1. Department of General Medicine , Yokohama City University School of Medicine , Yokohama , Kanagawa , Japan
2. Department of General Medicine , Saga University Hospital , Saga , Japan
3. Education and Research Center for Community Medicine, Faculty of Medicine , Saga University , Saga , Japan
4. Department of General Medicine, Faculty of Medicine , Juntendo University , Tokyo , Japan
5. Department of General Medicine , Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences , Okayama , Japan
6. Department of General Internal Medicine , Iizuka Hospital , Iizuka , Fukuoka , Japan
7. Department of Infectious Disease , Kyorin University School of Medicine , Tokyo , Japan
8. Department of General Internal Medicine , Asahi General Hospital , Asahi , Japan