1 Departments of Medicine at the University of California San Francisco, San Francisco, CA.
2 Departments of Medicine at the University of California San Francisco, San Francisco, CA; Departments of Medicine San Francisco Veterans Administration Health Care System, San Francisco, CA.
3 Departments of Medicine James A. Haley Veterans' Hospital, Tampa, FL.
4 Departments of Medicine at the University of California San Francisco, San Francisco, CA; Departments of Medicine San Francisco Veterans Administration Health Care System, San Francisco, CA. Electronic address: [email protected].