1. Hospital Care Research Unit; Hyogo Prefectural Amagasaki General Medical Center; Hyogo Japan
2. Department of Healthcare Epidemiology; School of Public Health in the Graduate School of Medicine, Kyoto University; Kyoto Japan
3. Department of Mathematics; Shimane University; Matsue Japan
4. Australian and New Zealand Intensive Care Research Centre, Department of Epidemiology and Preventive Medicine; Monash University; Melbourne Australia
5. Center for Innovative Research for Communities and Clinical Excellence (CiRC2LE); Fukushima Medical University; Fukushima Japan
6. Department of Anesthesia; Shiga University of Medical Science Hospital; Otsu Japan
7. Department of Respiratory Medicine; Hyogo Prefectural Amagasaki General Medical Center; Hyogo Japan