1. Division of Pulmonary and Critical Care Medicine, and
2. Department of Medicine, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, California
3. Division of Pulmonary and Critical Care Medicine, University of Utah, Salt Lake City, Utah
4. Department of Physical Medicine and Rehabilitation, Johns Hopkins University, Baltimore, Maryland; and
5. Geriatric Research, Education and Clinical Center, and
6. Department of Medicine, VA Greater Los Angeles Healthcare System, Los Angeles, California