Stroke rates are low among COVID-19 patients—but when they occur, the risk of death is substantial

The stroke rate among COVID-19 patients is low, according to new research published in Stroke. Cryptogenic stroke is more common than normal, however, and in-hospital mortality is significantly higher.

“Given early reports of an association between COVID-19 and cerebrovascular disease, there is a critical, unmet need to define associations and outcomes of patients with cerebrovascular disease and COVID-19,” wrote lead author Shadi Yaghi, MD, department of neurology at New York University School of Medicine, and colleagues. “Understanding factors associated with stroke in patients with COVID-19 will aid in the diagnosis, treatment, and prevention of COVID-19 associated cerebrovascular disease as well as potentially identify underlying mechanisms.”

The study’s authors tracked more than 3,500 hospitalized COVID-19 patients who received treatment from the same health system in New York City from March 15 to April 19, 2020. While just 0.9% of patients had imaging-confirmed ischemic stroke, some of the other findings were more troublesome.

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For instance, cryptogenic stroke was much higher among COVID-19 patients (65.6%) than historical controls (30.4%). For in-hospital mortality, the increase was even more significant (63.6% vs. 9.3%).

Patients with confirmed COVID-19 also had more severe strokes, with a median score of 19 on the National Institutes of Health Stroke Scale; non-COVID-19 patients had a median score of 8. D-dimer levels were also considerably higher—the median highest level was more than 10,000 for COVID-19 patients and 525 for non-COVID-19 patients.

“In patients with COVID-19 and ischemic stroke, a majority of strokes were classified as cryptogenic, possibly related to an acquired hypercoagulability, and were associated with increased mortality,” Yaghi et al. wrote. “Ongoing studies are testing the utility of therapeutic anticoagulation for stroke and other thrombotic event prevention, in select patients with COVID-19 and laboratory evidence suggestive of hypercoagulability.”