[1] Catholic Univ Korea, Eunpyeong St Marys Hosp, Coll Med, Div Pulm Crit Care & Sleep Med,Dept Internal Med, Seoul, South Korea
[2] Hanyang Univ, Hanyang Med Ctr, Dept Internal Med, Div Pulm Med & Allergy,Coll Med, Seoul, South Korea
[3] Pusan Natl Univ, Yangsan Hosp, Dept Internal Med, Yangsan, South Korea
[4] Yonsei Univ, Severance Hosp, Dept Internal Med, Div Pulmonol,Coll Med, Seoul, South Korea
[5] Chungnam Natl Univ, Coll Med, Dept Internal Med, Div Pulmonol, Daejeon, South Korea
[6] Kyungpook Natl Univ, Sch Med, Dept Internal Med, Daegu, South Korea
[7] Univ Ulsan, Coll Med, Asan Med Ctr, Div Pulm & Crit Care Med, Seoul, South Korea
[8] Chonnam Natl Univ, Med Sch, Dept Internal Med, Hwasun, South Korea
[9] Hwasun Hosp, Hwasun, South Korea
[10] Soonchunhyang Univ, Coll Med, Bucheon Hosp, Div Resp Allergy,Dept Internal Med, Bucheon, South Korea
[11] Inha Univ Hosp, Dept Internal Med, Incheon, South Korea
[12] Univ Ulsan, Coll Med, Asan Med Ctr, Dept Oncol, Seoul, South Korea
[13] Kosin Univ, Med Coll, Dept Internal Med, Pusan, South Korea
[14] Konkuk Univ, Sch Med, Dept Pulm Med, Seoul, South Korea
[15] Hallym Univ, Sacred Heart Hosp, Dept Internal Med, Div Pulm Allergy & Crit Care Med,Coll Med, Anyang, South Korea
[16] Catholic Univ Korea, Seoul St Marys Hosp, Dept Internal Med, Div Pulmonol, Seoul, South Korea