1 Biomedical Ethics Research Program, Mayo Clinic, Rochester, Minnesota, USA.
2 Division of General Internal Medicine, Mayo Clinic, Scottsdale, Arizona, USA.
3 Department of Medicine, Division of Geriatrics, University of California, San Francisco, San Francisco, California, USA.
4 San Francisco Veterans Affairs Medical Center, San Francisco, California, USA.
5 Richard A. and Susan F. Smith Center for Outcomes Research in Cardiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
6 Harvard Medical School Center for Bioethics, Boston, Massachusetts, USA.
7 Department of Medicine, Georgetown University, Washington, DC, USA.
8 Department of Philosophy, Georgetown University, Washington, DC, USA.
9 Kennedy Institute of Ethics, Georgetown University, Washington, DC, USA.
10 Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, Minnesota, USA.