Diurnal variation in outcomes after out-of-hospital cardiac arrest in Asian communities: The Pan-Asian Resuscitation Outcomes Study.

Objective: The present study aimed to determine whether the time of out-of-hospital cardiac arrest (OHCA) is associated with survival rate and neurological outcome after OHCA, as well as to compare the effect size of time of OHCA across six Asian regions.

Methods: We collected data from the Pan-Asian Resuscitation Outcomes Study registry, six Asian regions (Tokyo, Osaka, Aichi, Seoul, Taipei and Singapore) from 2009 to 2012. Adult OHCA cases were divided depending on the arrest time: I (00.01-06.00 hours), II (06.01-12.00 hours), III (12.01-18.00 hours) and IV (18.01-24.00 hours). Using a multivariable logistic regression analysis, we compared the outcomes of survival and good neurological recovery.

Results: Of 65 413 cases treated by the emergency medical service, 36 706 (56.1%) cases were analysed. There was the lowest OHCA incidence in time block I. Compared with time block I, the adjusted odds ratios and 95% confidence intervals for the standardised survival rate were 1.6 (1.3-1.9) in time block II, 1.4 (1.2-1.7) in time block III and 1.2 (1.0-1.4) in time block IV. Regarding the good neurological recovery rate, compared with time block I, the adjusted odds ratios and 95% confidence intervals were 1.9 (1.5-2.4) in time block II, 1.7 (1.3-2.1) in time block III and 1.4 (1.1-1.7) in time block IV. However, in the subgroup analysis, there were regional differences between Japan and the other regions.

Conclusions: We found diurnal similarities in OHCA occurrence, as well as differences in survival rate and good neurological recovery rate among Asian regions.