[1] Yonsei Univ, Coll Med, Dept Internal Med, 50-1 Yonsei Ro, Seoul 03722, South Korea
[2] Yonsei Univ, Coll Med, Inst Gastroenterol, Seoul, South Korea
[3] Yonsei Univ, Coll Med, Dept Lab Med, Seoul, South Korea
[4] Yonsei Univ, Coll Med, Dept Pathol, Seoul, South Korea
[5] Yonsei Univ, Coll Med, Dept Biostat, 50-1 Yonsei Ro, Seoul 03722, South Korea