An Exploratory Study on Changes in Patients in the Emergency Department due to Coronavirus Disease 2019 in Japan: A Single-center Retrospective Study

INTRODUCTION: This study assessed changes in patients transported to an emergency and critical care center before and after the coronavirus disease 2019 (COVID-19) pandemic in Japan and examined problems that should be addressed in emergency medical care. METHODS: This single-center retrospective observational study was conducted at a university hospital. The subjects were patients who were transported to a “tertiary emergency department” receiving advanced medical care. With January 16, 2020, as the cutoff date, 4,197 patients who were transported to the hospital from January 16, 2019, to January 15, 2021, were recruited. The patients were classified into nine disease groups using the International Classification of Diseases, Tenth Revision. The emergency department (ED) visit count in 2020 was compared with that in 2019 using Poisson regression. RESULTS: The number of patients transported to the tertiary ED in 2020 decreased by 7.8% compared with that in 2019. The number of patients transported to the tertiary ED decreased compared with that in the previous year during the period when the number of confirmed COVID-19 cases in Japan increased and showed the opposite trend when the number of confirmed cases decreased. As per diagnostic classification, it decreased for all diagnoses except External causes, and significant decreases were observed in Infectious (47.5%), Non-COVID-19 respiratory (28.4%), and Trauma (25.2%). In External causes, the rate of change for suicide cases alone increased to 43.2%. CONCLUSIONS: While the number of confirmed cases increased, the number of tertiary ED patients associated with COVID-19 decreased temporarily. It is necessary to fully consider the burden on medical institutions 1-2 months after the number of infected people peaks. It is also necessary to closely monitor suicides associated with COVID-19 as a factor that will cause changes in emergency medical care in the future.