Stroke is a possible complication of COVID-19, and researchers say they now know when that risk is highest.
A new study from the U.S. Centers for Disease Control and Prevention found the risk of COVID-related ischemic stroke appears greatest in the first three days after you’re diagnosed with the virus. Not just higher, but 10 times greater than during the period before a person contracts COVID-19.
“The findings of our study, especially the substantial high risk of stroke during early days of COVID-19, are consistent with the findings of other studies,” says study co-author Quanhe Yang, a senior scientist at the CDC.
“More and more evidence suggested that stroke following the diagnosis of COVID-19 is a possible complication of COVID-19 that patients and clinicians should understand. Vaccination and other preventive measures for COVID-19 are important to reduce the risk of infection and complications including stroke,” Yang adds.
Stroke is the fifth leading cause of death in the United States. Ischemic stroke, caused by a blocked blood vessel, is the most common type.
While previous studies have been inconsistent in their findings on stroke risk among adults with COVID-19, few have focused on older adults, who tend to have a greater risk of stroke.
What the study shows
For this study, the researchers used the health records of more than 37,300 U.S. Medicare beneficiaries aged 65 and older. They had been diagnosed with COVID-19 between April 1, 2020, and February 28, 2021, before most people had an opportunity to be vaccinated.
The data included patients hospitalized for stroke prior to the pandemic in 2019 through February 2021. Yang’s team compared stroke risk in the days just before and after the COVID-19 diagnosis to the risk during the other days of the study — that is, seven days before COVID diagnosis to 28 days after diagnosis.
That 10-times higher risk of the first three days quickly declined. At four to seven days, the risk was 60% higher than in the control period, and by days eight to 14, it was down to 44% higher. At 15 to 28 days after diagnosis, it was only 9% higher, the researchers reported.
“This provides a little bit of reassurance that early risk does decrease over time,” says Dr. Louise McCullough, chair of neurology at UT Health Houston and chief of neurology at Memorial Hermann Hospital in Houston.
The risk of stroke was higher for