Effects of the 2020 COVID-19 pandemic on outcomes of out-of-hospital cardiac arrest and bystander resuscitation efforts: a nationwide cohort study in Japan.

Background and importance There is limited knowledge about the nationwide impact of the 2020 COVID-19 pandemic in Japan on out-of -hospital cardiac arrest (OHCA) outcomes.Objectives The aim of this study was to investigate the impact of the 2020 COVID-19 pandemic on OHCA outcomes and bystander resuscitation efforts in Japan. Design Retrospective analysis of a nationwide population-based registry of OHCA cases. Settings and participants To conduct this study, we created a comprehensive database comprising 821 665 OHCA cases by combining and reconciling the OHCA database for 835 197 OHCA cases between 2017 and 2020 with another database, including location and time records. After applying exclusion and inclusion criteria, we analysed 751 617 cases.Outcome measures and analysis The primary outcome measure for this study was survival with neurologically favourable outcome (cerebral performance category 1 or 2). Results We compare OHCA characteristics and outcomes between prepandemic and pandemic years, and also investigated differences in factors associated with outcomes. We found that survival with neurologically favourable outcome and the rates of bystander cardiopulmonary resuscitation (CPR) slightly increased in the pandemic year [2.8% vs. 2.9%; crude odds ratio (OR), 1.07; 95% confidence interval (CI), 1.03-1.10; 54.1% vs. 55.3%, 1.05 (1.04-1.06), respectively], although the incidence of public access defibrillation (PAD) slightly decreased [1.8% vs. 1.6%, 0.89 (0.86-0.93)]. Calls for hospital selection by emergency medical service (EMS) increased during the pandemic. Subgroup analysis showed that the incidence of neurologically favourable outcome increased in 2020 for OHCA cases that occurred on nonstate of emergency days, in unaffected prefectures, with noncardiac cause, nonshockable initial rhythm, and during daytime hours. Conclusions During the 2020 COVID-19 pandemic in Japan, survival with neurologically favourable outcome of OHCA patients and bystander CPR rate did not negatively change, despite the decrement in PAD incidence. However, these effects varied with the state of emergency, region, and characteristics of OHCA, suggesting an imbalance between medical demand and supply, and raising concerns about the pandemic.