Association between the obesity and outcomes after out-of-hospital cardiac arrest - does sex matter?

Out-of-hospital cardiac arrest (OHCA) is a global public health problem. Obesity is one of the factors that reduces the odds of a return of spontaneous circulation (ROSC). The aim of this study was to assess whether there are sex differences in the prognostic impact of obesity on ROSC in OHCA patients.

A retrospective study and analysis of 33,636 (female: 12,000 and male: 21,636) medical records of patients with OHCA (ICD 10-I46) in Poland from 01.2021 to 06.2022 was performed. Patient comorbidity, information on: obesity, location of OHCA and initial rhythm were collected. Statistical analysis was performed using Python 3.9.13.

The study was approved by the Independent Bioethics Committee of the Medical University of Wroclaw (No KB-895/2022).

There was no difference in age between the two sexes. Upon subsequent stratification of the two sexes by obesity status, a markedly higher incidence of diabetes(p<0.001), hypertension(p<0.001), and heart failure(p<0.001) was observed, regardless of sex. In the univariate model, obesity decreased the odds of ROSC by 25.47% among women (p ≈ 0.034) and 19.76% (p ≈ 0.035) among men. In full model, obesity became insignificant (p ≈ 0.051) (Table 1). In models with all factors, the individuals with the VF/pVT initial rhythm were 4.204-fold more likely (vs. Asystole/PEA) to develop ROSC among the female individuals, but only 3.655-fold more likely among male individuals. If OHCA happened in a public place, both sexes showed similar, over 2-fold increase in odds of ROSC (2.204 among females, 2.130 among males). The impact of age on these odds was similar among the two sexes, decreasing the odds for ROSC (by 1.21% and 1.52% in women and men, respectively, per one-year increase in age). After stratification by both sex and obesity (Table 2), several factors appeared to have a different influence on the odds for ROSC. Although the public place location greatly increased the odds for ROSC among both sexes, women showed to have significantly lower location-associated OR if they were obese (2.126 vs. 4.264 in obese and non-obese women, respectively). Moreover, exclusively among non-obese women, hypertension decreased the odds of ROSC by 11.11% (p ≈ 0.032).

In both men and women, OHCA in a public place and an initial VF/pVT rhythm increased the odds of ROSC, while age (per one-year increase in age) decreased the odds. However, in women without obesity, VT/pVT increased the odds of ROSC by more than 4.2 times and in women with obesity by 2.7 times. In men without obesity, the initial VF/pVT rhythm increased the odds of ROSC by 3.7-fold and in men with obesity by only 1.9-fold. No such discrepancies were observed for OHCA location and age, where the odds of ROSC were similar. Prevention of obesity should be a global health priority.