1. Division of Pulmonary Allergy and Critical Care Medicine; Department of Internal Medicine; Busan Paik Hospital; Inje University College of Medicine; Busan South Korea
2. Division of Pulmonology; Department of Internal Medicine; Institute of Chest Disease; Severance Hospital; Yonsei University College of Medicine; Seoul South Korea
3. Department of Clinical Epidemiology and Biostatistics; Ulsan College of Medicine; Asan Medical Center; Seoul South Korea
4. Department of Allergy and Clinical Immunology; Asan Medical Center; University of Ulsan College of Medicine; Seoul South Korea
5. Department of Pulmonary and Critical Care Medicine; Asan Medical Center; University of Ulsan College of Medicine; Seoul South Korea