Osteoporotic Vertebral Fractures Early, Common in Glucocorticoid-Treated Rheumatic Disorders Among Children

In children with glucocorticoid (GC)-treated rheumatic disorders, osteoporotic vertebral fractures (VFs) occur early and are more common than non-VFs, according to results of a study published in The Journal of Clinical Endocrinology and Metabolism.

Researchers sought to determine the incidence and predictors of osteoporotic VFs and non-VFs and assess the potential for recovery over a period of 6 years following the initiation of GC therapy among pediatric patients with rheumatic disorders. Clinical outcomes were lumbar spine bone mineral density (LS BMD), VFs, and vertebral bone reshaping.

A prospective inception cohort study, led by the Canadian Steroid-induced Osteoporosis in the Pediatric Population (STOPP) Consortium, was conducted. Between January 1, 2005, and December 31, 2007, researchers enrolled children and adolescents aged between 1 month and 17 years from 10 university-affiliated children’s hospitals located across Canada. Rheumatic inflammatory conditions included juvenile dermatomyositis, systemic lupus erythematosus, juvenile idiopathic arthritis (JIA; excluding systemic arthritis), JIA with systemic arthritis, systemic vasculitides, and other rheumatic disorders, including systemic and localized scleroderma.

A total of 136 children with GC-treated rheumatic diseases were enrolled in the study. Mean participant age was 9.9±4.4 years. Overall, 75% of the participants were White, 7% were Black, 5% were of aboriginal/indigenous ethnicity, 3% were South Asian, and 10% were of mixed ethnicity.

Results of the study showed that the 6-year cumulative fracture incidence was 16.3% for VFs and 10.1% for non-VFs. Further, GC exposure was the highest in the initial 6 months of the study, with 63% (n=24/38) of cases of VF reported in the first 2 years. After a VF, 84% (n=16/19) of the participants exhibited complete vertebral body reshaping.

The number of children who experienced a lumbar VF was small, with the highest number of participants with VF from L1 to L4 reported at baseline (n=3). The LS BMD z-score for the study population at baseline was -0.56±1.18, and -0.53±1.18 when data from children with lumbar VFs were excluded. The unadjusted non-VF incidence rate was 1.6 (95% CI, 0.7-2.8) per 100 person-years, with a 6-year cumulative incidence rate of 10.1%. In addition, the unadjusted VF incidence rate was 2.7 (95% CI, 1.5-4.0) per 100 person-years, with a 6-year cumulative incidence rate of 16.3%.

Vertebral fracture was reported among 6.7% of the study participants at baseline, with a peak incidence of 5.1% at 12 months. Of all incident fractures, both VF and non-VF, 55% occurred within the first 2 years. Most of the bone morbidity observed in children with rheumatic diseases was seen in the initial 2 years of the current study, which was the period of peak GC exposure.

Study limitations included the fact that not all participants were followed up with until the attainment of adult height, which is an important assessment tool for complete vertebral body reshaping; the lack of blood tests and therefore the unavailability of data on bone and nutrition markers that may have predicted incident fractures; and the small sample size used to predict incident VF and non-VF.

Researchers concluded, “VF[s] are a potentially silent, but clinically important, manifestation of GC-associated osteoporosis, targeted case-finding strategies are needed to maximize their identification in at-risk children and to minimize unnecessary radiation from spine imaging.”

Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures. 

Reference

Ward LM, Ma J, Robinson ME, et al. Osteoporotic fractures and vertebral body reshaping in children with glucocorticoid-treated rheumatic disorders.  J Clin Endocrinol Metab. Published online July 7, 2021. doi:10.1210/clinem/dgab494