ObjectiveWe set out to determine which characteristics and outcomes of stroke are associated with COVID-19.MethodsThis case-control study included patients admitted with stroke to 13 hospitals in England and Scotland between 9 March and 5 July 2020. We collected data on 86 strokes (81 ischaemic strokes and 5 intracerebral haemorrhages) in patients with evidence of COVID-19 at the time of stroke onset (cases). They were compared with 1384 strokes (1193 ischaemic strokes and 191 intracerebral haemorrhages) in patients admitted during the same time period who never had evidence of COVID-19 (controls). In addition, the whole group of stroke admissions, including another 37 patients who appeared to have developed COVID-19 after their stroke, were included in two logistic regression analyses examining which features were independently associated with COVID-19 status and with inpatient mortality.ResultsCases with ischaemic stroke were more likely than ischaemic controls to occur in Asians (18.8% vs 6.7%, p<0.0002), were more likely to involve multiple large vessel occlusions (17.9% vs 8.1%, p<0.03), were more severe (median National Institutes of Health Stroke Scale score 8 vs 5, p<0.002), were associated with higher D-dimer levels (p<0.01) and were associated with more severe disability on discharge (median modified Rankin Scale score 4 vs 3, p<0.0001) and inpatient death (19.8% vs 6.9%, p<0.0001). Recurrence of stroke during the patient’s admission was rare in cases and controls (2.3% vs 1.0%, NS).ConclusionsOur data suggest that COVID-19 may be an important modifier of the onset, characteristics and outcome of acute ischaemic stroke.