Age-specific trends in poisoning-related out-of-hospital cardiac arrest in Japan: a retrospective nationwide registry study

Aim Poisoning-related out-of-hospital cardiac arrest (OHCA) may have distinct age-specific trends. We examined temporal changes in its proportion among all OHCA, population-based incidence, and neurological outcomes in Japan. Methods In this retrospective nationwide registry study, we analyzed adults aged ≥18 years OHCA treated by emergency medical services (EMS) in the Japanese Utstein registry from 2013 to 2023. Age-specific logistic regression estimated annual trends in the proportion of poisoning-related OHCA, adjusted for age and sex. Poisson regression with age-group population as the exposure estimated incidence trends. Neurological outcome trends were examined secondarily. Results Among 1,400,951 adults with OHCA treated by EMS, 3,723 (0.27%) had poisoning-related OHCA. In adults aged 18–29 years, the adjusted odds of poisoning-related OHCA increased (odds ratio per year, 1.027; 95% CI, 1.001–1.054), whereas population-based incidence showed a nonsignificant upward trend (incidence rate ratio, 1.020; 95% CI, 0.995–1.046). All-cause OHCA incidence declined among adults aged 18-29 years (incidence rate ratio, 0.991; 95% CI, 0.983–0.9997). The poisoning proportion decreased at ages 50–64 and ≥65 years; poisoning incidence declined significantly only at ≥65 years. Favorable neurological outcome after poisoning-related OHCA showed no clear improvement (adjusted odds ratio per year, 0.998; 95% CI, 0.949–1.050). Conclusion Poisoning-related OHCA became increasingly prominent among young adults but declined among older adults. Although the incidence increase in young adults was not statistically significant, its upward direction, declining all-cause OHCA incidence, and lack of clear neurological outcome improvement suggest increasing clinical importance of poisoning-related OHCA in young adults.