1. Department of Internal Medicine, Hangang Sacred Heart Hospital, Hallym University Medical Center, Seoul, Korea
2. Department of Internal Medicine, Kangwon National University College of Medicine, Chuncheon, Korea
3. Clinical Research Center of End Stage Renal Disease in Korea, Daegu, Korea
4. Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Korea
5. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
6. Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Korea
7. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
8. Department of Internal Medicine, The Catholic University of Korea College of Medicine, Seoul, Korea
9. Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea