1 Duke Palliative Care, Division of General Internal Medicine, Department of Medicine, Duke University School of Medicine, Durham, North Carolina.
2 Duke University Center for the Study of Aging and Human Development, Duke University, Durham, North Carolina3Geriatrics Research, Education and Clinical Center, Veterans Affairs Medical Center, Durham, North Carolina.
3 Duke University Center for the Study of Aging and Human Development, Duke University, Durham, North Carolina4Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, North Carolina.
4 Duke University Center for the Study of Aging and Human Development, Duke University, Durham, North Carolina3Geriatrics Research, Education and Clinical Center, Veterans Affairs Medical Center, Durham, North Carolina5Division of Geriatrics, Department of Medicine, Duke University School of Medicine, Durham, North Carolina.