Background: Little is known about the nationwide trend in the survival of out-of-hospital cardiac arrest (OHCA) in Japan and the differences in incidence and survival by age group and origin of arrest.
Methods and results: A nationwide, prospective, population-based observation covering the whole population of Japan and involving consecutive OHCA patients with resuscitation attempts was conducted from January 2005 to December 2009. The main outcome measure was 1-month survival with favorable neurological outcome. The nationwide trends in OHCA incidence and outcome by age and origin of arrest were assessed. Multiple logistic regression analysis for bystander-witnessed OHCA was used to adjust for factors that were potentially associated with favorable neurological outcome. During 5 years, 547 153 overall OHCAs and 169 360 bystander-witnessed OHCAs were enrolled. The annual incidence significantly increased among overall OHCAs and bystander-witnessed OHCAs. Neurologically favorable survival significantly increased from 1.6% (1676/102 737) in 2005 to 2.8% (3280/115 250) in 2009 (P<0.001), from 2.1% (638/30 556) to 4.3% (1558/36 361) (P<0.001), and from 9.8% (437/4461) to 20.6% (1215/5906) (P<0.001) among overall OHCA, bystander-witnessed OHCA, and bystander-witnessed ventricular fibrillation OHCA, respectively. Public-access automated external defibrillator use, either bystander-initiated chest compression-only cardiopulmonary resuscitation or conventional cardiopulmonary resuscitation, and earlier emergency medical services response time were associated with a better neurological outcome. Favorable neurological outcome among adult OHCA subjects significantly improved, but the outcome among younger children and very elderly subjects did not improve and was poor irrespective of origin of OHCA.
Conclusions: Nationwide improvements of favorable neurological outcome from OHCA were observed in Japan and differed by age group and origin of OHCA.