1. Department of Chest Medicine, Taipei Veterans General Hospital , Taipei , Taiwan
2. School of Medicine, National Yang Ming Chiao Tung University , Taipei , Taiwan
3. Institute of Public Health, School of Medicine, School of Medicine, National Yang Ming Chiao Tung University , Taipei , Taiwan
4. Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of California San Diego , La Jolla, California , USA
5. Graduate Institute of Biomedical Sciences, China Medical University , Taichung , Taiwan
6. Department of Internal Medicine, National Taiwan University Hospital , Taipei , Taiwan
7. College of Medicine, National Taiwan University , Taipei , Taiwan
8. Department of Chest Medicine, Far-Eastern Memorial Hospital , New Taipei City , Taiwan
9. Department of Medicine, National Taiwan University Cancer Center , Taipei , Taiwan
10. Division of Chest Medicine, China Medical University Hospital , Taipei Branch, Taipei , Taiwan
11. Department of Internal Medicine, National Taiwan University Hospital , Hsin-Chu Branch, Hsin-Chu , Taiwan