1. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Soonchunhyang University College of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.
4. Department of Internal Medicine, Ewha Woman's University School of Medicine, Seoul, Korea.
5. Department of Internal Medicine, Konyang University College of Medicine, Daejeon, Korea.
6. Department of Internal Medicine, Dankook University College of Medicine, Cheonan, Korea.
7. Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.