Poor outcomes of out-of-hospital cardiac arrest at dinnertime in the elderly: Diurnal and seasonal variations

Abstract Purpose To investigate differences in chronological variations in characteristics and outcomes of out-of-hospital cardiac arrests (OHCAs) between elderly and non-elderly patients. Methods We retrospectively analyzed bystander-witnessed OHCAs without prehospital involvement of physicians between January 2007 and December 2014 in Japan. We considered the following time periods: night-time (23:00–5:59) and non-night-time; we further divided non-night-time into dinnertime (18:00–20:29) and other non-night-time. Subsequently, we analyzed chronological variations in factors associated with OHCA survival using univariate and multivariable logistic regression analyses for unmatched and propensity-matched pairs, respectively. Results For elderly (≥65 years old, N = 201,073) and non-elderly (≥10, Conclusions Dinnertime, particularly in winter, is associated with lower survival in elderly OHCA patients.