[1] Ewha Womans Univ, Sch Med, Dept Internal Med, Seoul, South Korea
[2] Univ Ulsan, Coll Med, Dept Internal Med, Seoul, South Korea
[3] Ewha Womans Univ, Sch Med, Dept Paediat, Seoul, South Korea
[4] Keimyung Univ, Sch Med, Dept Internal Med, Daegu, South Korea