1. Division of Nephrology, Department of Internal Medicine, Veterans Health Service Medical Center, Seoul, Korea.
2. Veterans Medical Research Institute, Veterans Health Service Medical Center, Seoul, Korea.
3. Division of Nephrology, Department of Internal Medicine, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon, Korea.
4. Division of Nephrology, Department of Internal Medicine, Armed Forces Capital Hospital, Seongnam, Korea.
5. Department of Dermatology, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon, Korea.