An interrupted time-series analysis of the impact of COVID-19 on hospitalizations for vascular events in three Canadian provinces

Background COVID-19 infection is associated with a pro-coagulable state, thrombosis, and cardiovascular events. However, its impact on population-based rates of vascular events is less understood. We studied temporal trends in hospitalizations for stroke and myocardial infarction in three Canadian provinces (Alberta, Ontario, Nova Scotia) between 2014-2022. Methods Linked administrative data from each province were used to identify admissions for ischemic stroke, intracerebral hemorrhage, cerebral venous thrombosis, or myocardial infarction. Event rates/100,000/quarter, standardized to the 2016 Canadian population, were calculated. We assessed changes from quarterly rates pre-pandemic (2014-2020) compared to the pandemic period (2020-2022) using interrupted time series analysis with a jump discontinuity at pandemic onset. Age group and sex-stratified analyses were also performed. Results We identified 162,497 strokes and 243,182 myocardial infarctions. At pandemic onset there was no significant step change in strokes/100,000/quarter observed in any of the three provinces. During the pandemic, stroke rates were stable in Alberta and Ontario but increased in Nova Scotia (0.44/100,000/quarter, p-value 0.004). At pandemic onset, there was a significant step decrease in myocardial infarctions/100,000/quarter in Alberta (4.72, p-value <0.001) and Ontario (4.84, p-value <0.001), but not in Nova Scotia. During the pandemic, myocardial infarctions/100,000/quarter decreased in Alberta (-0.34, p-value 0.01) but remained stable in Ontario and Nova Scotia. No consistent patterns by age group or sex were noted. Conclusions Hospitalization rates for stroke or myocardial infarction across three Canadian provinces did not substantially increase during the first two years of the pandemic. Continued surveillance is warranted as the virus becomes endemic.