1 Rheumatology Department, Royal Derby Hospital, Derby, ARC Epidemiology Unit, University of Manchester, Manchester, Rheumatology Unit, Queen Alexandra Hospital, Portsmouth, Rheumatology Department, Nuffield Orthopaedic Centre, Oxford, Rheumatology Department, St George's Healthcare, London, Rheumatology Department, Royal Lancaster Infirmary, Lancaster, Rheumatology Department, St Helens Hospital, St Helens, Rheumatology Department, Addenbrooke's Hospital, Cambridge, National Rheumatoid Arthritis Society, Maidenhead, Department of Rheumatology, Trafford General Hospital, Manchester, Rheumatology Unit, Worthing and Southlands NHS Trust, Worthing and Department of Rheumatology, Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, UK.