Does obesity influence the return of spontaneous circulation among out-of-hospital cardiac arrest patients? A retrospective cohort study

INTRODUCTION: Several factors influence spontaneous circulation (ROSC) return in out-of-hospital cardiac arrest (OHCA) patients, and obesity can be one of them. The aim of this study was to investigate the influence of obesity on ROSC in patients following OHCA. MATERIAL AND METHODS: We conducted a retrospective study and analyzed 4,925,214 emergency medical system (EMS) records. Finally, data from 33,636 OHCA patients in Poland for whom EMS personnel responded between January 2021 and June 2022 were analyzed. RESULTS: The univariate analysis showed an association between ROSC and age (p < 0.001, OR: 0.981), location of the incident (p < 0.001, OR: 1.6), OHCA initial rhythm (p < 0.001, OR: 2.056), obesity (p ≈ 0.003 OR: 1.1.06) and some comorbidities. In the first multivariate model (whole population sample), significant predictors of ROSC were initial rhythm (Asystole/PEA; p < 0.001; OR: 0.516), age (p < 0.001; OR: 0.986), location of the incident (p < 0.001; OR: 1.468) and obesity (p = 0.023; OR: 0.924). In the second model (patients without obesity), the significant predictors (p < 0.001) of ROSC were initial rhythm (Asystole/PEA, OR: 0.263), public location of the incident (OR: 2.158) and age (OR: 0.986). In the third model (patients with obesity), the significant predictors of ROSC were initial rhythm (Asystole/PEA, p = 0.002; OR: 0.443), public location of the incident (p < 0.001; OR: 2.101), age (p < 0.001; OR: 0.981), and stroke (p = 0.005; OR: 2.047). CONCLUSIONS: In the study population of OHCA patients, obesity significantly predicted the odds of the prehospital return of spontaneous circulation, reducing the odds by 8.2%. In the overall study population and the groups of patients with and without obesity, OHCA in public places and ventricular fibrillation/pulsless ventricular tachycardia (VF/pVT) initiating rhythm were predictors of increased odds of ROSC and older age reduced these odds.