1. Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Gachon Medical School, Gil Medical Center, Incheon, Korea.
4. Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.
5. Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
6. Department of Internal Medicine, Pusan National University College of Medicine, Busan, Korea.
7. Department of Internal Medicine, Hallym University College of Medicine, Anyang, Korea.
8. Department of Internal Medicine, Sungkyunkwan University College of Medicine, Kangbuk Samsung Hospital, Seoul, Korea.
9. Department of Internal Medicine, Medical College of the Catholic University, Seoul, Korea.