Comorbidity and survival in the pre-hospital and in-hospital phase after out-of-hospital cardiac arrest.

Introduction: Cumulative disease burden may be associated with survival chances after out-of-hospital cardiac arrest (OHCA). The relative contributions of cumulative disease burden on survival rates at the pre-hospital and in-hospital phases of post-resuscitation care are unknown.

Methods: The association between cumulative comorbidity burden as measured by the Charlson Comorbidity Index (CCI) and pre-hospital and in-hospital survival rates was studied using data (2010-2014) from a prospective OHCA registry in the Netherlands. The association between CCI and survival rate (overall survival [OHCA-hospital discharge], pre-hospital survival [OHCA-hospital admission] and in-hospital survival [hospital admission-hospital discharge]) was assessed using logistic regression analyses. The relative contributions of CCI on pre-hospital and in-hospital survival rates were determined using the Nagelkerke test.

Results: We included 2510 OHCA patients aged ≥18y. CCI was significantly associated with overall survival rate (OR 0.71; 95%CI 0.61-0.83; P < 0.01). CCI was not associated with pre-hospital survival rate (OR 0.96; 95%CI 0.76-1.23; P = 0.92) whereas high CCI was significantly associated with low in-hospital survival rate (OR 0.41; 95%CI 0.27-0.62; P = 0.01). The relative contributions of CCI on pre-hospital and in-hospital survival were 1.1% and 8.1%, respectively.

Conclusion: Pre-existing high comorbidity burden plays a modest role in reducing survival rate after OHCA, and only in the in-hospital phase. The present study offers data that may guide clinicians in discussing resuscitation options during advance care planning with patients with high comorbidity burden. This may be helpful in creating a patients' informed choice.