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Stroke Rate in COVID-19: A More Accurate Estimate

Sue Hughes
March 19, 2021

A more accurate estimate of the stroke risk in patients hospitalized with COVID-19 infection has come from a large American Heart Association registry study.

Findings from the American Heart Association's COVID-19 Cardiovascular Disease Registry, including more than 20,000 US adults hospitalized with COVID-19 from March to November 2020, showed an overall rate of ischemic stroke of 0.75%.

Although that is lower than previous estimates of ischemic stroke risk with severe COVID-19 infection, it is still higher than that seen with other infections such as influenza or sepsis.

Twice the Risk of In-Hospital Mortality

Results also show that patients who had an ischemic stroke while hospitalized for COVID-19 had twice the likelihood of dying compared with those who did not have a stroke.

"These findings suggest that COVID-19 may increase the risk for stroke, though the exact mechanism for this is still unknown," said lead study author Saate S. Shakil, MD, a cardiology fellow at the University of Washington in Seattle. "As the pandemic continues, we are finding that coronavirus is not just a respiratory illness, but a vascular disease that can affect many organ systems," she added.

The findings were presented on March 19 at the virtual International Stroke Conference (ISC) 2021.

Shakil explained that when the COVID-19 pandemic first appeared there were reports of ischemic stroke occurring more frequently in patients hospitalized with this infection than would have been expected. Studies so far have estimated the stroke rate in COVID-19 patients as between 0.9% and 2%, and until now the largest study to investigate this has included 8000 patients, she noted.

The current findings come from a much larger database, with the current report including 21,073 patients hospitalized with COVID-19 between March and November 2020.

Results showed that of these patients 160 had an ischemic stroke while hospitalized for COVID-19, which translates into a rate of 0.75%.

Patients who had an ischemic stroke were more likely to be older (average 65 years) than patients hospitalized with COVID who did not have a stroke (61 years) and to be male (63% vs 54%).

Patients who had a stroke were also more likely to have comorbidities known to increase risk for stroke, such as hypertension, atrial fibrillation, diabetes, and existing cerebrovascular disease or a history of stroke. "This is not altogether surprising as these are known risk factors for experiencing an ischemic stroke regardless of COVID-19 infection."

Findings showed that 44% of patients who had an ischemic stroke also had type 2 diabetes compared with about one third of patients without stroke.

Hypertension was "extremely prevalent," occurring in 60% of all hospitalized COVID patients who did not have a stroke and 80% of those who did have a stroke, Shakil noted.

Atrial fibrillation was present in 18% of COVID patients who had an ischemic stroke versus 9% of those without stroke.

Stroke patients were twice as likely to be critically ill, as evidenced by intensive care unit admissions, and need for mechanical ventilation or dialysis compared with that of those who did not experience stroke, Shakil reported.

In addition, those who had an ischemic stroke had double the length of hospital stay (20 days) versus 10 days for those not experiencing a stroke, and they had twice the mortality rate, with in-hospital death rates of 37% compared with 16% for those who did not have a stroke.

Black Patients Have Highest Stroke Risk

When the findings are analyzed by race/ethnicity, significant racial disparities were found, Shakil observed, with non-Hispanic black patients overrepresented among COVID-19 patients who had an ischemic stroke compared with their overall makeup in the registry. "Interestingly, this trend appears to be reversed among Hispanic patients," she added.

The number of non-Hispanic white patients with an ischemic stroke was similar to that of their overall representation in the registry.

Hispanic patients had the lowest risk for ischemic stroke, at 0.52%; the risk in non-Hispanic whites was 0.75%, and in non-Hispanic blacks it was 0.91%. Non-Hispanic blacks accounted for 26% of the registry but 31% of those who experienced an ischemic stroke.

Shakil said she was not sure what to make of the data on showing lower risk in Hispanic patients. "We will be looking at that going forward."

"These results are for all comers in each racial group and the results have not been adjusted for baseline demographic or co-morbidities," Shakil cautioned, adding that the researchers plan to do further analyses to understand the drivers of these disparities.

"We know the COVID-19 pandemic has disproportionately affected communities of color, but our research suggests Black Americans may have higher risk of ischemic stroke after contracting the virus, as well," Shakil said. "Stroke on its own can have devastating consequences and recovering from COVID-19 is often a difficult path for those who survive. Together, they can exact a significant toll on patients who have had both conditions."

She added, "It is more important than ever that we curb the spread of COVID-19 via public health interventions and widespread vaccine distribution."

Moderator of an ISC news conference on the study, Louise McCullough, MD, PhD, chief of neurology at Memorial Hermann Hospital-Texas Medical Center, Houston, and ISC meeting chair, said this study shows the strength of large numbers.

"It is very impressive to have been able to get these data in such a short time," she said. "It really speaks to the value of having such large datasets."

McCullough said the effect of COVID on stroke may not be limited to the actual period of hospitalization. "Millions of people have been infected and recovered from this infection and the question is what is [this] disease going to do over next decade to these people? Is there going to be a chronic long-haul syndrome and is that going to affect rates of dementia and vascular disease in the future?

"This is something [that] can be ascertained from following individuals in these datasets," she added. "Even if COVID disappears next year it will not have really gone because of the sheer numbers of people it has affected."

Mitchell Elkind, MD, professor of neurology at Columbia University in New York City and president of the American Heart Association/American Stroke Association, pointed out that infections such as pneumonia or urinary tract infection are common complications of stroke and that there is evidence that stroke patients who also have an infection seem to be at a greater risk of developing poststroke dementia or cognitive decline.

"It appears that something about having a stroke affects your immune system and that leads to secondary degenerative problems of the brain and if you throw in an infection on top that then this can further exacerbate that problem," he said. "COVID may turn out to be a model for addressing some of those kinds of questions as well."

The study was funded by the American Heart Association. Shakil disclosed no relevant financial relationships.

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Reviewed on 3/22/2021
References
SOURCE: Medscape, March 19, 2021. International Stroke Conference (ISC) 2021. Late-breaking abstract 12. Presented March 19, 2021.

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