Neurologically favourable outcomes of cardiogenic out-of-hospital cardiac arrest with relation to the type of witness in Japan.

Aim: To assess the current situation and neurologically favourable outcomes after out-of-hospital cardiac arrest (OHCA) with respect to the type of witness.

Methods: This retrospective observational study used data from the All-Japan Utstein Registry of the Fire and Disaster Management Agency collected between January 1, 2016, and December 31, 2016. Patients with cardiogenic OHCA aged ≥18 years who were witnessed by bystanders were included. The primary outcome measure was a neurologically favourable outcome 1 month after the OHCA.

Results: Among the 123,554 patients with OHCA registered between January 1, 2016, and December 31, 2016, 24,856 patients were included. Of them, 15,139 were witnessed by family, and 9717 were witnessed by non-family (friends, 1306; colleagues, 951; passers-by, 997; others, 6463). When witnessed by family, the rate of neurologically favourable outcomes was significantly lower than that when witnessed by non-family (odds ratio [OR] = 0.45, 95% confidence interval [CI] = 0.41-0.49, P < 0.001). After adjusting for potential confounders, the rate of neurologically favourable outcomes remained lower when OHCA was witnessed by family (OR = 0.88, 95% CI = 0.79-0.99, P = 0.03). However, in subgroup analysis, adjusted ORs for neurologically favourable outcomes were slightly greater for 65-84-year-old women and ≥85-year-old women with family witnesses than for those with non-family witnesses. For all other groups, non-family witnesses outperformed family witnesses.

Conclusion: Family-witnessed OHCA events had fewer neurologically favourable outcomes before and after adjusting for confounders. BLS education for family members may lead to improved prognosis of witnessed cardiogenic OHCAs.