1. Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan;
2. Graduate School of Medical Sciences, The University of Fukui, Fukui, Japan;
3. Department of Health Services Research, The University of Tokyo, Tokyo, Japan;
4. Department of Health Care Informatics, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan;
5. Department of Emergency Medicine, University of Fukui Hospital, Fukui, Japan