1. Division of Geriatric Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
2. The Cecil G. Sheps Center for Health Services Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
3. Division of General Internal Medicine and Clinical Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
4. Moses Cone Hospital, Greensboro, North Carolina.