Private residence as a location of cardiac arrest may have a deleterious effect on the outcomes of out-of-hospital cardiac arrest in patients with an initial non-shockable cardiac rhythm: A multicentre retrospective cohort study

Aim We compared the outcomes between patients who experienced out-of-hospital cardiac arrest at private residences and public locations to investigate whether patient and bystander characteristics can explain the poorer outcomes of out-of-hospital cardiac arrests at private residences. Methods Adult patients with intrinsic out-of-hospital cardiac arrest (n = 6,191, age ≥18 years) were selected from a prospectively collected Japanese database (January 2012 and March 2013). Patients were grouped according to arrest location into private-residence or control (e.g., public station or road, workplace, school, and other public locations) groups. The primary outcome was a favourable neurological outcome 1 month after out-of-hospital cardiac arrest. Results The arrest location and initial cardiac rhythm had interaction effects on the outcome. After adjusting for patient and bystander characteristics and relative to the control group, a significantly poorer 1-month neurological outcome was observed in the private-residence group if the initial cardiac rhythm was non-shockable (odds ratio: 0.36, 95% confidence interval: 0.24–0.54), while it was not significant if the initial cardiac rhythm was shockable (odds ratio: 1.16, 95% confidence interval: 0.74–1.84). Conclusions Patients with out-of-hospital cardiac arrest at private residences had poorer outcomes than those with out-of-hospital cardiac arrest at public locations, even after adjusting for patient and bystander characteristics, if the initial cardiac rhythm was non-shockable. Our results suggest that poorer patient and bystander characteristics do not completely explain the poorer outcomes of out-of-hospital cardiac arrests; there may be unknown mechanisms through which the location of cardiac arrest affect the outcomes.