[1] Seoul Natl Univ Hosp, Dept Internal Med, Div Cardiol, Seoul, South Korea
[2] Seoul Natl Univ, Coll Med, Dept Internal Med, 101 Daehak Ro, Seoul 03080, South Korea
[3] Catholic Univ Korea, Coll Med, Dept Med Stat, Seoul, South Korea
[4] Soongsil Univ, Stat & Actuarial Sci, Seoul, South Korea
[5] Univ Liverpool, Liverpool John Moores Univ, Liverpool Ctr Cardiovasc Sci, Liverpool, England
[6] Liverpool Chest & Heart Hosp, Liverpool, England
[7] Aalborg Univ, Danish Ctr Clin Hlth Serv Res, Dept Clin Med, Aalborg, Denmark
[8] Seoul Natl Univ Hosp, 101 Daehak Ro, Seoul 03080, South Korea