1. Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
2. Department of Health Economics and Health Services Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
3. Department of Mathematics and School of Life Sciences, Technical University of Munich, Munich, Germany
4. Faculty of Medicine and Health, Department of Medical Sciences, Örebro University, Örebro, Sweden
5. Primary Care Centre Versus Arthritis, Keele University, Keele, UK
6. Department of Public Health, Research Unit for General Practice, University of Southern Denmark, Odense, Denmark