[1] Catholic Univ Korea, Suwon St Vincents Hosp, Dept Internal Med, Div Gastroenterol, Suwon 441400, South Korea
[2] Catholic Univ Korea, Incheon St Marys Hosp, Dept Internal Med, Div Gastroenterol, Inchon 421735, South Korea
[3] Catholic Univ Korea, Seoul St Marys Hosp, Dept Internal Med, Div Gastroenterol, Seoul 136701, South Korea
[4] Catholic Univ Korea, Bucheon St Marys Hosp, Dept Internal Med, Div Gastroenterol, Puchon 398213, South Korea