Stroke rate lower than thought in critically ill COVID-19 patients

Stroke occurred at a relatively low rate of 2.2 percent in critically ill COVID-19 patients in the intensive care unit (ICU) — which is lower than previously thought among COVID-19 patients, according to data from the COVID-19 Critical Care Consortium (CCCC) registry presented at the AAN 2021 Meeting.

“Stroke has been a known serious complication of COVID-19,” said presenting author Dr Jonathon Fanning from the University of Queensland, Brisbane, Australia.

“Cerebrovascular complications are particularly concerning, with a frequency from 1-6 percent reported in SARS CoV-2 positive patients,” he explained. “However, such reports have generally been restricted to small patient populations and not specifically focused on the most critically ill patients requiring ICU care.”

The international, multicentre, prospective, observational CCCC study included 2,699 adult patients (median age 53 years, 65 percent male) admitted to the ICU for acute respiratory distress syndrome resulting from SARS-CoV-2 infection. They were followed on stroke occurring as a complication of COVID-19, in terms of frequency, types, and outcomes. [AAN 2021, emerging science session 010]

Among these critically ill patients, acute stroke was infrequent, occurring in 59 patients (2.2 percent) during their ICU stay. Haemorrhagic stroke was more common than ischaemic stroke (46 percent vs 32 percent). The remaining 22 percent were unspecified stroke.

“Among the sickest of COVID patients, those admitted to an ICU, our research found that stroke was not a common complication, and that ischaemic stroke did not increase the risk of death,” Fanning reported.

Haemorrhagic stroke was significantly associated with an increased risk of death (hazard ratio [HR], 2.7, 95 confidence interval [Cl], 1.4–5.3), but ischaemic stroke was not (HR, 1.0, 95 percent Cl, 0.5–2.4).

While 72 percent of the patients with haemorrhagic stroke eventually died, only 15 percent of the death was due to stroke. Instead, multi-organ failure was the predominant cause of death in these patients.

“The survival model demonstrated that the probability of having a stroke in the ICU was small, but gradually increased over time,” said Fanning.

A recent large cohort study presented at ISC 2021 showed that the overall ischaemic stroke rate was 0.75 percent among 21,073 patients hospitalized with COVID-19 — which the investigator also pointed out was lower than expected. [ISC 2021, abstract LB12] 

Unlike the ISC study, the current CCCC cohort specifically looked at new-onset stroke as a complication among COVID-19 patients requiring ICU admission. 

“There is scarce research on new-onset stroke complicating ICU admissions, and many of the limitations of assessing stroke in ICU populations confound the true values and result in variability in reported incidence anywhere from a 1 to 4 percent incidence,” noted Fanning.