1. Department of Internal Medicine, Seoul National University Healthcare System Gangnam Center, Seoul, Korea.
2. Department of Internal Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
3. Department of Internal Medicine, St. Vincent's Hospital, The Catholic University of Korea College of Medicine, Suwon, Korea.
4. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
5. Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
6. Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea.
7. Department of Internal Medicine, Soonchunhyang University College of Medicine, Seoul, Korea.
8. Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.
9. Department of Internal Medicine, Jeju National University School of Medicine, Jeju, Korea.
10. Department of Internal Medicine, University of Ulsan College of Medicine, Seoul, Korea.