Survival From Pediatric Out-of-Hospital Cardiac Arrest During Nights and Weekends: An Updated Japanese Registry-Based Study.

Background: Disparities in survival after pediatric out-of-hospital cardiac arrest (OHCA) between on-duty hours and off-duty hours have previously been reported. However, little is known about whether these disparities have remained in recent years. Objectives: This study aimed to examine the association of outcomes after pediatric OHCA with time of day and day of week. Methods: This observational study analyzed the Japanese government-led nationwide population-based registry data of OHCA patients. Pediatric (<18 years) patients who experienced OHCA between 2012 and 2017 were included. A multivariable logistic regression model was used to examine the association of both time of day (day/evening vs night) and day of week (weekday vs weekend) with outcomes after OHCA. The primary outcome was 1-month survival. Results: A total of 7,106 patients (mean age, 5.7 ± 6.5 years; 60.9% male) were included. 1,897 events (26.7%) occurred during night hours, and 2,096 events (29.5%) occurred on weekends. Overall, 1,192 (16.8%) survived 1 month after OHCA. After adjusting for potential confounders, 1-month survival during day/evening (1,047/5,209 [20.1%]) was significantly higher than that at night (145/1,897 [7.6%]) (adjusted odds ratio: 2.31 [95% CI: 1.87-2.86]), whereas there was no significant difference in 1-month survival between weekdays (845/5,010 [16.9%]) and weekends (347/2,096 [16.6%]) (adjusted odds ratio: 1.04 [95% CI: 0.88-1.23]). Conclusions: One-month survival after pediatric OHCA remained significantly lower during night than during day/evening, although disparities in 1-month survival between weekdays and weekends have been eliminated over time. Further studies are warranted to investigate the mechanisms underlying decreased survival at night.