BackgroundThe PANLAR-EOA (early-onset-arthritis) project includes panamericanrheumatologists to determine regional characteristics of patients with early onset arthritis.ObjectivesTo describe the cohort of Paraguayan patients included in PANLAR-EOA project.MethodsLongitudinal, prospective, multicentricstudy. Patients were included according to the PANLAR-EOA project and registered in REPANARC(www.panlareoa.org) database. At baseline and annual visits, a large number of demographic, clinical and analytical variables were recorded. Quantitative variables were characterised by their means and standard deviations, while the qualitative variables were characterised according to the percentage of patients. The comparison of epidemiological and clinical variables was performed using the chi-squared test and the Wilcoxon test respectively for qualitative and quantitative variables, respectively.Results136 patients with early onset arthritis were included, out of which 88 completed the 12 months follow up and 58 the 24 months one. In these, 86%were female with a median age of 43.9±13.2 years. The most frequent race was mestiza in 80.1%. According to GRAFFAR index, middle class was the predominant social stratum (9.8±3.1). The average number of years of schooling was 12.8±3.8. Polyarticular onset was registeredin 61% patients. During follow-up, 43.1% had positive rheumatoid factor and 56.5% positive anti-CCP. The diagnostic delay was 3.9±3.0 months. Initially, 63.2% (86/136) were diagnosed with rheumatoid arthritis (RA) and 36.8% (50/136) with undifferentiated arthritis (UA). The most frequent treatment was methotrexate (85.3%, 90.9%, and 89.3% at baseline, 1 and 2 years of follow-up respectively). During follow-up, a significant diagnostic change was observed in patients with UA (p=0.004, OR=2.9 [95%CI, 1.4–6.5]). The variables associated with RA diagnosis werepresence of anti-CCP (p=0.000, OR=15.8 [95%CI,5.4–51.1]), rheumatoid factor (p=0.000, OR=9.2 [95%CI,3.4–27.0]), smoking (p=0.032, OR=8.8 [95%CI,1.1–404.7]), high body mass index (p=0.041, OR=1.94 [95%CI,−0.2–4.1]) and high activity measured by the DAS28 index (p=0.01). After one year of follow-up there was a significant decrease in disease activity according to DAS 28 (p=2.2e-09[95% CI, −1.5,–0.9]), SDAI(p=1.2e-11[95% CI, 18.2,–11.2]) and HAQ (p=7.2e-08[95% CI,−0.7,–0.4]). Similar results were found at the 2nd year of follow-up, DAS28 (p=8.8e-06[95% CI,−1.6,–0.7]), SDAI (p=2.1 e- 07 [95% CI,−20.0,−10.3]) and HAQ (p=3.4e-08[95% CI,−0.9,–0.5]).ConclusionsIn this cohort of early onset arthritis, diagnostic delay was lower than that observed in other series and the rate of change from diagnosis of UA to RA was statistically significant during the first year of follow-up. A good control of the inflammatory activity of the disease was observed, with a significant improvement of all the variables analysed during its evolution.Disclosure of InterestNone declared

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