[1] Gloucestershire Royal Hosp NHS Trust, Rheumatol Dept, Great Western Rd, Gloucester GL1 3NN, England
[2] Univ Hosp Bristol & Weston NHS Fdn Trust, Rheumatol Dept, Bristol Royal Infirmary, Marlborough St, Bristol BS1 3NU, England
[3] Royal Natl Hosp Rheumat Dis, Rheumatol Dept, Combe Pk, Bath BA1 3NG, England
[4] Univ West England, Ctr Hlth & Clin Res, Bristol Royal Infirmary, Room 5-054,Rheumatol Res B502, Bristol BS2 8HW, England