AB0560 DESCRIPTIVE ANALYSIS AND STUDY OF CORRELATIONS IN A COHORT OF PATIENTS WITH INFLAMMATORY MYOPATHIES
Authors: I. Carrión Barberà, A. Pros Simón, T. C. Salman Monte, M. Ciria, F. Vílchez-Oya, S. Labrada, T. Meraz, J. Monfort
Journal: Annals of the Rheumatic Diseases (2020)

Background: Inflammatory myopathies (IM) are a group of rare diseases that involve muscle inflammation. Several types are defined with a wide range of different manifestations and prognosis. Objectives: Describe the characteristics of the cohort of patients with IM in a tertiary hospital, in order to identify their demographic and clinical characteristics and try to find a correlation between them. Methods: Retrospective observational study of patients with IM: dermatomyositis (DM), polymyositis, antisynthetase syndrome (ASS), necrotizing autoimmune myopathy and overlap syndrome (OS). Clinical, biological, neurophysio and histopathological data were collected. Statistical analysis was performed using SPSS 23 IBM®. Results: 28 patients were included with a follow-up of 10.9 ± 9.8 years (y). According to the 2017 EULAR / ACR criteria for IM, 89.2% were classified as definitive MI, with an average score of 12.1 ± 3.2. Age at diagnosis 47.3 ± 17.7y; ratio 1.3; 78.6% Caucasian, 10.7% Asian and 10.7% Latino. 39.3% had DM, 3.6% hypomyopathic and 3.6% amyopathic DM, 28.6% OS and 17.9% ASS. Lung involvement was the most prevalent extramuscular manifestation (67.9%). Systemic sclerosis was the most frequent overlapping autoimmune disease (AD) (21.4%) and 2 patients (7.1%) overlapped more than 1 AD. In Table 1 are detailed the clinical characteristics of the patients, and in Figures 1 and 2, the autoantibody (aa) profile and treatments used. The incidence of neoplasm was 10.7% 10.3 ± 9.6y after the diagnosis of myopathy (3 breast neoplasms, 1 colon and 1 cutaneous lymphoma), and of them, 66.7% had two synchronous neoplasms. No neoplasms were observed in the 2 anti-TIF1-γ+ patients. The subtype of IM in these patients was 1 OS anti-RNP+, 1 DM anti-PL-12+ and 1 ASS anti-OJ+. 17.9% smoked and 21.4% had taken statins at some point, without it being related to the start of the myopathic clinic. A capillaroscopy was performed in 67.9%, being pathological in 63.1% The positivity of anti-RNP (p=0.01) and steroid bolus (p=0.039) were correlated with a more severe disease, defined as a summation index composed of a series of manifestations (pulmonary hypertension (PH), ischemic heart disease, venous/arterial thrombosis, myo/pericarditis, interstitial lung disease (ILD), severe infections, neoplasms or hospitalizations). Other statistically significant correlations between aa and clinical manifestations are detailed in Table 3, among which the anti-RNP+ with myopericarditis stands out. No correlation was found between the findings on capillaroscopy and the type of IM. Conclusion: The most frequent subtype of IM was DM. 10.3% of the patients presented a neoplasm, all with different subtypes of myopathy and aa. The presence of anti-RNP+ correlated with greater severity of the disease and myopericarditis. Likewise, significant differences were found between the subtypes of aa and certain clinical manifestations. There is no correlation between findings on capillaroscopy and the type of IM. Table 1. Clinical characteristics. Clinical manifestations Frequency % Presentation Acute 40.7 Subacute 22.2 Insidious 37 Muscular Weakness 82.1 Muscle Enzymes Elevation 85.7 Muscle Pain 67.9 Joint Manifestations (Mf ) 67.9 Systemic Mf 67.9 Digestive Mf 46.4 Raynaud’s Syndrome (RS ) 53.6 Sclerodactyly 32 Digital ulcers (DU ) 25 Calcinosis 10.7 ILD 67.9 Nonspecific Interstitial Pneumonia 63.2 Usual Interstitial Pneumonia 15.8 Organizing Pneumonia 10.5 Lymphocytic Interstitial Pneumonia 5.3 Undefined Pattern 5.3 PH 10.7 Serious Infections 17.9 Figure 1. Aa. Figure 2. Treatment. Table 2. Correlations between clinical manifestations and aa. Manifestations Autoantibodies p value DU Anti-MDA5 0.005 Sclerodactyly Anti-RNP 0.011 Pericarditis Anti-RNP 0.000 Myocarditis Anti-RNP 0.005 Diabetes Anti-RNP 0.027 RS Anti-PM/Scl 0.033 Calcinosis Anti-PM/Scl 0.027 Flexion Contractures Anti-PM/Scl 0.027 Arrhythmias Anti-PL-12 0.001 Disclosure of Interests: Irene Carrión Barberà Grant/research support from: I received a grant from the Spanish Rheumatology Foundation (FER) and laboratories KERN PHARMA for a brief stay abroad., Ana Pros Simón: None declared, Tarek Carlos Salman Monte: None declared, Manel Ciria: None declared, Francisco Vílchez-Oya: None declared, Selene Labrada: None declared, Toni Meraz: None declared, Jordi Monfort: None declared