Relationship between stroke onset timing and clinical outcomes in ischemic and hemorrhagic strokes: a systematic review.

Background: Cerebrovascular accident (CVA) is a critical medical pathology caused by the interruption of cerebral blood flow and leads to neuronal injury or neurodegeneration. Generally, CVAs are classified into two primary categories of ischemic and hemorrhagic. Investigation of circadian rhythm variation at the time of CVA onset is a critical subject for patient management, clinical treatment, and further scientific research. This systematic review aimed to investigate the relationship between the timing of stroke onset and patient outcomes in both ischemic and hemorrhagic strokes. Methods: Following searching strategy designation, international databases of Embase, PubMed, Scopus, WoS, ScienceDirect, and Google Scholar were searched using the MeSH-based keywords. No time restrictions were applied in this regard (by December 8, 2024). All English-based observational studies reporting the risk of CVA at various daytimes were enrolled for screenings and quality control. Finally, eligible studies were selected for data extraction and categorization. Results: According to the reports, ischemic strokes strictly occur in morning hours (06:00 to 12:00) while some studies recorded a bimodal pattern (dual peaks during morning and evening). It was also established that the strokes at night were more severe and yielded more unfavorable results. Scattered reports were found regarding the hemorrhagic strokes; some papers revealed the highest incidence in the early morning hours, while others reported the late evening or nighttime occurrence. In addition, some studies showed that nighttime hemorrhagic strokes are usually associated with greater severity and unfavorable clinical outcomes. Conclusion: This study clarified the effect of cyclic pattern on the incidence and outcome of stroke. These trends seem greatly accounted for improvement of prevention strategies, management of treatments, and enhancement of patient outcomes.