Effect of COVID-19 on First-Time Acute Stroke and Transient Ischemic Attack Admission Rates and Prognosis in Denmark: A Nationwide Cohort Study.

On March 13, 2020, the Danish authorities imposed extensive nationwide lockdown measures to prevent the spread of the novel coronavirus disease 2019 (COVID-19) and reprioritized limited healthcare resources. However, this strategy may have a detrimental effect on medical care to patients with other acute conditions such as stroke and may increase the reluctance of patients with symptoms to contact emergency medical services. To shed light on the possible collateral effects of a lockdown strategy and reprioritization within the healthcare system, we performed a nationwide cohort study to investigate stroke and transient ischemic attack (TIA) admission rates and prognosis in Denmark during the COVID-19 pandemic.

Data from several nationwide administrative registries were obtained, and they have been described previously.[1] The study population comprised every Danish citizen in 2 periods: (1) a combined period of January 2 to May 8 (2017-2019), and (2) January 2 to May 7, 2020. Weekly incidence rates and incidence rates before and after March 13 of first-time stroke/TIA admissions, overall and according to subtypes, in the 2 periods were compared with unadjusted Poisson regression. Furthermore, mortality rates among patients admitted with stroke/TIA, overall and according to subtypes, before and after March 13, were compared with the use of unadjusted Cox regression. The study is approved by the Capital Region of Denmark (approval P-2019-191) in accordance with the General Data Protection Regulation.

Before March 13, an average of 2862 patients were admitted with stroke/TIA in 2017 to 2019 compared with 2954 patients in 2020. After March 13, the corresponding numbers were 2323 and 2029, respectively. The admission rates of stroke/TIA were significantly lower during the first weeks of lockdown in 2020 but returned to a rate similar to that observed in 2017 to 2019 toward the end of the study period (Figure [A]). However, results differed according to subtypes. Although the admission rates of ischemic stroke and TIA were significantly lower during the first weeks of lockdown in 2020 before returning to rates similar to those observed in 2017 to 2019 toward the end of the study period, the admission rate of hemorrhagic stroke was not significantly different after lockdown in 2020 compared with 2017 to 2019 (Figure [B through D]). These results were consistent regardless of sex and age. In addition, expanding the study population to patients with a history of stroke/TIA yielded similar findings.

IRRs of stroke/TIA admissions and mortality rate ratios among patients admitted with stroke/TIA in 2017 to 2019 compared with 2020. A, Weekly IRRs of stroke/TIA admissions overall in 2020 compared with 2017 to 2019. B, Weekly IRRs of ischemic stroke admissions in 2020 compared with 2017 to 2019. C, Weekly IRRs of hemorrhagic stroke admissions in 2020 compared with 2017 to 2019. D, Weekly IRRs of TIA admissions in 2020 compared with 2017 to 2019. E, Mortality rate ratios among patients admitted with stroke/TIA, combined and according to subtypes, in 2020 compared with 2017 to 2019. IRRs indicate incidence rate ratios; and TIA, transient ischemic attack.

The mortality rates among patients admitted with stroke/TIA, overall and according to subtypes, before and after March 13 were not significantly different in 2020 compared with 2017 to 2019 (Figure [E]).

To the best of our knowledge, this is the first report to investigate the admission rate of stroke subtypes and subsequent prognosis on a nationwide scale during the COVID-19 pandemic.[2-4] The reasons for the significant decline in stroke admissions after lockdown are unclear. First, some individuals experiencing stroke symptoms may be more likely to stay home rather than attending emergency departments or seeking medical care because of fear of acquiring COVID-19 or to avoid adding to an overburdened healthcare system. Second, although speculative, a substantial decline in rates of influenza, a risk factor for stroke, has been observed in Denmark. Whatever the reasons, our findings reinforce the necessity of a clear public health message from governments worldwide to patients experiencing symptoms suggestive of stroke to still seek emergency medical services. Stroke admission rates returned to a rate similar to that observed in the preceding years toward the end of the study period, and the Danish authorities announced the first phase of reopening of the Danish society on April 6. Taken together, these findings may be useful for policy makers and healthcare planners if a new pandemic or a new COVID-19 wave should occur.

This finding that hemorrhagic stroke admissions did not decline after lockdown is not surprising because these patients in general have a considerably higher initial stroke severity and more often experience a clinically significant deterioration within the first hours after onset compared with patients with stroke of ischemic origin.[5]

It is reassuring that this report demonstrated that mortality among patients admitted with stroke, overall and according to subtypes, was not significantly higher after lockdown compared with the preceding years. These data do not indicate that patients present with more severe strokes or that reorganization of healthcare systems, which may have influenced in-hospital treatment delay, including effective triage and rapid identification of treatment options, has had an effect on very short-term mortality.

It would have been interesting to examine the volume of thrombolysis/thrombectomy during the pandemic, but these data were not available. Likewise, data on cause of death were not available, and we were not able to examine out-of-hospital deaths attributed to stroke. Last, the low number of deaths, limited follow-up, and lack of stroke severity data did not allow a long-term evaluation of the effect of the pandemic on stroke care.

Disclosures

None.