[1] Chonnam Natl Univ, Med Sch, Dept Internal Med, Gwangju, South Korea
[2] Chonnam Natl Univ Hosp, Gwangju, South Korea
[3] Catholic Univ Korea, Coll Med, Dept Biostat, Seoul, South Korea
[4] Chonnam Natl Univ, Chonnam Natl Univ Hosp, Dept Pediat, Med Sch, Gwangju, South Korea
[5] Soongsil Univ, Dept Stat & Actuarial Sci, Seoul, South Korea