Duchenne muscular dystrophy (DMD) is an X-linked recessive genetic disorder characterized by progressive muscle loss, loss of ambulation (LOA) and premature mortality. A significant comorbidity is the rapid decline in bone mineral density (BMD) Z-scores, increasing the risk of osteoporotic fractures. This study aimed to investigate the relationship between the natural course of BMD and fracture prevalence in patients with DMD receiving glucocorticoid treatment (aged 5–15 years) through a systematic literature review.
A comprehensive literature search was conducted using PubMed and EMBASE for peer-reviewed articles published between 2000 and 2023 relating to bone health (bone density and BMD) in DMD. Inclusion/exclusion criteria were applied, resulting in 43 published studies, encompassing 1996 patients with DMD, identified for review.
Strong associations were observed between age-adjusted lumbar spine (LS) BMD Z-scores, age and glucocorticoid treatment duration (P<0.001 for all associations). Of note, size-adjusted LS BMD also showed a significant association with age (P<0.01). For every 1-year increase in age, the size-adjusted LS BMD Z-score decreased by 0.236 units. LOA was significantly associated with an accelerated rate of decline in LS BMD Z-score compared to ambulatory patients (P<0.001). Vertebral fracture rates, assessed using routine lateral spine radiographs, also exhibited a strong positive correlation with age (P<0.01). This study highlights the association between age, glucocorticoid treatment and a decline in LS BMD Z-scores with increased fracture risk (including vertebral fractures) in patients with DMD. There is a critical need for novel therapeutic strategies targeting bone strength in DMD to prevent, delay and minimize fracture burden. Understanding the natural history of bone health parameters in DMD facilitates the design of clinical trials to assess and improve bone strength in the DMD population.