Characterization of the biomarkers related to the clinical course and outcomes of juvenile dermatomyositis.

Objective: This study aimed to evaluate the clinical characteristics of children diagnosed with juvenile dermatomyositis (JDM) in a tertiary medical centre in Taiwan and to identify important biomarkers for predicting the disease course and outcomes of JDM.

Methods: We retrospectively reviewed patients with JDM diagnosed at the National Taiwan University Hospital between 1 January 2001 and 31 December 2021. The endpoints for disease assessment included complete clinical response or remission. The JDM courses were divided into monocyclic, polycyclic, and chronic continuous statuses. The significant relationship between the predictors and outcomes was further analysed.

Results: A total of 47 patients were included in this study. The mean age at disease onset was 7.5 years. The female-to-male ratio was 1.35. The most common initial presentations were Gottron's sign (74%), followed by muscle weakness (66%) and facial rash (66%). Among all included patients, 35 (74.5%) patients achieved complete clinical remission, 15 (31.9%) had a monocyclic course, six (12.7%) had a polycyclic course, and 24 (51.1%) had a chronic continuous course. Negative facial rash and arthralgia were favourable factors for achieving complete clinical remission. Muscle weakness, higher lactate dehydrogenase (LDH), and higher erythrocyte sedimentation rate (ESR) at disease onset were related to the chronic continuous course. The most common long-term complication was calcinosis (29.8%).

Conclusion: Juvenile dermatomyositis is a rare disease, and only a few studies have been conducted in Asia. Our results identified the important predictors of the disease course and outcomes. The chronic continuous course requires more attention and aggressive treatment.