THU0351 MUSCLE INVOLVEMENT IN PATIENTS WITH SYSTEMIC SCLEROSIS AND ANTI-PM/SCL+ ANTIBODIES IS ASSOCIATED WITH CARDIAC AND PULMONARY INVOLVEMENT. ANALYSIS OF THE MULTICENTRE EUSTAR COHORT.
Authors: M. G. Lazzaroni, S. Zingarelli, P. Airò, Y. Allanore, O. Distler
Journal: Annals of the Rheumatic Diseases (2020)

Background: Anti-PM/Scl antibodies positivity has been associated with frequent skeletal muscle involvement in patients with Systemic Sclerosis (SSc) in different studies, including the EUSTAR cohort (1). Moreover, although myositis has been previously associated with heart involvement in SSc patients (2), this issue has never been explored among anti-PM/Scl+ patients. Objectives: To evaluate the cardiac involvement in anti-PM/Scl patients with SSc in the large multicentre EUSTAR database, with focus on the subgroup of patients with muscle involvement. Methods: Patients from the EUSTAR database were included when the item anti-PM/Scl was fulfilled in at least one visit. Results: Anti-PM/Scl status was available in 7,353 SSc patients from EUSTAR database: 295 were anti-PM/Scl+. After exclusion of 151 patients with multiple autoantibody positivity, 144 anti-PM/Scl + patients were compared with 7,058 anti-PM/Scl- patients. Among them, 3,120 (44.2%) were positive for ACA, 2,361 (33.5%) for anti-Topo I and 274 (3.88%) for anti-RNAP3. Regarding the specific cardiac outcomes, in the anti-PM/Scl+ as compared to the anti-PM/Scl- group, a decreased rate of elevated sPAP at ECHO was recorded (12.8% vs 25.0%, p:0.001), while no differences were observed in the frequency of conduction blocks (26.2% vs 23.7%, p:0.526), abnormal diastolic function (33.9% vs 36.4%, p:0.582), pericardial effusion (10.2% vs 10.9%, p:1.000) and LVEF ≤50% (4.76% vs 6.11%, p:0.818). In multivariate analysis, adjusted for age at disease onset, sex, and disease duration, the negative association of anti-PM/Scl with elevated sPAP was not confirmed (p:0.061). When comparing anti-PM/Scl+ patients with (n=47) and without (n=87) CK elevation, the former group had a higher frequency of conduction blocks (43.2% vs 17.5%, p:0.005; OR 95% CI 3.47, 1.51-7.97) and left ventricular dysfunction, both diastolic (45.6% vs 27.2%, p:0.050; OR 95% CI 2.25, 1.05-4.81) and systolic (LVEF ≤50% 13.3% vs 0%, p:0.018; OR 95% CI 16.8, 0.87-324). Moreover, anti-PM/Scl+ patients with CK elevation had significantly increased rate of lung fibrosis on HRCT (p:0.045), intestinal symptoms (p:0.017), joint contractures (p:0.045) and tendon friction rubs (p:0.034). Conclusion: In the largest series of anti-PM/Scl positive SSc patients so far reported, muscle involvement in anti-PM/Scl+ patients (defined as increased serum CK) seems to represent a marker of a more severe disease phenotype, including a higher frequency of cardio-pulmonary involvement. References: [1]Lazzaroni MG, et al. Ann Rheum Dis 2018. 77 (2), 421-2. [2]Follansbee WP, et al. Am Heart J 1993. 125: 194-203. Acknowledgments: Authors would like to thank the patients’ association GILS (Gruppo Italiano Lotta Sclerodermia) for the grant that supported the project. Disclosure of Interests: Maria Grazia Lazzaroni: None declared, Stefania Zingarelli: None declared, Paolo Airò: None declared, Yannick Allanore Grant/research support from: BMS, Inventiva, Roche, Sanofi, Consultant of: Actelion, Bayer AG, BMS, BI, Oliver Distler Grant/research support from: Grants/Research support from Actelion, Bayer, Boehringer Ingelheim, Competitive Drug Development International Ltd. and Mitsubishi Tanabe; he also holds the issued Patent on mir-29 for the treatment of systemic sclerosis (US8247389, EP2331143)., Consultant of: Consultancy fees from Actelion, Acceleron Pharma, AnaMar, Bayer, Baecon Discovery, Blade Therapeutics, Boehringer, CSL Behring, Catenion, ChemomAb, Curzion Pharmaceuticals, Ergonex, Galapagos NV, GSK, Glenmark Pharmaceuticals, Inventiva, Italfarmaco, iQvia, medac, Medscape, Mitsubishi Tanabe Pharma, MSD, Roche, Sanofi and UCB, Speakers bureau: Speaker fees from Actelion, Bayer, Boehringer Ingelheim, Medscape, Pfizer and Roche