AB1167 Differences and similarities in clinical manifestations and survival between adult-onset and childhood-onset patients with idiopathic inflammatory myopathies
Authors: L. Nuño, L. Carreño, F.J. Lόpez Longo
Journal: Annals of the Rheumatic Diseases (2013)

<h3>Background</h3> Idiopathic Inflammatory Myopathies (IIM) comprise an heterogeneous group of systemic diseases, with an important morbidity and mortality, depending on different age of onset. <h3>Objectives</h3> To study clinical manifestations, survival and causes of death in a cohort of patients with IIM, focusing on different age at onset. <h3>Methods</h3> All patients with diagnosis of IIM (criteria of Tanimoto) (1) and follow-up in outpatient clinic between January 1988 and December 2005 were included. Clinical data was retrieved from clinical history. Patients were classified into 5 serological subgroups examined by ELISA and Line Immuno Assay standard methods (anti-Jo-1 antibodies, anti-U1-RNP, anti-PM-Scl, anti-Mi-2 and anti-Ku) and 3 clinical subgroups: mixed connective tissue disease (Alarcόn-Segovia criteria) and IIM (Tanimoto criteria) (MCTD); overlap syndrome (Rheumatoid Arthritis, Systemic Erythematosus Lupus, or Scleroderma, all according to ACR criteria, and IIM according to Tanimoto Criteria); and Primary Myositis (Tanimoto criteria, not fullfiling other connective tissue disease criteria). Patients were classified into adult-onset IIM (A-IIM) and childhood-onset IIM (PED-IIM). Survival analysis was studied with Kaplan-Meier curves, Cox logistic regression and logrank statistics. P&lt;0,05 value was considered as significant. <h3>Results</h3> In the present study, 110 patients were included, with 7 cases (6,4%) lost to follow-up. 92 patients (83.6%) were classified as A-IIM, and 18 patients (16.4%) as PED-IIM. Mean age at diagnosis was 48±19 years for A-MII and 12±4 years for PED-IIM, with a higher frequency of women among PED-IIM (80.4% for A-IIM vs. 100% for PED-IIM; p=0.04). Distribution into serological and clinical subgroups was similar between both groups, with a higher frequency, although not significant, of MCTD in PED-IIM (19.6% in A-IIM vs. 33.3% in PED-IIM; p&gt;0.05) and anti-U1-RNP antibodies (33.7% vs. 55.6%; p=0.08).There were no differences in the distribution of other clinical and serological subgroups. Regarding clinical manifestations, PED-IIM had a higher frequency of arthritis (52.2% vs. 83.3%; p=0.015), and classical cutaneous dermatomyositis lesions, such as Gottron papules (12% vs. 33.3%; p=0.033) and heliotrope rash (16.3% vs. 38.9%; p=0.04). There were no significant differences between both groups regarding frequency of interstitial lung disease (70.5% in A-IIM vs. 66.7% PED-IIM) or other organ involvement. During follow-up, 31 patients died, 29.3% in A-IIM and 22.2% in PED-IIM, with a mean survival of 23.7±1.8 years for A-IIM and 27.3% ± 2.8 years for PED-IIM, without statistical differences. Main causes of death were infections and cardiovascular disease in both groups. <h3>Conclusions</h3> In our cohort, patients with childhood-onset IIM had a higher frequency of female distribution, arthritis and classical cutaneous dermatomyositis lesions compared to adult-onset IIM. Frequency of interstitial lung disease and anti-Jo-1 antibodies were similar between both groups. Survival rates and main causes of death were similar between adult-onset and childhood-onset IIM. <h3>References</h3> Tanimoto K et al. J Rheumatol 1995 Apr;22(4):668-74. <h3>Disclosure of Interest</h3> None Declared