1 Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
2 Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
3 Department of Chest Medicine, Masan National Tuberculosis Hospital, Masan, Republic of Korea.
4 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.