COVID-19 is associated with a greater risk of acute ischemic stroke than more traditional viral respiratory infections, according to new findings published in JAMA Neurology.
“Recent publications from China, France, and New York raise the possibility that COVID-19 might increase the risk of ischemic stroke,” wrote lead author Alexander E. Merkler, MD, Weill Cornell Medicine in New York City, and colleagues. “However, these studies lacked appropriate control groups. To evaluate whether COVID-19 is associated with a higher rate of ischemic stroke than would generally be expected from a viral respiratory infection, we compared the likelihood of acute ischemic stroke in patients with COVID-19 vs patients with influenza, a known stroke risk factor.”
The researchers tracked data from nearly 2,000 COVID-19 patients treated at one of two academic hospitals in New York City from March 4 to May 2, 2020. Stroke rates were compared with more than 1,400 patients treated for influenza A or influenza B from Jan. 1 to May 31, 2018, at a single facility, also in New York City.
Overall, 1.6% of COVID-19 patients treated in 2020 and 0.2% of influenza patients treated in 2018 had an acute ischemic stroke. After the authors made adjustments for such factors as age, sex and race, COVID-19 was still found to be associated with a greater risk of stroke than influenza.
“Our results were consistent across multiple sensitivity analyses, including analyses that adjusted for the number of vascular risk factors and ICU admission status, a surrogate for severity of illness,” Merkler et al. wrote. “Furthermore, we found that patients with COVID-19 infection who experienced an ischemic stroke were considerably more likely to die than patients with COVID-19 infection who did not experience an ischemic stroke.”
The team noted that its study did have certain limitations. For instance, some COVID-19 patients were “too unstable” to undergo certain imaging tests, meaning the stroke rate for that group may be even higher. Also, New York’s hospitals were so incredibly busy during the early months of the COVID-19 pandemic that “patients who sought emergency care with COVID-19 in our cohort had more severe illness than patients who sought emergency care with influenza in past years.” Testing criteria for COVID-19 also evolved as the study period moved on, which could have made an impact on the study’s findings.
Overall, however, the team’s research highlights the seriousness of the ongoing pandemic.
“These findings suggest that clinicians should be vigilant for symptoms and signs of acute ischemic stroke in patients with COVID-19 so that time-sensitive interventions, such as thrombolysis and thrombectomy, can be instituted if possible to reduce the burden of long-term disability,” the authors concluded. “In the meantime, further elucidation of thrombotic mechanisms in patients with COVID-19 may yield better strategies to prevent disabling thrombotic complications like ischemic stroke.”