The interaction of sex and age on outcomes in emergency medical services-treated out-of-hospital cardiac arrest: A 5-year multicenter retrospective analysis

Background: Studies have established that sex and age influence outcomes following out-of-hospital cardiac arrest (OHCA). However, a knowledge gap exists regarding their interaction. This study aimed to investigate the interaction of age and sex and how they cooperatively influence OHCA outcomes. Methods: This retrospective cohort study included adult, nontraumatic OHCA patients admitted to a university hospital and its affiliated hospitals in Taiwan from January 2017 to December 2021. Data including sex, age, body mass index, cardiac rhythm, and resuscitation information in the emergency department (ED) were collected from medical records. The study outcomes encompassed survival to intensive care unit (ICU) admission, survival to hospital discharge, and a favorable neurological outcome. Multivariable logistic regression was performed to estimate the influence of sex on study outcomes. Results: We analyzed a total of 2,826 eligible subjects categorized into three groups: young (18–44 years, 149 males and 57 females), middle-aged (45–64 years, 524 males and 188 females), and old (≥65 years, 1,049 males and 859 females). Analysis of the effects of sex according to age stratification showed that old males had higher odds for survival to ICU admission (OR: 1.49, 95% CI: 1.21–1.83) and favorable neurological outcomes (OR: 2.74, 95% CI: 1.58–4.76) than did old females. Analysis of the effects of age according to sex stratification revealed that old males had lower odds for survival to hospital discharge (OR: 0.33, 95% CI: 0.21–0.51) and favorable neurological outcomes (OR: 0.26, 95% CI: 0.16–0.43) than did young males. Old females also showed the same trend as males, with lower odds for survival to hospital discharge (OR: 0.37, 95% CI: 0.17–0.78) and favorable neurological outcomes (OR: 0.11, 95% CI: 0.05–0.25) than did young females. Conclusions: The interaction between sex and age in patients with OHCA results in diverse outcomes. Within the same sex, age demonstrated varying effects on distinct outcomes.