Mass Gathering Events at an Event Hall in Osaka Are a Non-direct Risk of Admission to a Neighboring Emergency Hospital

The influence of planned mass gathering events on surrounding residents is not understood sufficiently. The purpose of this study was to investigate how events at an event hall affect a neighboring emergency hospital throughout the year. This was a single-center, retrospective, observational study conducted on all patients who presented to the emergency department from January 1 to December 31, 2019. The event hall is located 200 meters from the hospital, and various events such as music concerts and professional baseball games are held at the hall throughout the year. We collected patient information from the electronic medical records. The factors associated with hospitalization were assessed using a multivariable logistic regression analysis. This study comprised 18,907 patients who visited our emergency department. The number of patients on event days was 9,981 and that on no-event days was 8,922. The mean (SD) number of patients visiting on event days was 56.4 (14.9), and that on no-event days was 47.5 (14.1) (p