Trends in Outcomes for Out-of-Hospital Cardiac Arrest by Age in Japan: An Observational Study

Population aging has rapidly advanced throughout the world and the elderly accounting for out-of-hospital cardiac arrest (OHCA) has increased yearly. We identified all adults who experienced an out-of-hospital cardiac arrest in the All-Japan Utstein Registry of the Fire and Disaster Management Agency, a prospective, population-based clinical registry, between 2005 and 2010. Using multivariable regression, we examined temporal trends in outcomes for OHCA patients by age, as well as the influence of advanced age on outcomes. The primary outcome was a favorable neurological outcome at 1 month after OHCA. Among 605,505 patients, 454,755 (75.1%) were the elderly (≥65 years), and 154,785 (25.6%) were the oldest old (≥85 years). Although neurological outcomes were worse as the age group was older (P < 0.0001 for trend), there was a significant trend toward improved neurological outcomes during the study period by any age group (P < 0.005 for trend). After adjustment for temporal trends in various confounding variables, neurological outcomes improved yearly in all age groups (18–64 years: adjusted OR per year 1.15 [95% CI 1.13–1.18]; 65–84 years: adjusted OR per year 1.12 [95% CI 1.10–1.15]; and ≥85 years: adjusted OR per year 1.08 [95% CI 1.04–1.13]). Similar trends were found in the secondary outcomes. Although neurological outcomes from OHCA ware worse as the age group was older, the rates of favorable neurological outcomes have substantially improved since 2005 even in the elderly, including the oldest old. Careful consideration may be necessary in limiting treatment on OHCA solely for the reason of advanced age.