[1] Soonchunhyang Univ, Div Allergy & Resp Med, Dept Internal Med, Seoul Hosp, 59 Daesagwan Ro, Seoul 04401, South Korea
[2] Univ Ulsan, Div Pulm & Crit Care Med, Asan Med Ctr, Coll Med, Seoul, South Korea
[3] Seoul Natl Univ, Div Pulm & Crit Care Med, Dept Internal Med, Coll Med, Seoul, South Korea
[4] Seoul Natl Univ, Lung Inst, Coll Med, Seoul, South Korea
[5] Sungkyunkwan Univ, Div Pulm & Crit Care Med, Samsung Med Ctr, Sch Med, Seoul, South Korea
[6] Soonchunhyang Univ, Div Allergy & Resp Med, Dept Internal Med, Bucheon Hosp, Gyeonggi Do, South Korea
[7] Gachon Univ, Gil Med Ctr, Div Pulmonol, Dept Internal Med, Inchon, South Korea
[8] Hallym Univ, Div Pulm Allergy & Crit Care Med, Dept Internal Med, Kangdong Sacred Heart Hosp, Seoul, South Korea
[9] Inha Univ Hosp, Pulm Div, Dept Internal Med, Inchon, South Korea
[10] Chung Ang Univ, Coll Med, Div Pulm Med, Dept Internal Med, Seoul, South Korea
[11] Korea Univ, Div Resp & Crit Care Med, Dept Internal Med, Anam Hosp,Coll Med, Seoul, South Korea
[12] Ewha Womans Univ, Dept Internal Med, Sch Med, Ewha Med Res Inst, Seoul, South Korea
[13] Univ Ulsan, Coll Med, Ulsan Univ Hosp, Div Pulm Med,Dept Internal Med, Ulsan, South Korea
[14] Inje Univ, Div Crit Care & Pulm Med, Dept Internal Med, Pusan Paik Hosp, Gimhae, South Korea
[15] Catholic Univ Korea, Div Allergy & Pulmonol, Dept Internal Med, Bucheon St Marys Hosp,Sch Med, Seoul, South Korea
[16] Yonsei Univ, Yonsei Univ Hlth Syst, Div Pulm & Crit Care Med, Dept Internal Med,Coll Med, Seoul, South Korea
[17] Soonchunhyang Univ, Dept Prevent Med, Coll Med, Cheonan, South Korea