Vol. 236 July 15, 2020 Are Black Lives Different ? ?

July 16, 2020


“Physicians still lack consensus on the meaning of race.
When the Journal took up the topic in 2003 with a debate about the role of race in medicine,(1) one side argued that racial and ethnic categories reflected underlying
population genetics and could be clinically useful.
Others held that any small benefit was outweighed by potential harms
that arose from the long, rotten history of racism in medicine.”
– NEJM (2)  June 17, 2020

We are presently involved in a heightened examination of racial differences in our society. We know that racism is a cultural phenomenon. We also know that there are subtle genetic differences between races. Is a person’s race identification important to providing excellent medical care to an individual? Are racial differences in risk factors the result of genetics or society?

The debate about Nature (genetics) vs. Nurture (society) is an ancient one. It has spawned numerous scientific studies in areas unrelated to race as diverse as autism in twins raised separately, musical tastes of children exposed to different genres in the nursery, (or even in utero),  alleged superior male mathematical performance in school, the emotional effects on siblings separated from each other at the time of parental divorce, etc. Right now the discussions continue about health inequities, disparity of health status, access, and outcomes among population groups are focussed on the effects of racism.

We know that there are genetic differences between races. Black Africans have an inherited red blood cell condition called sickle cell trait or sickle cell disease which protects them from being infected by malaria; a real medical advantage in Africa. That genetic trait is seen in Afro-Americans as well and it makes them more susceptible to the side effects of certain medications. In 1995 Roger Bannister speculated in an interview that black runners were faster because their Achilles tendons were longer than whites. Even Maxwell Gladwell (OMG, is nothing sacred) in a May 1997 New Yorker essay (OMG x 2!) seemed to endorse a Yale study that interpreted “the higher number of DNA variations in blacks over whites as the reason that blacks were superior in certain sports”. “Clearly, the genie [or gene] is out of the bottle.”  

In 2011 Gary Hunter, a PhD professor of Sports Medicine at University of Alabama and a black man who believes in the strong social forces influencing black lives, reconfirmed  “previous research indicated that ethnic groups such as African-Americans tend to have longer limbs and shorter calf muscles and thus longer Achilles tendons than Caucasians, which may be a contributing factor to why some African-Americans seem to excel in sports involving running; . . . unfortunately, aspiring athletes just can’t grow a longer tendon in hopes of running faster.” (3)  It is a physical fact determined by genes.

There is an ongoing conflict between the latest insights from population genetics and the clinical implementation of race. “For example, despite mounting evidence that race is not a reliable proxy for genetic difference, the belief that it is important has become embedded, sometimes insidiously, within medical practice. One subtle insertion of race into medicine involves diagnostic algorithms and practice guidelines that adjust or ‘correct’ their outputs on the basis of a patient’s race or ethnicity.” (2)

The expectations of computer-based artificial intelligence (AI) for informing diagnostic and therapeutic decisions for individual patients are growing. A recent special article  (2) sounds a loud warning bell about the danger of incorporating hidden racial bias from population-based data  inside the AI “black box”  (no pun intended) to help make medical decisions about individuals. The authors’ examples illustrate how risk factors that are NOT inherent to a race, but are actual outcomes of societal racism, can propagate race-based medicine when used as “race corrections” in assessment calculations of individual patients.

“When clinicians insert race into their tools, they risk interpreting racial disparities as immutable facts rather than as injustices that require intervention. Researchers and clinicians must distinguish between the use of race in descriptive statistics, where it plays a vital role in epidemiological analyses, versus in prescriptive clinical guidelines, where it can exacerbate inequities.(2)

Here are selected examples from the article of how population data including race identification might skew the diagnostic or therapeutic decisions made for an individual patient:

  1. Heart Disease
    According to American Heart Association guidelines, 3 points are added to the risk score if the patient is nonblack, i.e. the black patient is at lower risk of acute heart failure.
    Equity concern: “Regarding black patients as lower risk may raise the threshold for using clinical resources for black patient”.
  2. According to the Thoracic Surgeons Short Term Risk Calculator for complications of cardiac surgery, if a patient is identified as black the risk of operative mortality and major complications increases in some cases by 20%.
    Equity concern: When used to assess the patient’s risk pre-operatively, “this calculator could steer black patients away from this surgery as high risk”.
  3. Kidney Transplantation
    According to the Kidney Donor Risk Index, the risk of kidney transplantation graft failure is higher if the donor is African-American.
    Equity concern: “By reducing the pool of available kidneys the racial inequality in kidney access could be exacerbated.”
  4. Vaginal Birth after Cesarean (VBAC)
    The VBAC Risk Calculator subtracts from the expected success rate for any person identified as black or Hispanic.
    Equity concern: “These lower estimates of success may dissuade clinicians from offering trials of labor to person of color.”
  5. Urinary Tract Infection (UTI) in Children
    The UTI Calculator assigns a risk for black children under 2 y.o. as 2.5 times LESS than non-black children.
    Equity concern: “By systematically reporting lower risks for black children than for all non-black children this calculator could dissuade clinicians from pursuing definitive diagnostic testing in black children with UTI symptoms.”

Each example is citied by the authors as a possible source of diagnostic and/or therapeutic inequity when the resultant calculation is applied to a non-white individual patient. The authors are warning that if we fail to recognize and correct for the implicit racial bias in this data as it goes into the AI black box of decision-making, an element of the racial inequity of health resource delivery could become “hidden in plain sight”.

Also the authors point out, “What does black mean?”.  West Africans are the best sprinters. Kenyans are the best long distance runners. Both are black. Anybody who knows about the short muscle fibers of NFL lineman and the longer muscle fibers of wide receivers should not be surprised that there are more things to consider than skin color.

“Clinicians and medical researchers typically use the categories recommended by the Office of Management and Budget: five races and two ethnicities. But these categories are unreliable proxies for genetic differences and fail to capture the complexity of patients’ racial and ethnic backgrounds.”

The authors conclude: “Our understanding of race has advanced considerable in the past two decades. The clinical tools we use daily should reflect these new insights to remain scientifically rigorous. Equally important is the project of making medicine a more antiracist field. One step in this process is reconsidering race correction [in our clinical decisions] in order to ensure that they do not perpetuate the very inequities we aim to repair.”

So how do physicians use race well?  “Race should not be used as a proxy for genetics, ancestry, culture or behavior, but it is meaningful within the context of inequality. Race is enhanced as a descriptor when it is mobilized as a marker of potential risks drawn from external inequities and assumptions, rather than as a risk factor that is innately responsible for poorer health outcomes.” (4)

Amen. But we have a long ways to go.

References:

  1.  Phimister EG. Medicine and the Racial Divide,. NEJM 2003,348:1081-2
  2. Vyas D.A. et al. Hidden in Plain Sight — Reconsidering the Use of Race Correction in Clinical Algorithms. NEJM June 17, 2020,
  3. McCarthy JP, Hunter GR, Weinsier RL, et al. Ethnic differences in triceps surae muscle-tendon complex and walking economy. J Strength Cond Res. 2006;20:511-8
  4. Jennifer Tsai, M.D., E.Ed. What Role should Race Play in Medicine, Sci Am September 12, 2018

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