[1] Hanyang Univ Hosp, Dept Internal Med, Div Pulm Med & Allergy, Seoul, South Korea
[2] Hallym Univ, Kangnam Sacred Heart Hosp, Dept Internal Med, Div Pulm Allergy & Crit Care Med, Seoul, South Korea
[3] Gangneung Asan Hosp, Dept Pulm & Crit Care Med, Kangnung, South Korea
[4] Kangwon Natl Univ, Dept Internal Med, Chunchon, South Korea
[5] Kangwon Natl Univ, Ctr Environm Hlth, Chunchon, South Korea
[6] Konkuk Univ, Dept Internal Med, Sch Med, Seoul, South Korea
[7] Gyeonsang Natl Univ, Gyeongsang Natl Univ Hosp, Dept Internal Med, Sch Med, Jinju, South Korea
[8] Hanyang Univ, Div Pulm Med & Allergy, Dept Internal Med, Guri Hosp, Guri, South Korea
[9] Natl Canc Ctr, Div Pulmonol, Goyang, South Korea
[10] Natl Med Ctr, Dept Internal Med, Seoul, South Korea
[11] Dong A Univ Hosp, Dept Internal Med, Pusan, South Korea
[12] Seoul Natl Univ, Seoul Metropolitan Govt Boramae Med Ctr, Coll Med, Dept Internal Med, Seoul, South Korea
[13] CHA Bundang Med Ctr, Dept Allergy Pulm & Crit Care Med, Sungnam, South Korea
[14] Seoul Natl Univ, Dept Internal Med, Div Pulm & Crit Care Med, Bundang Hosp, Sungnam, South Korea
[15] Sungkyunkwan Univ, Sch Med, Dept Med, Div Pulm & Crit Care Med,Samsung Med Ctr, Seoul, South Korea
[16] Seoul Natl Univ Hosp, Dept Internal Med, Div Pulm & Crit Care Med, Seoul, South Korea
[17] Catholic Univ Korea, Div Pulm Allergy & Crit Care Med, Dept Internal Med, Coll Med,Seoul St Marys Hosp, Seoul, South Korea
[18] Catholic Univ Korea, Eunpyeong St Marys Hosp, Coll Med, Dept Internal Med, Seoul, South Korea
[19] Soonchunhyang Univ, Dept Internal Med, Cheonan Hosp, Cheonan, South Korea
[20] Soonchunhyang Univ, Dept Internal Med, Bucheon Hosp, Bucheon, South Korea
[21] Yonsei Univ, Dept Internal Med, Div Pulmonol, Severance Hosp, Seoul, South Korea
[22] Univ Ulsan, Coll Med, Dept Internal Med, Div Pulm Med,Ulsan Univ Hosp, Ulsan, South Korea
[23] Yonsei Univ, Dept Internal Med, Wonju Coll Med, Wonju, South Korea
[24] Jeju Natl Univ Hosp, Dept Internal Med, Jeju, South Korea
[25] Hallym Univ, Dept Internal Med, Chuncheon Sacred Heart Hosp, Chunchon, South Korea
[26] Inje Univ, Dept Internal Med, Div Pulm & Crit Care Med, Haeundae Paik Hosp, Pusan, South Korea
[27] Univ Ulsan, Asan Med Ctr, Dept Pulm & Crit Care Med, Coll Med, Seoul, South Korea