[1] Yonsei Univ, Severance Hosp, Coll Med, Dept Internal Med,Div Gastroenterol, Seoul, South Korea
[2] Hanyang Univ, Guri Hosp, Coll Med, Dept Internal Med, Seoul, South Korea
[3] Inje Univ, Sanggye Paik Hosp, Coll Med, Dept Internal Med,Div Gastroenterol, Seoul, South Korea
[4] Yonsei Univ, Coll Med, Dept Biomed Syst Informat, Biostat Collaborat Unit, Seoul, South Korea
[5] Chungnam Natl Univ, Chungnam Natl Univ Hosp, Coll Med, Dept Internal Med, Daejeon, South Korea
[6] Yonsei Univ, Coll Med, Dept Internal Med, Div Gastroenterol, 50-1 Yonsei Ro, Seoul 03722, South Korea
[7] Chungnam Natl Univ, Chungnam Natl Univ Hosp, Coll Med, Dept Internal Med,Div Gastroenterol, 282 Munhwa Ro, Daejeon 35015, South Korea