1. Department of Internal Medicine, Konkuk University Medical Center, Seoul, Korea.
2. Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
3. Department of Internal Medicine, Chonnam National University Hwasun Hospital, Hwasun, Korea.
4. Department of Internal Medicine, Kosin University Gospel Hospital, Busan, Korea.
5. Department of Medicine, Samsung Medical Center, Seoul, Korea.
6. Department of Internal Medicine, the Catholic University of Korea, Seoul, Korea.
7. Department of Internal Medicine, Hanyang University, Seoul, Korea.
8. Department of Internal Medicine, Gachon University, Incheon, Korea.
9. Department of Internal Medicine, Wonkwang University Hospital, Iksan, Korea.
10. Department of Internal Medicine, National Cancer Center, Ilsan, Korea.
11. Department of Internal Medicine, Daegu Fatima Hospital, Daegu, Korea.
12. Department of Internal Medicine, Soonchunhyang University Hospital, Bucheon, Korea.
13. Department of Internal Medicine, Yonsei University, Seoul, Korea.
14. Department of Internal Medicine, Dankook University Hospital, Cheonan, Korea.