1 Department of Rheumatology, University College London, London, UK.
2 Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.
3 NIHR Leeds Biomedical Research Centre, University of Leeds and Leeds Teaching Hospitals NHS Trust, Leeds, UK.
4 Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK. Electronic address: laura.coates@ndorms.ox.ac.uk.