[1] Soonchunhyang Univ, Div Allergy & Resp Med, Dept Internal Med, Bucheon Hosp, Bucheon, South Korea
[2] Univ Ulsan, Asan Med Ctr, Dept Pulm & Crit Care Med, Coll Med, Seoul, South Korea
[3] Sungkyunkwan Univ, Dept Crit Care Med, Samsung Med Ctr, Sch Med, Seoul, South Korea
[4] Sungkyunkwan Univ, Div Pulm & Crit Care Med, Samsung Med Ctr, Sch Med, Seoul, South Korea
[5] Myoungji Hosp, Dept Integrated Internal Med, Goyang, South Korea
[6] Ulsan Univ Hosp, Dept Internal Med, Ulsan, South Korea
[7] Inje Univ, Ilsan Paik Hosp, Div Pulm & Crit Care Med, Dept Internal Med,Coll Med, Goyang, South Korea
[8] Jeju Natl Univ, Jeju Natl Univ Hosp, Dept Internal Med, Sch Med, Jeju, South Korea
[9] Inje Univ, Coll Med, Dept Internal Med, Div Pulmonol Allergy & Crit Care Med, Busan, South Korea
[10] Pusan Natl Univ, Div Pulm Allergy & Crit Care Med, Dept Internal Med, Yangsan Hosp, Yangsan, South Korea
[11] Inje Univ, Div Pulm & Crit Care Med, Dept Internal Med, Sanggye Paik Hosp, Seoul, South Korea
[12] Jeonbuk Natl Univ, Res Ctr Pulm Disorders, Dept Internal Med, Sch Med, Jeonju, South Korea
[13] Sungkyunkwan Univ, Div Pulm & Crit Care Med, Dept Internal Med, Kangbuk Samsung Hosp,Sch Med, Seoul, South Korea
[14] Konkuk Univ, Div Pulm Allergy & Crit Care Med, Dept Internal Med, Sch Med, Seoul, South Korea
[15] Korea Univ, Div Pulm Allergy & Crit Care Med, Dept Internal Med, Guro Hosp, Seoul, South Korea
[16] Chungnam Natl Univ Hosp, Dept Pulm & Crit Care Med, Daejeon, South Korea
[17] Chungnam Natl Univ, Div Pulm & Crit Care Med, Dept Internal Med, Sejong Hosp, Sejong, South Korea