1. Division of Pulmonary, Critical Care, and Sleep Medicine, University of California San Francisco, San Francisco, California;
2. The Center for Health Research, Kaiser Permanente Northwest, Portland, Oregon;
3. Divison of Pulmonary and Critical Care, David Geffen School of Medicine, University of California, Los Angeles, California;
4. Department of Medicine and Epidemiology, Columbia University Medical Center, New York, New York;
5. Division of Pulmonary, Critical Care, and Sleep Medicine, National Jewish Health, Denver, Colorado;
6. Division of Pulmonary, Critical Care, and Occupational Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa;
7. Division of Thoracic Medicine and Surgery, Temple University, Philadelphia, Pennsylvania;
8. Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, Michigan;
9. Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland;
10. Department of Radiology, University of Iowa, Iowa City, Iowa;
11. Division of Respiratory, Critical Care, and Occupational Pulmonary Medicine, University of Utah, Salt Lake City, Utah;
12. Division of Pulmonary, Critical Care, Sleep, and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois;
13. Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
14. Pulmonary, Critical Care, Allergy, and Immunologic Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina