Age and sex analyses of out-of-hospital cardiac arrest in Osaka, Japan

Objective: To determine effective interventional targets for out-of-hospital cardiac arrests by analyzing the distribution characteristics of arrest patients according to age and sex with special emphasis on ventricular fibrillation (VF). Methods: All patients who suffered out-of-hospital cardiac arrest in Osaka Prefecture, Japan during 2 years, were prospectively recorded based on the Utstein style. The number and the incidence rate of cases of arrest, witnessed arrest, and witnessed VF were evaluated according to age and sex. The percentage of resuscitation attempts in arrest cases was also calculated. Results: We recorded 10 139 consecutive out-of-hospital cardiac arrest cases. Resuscitation was attempted in 97.0% of 10 139 and showed no significant differences by age and sex. The incidence rate of cardiac arrests increased exponentially with age. Men showed a significantly higher incidence rate of out-of-hospital arrests than women in every age group. Most of the witnessed VF cases showed cardiac aetiology and were predominantly observed in men in their 50s, 60s and 70s. The incidence rates of witnessed VF were also greater in them. Conclusion: Our study provides evidence that there are significant age and sex related epidemiological differences in cardiac arrests and we need to understand them better. Strategies that focus on high yielded patients, those in witnessed VF, should be pursued. These efforts should be expected to yield sex and age related differences in survivors. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.