Age, pre-existing vascular conditions and severe infection are tied to greater odds that a  patient hospitalized with COVID-19 will have a stroke, a new study finds.

Investigators analyzed 61 studies involving more than 100,000 hospitalized patients admitted with COVID-19. Stroke occurred in 14 out of every 1,000 cases. Most patients had been admitted with COVID-19 symptoms, with stroke occurring a few days later.  

Patients who developed stroke were, on average, five years older than those who did not, but an average of six years younger than patients without COVID-19 who developed stroke.

Conditions most highly linked to stroke were high blood pressure, diabetes and coronary artery disease. And perhaps not surprisingly, the more severe the SARS-­CoV­-2 infection, the greater the chances of experiencing a stroke.

One unanswered question is whether COVID-19 increases the risk of stroke or whether the association simply is the result of widespread cases in the community, the authors said.

“The picture is complicated,” explained Stefania Nannoni, M.D., of the University of Cambridge in England. “A number of COVID-19 patients are already likely to be at increased risk of stroke, and other factors such as the mental stress of COVID-19 may contribute to stroke risk.”

“On the other hand, we see evidence that COVID-19 may trigger – or at least be a risk factor for – stroke in some cases,” she added. “In fact, the virus that causes the disease appears to be more associated with stroke when compared with other coronaviruses, and significantly more than seasonal flu.”

Although the percentage of people with COVID-19 who develop stroke is relatively low, clinicians will need to remain alert for signs and symptoms, while bearing in mind that the profile of an at-risk patient is younger than might be expected, concluded Hugh Markus, FRCP, who leads the Stroke Research Group at Cambridge.

The study was published in the International Journal of Stroke.