Long‐term muscular outcome and predisposing and prognostic factors in juvenile dermatomyositis: A case–control study

Abstract

Objective. To compare muscle strength, physical health, and HLA-DRB1 allele carriage frequencies in patients with longstanding juvenile dermatomyositis (DM) with that of controls, and to determine the presence of and risk factors for muscle weakness and magnetic resonance imaging (MRI)-detected muscle damage in juvenile DM patients. Methods. Fifty-nine patients with juvenile DM examined a median of 16.8 years (range 2.0 -38.1 years) after disease onset were compared with 59 age-and sex-matched controls. Muscle strength/endurance was measured by manual muscle testing (MMT) and the Childhood Myositis Assessment Scale (CMAS); health status was measured by the Short Form 36. HLA-DRB1 alleles were determined by sequencing in patients and 898 healthy controls. In patients, disease activity/ damage was measured by the Disease Activity Score (DAS), Myositis Damage Index (MDI), Health Assessment Questionnaire/Childhood Health Assessment Questionnaire, and MRI scans of the thigh muscles. Early disease characteristics were obtained by chart review. Results. Patients had lower muscle strength/endurance (P < 0.001 for both) and physical health (P ‫؍‬ 0.014) and increased HLA-DRB1*0301 (P ‫؍‬ 0.01) and DRB1*1401 (P ‫؍‬ 0.003) compared with controls. In patients, persistent muscle weakness was found in 42% with MMT (score <78) and in 31% with the CMAS (score <48), whereas MRI-detected muscle damage was found in 52%. Muscle weakness and MRI-detected muscle damage were predicted by MDI muscle damage and a high DAS 1 year postdiagnosis. Conclusion. A median of 16.8 years after disease onset, juvenile DM patients were weaker than the controls; muscle weakness/reduced endurance was found in 31-42% of patients and MRI-detected muscular damage was found in 52% of patients. The outcomes were predicted by high disease activity and muscle damage present 1 year postdiagnosis.

In juvenile dermatomyositis, cardiac systolic dysfunction is present after long-term follow-up and is predicted by sustained early skin activity

“…After a manual and electronic search in medical records, a retrospective inception cohort of JDM patients, diagnosed between January 1970 and June 2006 in Norway was identified and tracked through the Norwegian population register 15 16. Of 66 patients included, 4 were deceased and 3 did not want to participate; the remaining 59 (95%) represent our study population.…”

“…Inactive disease was defined by the proposed Pediatric Rheumatology International Trials Organisation (PRINTO) criteria of 2012, including at least three of the four following: manual muscle test (MMT-8) ≥78 (0–80),16 physician global assessment of muscle activity (phyGloVAS) ≤0.2, Childhood Myositis Assessment Scale ≥48 and creatine kinase ≤150 20. JDM inactive patients off medication are abbreviated JDM inactive; the remaining patients are abbreviated JDM active.…”

Cardiac dysfunction in juvenile dermatomyositis: a case-control study

“…By manual and electronic search in the in the medical records, we identified a retrospective inception cohort of patients with JDM diagnosed between January 1970 and June 2006 in Norway, as previously described in detail 21–23. A total of 66 patients fulfilled the inclusion criteria; 4 were deceased.…”

“…ECG and echocardiography were performed. In patients with JDM, blood samples included anti-nuclear antibodies (ANAs), myositis specific or associated antibodies, muscle enzymes and cardiac markers (pro-B-type natriuretic peptide (BNP) and troponin-T in 37 patients) were analysed 23. Disease activity was measured by disease activity score (DAS) for JDM24 (range 0–20, 0 means no activity), which consists of DAS skin (0–9) and DAS muscle (0–11).…”

Juvenile Dermatomyositis

“…The authors could not determine a prediction model of disease course. In another study examining the long-term outcomes and prognostic factors in JDM, sustained muscle and skin disease activity in addition to early muscle damage 1 year after diagnosis predicted muscle weakness and MRI-detected muscle damage [58].…”