1. Department of Emergency Medicine, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Preventive Medicine and Public Health, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Emergency Nursing, Yonsei University Health System, Seoul, Korea.
4. Department of Emergency Medicine, Inje University Ilsan Paik Hospital, Goyang, Korea.
5. Biostatistics Collaboration Unit, Department of Biomedical Systems Informatics, Yonsei University College of Medicine, Seoul, Korea.