1. Division of Gastroenterology and Hepatology, Department of Medicine, Faculty of Medicine, Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand
2. Center of Excellence in Digestive diseases and Gastroenterology Unit, Department of Medicine, Thammasat University, Pathumthani, Thailand
3. Department of Medicine, Chulabhorn International College of Medicine (CICM) at Thammasat University, Pathumthani, Thailand