Abstract Sun605: Gender Modifies The Survival Benefit of Cardiopulmonary Resuscitation after Out-of-Hospital Cardiac Arrest: Multicenter, Cohort Study, The SOS-KANTO 2017 Study

Background: cardiopulmonary resuscitation (CPR) is crucial for survival in patients with out-of-hospital cardiac arrest (OHCA). Therefore, it is imperative to study factors that may modify the effectiveness of CPR. Bystander CPR is one of the most powerful first-aid techniques, and many have debated the factors that hinder its initiation. Female gender has been associated with a reduced likelihood of receiving CPR in public; however, no studies have investigated how gender may influence the effectiveness of CPR. Hypothesis: gender modifies the survival benefit of bystander CPR in OHCA. Methods: this multicenter prospective cohort study collected data from September 2019 through March 2021. Information on OHCA characteristics and patient care was gathered by 42 facilities located in the Kanto region of Japan. Terminology and definitions followed the Utstein templates and relevant international guidelines. Adult patients aged 18 and older were included, while those with missing information on gender, witness status, or bystander CPR were excluded. The primary outcome was 30-day survival. Crude statistics were used to compare survival rates by gender (women and men) between patients who did and did not receive bystander CPR. Cox proportional hazards regression was employed to adjust for potential confounders, including age, location of OHCA by prefecture, time of OHCA occurrence, witnessed arrest, initial rhythm, cause of cardiac arrest, and the use of therapeutic hypothermia. Results: out of a total of 9,909 patients, 9,081 were included in the analysis. Of these, 3,459 were women and 5,622 were men. A higher proportion of women received bystander CPR (n = 1,582; 45.5%) compared to men (n = 2,399; 42.7%; p = 0.004). Among women, the survival rate was 5.4% for those who received bystander CPR and 3.4% for those who did not, yielding a risk ratio of 1.6. In men, the corresponding survival rates were 11.0% with bystander CPR and 4.5% without, with a risk ratio of 2.4. The hazard ratio (HR) of bystander CPR for 30-day survival was 1.3 in women (95% CI: 0.9–1.9; p = 0.124) and 1.5 in men (95% CI: 1.2–1.9; p < 0.001). Conclusions: in this study setting in Japan, women received bystander CPR in numbers similar to those of men when OHCA occurred. However, the increase in the chance of survival from bystander CPR for women appeared to be not as high as that for men.