Background Juvenile dermatomyositis (JDM) is a rare inflammatory myopathy seen in children. There have been few studies on long-term outcome in children with JDM
Objectives To assess long-term outcome of JDM using validated measures of outcome
Methods All children diagnosed to have JDM for more than 2 years and registered in Pediatric Rheumatology Clinic at PGIMER, Chandigarh, India, were deemed eligible for recruitment. Study period was from January 1, 2015 to June 30, 2016. Those who were not on regular follow-up were called for assessment which was done by a single observer using Childhood Myositis Assessment Scale (CMAS), Manual Muscle Testing 8 (MMT8), Myositis Disease Activity Assessment Tool (MDAAT), abbreviated cutaneous assessment tool (aCAT), Myositis Damage Index (MDI) and Childhood Health Assessment Questionnaire (CHAQ).
Results Thirty-five children were enrolled in this study, 22 (62.9%) were on regular follow-up. Mean age was 13.9yrs (range 4–29yrs). Mean age at diagnosis was 7.51yrs with median interval between onset of symptoms and diagnosis being 5 months. Mean duration of disease at the time of enrolment was 7.18yrs. Disease course was monocyclic in 24 (68.6%). Muscle strength was normal in 71.4%. Severe involvement defined as MMT8 score below 64 was seen in 8.6%. Cutaneous activity was determined by aCAT with 40% children having some form of cutaneous activity. Based on MYOACT, 31.4% children had evidence of disease activity at the time of cross-sectional assessment with skin being the commonest organ system involved in 28.6% followed by muscles in 22.9%. Twenty-one (60%) children had some form of cutaneous damage. Calcinosis in 12 (34.3%) and lipodystrophy in 8 (22.9%). Twenty four subjects had an MDI score of ≥1 suggesting damage in at least one organ system. Most commonly affected organs were skin, endocrine and muscles in 20, 12 and 9 subjects respectively. Nine (25.7%) subjects in our study had some form of a physical dysfunction suggested by a CHAQ score above 0. Previous studies on long-term outcomes in children with JDM have either not used validated outcome measures or have used fewer measures [1–3].
Conclusions Highlight of our study is the use of validated outcome measures for evaluation of long-term outcomes. After mean disease duration of 7.18 yrs, 1/3rd subjects had evidence of disease activity with almost 1/10th having moderate to severe activity. About 2/3rd had damage in at least one organ system. Skin was the most common organ affected by activity as well as damage. About 1/4th had reduced physical functioning. Thus, JDM is not a disease where one time treatment would suffice and regular long-term follow-up is required. Counselling of the caregivers is also critical for them to adhere to follow-up. Larger long-term studies using validated outcome measures are required to confirm these findings.
Singh S, Bansal A. Twelve years experience of juvenile dermatomyositis in North India. Rheumatol. Int. 2006;26:510–5.
Huber AM, Lang B, LeBlanc CM, Birdi N, Bolaria RK, Malleson P, et al. Medium- and long-term functional outcomes in a multicenter cohort of children with juvenile dermatomyositis. Arthritis Rheum. 2000;43:541–9.
Ravelli A, Trail L, Ferrari C, Ruperto N, Pistorio A, Pilkington C, et al. Long-term outcome and prognostic factors of juvenile dermatomyositis: a multinational, multicenter study of 490 patients. Arthritis Care Res. 2010;62:63–72.
Disclosure of Interest None declared