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.