Evaluation of Severity in Juvenile and Adult-onset Dermatomyositis

Study Overview
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Brief Summary
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Dermatomyositis (DM) are rare and heterogeneous systemic autoimmune diseases, characterized by the association of muscle inflammation, skin inflammation and vasculopathy. DM concern both adults and children. DM can be life-threatening (interstitial lung disease, infectious complications) and responsible of significant functional disability (muscle weakness). Age of onset appear to be an independent prognostic factor. Juvenile-onset DM is characterized by a higher frequency of calcinosis, skin ulceration and digestive vasculitis. In adults, interstitial lung disease and cancer are more frequent with higher mortality. Data concerning the comparison of the initial severity between juvenile and adult-onset DM are limited. The main objective is to compare global severity between juvenile DM and adult-onset DM at initial diagnosis. Secondary objectives are: to compare organ-specific severity between juvenile DM and adult-onset DM at diagnosis. to compare damage during follow-up and at last follow-up between juvenile DM and adult-onset DM. to compare activity at the last follow-up between juvenile DM and adult-onset DM. to compare iatrogenic complications between juvenile DM and adult-onset DM.

Official Title
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Evaluation of Severity in Juvenile Dermatomyositis and Adult-onset Dermatomyositis: a National Multicentric Retrospective Study

Conditions
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Dermatomyositis

Intervention / Treatment
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* Other: evaluation of clinical severity


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient with dermatomyositis according to 2017 American College of Rheumatology (ACR)/ European Alliance of Associations for Rheumatology (EULAR) classification Exclusion Criteria: Patient with cancer-associated dermatomyositis (within 3 years before or after diagnosis of dermatomyositis) Patient with antisynthetase syndrome
Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Juvenile dermatomyositis<br>Dermatomyositis before 18 years-old | Other: evaluation of clinical severity<br>* evaluation of clinical severity<br>|
| Adult-onset dermatomyositis<br>Dermatomyositis from 18 years-old | Other: evaluation of clinical severity<br>* evaluation of clinical severity<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| number of patients with global severity | presence of at least one criteria among: severe muscle disease (Childhood Myositis Assessment Scale - CMAS - score < 15, and/or Manual Muscle Testing 8 - MMT8 - score < 30, and/or Medical Research Council - MRC - muscle testing < 3, and/or dysphagia and/or swallowing difficulties), symptomatic interstitial lung disease (ILD), digestive vasculitis (digestive bleeding and/or vasculitis on CT-scan), myocarditis on cardiac MRI, severe skin ulcerations, intensive care unit admission | baseline (J0) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| number of patients with muscular severity | presence of at least one of the following criteria: CMAS score < 15, MMT8 score < 30, MRC muscle testing < 3, dysphagia, swallowing difficulties | baseline (J0) | 
| number of patients with pulmonary severity | presence of symptomatic ILD | baseline (J0) | 
| number of patients with digestive severity | presence of digestive vasculitis: digestive bleeding and/or vasculitis on CT-scan | baseline (J0) | 
| number of patients with cutaneous severity | presence of severe skin ulcerations | baseline (J0) | 
| myositis damage index (MDI) score | myositis damage index (MDI) extent of damage score: from 0 (better outcome) to 38 (worse outcome) | 2 years of follow-up, at 5 years of follow-up and at last follow-up | 
| number of patients with remission at last follow-up | absence of disease activity without any immunosuppressive/immunomodulatory treatment for at least 2 years | up to 10 years | 
| number of patients with disease activity at last follow-up | presence of at least one of the following criteria: elevated creatinine kinase (CK) level and/or recent muscle testing deterioration and/or muscle inflammation on MRI, and/or skin manifestations and/or progressive ILD | up to 10 years |