1. Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
2. Department of Internal Medicine, Hallym University Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Nowon Eulji Medical Center, Eulji University School of Medicine, Seoul, Korea.
4. Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
5. Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
6. Department of Internal Medicine, National Health Insurance Service Ilsan Hospital, Goyang, Korea.
7. Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
8. Department of Internal Medicine, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Korea.
9. Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
10. Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea.
11. Diabetes Center, Endocrinology and Metabolism, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
12. Department of Internal Medicine, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
13. Department of Internal Medicine, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
14. Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, Korea.
15. Department of Internal Medicine, Inje University Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
16. Department of Internal Medicine, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea.
17. Department of Internal Medicine, Chonbuk National University Hospital, Chonbuk National University Medical School, Jeonju, Korea.
18. Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.