Increased Risk of Acute Hemorrhagic Stroke After Severe Acute Respiratory Syndrome Coronavirus 2 Infection

ABSTRACT Background Coronavirus disease (COVID‐19), caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), leads to various complications. A history of SARS‐CoV‐2 infection has been suggested as a risk factor for acute hemorrhagic stroke, albeit evidence is limited. Aim We aimed to investigate the role of SARS‐CoV‐2 infection in a risk for acute hemorrhagic stroke. Methods Patients diagnosed with COVID‐19 were identified using the Japanese inpatient and outpatient claims database between January 1, 2020, and December 31, 2022. Self‐controlled case series (SCCS) and nested case–control analyses were conducted. Results Among 399,381 patients diagnosed with COVID‐19, 1223 also had acute hemorrhagic stroke, of whom 1201 were included in the SCCS analyses. The incidence rate ratios for acute hemorrhagic stroke were 1.90 (95% confidence interval [CI]: 1.50–2.41), 1.40 (95% CI: 1.07–1.82), and 1.18 (95% CI: 0.90–1.57) for the 1–30, 31–60, and 61–90 days following the COVID‐19 diagnosis, respectively. Using nested case–control analysis, 1223 cases with acute hemorrhagic stroke were matched with 4892 controls; 51.2% (626/1223) of cases and 7.7% (375/4892) of controls were diagnosed with COVID‐19 in the previous 0–30 days of acute hemorrhagic stroke occurrence. Conditional logistic regression analyses in matched patients revealed an adjusted odds ratio for receiving a COVID‐19 diagnosis 0–30 days before an acute hemorrhagic stroke diagnosis of 13.6 (95% CI: 10.4–17.8). Conclusion Based on the data from the Japanese inpatient and outpatient claims database, SARS‐CoV‐2 infection is a risk factor for acute hemorrhagic stroke.