1. Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Daegu Fatima Hospital, Daegu, Korea.
3. Department of Internal Medicine, Kanganm Sacred Heart Hospital, Hallym University School of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea.
5. Department of Internal Medicine, Daegu Catholic University, Daegu, Korea.
6. Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.