ABSTRACT
Background: The risk of thrombosis increases in infectious diseases, yet observational studies from single centers have shown a decrease in admission of acute ischemic stroke patients during the COVID-19 pandemic. To investigate unselected stroke admission rates, we performed a nationwide study in Denmark. Methods: We extracted information from Danish national health registries. The following mutually exclusive time periods were compared to the year before the lockdown: 1) 1st national lockdown, 2) gradual reopening, 3) few restrictions, 4) regional lockdown, 5) 2nd national lockdown. Results: Generally, admission rates were unchanged during the pandemic. In the unadjusted data, we observed a small decrease in the admission rate for all strokes under the first lockdown (incidence rate ratio: 0.93, confidence interval [CI]: 0.87-0.99) and a slight increase during the periods with gradual reopening, few restrictions, and the regional lockdown driven by ischemic strokes. We found no change in the rate of severe strokes, mild strokes, or 30-day mortality. An exception was the higher mortality for all stroke during the 1st lockdown (risk ratio: crude 1.30 [CI: 1.03-1.59];adjusted 1.17 [CI: 0.93-1.47]). The quality of care remained unchanged. Discussion: In Denmark, stroke admission rates remained largely unchanged during the pandemic. The increased short-term mortality rate in patients admitted with stroke observed during the 1st lockdown probably reflects that the frailest patients were more prone to die in the beginning of the pandemic. It seems unlikely that patients avoided admission, since admission rates for mild strokes and transient ischemic attacks were unchanged.