University of Copenhagen - The Parker Institute, University of Copenhagen - The Parker Institute, University of Copenhagen - The Parker Institute, Copenhagen University Hospital - The Parker Institute, University of Oxford - Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), Independent, Royal National Hospital for Rheumatic Diseases, Duke University - School of Medicine, University of Toronto - University Health Network, Johns Hopkins University, OMERACT Patient Research Partner, Stanford University, Swedish Medical Center, University College Dublin (UCD) - UCD Conway Institute, Leeds Teaching Hospitals NHS Trust, University of Ottawa, National University of Singapore (NUS) - Singapore General Hospital and Bispebjerg and Frederiksberg Hospitals - Section for Biostatistics and Evidence-Based Research