Comparison of neurological outcomes between out-of-hospital cardiac arrest due to anaphylaxis and cardiac causes: a nationwide population-based observational study.

Objective: To compare the neurological outcomes of out-of-hospital cardiac arrest due to anaphylaxis (OHCA-A) and cardiac causes (OHCA-C).

Design: Retrospective observational study.

Setting: Japanese nationwide dataset from 2012 to 2021.

Participants: In total, 153 890 patients were included in this study, of which 331 had OHCA-A and 153 559 had OHCA-C.

Outcome Measures: The primary outcome was a favourable neurological outcome 1 month after cardiac arrest. The secondary outcome was survival at 1 month.

Results: Patients with OHCA-A had a significantly higher favourable neurological outcome rate (24.2% vs 11.7%, p<0.001) and higher survival rate at 1 month (33.2% vs 16.1%, p<0.001) than patients with OHCA-C. Multivariable logistic regression analysis revealed that OHCA-A was associated with higher odds of favourable neurological outcomes (adjusted OR (adj OR): 1.86; 95% CI 1.34 to 2.59) and survival at 1 month (adj OR: 2.43; 95% CI 1.78 to 3.31). Similarly, the propensity score-matched cohort showed favourable neurological outcomes in patients with OHCA-A (OR: 2.91; 95% CI 1.83 to 4.65).

Conclusion: Compared with OHCA-C, OHCA-A is associated with favourable neurological outcomes and warrants more aggressive resuscitation efforts.