Higher rate of stroke among hospitalized COVID-19 vs influenza patients
A retrospective cohort study of nearly 2,000 patients hospitalized with coronavirus disease 2019 (COVID-19) found a higher rate of ischaemic stroke compared with a cohort of patients with influenza A/B.
Of 1,916 patients who visited an emergency department (ED) or were hospitalized with COVID-19 at two academic hospitals in New York City, New York, US between March and May 2020, 31 (1.6 percent; 95 percent confidence interval [CI], 1.1 to 2.3) had an acute ischaemic stroke. In comparison, 3 of 1,486 patients (0.2 percent; 95 percent CI, 0.0 to 0.6) with an ED visit or hospitalization who had laboratory-confirmed influenza A or B between January 2016 and May 2018 had an acute ischaemic stroke. [JAMA Neurol 2020, doi:10.1001/jamaneurol.2020.2730]
“[COVID-19] patients who were diagnosed with acute ischaemic stroke were significantly older and, on average, had more stroke risk factors, higher laboratory markers of inflammation, and more critical illness than patients without ischaemic stroke,” reported the researchers.
The median age of patients with acute ischaemic stroke was 69 years (interquartile range, 66–78). The youngest patient with ischaemic stroke in the cohort was 51 years of age. More than one-third of ischaemic strokes (35 percent) occurred in patients who had severe COVID-19 infection and received mechanical ventilation.
In an unadjusted analysis, patients with COVID-19 were more likely to have an acute ischaemic stroke than patients with influenza (odds ratio [OR], 8.1; 95 percent CI, 2.5 to 26.6). “Our results were similar after adjustment for age, sex, and race [OR, 7.6; 95 percent CI, 2.3 to 25.2],” wrote the researchers.
The association between COVID-19 and acute ischaemic stroke persisted across multiple sensitivity analyses, with the magnitude of relative associations ranging from 4.0 to 9.3. This included a sensitivity analysis that adjusted for the number of vascular risk factors and intensive care unit (ICU) admissions (OR, 4.6; 95 percent CI, 1.4 to 15.7).
“Acute viral infections, including influenza, act as triggers that increase the short-term risk of ischaemic stroke and other arterial thrombotic events, such as myocardial infarction. COVID-19 infection, in particular, is associated with a vigorous inflammatory response accompanied by coagulopathy, with elevated D-dimer levels and frequent presence of antiphospholipid antibodies, which may explain the high prevalence of thromboses seen in these patients,” proposed the researchers. [Ann Clin Transl Neurol 2018;5:456-463; Circ Res 2017;120:472-495; N Engl J Med 2020;382:e38; Thromb Res 2020;191:145-147; Thromb Haemost 2020;120:998-1000]
Compared with COVID-19 patients, patients with influenza were on average younger; more often women; less often had hypertension, diabetes, coronary artery disease, chronic kidney disease, or atrial fibrillation; and more often had hyperlipidaemia. Patients with influenza were also less likely to be admitted to an ICU or receive mechanical ventilation.
“Although the baseline stroke risk factors, such as hypertension, diabetes, and coronary artery disease, were more common in patients with COVID-19 than in patients with influenza, we identified a higher risk of ischaemic stroke with COVID-19 vs influenza even when adjusting for the number of vascular risk factors,” wrote the researchers.
“Patients with COVID-19 who experienced an ischaemic stroke were considerably more likely to die than patients with COVID-19 who did not experience an ischaemic stroke,” wrote the researchers. Among COVID-19 patients, the inpatient mortality rate was 32 percent in those with ischaemic stroke vs 14 percent in those without (p=0.003).