1. Durham VA Health Care System, NC, USA
2. Department of Population Health Sciences, Duke University School of Medicine, Durham, NC, USA
3. Duke-Margolis Center for Health Policy, Durham, NC, USA
4. Department of Medicine, Duke University School of Medicine, Durham, NC, USA
5. Department of Health Services, Policy and Practice, Brown University, Providence, RI, USA
6. Center for Gerontology and Healthcare Research, Brown University School of Public Health, Providence, RI, USA