Background:In early rheumatoid arthritis (ERA) a window of opportunity (WoO) is well established since its first proposal in 2002 (1). ERA patients achieved a better clinical outcome when DMARD therapy was initiated within the first 12-16 weeks after start of symptoms (disease duration (Xd) (2). To the best of our knowledge, comparable data are missing for early psoriatic arthritis (EPsA), even though the benefit of tight control is known in EPsA (3,4). In contrast to ERA early PsA is usually defined as Xd <24months (3,4).Objectives:To study in a setting of routine rheumatologic care if a WoO like in ERA also can be observed in EPsA comparable to ERA.Methods:n=90 consecutive outpatients with definite PsA were recruited in this retrospective longitudinal cohort study with the following inclusion criteria: DMARD- and steroid-naïve at the first time of visit in our outpatient clinic (t0), minimum follow-up of 3 years, classification as very early psoriatic arthritis (VEPsA, Xd≤3 months, n=30), late early psoriatic arthritis (LEPsA, > 3 Xd ≤ 12 months, n=30) and late psoriatic arthritis (LAPsA, Xd > 36 months, n=30). Standardized assessments had been performed at regular intervals of 3 months within the framework of routine rheumatologic care. Outcome at 3 years (t36) was analyzed within groups and between groups (DAS28, Physician Global Assessment (PhG), HAQ, fatigue, morning stiffness).Results:Cohorts did not differ between gender and age (mean age 54 years). There was no significant difference in DAS28, HAQ, PhG and morning stiffness at t0. Fatigue at t0 differed between cohort 1 and 3 significantly (p<0.03). In all cohorts DAS28 and PhG have been decreased at t36 significantly (minimal p< 0.006). In comparison to VEPsA LEPsA showed a significant difference in DAS28 (p<0.04) and PhG (p<0.05), but not in morning stiffness and fatigue. Highly significant differences between VEPsA and LAPsA were observed for DAS28 (p <0.007), morning stiffness (p < 0.001), PhG (p<0.05) and fatigue (p < 0.006) at t36.Conclusion:Significant and relevant differences between the outcomes at 3 years of patients with VEPsA, LEPsA and LAPsA could be identified in this retrospective pilot study. Particularly the highly significant difference between VEPsA and LAPsA (<3 months vs. >36months) is remarkable. The data suggest a window of opportunity also in patients with EPsA. With a time interval of Xd≤12 this window seems to be longer than in ERA. Further studies with higher number of patients were needed to confirm our findings from this real life setting.References:[1]O´Dell JR Treating Rheumatoid Arthritis Early: A Window of Opportunity? Arthritis Rheum 2002;46:283–285[2]Nell VPK, Machold KP, Eberl G, Stamm TA, Uffmann M, Smolen JS Rheumatology 2004 43:906-914[3]Coates LC, Moverley AR, McParland Let al. Effect of tight control of inflammation in early psoriatic arthritis (TICOPA): a UK multicentre, open-label, randomised controlled trial.Lancet2015,386:2489–98.[4]Coates LC, Mahmood F, Freeston J, Emery P, Conaghan PG, Helliwell PS Long-term follow-up of patients in the TIght COntrol of inflammation in early Psoriatic Arthritis (TICOPA) trial Rheumatology (Oxford) 2019 kez369Disclosure of Interests:None declared