Stroke 'Not a Common Complication' in COVID-19: New Studies

April 18, 2021

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Two new large international studies have found relatively low rates of stroke in patients hospitalized with COVID-19.  

One study showed a stroke rate of 2.2% among patients with COVID-19 admitted to intensive care in 52 different countries. Another found a stroke rate of 1.48% in patients hospitalized with COVID-19 from 70 different countries. These researchers also found a reduction in stroke presentations and stroke care during the pandemic.

Both studies will be presented at the American Academy of Neurology (AAN) 2021 Annual Meeting being held virtually April 17 to 22, 2021.

"Stroke has been a known serious complication of COVID-19, with some studies reporting a higher-than-expected occurrence, especially in young people," said coauthor of the intensive care study, Jonathon Fanning, MBBS, PhD, University of Queensland in Brisbane, Australia.

"However, among the sickest of COVID patients, those admitted to an ICU, our research found that stroke was not a common complication, and that ischemic stroke did not increase the risk of death," he added.

Hemorrhagic Stroke More Common?

In this study, researchers analyzed a database of 2699 patients who were admitted to the intensive care unit (ICU) with COVID-19 in 52 countries and found that 59 of these patients (2.2%) subsequently sustained a stroke. 

Most of the strokes identified in this cohort were hemorrhagic (46%), with 32% being ischemic and 22% unspecified. Hemorrhagic stroke was associated with a fivefold increased risk for death compared with patients who did not have a stroke. Of those with a hemorrhagic stroke, 72% died, but only 15% died of the stroke. Rather, multiorgan failure was the leading cause of death.

There was no association between ischemic stroke and mortality.

"There is scarce research on new-onset stroke complicating ICU admissions, and many of the limitations of assessing stroke in ICU populations confound the true values and result in variability in reported incidence anywhere from a 1%-4% incidence," Fanning said. 

He noted that a  large Korean study had shown a 1.2% rate of stroke in patients without COVID admitted to non-neurologic ICUs. "In light of this, I think this 2% is higher than we would expect in a general ICU population, but, in the context of earlier reports of COVID-19–associated risk for stroke, this figure is actually somewhat reassuring," Fanning told Medscape Medical News.  

Asked how this study compared with the large American Heart Association (AHA) study recently reported that showed an overall rate of ischemic stroke of 0.75%, Fanning said the two studies reported on different populations, which makes them difficult to compare.

"Our study specifically reports on new-onset stroke complicating ICU admission," he noted. "The AHA study is a large study of all patients admitted to hospital. But both studies identified less than previous estimates of COVID-related stroke."

Largest Sample to Date  

The other study, which includes 119,967 COVID-19 hospitalizations and represents the largest sample reporting the concomitant diagnoses of stroke and SARS-CoV-2 infection to date, was presented at the AAN meeting by Thanh N. Nguyen, MD, Boston University School of Medicine, Massachusetts.

This study has also been published online in Neurology, with first author Raul G. Nogueira, MD, Emory University School of Medicine, Atlanta, Georgia.  

In this international observational, retrospective study across 6 continents, 70 countries, and 457 stroke centers, there was a 1.48% stroke rate across 119,967 COVID-19 hospitalizations. SARS-CoV-2 infection was noted in 3.3% (1722) of all stroke admissions, which numbered 52,026.

The researchers identified stroke diagnoses by International Classification of Diseases, 10th revision, codes and/or classifications in stroke center databases, and rates of stroke hospitalizations and numbers of patients receiving thrombolysis were compared between the first 4 months of the pandemic (March to June 2020) compared with two control 4-month periods.

Global Decline in Stroke Care During Pandemic

Results showed a global decline in the number of stroke patients admitted to the hospital as well as acute stroke treatments, such as thrombolysis, during the first wave of the COVID-19 pandemic.  

The researchers found that there were 91,373 stroke admissions in the 4 months immediately before the pandemic compared to 80,894 admissions during the first 4 pandemic months, representing an 11.5% decline.

They also report that 13,334 stroke patients received intravenous thrombolysis in the 4 months preceding the pandemic compared to 11,570 during the first 4 pandemic months, representing a 13.2% drop.

Interhospital transfers after thrombolysis for a higher level of stroke care decreased from 1337 before the pandemic to 1178 during the pandemic, a reduction of 11.9%.  

There were greater declines in primary compared to comprehensive stroke centers for stroke hospitalizations (change, –17.3% vs –10.3%) and for the number of patients receiving thrombolysis (change, –15.5% vs –12.6%).

The volume of stroke hospitalizations increased by 9.5% in the 2  later pandemic months (May, June) vs the 2 earlier months (March, April), with greater recovery in hospitals with lower COVID-19 hospitalization volume, high-volume stroke centers, and comprehensive stroke centers.

Nguyen suggested that reasons for the reductions in these stroke numbers at the beginning of the pandemic could include a reduction in stroke risk due to a reduction of exposure to other viral infections or patients not presenting to the hospital for fear of contracting the coronavirus.

The higher recovery of stroke volume in high-volume stroke centers and comprehensive stroke centers may represent patients with higher needs — those having more severe strokes — seeking care more frequently than those with milder symptoms, she noted.

"Preserving access to stroke care and emergency stroke care amidst a pandemic is as important as educating patients on the importance of presenting to the hospital in the event of stroke-like symptoms," Nguyen concluded.

"We continue to advocate that if a patient has stroke-like symptoms, such as loss of speech, strength, vision, or balance, it is important for the patient to seek medical care as an emergency as there are treatments that can improve a patient's ability to recover from disabling stroke in earlier rather than later time windows," she added.

In the publication, the authors write, "Our results concur with other recent reports on the collateral effects of the COVID-19 pandemic on stroke systems of care," but add that "this is among the first descriptions of the change at a global level, including primary and comprehensive stroke centers."

They say that hospital access related to high COVID-19 burden was unlikely a factor because the decline was seen in centers with a few or no patients with COVID-19. They suggest that patient fear of contracting coronavirus may have played a role along with a decrease in presentation of transient ischemic attacks, mild strokes, or moderate strokes, and physical distancing measures may have prevented the timely witnessing of a stroke.

American Academy of Neurology (AAN) 2021 Annual Meeting. Emerging Science #010. Presented April 18. #N3.002. Presented April 19, 2021.

Neurology. Published online March 25, 2021. Abstract  

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