1. Division of Pulmonary and Critical Care Medicine, Lundquist Institute at Harbor-University of California, Los Angeles Medical Center, David Geffen School of Medicine at UCLA, Torrance, California
2. Los Angeles County Department of Health Services, Los Angeles, California
3. Division of Pulmonary and Critical Care Medicine, Ronald Reagan University of California, Los Angeles Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, California
4. Division of Pulmonary and Critical Care Medicine, Olive View Medical Center, David Geffen School of Medicine at UCLA, Sylmar, California
5. Division of Pulmonary and Critical Care Medicine, Los Angeles County-University of Southern California Medical Center, Keck School of Medicine of University of Southern California, Los Angeles
6. Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine at UCLA, Los Angeles, California
7. Division of Geriatric, Hospital, Palliative, and General Internal Medicine, Los Angeles County-University of Southern California Medical Center, Keck School of Medicine of University of Southern California, Los Angeles