1. The Inova Center of Outcomes Research, Inova Heart and Vascular Institute, 3300 Gallows Road, I-465, Falls Church, VA 22042, USA
2. Division of Cardiology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
3. Division of Geriatric Medicine and Gerontology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21224, USA
4. Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
5. Division of Cardiovascular Medicine, Department of Medicine, University of Michigan, Ann Arbor, MI 48109, USA
6. Geriatric Cardiology Section, University of Pittsburgh, Pittsburgh, PA, USA
7. Geriatric Research, Education, and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, USA