Abstract Body: Introduction
Ischemic stroke in adults demonstrates circadian variation in the timing of onset of symptoms, with the highest risk between 6am and noon (1-4). The influence of circadian timing on stroke biology may differ between children and adults, possibly related to the immature circadian system, variations in school versus work schedules, and diverse stroke pathophysiology (5). The goal of our study was to assess whether timing of ischemic stroke onset demonstrates circadian variability in children.
Methods
We queried the International Pediatric Stroke Study, an international multicenter observational registry of children <18 years with arterial ischemic stroke (AIS). Included patients were aged 29 days-18 years with outpatient AIS and known time of stroke symptom onset. Clinical and radiographic features were compared according to 4 distinct time epochs: 6:00-11:59 (morning), 12:00-17:59 (afternoon), 18:00-23:59 (evening) and 00:00-5:59 (night). Clinical outcomes were defined by the Pediatric Stroke Outcome Measure (PSOM). Baseline, clinical and outcome characteristics were compared between the 4 time epochs using independent samples Kruskal-Wallis and Chi-square tests. Pairwise comparisons were conducted where needed.
Results
A total of 478 patients met inclusion criteria, 54% male, mean age 9.9±SD 5.7 years. Time of stroke onset by hour is shown in Figure 1. Most strokes occurred in the afternoon (n=185, 38.7%), followed by morning (n=156, 32.6%). Table 1 shows demographic and clinical characteristics by time epoch; clinical and arteriopathy risk factors were more prevalent in nighttime strokes (23/36, 70%, p=0.034). Median PSOM scores at 6 months appeared to be better after evening strokes (0.5, IQR 0-1.5) as compared to morning strokes (1, IQR 0.5-2) and afternoon strokes (1, IQR 0.5-3, p=0.033), but failed adjustment for multiple comparisons (figure 2).
Conclusion
Circadian influence on stroke timing appears to differ between adults and children. Further prospective studies with larger sample sizes are needed to understand the impact of circadian rhythm on stroke in childhood.