[1] Univ Ulsan, Ulsan Univ Hosp, Dept Gastroenterol, Coll Med, Ulsan, South Korea
[2] Univ Ulsan, Asan Med Ctr, Dept Gastroenterol, Coll Med, 88 Olymp Ro 43 Gil, Seoul 05505, South Korea
[3] Kyung Hee Univ, Ctr Crohns & Colitis, Dept Gastroenterol, Coll Med, Seoul, South Korea
[4] Catholic Univ Korea, Dept Internal Med, Div Gastroenterol, Seoul St Marys Hosp, Seoul, South Korea
[5] Seoul Natl Univ Hosp, Dept Internal Med, Div Gastroenterol, Seoul, South Korea
[6] Univ Ulsan, Asan Med Ctr, Inflammatory Bowel Dis Ctr, Coll Med, Seoul, South Korea