Association Between Circadian Onset Time and Clinical Outcomes in Acute Ischemic Stroke

It has been demonstrated that the circadian rhythm influences the onset of ischemic stroke, however its impact on treatment strategies and clinical outcomes remains uncertain. The aim of this study was to investigate the association between the circadian timing of stroke onset and vascular risk profiles, stroke severity, prognosis, and treatment methods in patients with acute ischemic stroke.

We retrospectively reviewed acute ischemic patients with stroke admitted to our University Hospital Stroke Unit (August 2017-December 2023). Patients were grouped by stroke onset time: Group 1 (wake-up/00:00-awakening), Group 2 (awakening-12:00), Group 3 (12:00-18:00), and Group 4 (18:00-00:00). Demographic and clinical characteristics, and acute stroke treatments, including intravenous thrombolysis (IV tPA) and thrombectomy were recorded. Outcomes were assessed using the modified Rankin Scale (mRS) at the first follow-up. Following univariate analyses, multivariable binary logistic regression identified independent predictors of IV tPA administration.

Among 1047 admissions, 751 patients met the inclusion criteria. There were 212 patients (28.2%) in Group 1, 231 patients (30.8%) in Group 2, 158 patients (21%) in Group 3, and 150 patients (20%) in Group 4. The prevalence of hypertension was significantly lower in Group 3 (p=0.0027). Multivariable analysis identified higher admission National Institutes of Health Stroke Scale scores (OR 1.202, p <0.001) and stroke onset time as independent predictors of IV tPA administration. Group 1 patients were significantly less likely to receive IV tPA (p <0.001), with no significant differences in etiology, mortality, or follow-up mRS scores.

This study shows that IV tPA is less frequently administered to patients who experienced ischemic stroke during sleep. This finding highlights the need for tools that can enable earlier detection of stroke occurring during sleep. Despite the differences in IV tPA administration rates, stroke onset time did not significantly impact overall patient prognosis, including mortality and functional outcomes.