Acute ischemic stroke incidence after influenza or coronavirus disease 2019 among older US adults: A cross-sectional study using electronic health records

Background: Although coronavirus disease 2019 and influenza are recognized risk factors for thrombotic conditions, the incidence of acute ischemic stroke following these infections since 2022 remains unknown. Methods: Patients aged ≥65 years with no prior history of stroke, coronavirus disease 2019, or influenza who developed acute ischemic stroke from 3 days before to 28 days after a coronavirus disease 2019 or influenza diagnosis were identified using PCORnet and HealthVerity data collected from 1 January to 31 December 2022. Demographic characteristics, underlying conditions, level of care, outcomes, and acute ischemic stroke incidence were described and compared between patients with early acute ischemic stroke occurring from −3 to 7 days from the diagnosis date and late acute ischemic stroke occurring from 8 to 28 days. Results: Among 245,352 patients in PCORnet and 639,396 patients in HealthVerity aged ≥65 years with COVID-19, the incidence of early acute ischemic stroke following coronavirus disease 2019 (PCORnet: 962 per 100,000; HealthVerity: 447 per 100,000) and influenza (PCORnet: 589 per 100,000; HealthVerity: 387 per 100,000) was significantly higher than that of late acute ischemic stroke (coronavirus disease 2019 PCORnet: 81 per 100,000; HealthVerity: 141 per 100,000; influenza PCORnet: 75 per 100,000; HealthVerity: 15 per 100,000) (all p < 0.01). Conclusions: Although acute ischemic stroke incidence may have declined since 2020–2021, the persistent risk of acute ischemic stroke associated with acute coronavirus disease 2019 and influenza underscores the importance of continued monitoring and preventive strategies in older adults.