[1] Dongguk Univ, Ilsan Hosp, Dept Internal Med, Goyang, South Korea
[2] Natl Hlth Insurance Serv, Ilsan Hosp, Dept Res & Anal, Goyang, South Korea
[3] Yonsei Univ, Grad Sch, Dept Biostat & Comp, Seoul, South Korea
[4] Natl Hlth Insurance Serv, Ilsan Hosp, Dept Internal Med, Goyang, South Korea