AB0149 CHARACTERISATION OF RHEUMATOID ARTHRITIS PROGRESSION IN AN EARLY UNDIFFERENTIATED ARTHRITIS COHORT
Authors: M. Novella-Navarro, J. L. Cabrera-Alarcón, A. Martínez-Feito, L. Nuño, C. Plasencia, M. Juarez, D. Peiteado, A. Villalva, A. Balsa
Journal: Annals of the Rheumatic Diseases (2021)

Background: Since the publication of 2010 ACR/ELUAR classification criteria for Rheumatoid Arthritis (RA), identification of patients with RA at early stages of the disease has improved. Nevertheless, up to 56% of patients are diagnosed with undifferentiated arthritis (UA) at the first visit to Rheumatology Departments, of which about 20-30% will progress to RA. For this reason, Early Arthritis Clinics (EAC) have been progressively implemented in Rheumatology departments in order to identify and have a tight follow-up of these patients. Objectives: a) To analyze the progression rate from UA to RA in a cohort of EAC. b) To identify differences in clinical features at baseline that characterize the progression to RA of these patients. Methods: Prospective study from a cohort of EAC between 2010 and 2018. Patients diagnosed with UA at first consultation were included and with a follow-up of 2-years. Final diagnosis was assessed at the end of study period defining two groups: RA progression (RA-group) vs no progression (non-RA-group).Baseline characteristics were recorded for both groups: sex, age, smoking habit, duration of symptoms, morning stiffness, tender joint count (TJC), swollen joint count (SJC), Rheumatoid Factor (RF), Anti-Citrullinated-Peptide-Antibodies (ACPA), DAS-28, erythrocyte sedimentation rate (ESR), C-Reactive Protein (CRP), Pain visual analogue scale (VAS). Differences in sociodemographic, clinical and serological features between groups were analyzed using T-test, chi-square test and U-Mann Whitney depending on the nature of variables. Results: A total of 228 patients with UA were included, of which 54 (23,3%) progressed to RA (patients characteristics are shown in table 1). Regarding serological characterization, we found that in our cohort, 44.4% of patients who developed RA had FR and ACPA positivity, 13% RF positive, 7.4% ACPA positive. In contrast 35% patients were seronegative. From non-RA group, 73% of patients were seronegative, 18% RF positive, 4.5% ACPA positive and 4.5% double positive. Table 1. Variable Total (n=228) RA (n=54) Non-RA (n=174) p-value Female sex n(%) 165 (71.7) 42 (77.8) 121 (69.5) 0.31* Age (mean SD) 51.47 (16.46) 52.9 (16.15) 51.26 (16.61) 0.53 § Smoking habit n (%) 0.12* -smokers 49 (21.2) 14 (25.9) 33 (19) -exsmokers 52 (22.5) 15 (27.8) 37 (21.3) -non-smokers 113 (48.9) 19 (35.2) 93 (53.4) Duration of symptoms (weeks) (median IQR) 8 (4-19) 12 (8-24) 8 (4-16) 0.006 ¶ Morning stiffnes &gt;60min n (%) 53 (22.9) 15 (27.8) 38 (21.8) 0.26* Patient health assessment (meadian IQR) 39 (16-68) 58 (22-75) 34 (14-64) 0.01 ¶ Pain (VAS) (median IQR) 45 (18-68.2) 54 (30-71) 39 (14.5-67.5) 0.02 ¶ Tender Joint Count (median IQR) 2 (1-6) 4 (1-9) 2 (1-6) 0.04 ¶ Swollen Joint Count (median IQR) 2 (1-4) 3 (1-6) 2 (1-4) 0.01 ¶ Baseline DAS28 (mean SD) 3.97 (1.39) 4.44 (1.54) 3.82 (1.33) 0.006 § HAQ (median IQR) 0.75 (0.25-1.5) 1.12 (0.37-1.56) 0.62 (0.12-1.37) 0.06 ¶ CRP(mean SD) 2.2 (8.01) 1.39 (3.25) 2.3 (8.9) 0.44 § ESR (mean SD) 23.74 (19.5) 24.62 (16.22) 22.8 (19.3) 0.54 § RF n (%) 70 (30.3) 31 (57.4) 39 (22.4) &lt;0.001* ACPA n (%) 44 (19) 28 (51.9) 16 (9.2) &lt;0.001* No differences between age at onset, sex an smoking habit were found. Duration of symptoms until first visit to Rheumatology Department was longer RA-group. Regarding joint involvement, TCJ and SCJ were higher in RA-group at baseline and also VAS pain and patients´global health assessment. Conclusion: One out of four patients diagnosed with early UA are at risk of RA development within the following 2 years. This fact implies that these patients benefit from EAC in order to have a tight control of the disease and have the chance of starting treatment as soon as possible. References: Combe B et al. 2016 update of the EULAR recommendations for the management of early arthritis. Ann Rheum Dis 2017;76:948-959. van Steenbergen HW et al. Preventing progression from arthralgia to arthritis: targeting the right patients. Nat Rev Rheumatol. 2018 Jan;14(1):32-41. Disclosure of Interests: None declared