1 Center for Health Services Research in Primary Care, Durham Veterans Affairs Health Care System, and Department of Population Health Sciences, School of Medicine, Duke University, Durham, NC, USA.
2 Institute of Nursing Science, Department of Public Health, University of Basel, Basel, Switzerland and Division of Gerontology, and Geriatrics, Department of Chronic Diseases Metabolism, and Ageing, KU Leuven, Leuven, Belgium.
3 Institute of Nursing Science, Department of Public Health, University of Basel, Basel, Switzerland and Academic Centre for Nursing and Midwifery, Department of Public Health and Primary Care, KU Leuven, Leuven, Belgium.