Short- and Long-Term Outcome in Elderly Patients After Out-of-Hospital Cardiac Arrest: A Cohort Study

Objective: Determinants of outcome and long-term survival are unknown in elderly patients successfully resuscitated after out-of-hospital cardiac arrest. Our aim was to identify factors associated with short- and long-term neurologic outcome in such patients. Design: Retrospective cohort study. Setting: Tertiary hospital in Paris, France. Patients: Patients aged over 75 admitted in our ICU after an out-of-hospital cardiac arrest between 2000 and 2009. Interventions: None. Measurements and Main Results: Two hundred twenty-five patients were included in the study. Fifty-seven patients (25.3%) had a good neurologic outcome at ICU discharge (Cerebral Performance Category 1-2). By multivariate logistic regression analysis, factors associated with good short-term outcome were time from collapse to cardiopulmonary resuscitation less than or equal to 3 minutes (odds ratio = 4.06; 95% CI, 1.49-11.09, p = 0.006) and blood lactate level less than or equal to 5.1 mmol/L (odds ratio = 3.30; 95% CI, 1.05-10.39, p = 0.04), but age less than or equal to 79.5 years and use of induced hypothermia were not. Long-term survivors were assessed for cognitive and functional status (using Cerebral Performance Category and Overall Performance Category scales), and their survival was compared with a large community-based cohort of participants over 75 years. The 1-year survival of ICU survivors (mean follow-up, 28.4 mo) was 69.3% (95% CI, 55.8-79.5) as compared with 95.3% (95% CI, 93.3-97.3) in the control community-based cohort (p< 0.001), resulting in a standardized mortality ratio of 3.49 (95% CI, 2.42-4.85). By multivariate Cox proportional hazard model, factors associated with long-term survival were initial shockable rhythm (hazard ratio = 1.41; 95% CI, 1.01-1.96; p = 0.04), epinephrine cumulate dose less than or equal to 3 mg (hazard ratio = 1.48; 95% CI, 1.06-2.08; p = 0.02), and blood lactate level less than or equal to 5.1 mmol/L (hazard ratio = 2.11; 95% CI, 1.5-2.96; p < 0.001). When available at end of follow-up, 91% and 74% of the patients were classified Cerebral Performance Category 1 and Overall Performance Category 1, respectively. Conclusions: Neurologic outcome in successfully resuscitated elderly patients depends on cardiac arrest characteristics rather than age. Short-term survival is 25% with acceptable long-term outcome among survivors.