Bone Abstracts

Objectives: Deteriorating bone mineral density and fragility fractures are common complications of Duchenne Muscular Dystrophy (DMD). This study aims to evaluate the effects of bisphosphonate therapy and testosterone supplementation (for pubertal induction) on the bone health of children with DMD.

Methods: This retrospective cohort study examined the clinical records of children with DMD managed at the Neurogenetics and Endocrine clinics at The Children’s Hospital at Westmead, NSW, Australia. A total of 50 boys were included in the study; 24 had received both corticosteroid and bisphosphonate treatment, of which 15 had also received testosterone for pubertal induction. 18 had received corticosteroid treatment only, 1 had received bisphosphonate therapy only, and 7 had received neither. The most common bisphosphonate regimen prescribed was intravenous zoledronate at a dose of 0.05 mg/kg six-monthly. Pubertal induction involved oral Andriol Testocaps (40 mg daily) increasing by 40 mg six-monthly to a maximum dose 160 mg daily. Primary outcome measures included bone mineral density (BMD) as measured by DXA in addition to fracture incidence.

Results: Total BMD z-scores (height-adjusted) were greater for children on bisphosphonate and corticosteroid therapy (median −0.319) compared to children who received corticosteroid treatment alone (median −1.323, P=0.02). Similarly, lumbar spine BMD z-scores improved from a median of −1.053 to 1.129 (P<0.01). There was no significant change in the incidence of fragility fractures pre and post bisphosphonate treatment. Pubertal induction did not increase BMD beyond that obtained from zoledronate alone.

Conclusion: Bisphosphonates play an important role in maintaining optimal bone mineral density in DMD. Larger studies are required to determine the best practice for pubertal induction in order to maximise bone accrual.

Disclosure: The authors declared no competing interests.