The ESPOIR cohort: a ten-year follow-up of early arthritis in France: methodology and baseline characteristics of the 813 included patients

The French Society of Rheumatology initiated a large national multicenter, longitudinal and prospective cohort, the so-called "ESPOIR cohort study" in order to set up databases to allow various investigations on diagnosis, prognostic markers, epidemiology, pathogenesis and medico-economic factors in the field of early arthritis and rheumatoid arthritis.Patients were recruited if they had undifferentiated arthritis or rheumatoid arthritis, of less than 6 months disease duration and if they were DMARD and steroids naïve. Patients have then to be followed every 6 months during the first 2 years then every year during at least 10 years. Clinical, biological, radiographic and medico-economic databases have been constituted to fit in the different objectives of the project and more than 20 scientific studies have already been accepted by the scientific committee.813 patients were included (76.75% were female). The mean age was 48.07+/-12.55 years. The mean delay from the onset of symptoms to referral to the rheumatologist was 74.8+/-76.6 days. Baseline swollen and tender joint counts were 7.19+/-5.37 and 8.43+/-7.01; DAS28 score was 5.11+/-1.31. CRP was abnormal in 38.9% of the patients; 44.2%, 45.8% and 38.8% had respectively IgM rheumatoid factor (RF), IgA RF and anti-CCP antibodies. HLA DRB1*01 or 04 genes were found in 56.7% of them. Finally, 22% of these patients had erosions on hand or feet at baseline.