1. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Seoul National University Hospital Healthcare System Gangnam Center, Seoul, Korea.
3. Department of Internal Medicine, Dankook University College of Medicine, Cheonan, Korea.
4. Department of Internal Medicine, Konkuk University Chungju Hospital, Konkuk University School of Medicine, Chungju, Korea.
5. Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.