Trends in survival among elderly patients with out-of-hospital cardiac arrest: a prospective, population-based observation from 1999 to 2011 in Osaka

BackgroundLittle is known about the improvement in out-of-hospital cardiac arrest (OHCA) survival among elderly patients. The aim of this study was to evaluate the trends in the survival after bystander-witnessed OHCA of cardiac origin in this age group.MethodsThis prospective, population-based, observation of the whole population of Osaka, Japan included consecutive OHCA patients aged ≥65 years with emergency responder resuscitation attempts from January 1999 to December 2011. The primary outcome measure was one-month survival with neurologically favorable outcome, and the trends in the outcome from OHCA were evaluated by location. Multiple logistic regression analysis was used to assess factors that were potentially associated with neurologically favorable outcome.ResultsDuring the study period, a total of 10,876 bystander-witnessed OHCA of cardiac origin were eligible for our analyses. In whole arrests, the proportion of one-month survival with neurologically favorable outcome improved from 1.4% in 1999 to 4.8% in 2011 (P for trend <0.001). The proportion of neurologically favorable outcome in homes and public places improved from 0.7% in 1999 to 3.2% in 2011 (P for trend <0.001) and from 4.2% in 1999 to 20.9% in 2011 (P for trend <0.001), respectively, whereas, in nursing homes, the proportion of neurologically favorable outcome did not improve. In a multivariate analysis, bystander-initiated cardiopulmonary resuscitation and emergency response time were significant predictors for neurologically favorable outcome.ConclusionsIn this population, survival from OHCA among elderly patients significantly improved during the study period, but the trends differed by the OHCA location.