[1] Keimyung Univ, Sch Med, Dept Internal Med, Div Gastroenterol, Taegu, South Korea
[2] Yeungnam Univ, Coll Med, Dept Internal Med, Div Gastroenterol & Hepatol, Taegu 705703, South Korea
[3] Kyungpook Natl Univ, Sch Med, Dept Internal Med, Div Gastroenterol & Hepatol, Taegu, South Korea
[4] Catholic Univ Daegu, Sch Med, Dept Internal Med, Div Gastroenterol & Hepatol, Taegu, South Korea
[5] Dongguk Univ, Sch Med, Dept Internal Med, Div Gastroenterol & Hepatol, Gyeongju, South Korea
[6] Soonchunhyang Univ, Sch Med, Dept Internal Med, Div Gastroenterol, Gumi, Gyeongsang Buk, South Korea