From the Journals

Juvenile dermatomyositis derails growth and pubertal development



Children with juvenile dermatomyositis showed significant growth failure and pubertal delay, based on data from a longitudinal cohort study.

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“Both the inflammatory activity of this severe chronic rheumatic disease and the well-known side effects of corticosteroid treatment may interfere with normal growth and pubertal development of children,” wrote Ellen Nordal, MD, of the University Hospital of Northern Norway, Tromsø, and colleagues.

The goal in treating juvenile dermatomyositis (JDM) is to achieve inactive disease and prevent permanent damage, but long-term data on growth and puberty in JDM patients are limited, they wrote.

In a study published in Arthritis Care & Research, the investigators reviewed data from 196 children and followed them for 2 years. The patients were part of the Paediatric Rheumatology International Trials Organisation (PRINTO) observational cohort study.

Overall, the researchers identified growth failure, height deflection, and/or delayed puberty in 94 children (48%) at the last study visit.

Growth failure was present at baseline in 17% of girls and 10% of boys. Over the 2-year study period, height deflection increased to 25% of girls and 31% of boys, but this change was not significant. Height deflection was defined as a change in the height z score of less than –0.25 per year from baseline. However, body mass index increased significantly from baseline during the study.

Catch-up growth had occurred by the final study visit in some patients, based on parent-adjusted z scores over time. Girls with a disease duration of 12 months or more showed no catch-up growth at 2 years and had significantly lower parent-adjusted height z scores.

In addition, the researchers observed a delay in the onset of puberty (including pubertal tempo and menarche) in approximately 36% of both boys and girls. However, neither growth failure nor height deflection was significantly associated with delayed puberty in either sex.

“In follow-up, clinicians should therefore be aware of both the pubertal development and the growth of the child, assess the milestones of development, and ensure that the children reach as much as possible of their genetic potential,” the researchers wrote.

The study participants were younger than 18 years at study enrollment, and all were in an active disease phase, defined as needing to start or receive a major dose increase of corticosteroids and/or immunosuppressants. Patients were assessed at baseline, at 6 months and/or at 12 months, and during a final visit at approximately 26 months. During the study, approximately half of the participants (50.5%) received methotrexate, 30 (15.3%) received cyclosporine A, 10 (5.1%) received cyclophosphamide, and 27 (13.8%) received intravenous immunoglobulin.

The study findings were limited by several factors, including the short follow-up period for assessing pubertal development and the inability to analyze any impact of corticosteroid use prior to the study, the researchers noted. However, “the overall frequency of growth failure was not significantly higher at the final study visit 2 years after baseline, indicating that the very high doses of corticosteroid treatment given during the study period is reasonably well tolerated with regards to growth,” they wrote. But monitoring remains essential, especially for children with previous growth failure or with disease onset early in pubertal development.

The study was supported by the European Union, Helse Nord Research grants, and by IRCCS Istituto Giannina Gaslini. Five authors of the study reported financial relationships with pharmaceutical companies.

SOURCE: Nordal E et al. Arthritis Care Res. 2019 Sep 10. doi: 10.1002/acr.24065.

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