[1] Konkuk Univ, Sch Med, Dept Internal Med, Div Pulm & Allergy,Med Ctr, Seoul, South Korea
[2] Catholic Univ Korea, Coll Med, Dept Internal Med, Div Pulm Allergy & Crit Care Med,Seoul St Marys H, 222 Banpo Daero, Seoul 06591, South Korea
[3] Univ Ulsan, Ulsan Univ Hosp, Dept Internal Med, Coll Med, 877 Bangeojinsunhwan Doro, Ulsan 44033, South Korea