Treatment outcomes in 63 cases of juvenile dermatomyositis-associated calcinosis

Objective We performed a multi-institutional retrospective review of patients treated for juvenile dermatomyositis (JDM)-associated calcinosis to analyse the association between treatment outcomes and patient, disease, and treatment characteristics. Methods Childhood Arthritis and Rheumatology Research Alliance investigators searched their electronic health records for patients with JDM and calcinosis treated between 2003 and 2019 and analysed data at JDM diagnosis, calcinosis diagnosis, and calcinosis treatment. Statistical methods included univariable and multivariable analyses, Kaplan-Meier estimates, and multivariable Cox models. Results Data were collected for 63 patients from 11 institutions. Median (IQR) age was 7.8 (4.1–≠11.1) years at JDM diagnosis and 9.4 (5.7–13.3) years at calcinosis diagnosis. Calcinosis was present at JDM diagnosis in 32% of patients (n=20). JDM was active in 76% of patients (47/62) at calcinosis diagnosis. Anti-nuclear matrix protein 2 (anti-NXP2) antibody was the most commonly detected myositis autoantibody (38%, 12/32). The presence of anti-NXP2 or anti-melanoma differentiation-associated gene 5 autoantibody did not significantly affect the probability of any calcinosis improvement (p=0.30). Patients received 103 unique treatment regimens of immunomodulatory agents with or without calcium-modifying agents, but those who received both had the greatest probability of improvement. Intravenous immunoglobulin (IVIG) was associated with a significantly higher probability of calcinosis improvement (p=0.02) than treatments without IVIG. Overall, 79% of patients (n=50) showed improved calcinosis. Conclusion Despite wide variations in treatment, many patients showed calcinosis improvement over time, especially those treated with IVIG. Studies using validated outcomes assessments may be needed to develop effective treatment plans for JDM-associated calcinosis.