[1] Natl Evidence Based Healthcare Collaborating Agcy, Off Hlth Serv Res, Seoul, South Korea
[2] Natl Strateg Coordinating Ctr Clin Res, Dept Res Support, Seoul, South Korea
[3] Konkuk Univ, Sch Med, Dept Internal Med, Seoul, South Korea
[4] Seoul St Marys Hosp, Dept Internal Med, Seoul, South Korea
[5] Yeouido St Marys Hosp, Dept Internal Med, Seoul, South Korea
[6] Yonsei Univ, Coll Med, Dept Internal Med, Seoul 120749, South Korea
[7] Hallym Univ, Kangdong Sacred Heart Hosp, Dept Internal Med, Div Pulm Allergy & Crit Care Med, Chunchon, South Korea
[8] Ewha Womans Univ, Sch Med, Dept Internal Med, Seoul, South Korea
[9] Univ Ulsan, Coll Med, Asan Med Ctr, Dept Pulm & Crit Care Med, Seoul 138736, South Korea
[10] Univ Ulsan, Coll Med, Asan Med Ctr, Clin Res Ctr Chron Obstruct Airway Dis, Seoul 138736, South Korea