[1] Keimyung Univ, Sch Med, Dept Internal Med, Div Gastroenterol, Taegu, South Korea
[2] Yeungnam Univ, Coll Med, Div Gastroenterol & Hepatol, Dept Internal Med, Gyongsan, South Korea
[3] Kyungpook Natl Univ, Sch Med, Div Gastroenterol & Hepatol, Dept Internal Med, Taegu, South Korea
[4] Catholic Univ Daegu, Sch Med, Div Gastroenterol & Hepatol, Dept Internal Med, Taegu, South Korea
[5] Dongguk Univ, Sch Med, Div Gastroenterol & Hepatol, Dept Internal Med, Gyeongju 780350, Gyeongsang Buk, South Korea