Effect of dexamethasone on autoantibody levels and arthritis development in patients with arthralgia: a randomised trial.

BACKGROUND Rheumatoid arthritis is characterised by antibodies to citrullinated proteins (ACPA) and rheumatoid factor (RF) in the preclinical phase. OBJECTIVE To determine whether an intervention aimed at decreasing autoantibody levels in people at risk may be effective in preventing progression to arthritis. METHODS 83 patients with arthralgia positive for ACPA or IgM-RF were randomly allocated to intramuscular injections of 100 mg dexamethasone or placebo at baseline and 6 weeks. The primary end point was a 50% antibody reduction or normalisation at 6 months. RESULTS The primary end point was reached in one patient in each group. Patients treated with dexamethasone had reductions of antibody levels after 1 month (ACPA 222% and IgM-RF 214%), which persisted at 6 months for ACPA. During a median follow-up of 26 months, arthritis development in both groups was similar (20% vs 21%). CONCLUSION In autoantibody-positive patients with arthralgia, dexamethasone treatment decreases ACPA and IgM-RF levels, but does not prevent arthritis development. TRIAL REGISTRATION NUMBER ISRCTN73232918.