To the Editor We read with interest the article by Merkler et al1 regarding the increased incidence of ischemic stroke in patients with coronavirus disease 2019 (COVID-19) compared with those with influenza. The authors also reported that 13% of patients with COVID-19 were receiving anticoagulation at the time of the stroke.1 Could the authors comment on the rate of anticoagulant use in patients with COVID-19 who did not have an ischemic stroke? This would also be helpful to assess the possibility that anticoagulation may have been protective.
We would also like to know how many cases were excluded from the analysis because of hemorrhagic stroke in the COVID-19 and influenza populations. Recent data have suggested that hemorrhagic stroke may be common in patients with COVID-19,2,3 especially those receiving prophylactic anticoagulation.4 Varatharaj and colleagues,3 in a UK surveillance study of neurological complications associated with COVID-19, reported that 9 of 125 individuals (7.2%) had an intracerebral hemorrhage. Although individual case reports have suggested intracerebral hemorrhage as a complication of COVID-19, controlled data are still lacking to support an association.
We note that in the report by Merkler et al,1 10% of patients with an acute ischemic stroke received intravenous thrombolysis. The authors report that in the entire cohort, 2 of 31 patients (7%) had a symptomatic hemorrhagic transformation.1 However, it is unclear from the study how many patients receiving intravenous thrombolysis had a symptomatic or asymptomatic hemorrhagic transformation. Understanding the risk of intracranial hemorrhage in patients with COVID-19 is of paramount importance to inform the risk-benefit assessment of the use of both intravenous thrombolysis and anticoagulation in this patient population.
Corresponding Author: Michael Silverman, MD, Division of Infectious Diseases, Western University, 268 Grosvenor St B3-414, London, ON N6A 4V2, Canada (michael.silverman@sjhc.london.on.ca).
Published Online: March 8, 2021. doi:10.1001/jamaneurol.2021.0117
Conflict of Interest Disclosures: None reported.