Background New ACR/EULAR criteria for classification of rheumatoid Arthritis (RA) were recently proposed. The aim of this analysis was to examine the impact of fulfilling the 2010 ACR/EULAR criteria at the initial visit on longterm progression of disease activity

Methods This is an observational cohort study within the Swiss RA registry. For this analysis we included patients suffering from an untreated early RA or undifferentiated arthritis (disease duration ≤1 year). The diagnosis was defined by the data-entering physician. Baseline diagnosis of RA/UA was reassessed according to the 2010 ACR/EULAR criteria scoring from 0 -10. The assessment was based on the 28 joint count for joint involvement (0-5 points) as defined by the criteria. Elevated acute phase reactants were determined if C reactive protein was ≥10mg/l or erythrocyte sedimentation rate was ≥28mm/h (1 point). Disease duration was determined positive (1 point) if the patient suffered ≥42 days starting from the first reminiscent symptoms. As the level of rheumatoid factor and CCP antibodies are not entered into the data base 0 points were dedicated to rheumatoid factor (RF) neg and anti citrullinated protein antibody (ACPA) neg patients, 2point for RF pos or ACPA pos patients and 3 points for RF pos and ACPA pos patients. We evaluated fulfilment of the 2010 ACR/EULAR criteria at baseline. The clinical picture was assessed comparing patients depending on fulfilling (≥6 points) the 2010 ACR/EULAR criteria at baseline. Our primary outcome was DAS28 and HAQ scores at 2 years

Results A total number 494 patients fulfilled inclusion criteria. 129 patients fulfilled the 2010 ACR/EULAR at baseline, 365 were not classifiable as RA according to the new criteria at baseline. Mean disease duration, sex and disease activity at inclusion for ACR/EULAR neg and ACR/EULAR pos patients did not differ significantly. Of the patients fulfilling ACR/EULAR at baseline 67.4% were RF positive and 54.3% ACPA positive compared to 50.74% and 17.5%, respectively, for patients not fulfilling the ACR/EULAR criteria at baseline (p<0.05). The patients fulfilling ACR/EULAR criteria at baseline developed a 50.74% reduction of disease activity as assessed by DAS 28 scores as compared by 28.41% reduction in ACR/EULAR negative patients independent on the treatment applied. HAQ scores decreased in parallel by 90% and 30%. No significant differences in the treatment protocol were found.

Conclusions The 2010 ACR/EULAR criteria appear to select a subset of patients who will evolve more favorably on conventional antirheumatic therapy. Our data suggest that treatment decisions according to the new ACR/EULAR criteria for RA allows selecting patients who are more likely to respond to the anti rheumatic therapy.

Disclosure of Interest None Declared