1. Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross, Bangkok, Thailand
2. National Gastric Cancer and Gastrointestinal Diseases Research Center, Pathumthani, Thailand
3. Department of Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
4. Department of Medicine, Thammasat University Hospital, Pathum Thani, Thailand
5. Thonburi Hospital, Bangkok, Thailand
6. Department of Medicine, Faculty of Medicine, Khon Kaen University, Thailand
7. Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
8. Department of Medicine, Faculty of Medicine, Chiang Mai University, Thailand
9. NKC institute of Gastroenterology and Hepatology, Songklanagarind Hosptial, Hat Yai, Songkhla, Thailand
10. Udonthani Hospital, Udon Thani, Thailand
11. Rajavithi Hospital, Bangkok, Thailand
12. Phramongkutklao Hospital, Bangkok, Thailand
13. Bumrungrad Hospital, Bangkok, Thailand
14. Vachira Hospital, Bangkok, Thailand