Prognostic impact of bystander-patient relationship and age in patients with out-of-hospital cardiac arrest.

AIM OF THE STUDY: Bystander presence improves outcomes after out-of-hospital cardiac arrest (OHCA). Although bystander type is reportedly associated with neurological outcomes, the potential modifying effect of age on this association remains uncertain.

METHODS

Using the All-Japan Utstein Registry, we included adults with witnessed OHCA between 2005 and 2023. Patients were categorized into 3 groups according to the bystander-patient relationship (family members, friends and colleagues, and passersby) and further divided into 4 age categories (18-69, 70-79, 80-89, and ≥90 years). The primary endpoint was 1-month neurologically favorable survival.

RESULTS

Of the 554,923 patients included, 459,841 (82.9%) were witnessed by family members, 55,112 (9.9%) were witnessed by friends or colleagues, and 39,970 (7.2%) were witnessed by passersby. With advancing age, the proportion of patients witnessed by family members increased (P<0.001). The probability of neurologically favorable survival at 1 month was lowest in the family members group, followed by the passersby and the friends and colleagues group (4.2% vs. 10.1% vs. 15.3%, P<0.001). This trend overall remained consistent across age groups. Multivariable analysis showed that OHCA witnessed by family members was associated with poorer neurological outcomes. Among younger patients (aged 20-40 years), however, OHCA witnessed by family members was related to better neurological outcomes.

CONCLUSIONS

Patients with OHCA witnessed by family members had worse neurological outcomes than those witnessed by friends, colleagues, and passersby. This association differed by patient age, with family-member-witnessed OHCA associated with more favorable outcomes in younger patients but poorer outcomes in the elderly.