new research suggests. Investigators carried out a meta-analysis of data, including 160 patients with COVID-19 and stroke, and found that nearly half of patients under the age of 50 were asymptomatic at the time of stroke onset.
Although younger patients had the highest risk of stroke, the highest risk of death was in patients who were older, had other chronic conditions, and had more severe COVID-19–associated respiratory symptoms.
“One of the most eye-opening findings of this study is that, for patients under 50 years old, many were totally asymptomatic when they had a stroke related to COVID-19, [which] means that, for these patients, the stroke was their first symptom of the disease,” lead author Luciano Sposato, MD, MBA, associate professor and chair in stroke research at Western University, London, Ont.
The study was published online Sept. 15 in Neurology.
“In early April of 2020, we realized that COVID-19 was a highly thrombogenic disease,” said Dr. Sposato. “Almost in parallel, I started to see anecdotal reports in social media of strokes occurring in patients with COVID-19, and there were also very few case reports.”
The investigators “thought it would be a good idea to put all the data together in one paper,” he said, and began by conducting a systematic review of 10 published studies of COVID-19 and stroke (n = 125 patients), which were then pooled with 35 unpublished cases from Canada, the United States, and Iran for a total of 160 cases.
The analysis examined in-hospital mortality rates of patients with stroke and COVID-19.
In addition, the researchers conducted a second review of 150 papers, encompassing a final cohort of 3,306 COVID-19 patients with stroke of any type and 5,322 with ischemic stroke.
“Some studies reported data for only ischemic stroke, and some reported data for all strokes considered together, which resulted in a different number of patients on each meta-analysis, with a lower number of ‘any stroke’ cases,” Dr. Sposato explained. “This review looked at the number of patients who developed a stroke during admission and included thousands of patients.”
Dr. Sposato noted that the first review was conducted on single case reports and small case series “to understand the clinical characteristics of strokes in patients with COVID-19 on an individual patient level,” since “large studies, including hundreds of thousands of patients, usually do not provide the level of detail for a descriptive analysis of the clinical characteristics of a disease.”
Cluster analyses were used to “identify specific clinical phenotypes and their relationship with death.” Patients were stratified into three age groups: <50, 50-70, and >70 years (“young,” “middle aged,” and “older,” respectively). The median age was 65 years and 43% were female.
Mortality ‘remarkably high’
The review showed that 1.8% (95% confidence interval, 0.9%-3.7%) of patients experienced a new stroke, while 1.5% (95% CI, 0.8%-2.8%) of these experienced an ischemic stroke. “These numbers are higher than historical data for other infectious diseases – for example, 0.75% in SARS-CoV-1, 0.78% in sepsis, and 0.2% in influenza,” Dr. Sposato commented.
Moreover, “this number may be an underestimate, given that many patients die without a confirmed diagnosis and that some patients did not come to the emergency department when experiencing mild symptoms during the first months of the pandemic,” he added.
Focusing on the review of 160 patients, the researchers described in-hospital mortality for strokes of all types and for ischemic strokes alone as “remarkably high” (34.4% [95% CI, 27.2%-42.4%] and 35.7% [95% CI, 27.5%-44.8%], respectively), with most deaths occurring among ischemic stroke patients.
“This high mortality rate is higher than the [roughly] 15% to 30% reported for stroke patients without COVID-19 admitted to intensive care units,” Dr. Sposato said.
Many “young” COVID-19 patients (under age 50) who had a stroke (42.9%) had no previous risk factors or comorbidities. Moreover, in almost half of these patients (48.3%), stroke was more likely to occur before the onset of any COVID-19 respiratory symptoms.
Additionally, younger patients showed the highest frequency of elevated cardiac troponin compared with middle-aged and older patients (71.4% vs. 48.4% and 27.8%, respectively). On the other hand, mortality was 67% lower in younger versus older patients (odds ratio, 0.33; 95% CI, 0.12-0.94; P = .039).
Dr. Sposato noted that the proportion of ischemic stroke patients with large-vessel occlusion was “higher than previously reported” for patients with stroke without COVID-19 (47% compared with 29%, respectively).
“We should consider COVID-19 as a new cause or risk factor for stroke. At least, patients with stroke should probably be tested for SARS-CoV-2 infection if they are young and present with a large-vessel occlusion, even in the absence of typical COVID-19 respiratory symptoms,” he suggested.
The researchers identified a “high-risk phenotype” for death for all types of stroke considered together: older age, a higher burden of comorbidities, and severe COVID-19 respiratory symptoms. Patients with all three characteristics had the highest in-hospital mortality rate (58.6%) and a threefold risk of death, compared with the rest of the cohort (OR, 3.52; 95% CI, 1.53-8.09; P = .003).
“Several potential mechanisms can explain the increased risk of stroke among COVID-19 patients, but perhaps the most important one is increased thrombogenesis secondary to an exaggerated inflammatory response,” Dr. Sposato said.
Not just elders
Commenting on the study, Jodi Edwards, PhD, director of the Brain and Heart Nexus Research Program at the University of Ottawa Heart Institute, said the findings are “consistent with and underscore public health messaging emphasizing that COVID-19 does not only affect the elderly and those with underlying health conditions, but can have serious and even fatal consequences at any age.”
Dr. Edwards, who was not involved with the study, emphasized that “adherence to public health recommendations is critical to begin to reduce the rising incidence in younger adults.”
Dr. Sposato acknowledged that the study was small and that there “can be problems associated with a systematic review of case reports, such as publication bias, lack of completeness of data, etc, so more research is needed.”
Dr. Sposato is supported by the Kathleen & Dr. Henry Barnett Research Chair in Stroke Research at Western University, the Edward and Alma Saraydar Neurosciences Fund of the London Health Sciences Foundation, and the Opportunities Fund of the Academic Health Sciences Centre Alternative Funding Plan of the Academic Medical Organization of Southwestern Ontario. Dr. Sposato reported speaker honoraria from Boehringer Ingelheim, Pfizer, Gore, and Bayer and research/quality improvement grants from Boehringer Ingelheim and Bayer. The other authors’ disclosures are listed on the original article. Dr. Edwards has disclosed no relevant financial relationships.
A version of this article originally appeared on Medscape.com.