Does Advanced Age Matter in Outcomes after Out-of-hospital Cardiac Arrest in Community-dwelling Adults ?

Abstract

To assess whether advanced age is an independent predictor of survival to hospital discharge in community-dwelling adult patients who sustained an out-of-hospital cardiac arrest in a suburban county. A prospective cohort study was conducted in a suburban county emergency medical services system of community-dwelling adults who had an arrest from a presumed cardiac cause and who received out-of-hospital resuscitative efforts from July 1989 to December 1993. The cohorts were defined by grouping ages by decade: 19-39, 40-49, 50-59, 60-69, 70-79, and 80 or more. The variables measured included age, gender, witnessed arrest, response intervals, location of arrest, documented bystander cardiopulmonary resuscitation, and initial rhythms. The primary outcome was survival to hospital discharge. Results are reported using analysis of variance, chi square, and adjusted odds ratios from a logistic regression model. Age group 50-59 served as the reference group for the regression model. Of the 2,608 total presumed cardiac arrests, the overall survival rate to hospital discharge was 7.25%. Patients in age groups 40-49 and 50-59 experienced the best rate of successful resuscitation (10%). Each subsequent decade had a steady decline in successful outcome: 8.1% for ages 60-69; 7.1% for ages 70-79; and 3.3% for age 80+. In a post-hoc analysis, further separation of the older age group revealed a successful outcome in 3.9% of patients ages 80-89 and 1% in patients 90 and older. Patients aged 80 years or more were more likely to arrest at home, were more likely to have an initial bradyasystolic rhythm, yet had a similar rate of resuscitation to hospital admission. In the regression model, age 80 or older was associated with a significantly worse survival to hospital discharge (OR = 0.4, 95% CI = 0.20 to 0.82). There was a twofold decrease in survival following out-of-hospital cardiac arrest to discharge in patients aged 80 or more when compared with the reference group in this suburban county setting. However, resuscitation for community-dwelling elders aged 65-89 is not futile. These data support that out-of-hospital resuscitation of elders up to age 90 years is not associated with a universal dismal outcome.