[1] Sungkyunkwan Univ, Kangbuk Samsung Hosp, Dept Internal Med, Div Gastroenterol,Sch Med, Seoul, South Korea
[2] Yonsei Univ, Dept Biomed Syst Informat, Biostat Collaborat Unit, Coll Med, Seoul, South Korea
[3] Yonsei Univ, Grad Sch Publ Hlth, Dept Biostat, 50-1 Yonsei Ro, Seoul, South Korea
[4] Yonsei Univ, Dept Internal Med, Coll Med, 50-1 Yonsei Ro, Seoul, South Korea
[5] Yonsei Univ, Inst Gastroenterol, Coll Med, 50-1 Yonsei Ro, Seoul, South Korea