Study of the Prevalence of Polymyositis and Dermatomyositis in Normandy

Study Overview
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Brief Summary
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Polymyositis and dermatomyositis are characterized by the association to a myopathic syndrome, inflammatory infiltrates in the skeletal muscle. They remain, even today, an important factor of morbidity and mortality in these patients. At present, studies that evaluated the prevalence of polymyositis / dermatomyositis are very few; they were mainly recorded in the United States and Japan, the prevalence of polymyositis / dermatomyositis has been estimated between 3.5 and 21.5 cases / 100 000 (according to the old diagnostic criteria of Bohan and Peter). However, previous works are old and retrospective; above all, they have almost always been performed (90% of cases) from cases reported to the hospital, leading to selection bias and an underestimate of the true prevalence of polymyositis / dermatomyositis in the general population. Thus, these data lead to achieve this epidemiological study, descriptive, multicenter, based on the population of Normandy.

Official Title
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Study of the Prevalence of Polymyositis and Dermatomyositis in Normandy

Conditions
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Polymyositis, Dermatomyositis

Intervention / Treatment
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* Other: Patients with polymyositis / dermatomyositis


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients with polymyositis / dermatomyositis, meeting the diagnostic criteria for ENMC; patient living Normandy ; patient has been informed and has given its verbal agreement ; Exclusion Criteria: patients with myositis diagnosed before inclusion (including pathophysiology, clinical phenotype and therapeutic care are different from polymyositis / dermatomyositis)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| patients with polymyositis / dermatomyositis<br>recruitment of patients with polymyositis / dermatomyositis will be used: medical specialists , hospital and liberals who support patients with polymyositis / dermatomyositis ( internists , dermatologists, neurologists, pulmonologists , rheumatologists ) ; general practitioners the PMSI data for public and private hospitals ; 4 ) data boxes regional health insurance (primary health insurance fund , MSA Normandy , Social Scheme for Self ) 5) Norman patients, members of an association of patients with polymyositis / dermatomyositis : the French Muscular Dystrophy Association | Other: Patients with polymyositis / dermatomyositis<br>* recruitment of patients with polymyositis / dermatomyositis using : medical specialists , hospital and liberals who support patients with polymyositis / dermatomyositis ( internists , dermatologists, neurologists, pulmonologists , rheumatologists ) ; general practitioners the PMSI data for public and private hospitals ; 4 ) data boxes regional health insurance (primary health insurance fund , MSA Normandy , Social Scheme for Self ) 5) Norman patients, members of an association of patients with polymyositis / dermatomyositis : the French Muscular Dystrophy Association<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Confirmed diagnosis of polymyositis / dermatomyositis | recruitment of patients with polymyositis / dermatomyositis | approximately 1 month |