1. Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Inje University College of Medicine, Busan, Korea.
5. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
6. Department of Internal Medicine, Kyungpook National University Graduate School of Medicine, Daegu, Korea.
7. Department of Internal Medicine, Dongguk University College of Medicine, Goyang, Korea.
8. Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
9. Department of Internal Medicine, Kyung Hee University College of Medicine, Seoul, Korea.
10. Department of Internal Medicine, Eulji University College of Medicine, Seoul, Korea.
11. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
12. Department of Internal Medicine, Jeju National University School of Medicine, Jeju, Korea.
13. Department of Gastroenterology, Ajou University School of Medicine, Suwon, Korea.
14. Department of Gastroenterology, University of Ulsan College of Medicine, Seoul, Korea.
15. Department of Internal Medicine, The Catholic University of Korea College of Medicine, Seoul, Korea.
16. Department of Internal Medicine, Konkuk University College of Medicine, Seoul, Korea.
17. Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea.
18. Department of Internal Medicine, Soonchunhyang University College of Medicine, Seoul, Korea.
19. Department of Internal Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
20. Department of Internal Medicine, Hanyang University College of Medicine, Guri, Korea.