1. Department of Gastroenterology, Sendai Kousei Hospital , Sendai , Japan
2. Digestive Disease Center, Showa University Koto Toyosu Hospital , Tokyo , Japan
3. Department of Health Administration and Policy, Tohoku University Graduate School of Medicine , Sendai , Japan
4. Department of Internal Medicine, Soma Central Hospital , Fukushima , Japan
5. Department of Health Policy and Informatics, Tokyo Medical and Dental University Graduate School of Medicine , Tokyo , Japan