International Big Data Centre in Emergency Medicine

This observational study aims to use electronic health records to build an International Big Data Centre in Emergency Medicine, within the Institute of Sciences in Emergency Medicine (ISEM) at the Guangdong Provincial People's Hospital. The main questions it seeks to answer are not limited to the following: * Identify the relationship between Emergency Department Length of Stay (EDLOS), Mortality, and Adverse Events (AE) * Identify the risk factors associated with high mortality and AE rate among patients who experience prolonged EDLOS * Other research questions related to emergency medicine, such as building prediction and cluster models for acute diseases

Inclusion Criteria: * Every patient who ever visited Emergency Department from 2011-2022 Exclusion Criteria: * Patients with missing demographic (age, gender, etc.) and triage data