Influence of comorbidity on survival after out-of-hospital cardiac arrest in the United States

AIM: Association between survival rate and Elixhauser Comorbidity Index (ECI) among individuals suffering an Out-of-Hospital Cardiac Arrest (OHCA) in the United States (US) METHODS: We utilized the US National Emergency Department Sample (NEDS) dataset to retrospectively identify individuals experiencing OHCA between January 1, 2006 to December 31, 2015; using the International Classification of Diseases, Ninth Revision-Clinical Modification (ICD-9-CM) and Tenth Revision-Clinical Modification (ICD-10-CM) codes. Logistic regression analysis with twenty-nine ECIs as predictor variables were performed to compute for odds ratio (OR), after controlling for age and gender. Linear regression analysis performed to assess survival trend after clustering based on ECI. We also assessed the association of ECI with survival rate after stratifying patients based on cardiac rhythm (shockable versus non-shockable). RESULTS: We identified 1,282,520 (16.4%, survived-to-discharge) weighted observations presenting primarily after OHCA in the US during the study period. Annual percentage change (APC) in survival rate among OHCA patients with no ECI and those with \u3e 3 ECI was -1.53% (95% CI: -1.98% to -1.09%, Ptrend \u3c 0.001) and 1.2% (95% CI: 0.69% to 1.7%, Ptrend = 0.001), respectively. Adjusted OR for ECI was 1.31 (95% CI: 1.3 to 1.31, P \u3c 0.001). Percentage change in the survival rate among shockable and non-shockable rhythm was 5.6% (95%CI: -3.9% to 15.13%, Ptrend = 0.127) and 1.04% (95% CI: 0.01% to 2.07%, Ptrend = 0.05), respectively, with a unit increase in ECI. CONCLUSION: In the US, OHCA patients with higher ECI have greater survival-to-discharge rate, demonstrating Comorbidity Paradox