Out-of-hospital cardiac arrest outcomes' determinants: an Italian retrospective cohort study based on Lombardia CARe.

This study on the Lombardia Cardiac Arrest Registry (Lombardia CARe,) the most complete nationwide out-of-hospital cardiac arrest (OHCA) registry in Italy, aims at evaluating post-OHCA intra-hospital mortality risk according to patient's characteristics and emergency health service management (EMS), including level of care of first-admission hospital. Out of 12,581 patients included from 2015 to 2022, we considered 1382 OHCA patients admitted alive to hospital and survived more than 24 h. We estimated risk ratios (RRs) of intra-hospital mortality through log-binomial regression models adjusted by patients' and EMS characteristics. The study population consisted mainly of males (66.6%) most aged 60-69 years (24.7%) and 70-79 years (23.7%). Presenting rhythm was non-shockable in 49.9% of patients, EMS intervention time was less than 10 min for 30.3% of patients, and cardiopulmonary resuscitation (CPR) was performed for less than 15 min in 29.9%. Moreover, 61.6% of subjects (n = 852) died during hospital admission. Intra-hospital mortality is associated with non-shockable presenting rhythm (RR 1.27, 95% CI 1.19-1.35) and longer CPR time (RR 1.39, 95% CI 1.28-1.52 for 45 min or more). Patients who accessed to a secondary vs tertiary care hospital were more frequently older, with a non-shockable presenting rhythm and longer EMS intervention time. Non-shockable presenting rhythm accounts for 27% increased risk of intra-hospital death in OHCA patients, independently of first-access hospital level, thus demonstrating that patients' outcomes depend only by intrinsic OHCA characteristics and Health System's resources are utilised as efficiently as possible.