[1] Konkuk Univ, Konkuk Univ Hosp, Sch Med, Div Pulm & Allergy,Dept Internal Med, Seoul, South Korea
[2] Dongguk Univ, Dongguk Univ Gyeongju Hosp, Div Pulm & Crit Care Med, Dept Internal Med,Coll Med, Gyeongju, South Korea
[3] Catholic Univ Korea, Seoul St Mary Hosp, Div Pulm & Crit Care Med, Dept Internal Med,Coll Med, Seoul, South Korea
[4] Hanyang Univ, Div Pulm & Allergy, Dept Internal Med, Coll Med, Seoul, South Korea
[5] Hallym Univ, Div Pulm Allergy & Crit Care Med, Dept Internal Med, Chuncheon Sacred Heart Hosp, Chunchon, South Korea
[6] Ajou Univ, Dept Pulm & Crit Care Med, Sch Med, Suwon, South Korea
[7] Univ Ulsan, Ulsan Univ Hosp, Div Pulm & Crit Care Med, Dept Internal Med,Coll Med, Ulsan, South Korea
[8] Hallym Univ, Div Pulm Allergy & Crit Care Med, Kangdong Sacred Heart Hosp, Seoul, South Korea