[1] Seoul Natl Univ Hosp, Dept Internal Med, 101 Daehak Ro, Seoul 03080, South Korea
[2] Seoul Natl Univ, Coll Med, Dept Internal Med, Seoul, South Korea
[3] Soongsil Univ, Dept Stat & Actuarial Sci, Seoul, South Korea
[4] Univ Liverpool, Liverpool Ctr Cardiovasc Sci, Liverpool, Merseyside, England
[5] Liverpool Chest & Heart Hosp, Liverpool, Merseyside, England
[6] Aalborg Univ, Dept Clin Med, Aalborg, Denmark