[1] Catholic Univ Korea, Incheon St Marys Hosp, Div Nephrol, Dept Internal Med, Inchon, South Korea
[2] Catholic Univ Korea, Yoido St Marys Hosp, Div Nephrol, Dept Internal Med, Seoul, South Korea
[3] Catholic Univ Korea, St Vincents Hosp, Div Nephrol, Dept Internal Med, Suwon, South Korea
[4] Yonsei Univ, Wonju Coll Med, Div Nephrol, Dept Internal Med, Wonju, South Korea