1. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea
2. Institute of Gastroenterology, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
3. Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
4. Department of Internal Medicine, Seoul National University Bundang Hospital, 166 Gumin-ro, Bundang-gu, Seongnam-si, Gyunggi-do 463-707, South Korea
5. Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, South Korea
6. Department of Internal Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea