Methodology: The trial design is innovative and based on random selection of a sample of patients in an observational cohort of patients as described in the recent publication "Cohort Multiple Randomised Controlled Trials Design" (Ref.: BMJ 2010; 340: c1066). A randomly selected sample of eligible patients from the cohort will be asked to take part in the study. Changes in the randomised sample will be compared to those of other potentially eligible patients from the cohort. The cohort used will be the ESPOIR cohort, a cohort including 813 patients who initially presented with early undifferentiated polyarthritis that developed into rheumatoid arthritis with anti-citrulline antibodies in approximately 40 to 50% of cases.