1 Departments of Family Medicine and Internal Medicine, Cecil G. Sheps Center for Health Services Research School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC. Electronic address: psloane@med.unc.edu.
2 Cecil G. Sheps Center for Health Services Research and Schools of Social Work and Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC.
3 Division of Geriatric Medicine, University of Pittsburgh, Pittsburgh, PA.