[1] Catholic Univ Korea, Coll Med, Dept Internal Med, Div Nephrol, 222 Banpo Daero, Seoul 137701, South Korea
[2] Incheon St Marys Hosp, Dept Internal Med, Incheon, South Korea
[3] Seoul St Marys Hosp, Dept Internal Med, Seoul, South Korea
[4] Yeouido St Marys Hosp, Dept Internal Med, Seoul, South Korea