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

Abstract. Objective: 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. Methods: 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 by-stander 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. Results: 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 seperation 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). Conclusions: 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.