[1] Soonchunhyang Univ Hosp, Div Gastroenterol, Dept Internal Med, Cheonan, Choongnam, South Korea
[2] Soonchunhyang Univ Hosp, Dept Internal Med, Seoul, South Korea
[3] Soonchunhyang Univ Hosp, Dept Internal Med, Puchon, South Korea
[4] Yonsei Univ, Dept Internal Med, Seoul 120749, South Korea
[5] Yonsei Univ, Dept Internal Med, Wonju, South Korea
[6] Sungkyunkwan Univ, Dept Internal Med, Seoul, South Korea
[7] Kyung Hee Univ, Dept Internal Med, Seoul, South Korea
[8] Univ Ulsan, Dept Internal Med, Seoul, South Korea
[9] Univ Youngnam, Dept Internal Med, Taegu, South Korea
[10] Univ Ewha, Dept Internal Med, Seoul, South Korea
[11] Korea Univ, Dept Internal Med, Seoul 136701, South Korea
[12] Korea Univ, Dept Internal Med, Ansan, South Korea
[13] Univ Catholic Bucheon, Dept Internal Med, Puchon, South Korea
[14] Hanyang Univ, Dept Internal Med, Kuri, South Korea
[15] Univ Kwandong, Dept Prevent Med, Kangnung, South Korea