POS1304 JUVENILE SYSTEMIC SCLEROSIS (JSSC) PATIENTS WITH OVERLAP CHARACTERISTICS DO NOT HAVE MILD DISEASE. RESULTS FROM THE JSSC INCEPTION COHORT. WWW.JUVENILESCLERODERMA.COM

Background:Juvenile systemic sclerosis (jSSc) is an orphan disease with a prevalence of around 3 in 1, 000,000 children. It is known that in pediatric jSSc cohorts, there are a significant number of patients with overlap features, such as arthritis and myositis. However, the disease burden between those with and without overlap features in jSSc has not been defined.Objectives:Compare the clinical phenotype between children with and without overlap features in the juvenile systemic scleroderma inception cohort (jSScC).Methods:A cross-sectional study was performed using baseline visit data. Demographic, organ system evaluation, autoantibody profile, treatment, and patient and physician reported outcome variables were extracted from jSScC. Comparison between patients with and without overlap features was performed using chi-square test and Mann Whitney U-test.Results:At the time of data extraction, 175 jSSc patients were enrolled in the cohort, 81% were Caucasian and 81% female. Mean disease duration was 3.1 year (±2.7). Mean age at Raynaud´s onset was 10 years (±3.8) and mean age of first non-Raynaud´s was 10.2 years (±3.8). Overlap features occurred 17% (n=30) of the cohort, 12.5% in the diffuse cutaneous (dc) jSSc and in 30% in the limited cutaneous (lc) jSSc. Significant differences in clinical characteristics were found between those patients with compared to without overlap characteristics. Patients with overlap features presented more frequently with Gottron papules (p=0.007), swollen joints (p=0.019), muscle weakness (p=0.003), and lung involvement documented by decreased DLCO < 80% (p=0.06) and/or abnormal high resolution computed tomography (p=0.049). Anti-PM/Scl autoantibodies were also more common in this group (p=0.001). Significantly more patients without overlap features had Raynaud´s (p=0.006). Physician Global Assessment of disease activity was significantly higher in patients with overlap features (41 vs 34; p=0.041). (Table 1.)Table 1.Demographic and clinical characteristics of jSSc patients with and without overlap features.Whole CohortN=175Patients without overlapN=145Patients with overlapN=30P valueFemale to Male Ratio 4.3:1(142/33)4:1(116/29)6.5:1(26/4)0.395Cutaneous subtypeDiffuse subtype (N)73% (128)11216Limited subtype (N)27% (47)3317Mean disease duration (years)3.1 (± 2.7)3.2 (± 2.8)3.1 (± 2.2)0.291Mean age of onset of Raynaud´s (years)10.0 (± 3.8)17 non-Raynaud10.0 (± 3.8)10 non-Raynaud10.0 (± 3.7)7 non-Raynaud0.931Mean age of onset of non-Raynaud´s (years)10.2 (± 3.8)10.2 (± 3.9)9.8 (± 3.7)Disease modifying drugs (N)88% (154) 89% (129)83% (25)0.388Raynaud´s phenomenon90% (158)93% (135)77% (23)0.006Anti-PMScl18% (12/68)9% (5/53)47% (7/15)0.001Gottron Papules (N)27% (46/171)23% (33/144)48% (13/27)0.007DLCO 44% (39/88)39% (28/71)65% (11/17)0.06Abnormal findings in HRCT (N)44% (59/133)40% (43/107)62% (16/26)0.049Proportion of patients with swollen joints 18% (32) 14% (21) 37% (11)0.019Muscle Weakness (N) 21% (31/149)16% (20/123) 42% (11/26)0.003Physician global disease activity(0-100) min -max35 (0-90) n=14134 (0-90) n=11441 (0-80) n=270.041Conclusion:Results from this large international cohort of jSSc patients demonstrate significant differences between patients with and without overlap features. Patients with overlap have significantly more interstitial lung disease and more physician rated disease activity and should not be considered to have more “mild disease”.Supported by the “Joachim Herz Stiftung”Disclosure of Interests:None declared