Penn study finds relatively low levels of stroke in coronavirus patients

Previous studies have raised concerns that the coronavirus can lead to big strokes in young patients, but a new analysis from Penn Medicine finds that most strokes in patients at Penn’s three Philadelphia hospitals were in older people with known stroke risk factors like high blood pressure and diabetes.

Only one stroke patient was under age 50.

Doctors had worried that stroke might be a “huge risk” for coronavirus patients, said Brett L. Cucchiara, a stroke neurologist who is senior author of the paper, published this month in the journal Stroke. The risk is “real, but it’s not really as big a problem as we were worried it was going to be.”

Pascal M. Jabbour, a vascular neurosurgeon at Jefferson Health, said multiple studies have found associations between COVID-19 and clotting in various parts of the body. He was part of a much-publicized study with researchers at Mount Sinai Hospital in New York in the spring that looked at stroke patients with major blockages during the peak of the East Coast coronavirus surge. Their small study of 14 COVID-19 patients with stroke found that about 40% were under age 55 and 55% had no risk factors for stroke.

In some, stroke was the first symptom of the coronavirus. A more recent and still unpublished study involving 12 centers in the United States and Europe and 50 stroke patients found that about a third were under age 55 and a third had stroke as their first symptom. Thirty-eight percent had no stroke risk factors.

“This is something important,” Jabbour said. “We shouldn’t downplay this thing.”

He said the public needs to know to take stroke symptoms like sudden numbness or loss of balance seriously when the coronavirus is circulating. “The message from both papers should be, regardless, if you have stroke symptoms, you need to call 911.”

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Because Jabbour’s team looked only at people who had strokes, he could not say how unusual it is for coronavirus patients to have the large-vessel blockages he targeted.

The Penn team looked only at strokes, not at whether patients developed clots outside the brain.

They examined data on 844 patients hospitalized with COVID-19 from March 15 to May 3. Of those, 2.5% had strokes caused by clots, a low percentage when considering how many COVID-19 patients do not need hospitalization, Cucchiara said. While he does not have this sort of data on people with other conditions, he said that stroke rate would probably not be unusual in people in an intensive care unit, but those patients usually are older with more chronic health problems. The COVID-19 patients had an average age of 59. “We don’t normally see a population that’s relatively young that’s this sick,” Cucchiara said.

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An early study from Wuhan, China, found that 2.3% of hospitalized coronavirus patients had strokes. A large study in New York found a rate of almost 1%.

Studies have also found that the risk for stroke is higher among people who have recently had the flu. Jabbour cited a recent study that found stroke risk was 7.5 times higher in COVID-19 patients than in those with the flu.

Sixty-eight percent of the COVID-19 patients at the Hospital of the University of Pennsylvania, Penn Presbyterian Medical Center, and Pennsylvania Hospital during the study time period were Black, a figure that surprised Cucchiara. Black patients accounted for 80% of the people who had strokes. Because they are more likely to have risk factors like high blood pressure and diabetes, Black individuals tend to be at higher risk for strokes than other groups. Most of the coronavirus patients who had strokes had high blood pressure, diabetes, or other risk factors like heart failure. More than one-third had a previous stroke.

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Nearly 1% of the patients had bleeding in the brain, a type of stroke that is especially dangerous. That was more than Cucchiara had expected. Patients are now even more likely to receive blood thinners because doctors want to prevent clots. “This is kind of a cautionary note,” Cucchiara said.

Most of the patients in the Penn study had strokes after they were hospitalized. On average, the strokes occurred 21 days after symptoms began.

Cucchiara doubts the coronavirus directly causes clotting, but said inflammation caused by viral infection can make blood clot more easily. Critical illness may also be a factor. Stroke may be more common in patients who are immobilized and hooked to machines and IV lines.

Jabbour said the studies are not contradictory. They are just pieces of information from different perspectives as scientists try to understand this new disease. “This is a multifaceted disease,” he said. “Really, we’re still collecting data.”