THU0364 SYSTEMIC SCLEROSIS OVERLAP AND NON-OVERLAP SYNDROMES SHARE SIMILAR CLINICAL CHARACTERISTICS BUT DRAMATICALLY DIFFERENT TREATMENT.

Background:Overlap between systemic sclerosis (SSc) and another auto-immune systemic disease (AISD) in the same patient seems to be more frequent than each disease’s prevalence would explain.Objectives:Our aim was to investigate for overlap syndrome from 2 French cohorts of SSc patients and to compare their characteristics with non-overlap SSc.Methods:Our study was retrospective observational and bicentric. Patients responding to the 2013 ACR-EULAR scleroderma classification criteria for SSc were screened for concomitant AISD. Patients satisfying 2010 ACR-EULAR diagnostic criteria for rheumatoid arthritis (RA) and/or 2016 ACR-EULAR classification criteria for Sjögren’s syndrome (SgS) and/or 2012 SLICC systemic lupus erythematosus (SLE) classification criteria were included in our study. Patient, disease, and treatment characteristics were retrospectively retrieved from medical records and were compared to a SSc cohort.Results:A population of 534 SSc patients was studied. Thirty-four (6.4%) patients were identified as having overlap syndrome. There was 21 (3.9%) patients with RA, 14 (2.6%) with GSS and 4 (0.7%) with SLE (5 patients had 2 AISD). Diagnosis of RA, SLE or SgS was made after diagnosis of SSc for 22 (65%) patients, concomitantly for 10 patients (29%), and before for 2 (6%) patients. Interestingly, two patients with SSc/RA overlap were tested ACPA-positive 2 and 5 years before the first arthritis, respectively. Patients with SSc/RA were severe with 81% of them having erosive disease and despite treatment, only 48% (10/21) patients achieved RA remission (DAS28-CRP < 2.6) at the time of their last visit. Disease duration was longer in patients with SSc overlap syndrome compared to non-overlap patients (15.5 ± 10.6 yearsvs.9.5 ± 8, p < 0.001). Proportion of limited cutaneous SSc was similar in overlap and non-overlap groups (70.6%vs.75.5%, respectively, p = NS), as was the positivity for anti-centromeres antibodies (50%vs.43.2%, respectively, p = NS). The disease phenotype of SSc overlap syndrome was similar to the one of non-overlap SSc in terms of prevalence of pulmonary arterial hypertension, interstitial lung disease, digital ulcer and mortality. With respect to treatments, patients with overlap were more likely to receive glucocorticoids (85.3%vs.45%, p < 0.001), immunosuppressive drugs (82.4%vs.49.2%, p < 0.001) and biologic DMARD (bDMARD, 52.9 %vs.3.8%, p < 0.001). The most prescribed bDMARDs in the overlap population was tocilizumab (40.6%), TNF-alpha inhibitor (29.4%) and rituximab (26.5%) (p < 0.001 for all comparisonvs.non-overlap SSc).Conclusion:We found a prevalence of overlap syndrome higher than 5% among SSc patients. While SSc overlap and non-overlap share common characteristics, overlap patients are more likely to receive glucocorticoids and biologics such as anti-TNF. These overlap should be searched actively (eg, screening for ACPA) since some treatment used for other autoimmune diseases such as glucocorticoids or TNF-alpha inhibitor may be harmful in SSc.Disclosure of Interests:Marc SCHERLINGER Consultant of: Amgen, Mylan, Fresenius Kabi, Johanna Lutz: None declared, Jean Sibilia: None declared, Jacques-Eric Gottenberg Grant/research support from: BMS, Pfizer, Consultant of: BMS, Sanofi-Genzyme, UCB, Speakers bureau: Abbvie, Eli Lilly and Co., Roche, Sanofi-Genzyme, UCB, Thierry Schaeverbeke: None declared, Christophe Richez Consultant of: Abbvie, Amgen, Mylan, Pfizer, Sandoz and UCB., Emmanuel Chatelus: None declared, Marie-Elise Truchetet: None declared