The Juvenile Dermatomyositis National Registry and Repository (UK and Ireland) - clinical characteristics of children recruited within the first 5 yr

Objectives. To identify epidemiological, clinical and laboratory characteristics of juvenile dermatomyositis (JDM) in a national multi-centre cohort of patients, and to review recent changes in the understanding of management and prognosis in the light of these data. Methods. All children with idiopathic inflammatory myositis recruited to the Juvenile Dermatomyositis National Registry and Repository (UK and Ireland) were included. Features at presentation, and later in disease, were assessed and evaluated. A total of 63 out of 175 children with a new diagnosis of myositis were recruited at the time of diagnosis and followed prospectively. Out of the 175 children, 122 diagnosed prior to 2000 were recruited retrospectively, with subsequent data collected prospectively. Results. One patient died (0.7%), which is equivalent to one death per 465 patient years. Data were available at the time of analysis on 151 registered patients. The most common presenting features were characteristic rash, weakness, tiredness, Gottron's patches and myalgia. Muscle biopsy, magnetic resonance imaging and muscle enzymes were frequently, but not always, abnormal. Muscle enzymes and erythrocyte sedimentation rate were not useful markers of disease activity. Conclusions. The JDM National Registry and Repository captures data on a significant cohort of children with inflammatory myositis. The current study reports the largest European cohort of children with dermatomyositis to date. This powerful resource will help improve our understanding of this rare disease. Prospective data collection will allow a fuller analysis of poor prognostic features, impact of therapy, and variable outcome of childhood myositis.