Greater COVID-19 Infection Risk, Worse Outcomes In Cancer Patients

Patients with cancer, especially those who are African American, are at significantly higher risk for COVID-19 infection and for worse outcomes, a new study suggests.

Compared to the general population, patients with a recent cancer diagnosis have a seven-fold higher risk of COVID-19 infection, researchers found, based on an analysis of electronic health records data from 73.4 million U.S. patients, of whom 2.5 million had one of 13 common cancers. African American patients recently diagnosed with cancer were two to five times as likely as white cancer patients to develop a COVID-19 infection, according to the report published in JAMA Oncology.

"We analyzed data from the entire U.S. population," said the study's lead author Rong Xu, a professor of biomedical informatics and director of the Center for Artificial Intelligence in Drug Discovery at Case Western Reserve University School of Medicine in Cleveland, Ohio. "So, if it's there, with a huge data set we can find it."

Xu suspects that the differences in risk between whites and Blacks are not due to genetics. "African Americans have a hugely increased risk compared to Caucasians, even with the same cancer," she said. "We think it's related to factors such as healthcare access or socioeconomic status."

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To explore the possible impact of cancer on COVID-19 risk, Xu and her colleagues performed a retrospective case-control study using de-identified electronic health record data collected by IBM Watson Health Explorys since 1999 from 360 hospitals and 317,000 clinicians across 50 U.S. states, representing 20% of the U.S. population.

The analysis was based on records from 73,449,510 patients, including 2,523,920 who had been diagnosed with at least one of 13 common cancers. A total of 273,140 of those cancers had been diagnosed within the past year. Among the 16,570 diagnosed with COVID-19, 1,200 also had a cancer diagnosis and 690 of the 1,200 had a recent cancer diagnosis.

Patients with a cancer diagnosis were at significantly raised risk for COVID-19 infection (adjusted odds ratio 7.14), with the strongest association for recently diagnosed leukemia (aOR 12.16), non-Hodgkin lymphoma (aOR 8.54) and lung cancer (aOR 7.66). The weakest association was with thyroid cancer (aOR: 3.10).

Among patients with a recent diagnosis of cancer, the risk for COVID-19 infection was significantly increased among African Americans compared to whites. Depending on cancer type, the added risk ranged from an aOR of 5.44 with breast cancer to aOR 2.53 with lung cancer.

Patients with cancer and COVID-19 also had significantly worse outcomes (hospitalization: 47.46%; death: 14.93%) compared to those with COVID-19 but no cancer (hospitalization: 24.26%; death: 5.2%) and patients with cancer and without COVID-19 (hospitalization: 12.39%; death: 4.03%).

These data suggest that cancer and COVID-19 work synergistically, Xu said.

The new study falls in line with other recent research, said Dr. Deborah Doroshow, an assistant professor of medicine at the Tisch Cancer Institute at the Icahn School of Medicine at Mount Sinai in New York City. "Using a very large database, it really confirms findings among patients with cancer," Dr. Doroshow said. "The question now is: what are we going to do about it."

What studies like Xu's don't tell us is why we are seeing these associations, Dr. Doroshow said. "But we can make educated guesses as to why cancer patients might be more likely to get COVID-19," she added. "Patients with cancer have disordered immune systems, especially those with blood cancers. And they may be on treatments that suppress the immune system."

As for African American patients having a higher risk, these kinds of large retrospective studies have only certain types of information available, Dr. Doroshow said. There's generally no information on socioeconomic status, she added.

"There can be a lot of reasons for the increased risk among African American patients," Dr. Doroshow said. "They are more likely to be living in multigenerational homes; they are more likely to be essential workers; and they are more likely to be using public transportation."

—Linda Carroll

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