UnitedHealth Group studies COVID-19 risks with sickle cell

UnitedHealth Group is backing a study that hopes to determine whether carrying the genetic trait that causes sickle cell disease could put a subset of Black Americans at greater risk from COVID-19.

Sickle cell disease is an inherited blood disorder that afflicts about 100,000 Americans, often with debilitating pain and shortened lives. People with the disease receive the sickle cell gene from both parents, while those who inherit the gene from just one parent are carriers of the trait.

Federal health officials in June added sickle cell disease to the list of health problems that put people at higher risk of serious illness with COVID-19. The new study, financed by Minnetonka-based UnitedHealth Group, asks if there's also a greater risk for carriers of sickle cell trait — a much larger group that includes about 8% of Black Americans.

"COVID can be seen as really kind of a stress test that has exposed these fault lines in American health and health care," said Dr. Herman Taylor, director of the Cardiovascular Research Institute at Morehouse School of Medicine in Atlanta and a lead investigator on the study.

"African Americans find themselves as a population more vulnerable in this moment, and the vulnerability has roots in social vulnerability, it has roots in access to care, it has roots in pre-existing illnesses like high blood pressure and diabetes," Taylor said. Those factors are the major driver of racial disparities leading to worse COVID-19 outcomes for Black Americans, he said, but sickle cell trait is one of several "conditions that really warrant particular attention as perhaps contributory to the disparity."

UnitedHealth Group's research and development division is putting $600,000 toward the new study of up to 300 adults admitted to Grady Memorial Hospital in Atlanta. Researchers will screen study participants for sickle cell trait to determine if a disproportionate number of carriers are sickened by the pandemic virus and whether they also have different health outcomes compared with non-carriers.

Mortality rates due to COVID-19 in the U.S. have disproportionately affected Black Americans and other communities of color. An April report from the U.S. Centers for Disease Control and Prevention (CDC) looked at COVID-19 hospitalizations in 14 states where African Americans accounted for 18% of the population but one-third of COVID-19 hospitalizations, say researchers on the sickle cell trait study. Disparities are being found in Minnesota, as well.

In June, the CDC published a report on a registry of sickle cell disease patients suggesting high rates of hospitalizations, intensive care visits and deaths with COVID-19.

More studies are needed since registry numbers might highlight the worst outcomes without capturing many mild cases, said Dr. Yvonne Datta, a hematologist/oncologist with University of Minnesota Medical School and M Health Fairview. Sickle cell disease is sometimes found in whites and Hispanics, Datta said, but the disease is much more common in the African American community.

"One question that comes up is, with the increased rates of bad outcomes [with COVID-19] in African Americans, is some of that due to sickle cell trait?" said Datta, who is not part of the new study.

Largely a 'non-disease'

It's not clear why patients with sickle cell disease might fare worse with COVID-19, although there are theories that factor in the striking similarities in how both diseases affect patients in extreme cases.

Discovering whether there's a risk for carriers of sickle cell trait could prompt more patients to get screened to find out if they are carriers, said Dr. Deneen Vojta, executive vice president for the research and development group at UnitedHealth Group. Many people don't know they have it, doctors say. Study results might also influence treatments, said Dr. Thomas Adamkiewicz, another lead investigator on the study from Morehouse School of Medicine.

Sickle cell trait is largely an asymptomatic condition that's arguably a "non-disease," Taylor said. Carriers experience ill effects only in extreme circumstances such as very strenuous athletic activity at a high altitude.

Those low-oxygen conditions can stimulate sickling of red blood cells that cascade into other problems, such as obstruction of small blood vessels that lead to organs, Taylor said. Researchers wonder if COVID-19 might be another stressor that triggers serious health consequences.

Sickling of red blood cells protected people against malaria in parts of the world where it was endemic for generations, Taylor said, such as West Africa, the southern Mediterranean region and west Asia. The trait, he added, doesn't offer a health advantage in the U.S., where social factors contribute to a number of health disparities that harm Blacks.

With COVID-19, Black Americans are more likely to work service jobs where social distancing to stop the spread of the virus can be difficult. What's more, the wealth gap with white Americans means many more African Americans face intense pressure to go in to work, Taylor said.

Black Americans are more likely to live in multigenerational homes or apartments, Taylor said, with smaller spaces that don't allow for social distancing. They also are more reliant on public transportation over private cars.

Control of health problems that increase COVID-19 risks is often impaired in the Black community, Taylor said, by diminished access to health care as well as the cost and availability of high-quality foods.

"What COVID has done for us is sort of put a magnifying glass on disparities that have existed really since the founding of the republic," he said.

A study on potential COVID-19 risks with sickle cell trait is needed, said Dr. Douglas Rausch, division director for hematology/oncology at Hennepin Healthcare. Rausch pointed to a report from a medical journal in June that also speculated on a connection between carrying the trait and suffering serious illness from the coronavirus.

Rausch and other doctors are working with the Minnesota Department of Health on a project to better understand the scope of sickle cell disease in the state. The work suggests about 600 patients have the disease in Minnesota, he said, and about 25,000 state residents might have sickle cell trait.

"I really admire this research idea," said Rausch, who is not part of the new study.

Beyond its own merits, the study is one step, he said, toward addressing a long-standing shortfall in research funding for sickle cell patients.

"We've got a lot of catching up to do," Rausch said.

Christopher Snowbeck • 612-673-4744