1. Department of Internal Medicine, Kangdong Sacred Heart Hospital, Seoul, Korea.
2. Department of Internal Medicine, Ilsan-Paik Hospital, Inje University College of Medicine, Goyang, Korea.
3. Division of Nephrology, Department of Internal Medicine, Ewha Womans University School of Medicine, Ewha Medical Research Center, Seoul, Korea.
4. Department of Internal Medicine, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
5. Division of Nephrology, Department of Internal Medicine, Kyunghee University, Seoul, Korea.
6. Division of Nephrology, Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea.
7. Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
8. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.