[1] Korea Univ, Coll Med, Dept Internal Med, Div Gastroenterol, Seoul 136705, South Korea
[2] Catholic Univ Korea, Coll Med, Dept Internal Med, Gyeonggido, South Korea
[3] Sungkyunkwan Univ, Dept Internal Med, Sch Med, Gyeonggido, South Korea
[4] Soon Chun Hyang Univ, Coll Med, Dept Internal Med, Gyeonggido, South Korea
[5] Younsei Univ, Coll Med, Dept Internal Med, Gyeonggido, South Korea
[6] Yeungnam Univ, Coll Med, Dept Internal Med, Gyeonggido, South Korea
[7] Hallym Univ, Coll Med, Dept Internal Med, Gyeonggido, South Korea
[8] Ajou Univ, Coll Med, Dept Internal Med, Gyeonggido, South Korea
[9] Ewha Womans Univ, Dept Internal Med, Coll Med, Seoul, South Korea
[10] Seoul Natl Univ, Coll Med, Dept Internal Med, Seoul 151, South Korea
[11] Chung Ang Univ, Coll Med, Dept Internal Med, Seoul 156756, South Korea
[12] Inje Univ Coll Med, Dept Internal Med, Seoul, South Korea
[13] Univ Ulsan, Coll Med, Seoul, South Korea
[14] Dongguk Univ Coll Med, Seoul, South Korea