Affiliation: | 1. Division of Nephrology, Department of Internal Medicine, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwonsi, Gyeonggido, Korea;2. Division of Nephrology, Department of Internal Medicine, College of Medicine, Uijeongbu St. Mary's Hospital, The Catholic University of Korea, Uijeongbusi, Gyeonggido, Korea |