Comorbidity and favorable neurologic outcome after out-of-hospital cardiac arrest in patients of 70 years and older

Introduction: Advanced age is reported to be associated with lower survival after out-of-hospital cardiac arrest (OHCA). We aimed to establish survival rate and neurological outcome at hospital discharge after OHCA in older patients and evaluated whether pre-OHCA comorbidity was associated with favorable neurologic outcome. Methods: From a prospective registry of all cardiopulmonary resuscitation (CPR) attempts after OHCA, we established survival in 1332 patients aged ≥70 years in whom resuscitation with non-traumatic etiology was attempted in 2009-2011. Pre-OHCA factors (age, gender, residing in long-term care institution, Charlson Comorbidity Index [CCI] score) and resuscitation parameters (initial rhythm, bystander witnessed, bystander CPR and time to defibrillator connection) with survival at hospital discharge with favorable neurologic outcome were regressed in the 851 patients of whom CCI was known. Results: We found a 12% survival to discharge rate in patients aged ≥70 years (70-79 years: 16%; ≥80 years: 8%, p=0.001). Among surviving patients, 90% survived with favorable neurologic outcome. In a model with only pre-OHCA factors age was significantly associated with outcome (age OR 0.94, 95%CI 0.91-0.98), p=0.003). High CCI score (≥4) was not statistically significant when associated with survival (7% vs. 12%, OR 0.53, 95%CI (0.25-1.13), p=0.10). When adjusted for resuscitation parameters, OR for high CCI was 0.71 (95% CI 0.28-1.80, p=0.47), also none of the other pre-OHCA factors remained statistically significant. Conclusion: In the Netherlands, the survival rate in older patients was 12%; the great majority survived with favorable neurologic outcome. Resuscitation-related factors and not comorbidity determine outcome after OHCA in older patients.