AB0445 FIRST CLINICAL ANALYSIS OF MYOSITIS PATIENTS REGISTERED AT REUMA.PT/MYOSITIS PROTOCOL: DATA FROM A SINGLE-CENTER

Background: Idiopathic inflammatory myopathies are a group of rare heterogeneous diseases that require multidisciplinary and standardized approach. Objectives: To clinically characterize patients with followed at an hospital’s Rheumatology Department, using the Rheumatic Diseases Portuguese Register (Reuma.pt). Methods: An observational transversal study was performed. Data on demographic variables, clinical features, antibodies treatment were collected. Results: Of 121 included patients, 78% female, median age 56 [44-68] years disease duration 2 [0-4] years. The most frequent diagnosis dermatomyositis (DM; n=28, 23%) by antisynthetase syndrome (ASyS; n=21, 17.4%). At time analysis, Manual Muscle Test (MMT-8) 80 [78-80], modified skin Disease Activity Score 0 [0-2] global activity 0.5 [0-0.75]. Calcinosis found in 6% (n=7), mostly DM cases. Interstitial lung (ILD) present 29 (24%), those, 52% (n=15) had (ASyS). Three presented as paraneoplastic syndrome. Ninety-nine (82%) myositis autoantibody identified: autoantibodies commonly identified (n=20, 16%). 62% treated steroids 35% ≥2 disease-modifying anti-rheumatic drugs. Table 1 depicts main characteristics immunologic profile for each Conclusion: In our cohort subtype DM. Almost quarter associated ILD, which is important cause morbidity mortality. ILD more ASyS related to anti-Jo1 antibodies, consistent literature. 1. Clinical immunological patients. Diagnosis (n) features Myositis Skin disease, [IQR]/ (n ) MMT-8, [IQR] Lung Others Malignancy Definite (28) DAS (3) Mechanic hands (2) [75-80] NSIP (2); COP (1) Arthritis (6) Breast cancer anti-Ro52 (6); anti-Mi2b (5); anti-PmScl100 (4); anti-MI2a (3); anti-NXP2 anti-SAE anti-MDA5 anti-Ku anti-Tif1g Antisynthetase (21) [0-0] (4) [80-80] (11); UIP LIP (15); RP (10) – (14); (12); (1); anti-PL7 anti-PL12 Probable (19) [78-80] anti-Mi2a anti-PmScl75 CADM (16) [77-80] anti-EJ anti-SRP MCTD (12) [0-1] [79-80] (8); anti-U1 RNP (7) PM [72-80] Ovarian non-Hodgkin lymphoma UCTD (5) anti-ThTo Overlap syndromes (8) anti-Ro60 anti-RNAPIII anti-NOR90 Necrotizing myopathy dermatomyositis; amyopathic mixed connective tissue disease; polymyositis; undifferentiated interstitial nonspecific pneumonia; lymphocytic pneumonitis; usual cryptogenic organizing Raynaud phenomenon Disclosure Interests: None declared.