,” she says.
Moffett agrees. “A lot of this movement has been spearheaded by medical students, who are very distrustful of race as a concept in a way that many older clinicians are not,” he says. “When they’re taught this in medical school, they just say, ‘well, that doesn’t make any sense’, ‘there’s no biological basis for this’, ‘why are we using race in these models?’.”
Significant challenges remain, says Nkinsi, because racism is so deeply embedded in Western medicine. “Medicine is very hierarchical. It’s very much based on this kind of false meritocracy where for the longest time white men were running everything. You can’t question your superiors, medical students and younger physicians are supposed to just take things as they’re taught,” she says. “What I’m trying to tell people is that it’s not just the algorithms, it’s the entire system and the way that we educate doctors that is creating this problem.”
False beliefs and racial biases
The use of race-based adjustments in routine medical tests (see main story) isn’t the only thing contributing to racial-ethnic health disparities. False beliefs about biological differences between racial groups may also contribute.
For example, harmful beliefs, such as the false notion that Black people feel less pain than white people, may result in physicians and .
A and residents found that about half of them endorsed at least one of a list of incorrect statements about biological differences between Black and white people. These included statements such as “Black people’s nerve-endings are less sensitive than White people’s nerve-endings” and “Black people’s skin has more collagen (i.e. it’s thicker) than White people’s”. The study also found that these false beliefs predicted racial biases in the assessment of pain in fictional patients and in subsequent treatment recommendation.
Racial biases in medicine are also embedded in technology. In 2019, a study revealed that Black people in the US may have been missing out on healthcare because of racial bias in a widely used algorithm. The study suggested that the proportion of Black people referred for extra care would more than double if the bias were removed.
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