Influence of Previous Comorbidities on Hospital Outcome After Cardiac Arrest

Introduction: Despite improvements, overall survival after out-of-hospital cardiac arrest (OHCA) remains low, even in those with return of spontaneous circulation (ROSC). In addition to usual prognostic characteristics, patients’ medical history may also influence the outcome. This study aimed to investigate the role of comorbidities on hospital mortality, neurological outcome and mode of death in OHCA patients with successful ROSC. Methods: From Jan 2012 to Sep 2017, all consecutive non-traumatic OHCA adults with stable ROSC admitted in ICU were included. Utstein characteristics, circumstances and in-hospital interventions were prospectively recorded. Comorbidities were measured using Charlson Comorbidity Index (CCI), divided into 3 groups (CCI=0,CCI=1-3,CCI>3).The influence of CCI on mortality and poor neurological outcome at discharge (with a Cerebral Performance Categories level>2) was assessed using logistic regression and association with mode of death (withdrawal of life sustaining treatments (WLST) or other causes) using multinomial regression. Results: During the study period, among 777 patients admitted alive and analyzed, 504 (65%) pts were discharged as CPC>2 and 484 (62%) died in ICU with 48%, 61% and 70% in CCI-0, CCI 1-3 and CCI>3 respectively. After adjustment, an increase in CCI was associated with poor neurological outcome (ORadj 2.22 [1.21-4.08] for CCI=1-3 and ORadj=2.86 [1.50-5.45] for CCI>3; ref CCI=0). Other independent predictors were an initial non shockable rhythm (OR=3.70[2.38-5.88]), absence of bystander cardiopulmonary resuscitation (CPR) (OR=1.96[1.20-3.22]), higher dose of epinephrine (OR= 5.88 [3.70-9.09]), longer resuscitation (CA-CPR, OR=1.69 [1.10-2.63] and CPR-ROSC, OR=2.43 [1.56-3.85]). Using multinomial regression, an increased CCI was associated with all modes of death, but particularly with WLST (RRadj=2.43 [1.25-4.71] for CCI=1-3 and 4.27[2.15-8.48] for CCI>3, ref CCI=0). Conclusion: A high number of comorbidities, as assessed by CCI, was associated with a worse neurological and a higher mortality in patients admitted alive after cardiac arrest. Presence and burden of comorbidities should be considered in the evaluation of the prognosis in patients admitted after cardiac arrest