[1] CHA Univ, Sch Med, CHA Bundang Med Ctr, Div Gastroenterol,Dept Internal Med, Pochon, South Korea
[2] Soongsil Univ, Seoul, South Korea
[3] Catholic Univ Korea, Seoul, South Korea
[4] CHA Univ, CHA Bundang Med Ctr, Dept Internal Med, Seongnam, South Korea
[5] Yonsei Univ, Coll Med, Dept Internal Med, Seoul, South Korea