1. Department of Internal Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea.
2. Department of Internal Medicine, Keimyung University School of Medicine, Daegu, Korea.
3. Department of Internal Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea.
4. Department of Internal Medicine, The Catholic University of Korea College of Medicine, Seoul, Korea.
5. Department of Internal Medicine, Hallym University College of Medicine, Chuncheon, Korea.
6. Department of Gastroenterology, Ajou University School of Medicine, Suwon, Korea.
7. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.