1. University of Manchester Department of Medicine, University of Salford, Salford M6 8HD, UK
2. Department of Medicine Rheumatic Diseases Centre, University of Salford, Salford M6 8HD, UK
3. Department of Medicine Clinical Biochemistry, University of Salford, Salford M6 8HD, UK
4. Department of Medicine Hope Hospital and Computing Services Section, University of Salford, Salford M6 8HD, UK