Bone Abstracts

Background: Osteoporosis is common in subjects with Duchenne muscular dystrophy (DMD). Studies in paediatric DMD identified a high frequency of fragility fractures but there are no studies in the adult population. Recent updated international standards of care (2018) for children and adults with DMD recommend the following for bone monitoring:

- Lateral thoracolumbar spine x-rays to screen for vertebral fracture (1–2 yearly if on glucocorticoid; 2–3 yearly otherwise)

- DXA spine bone mineral density (BMD) annually

Objectives: This retrospective study aims to audit bone health monitoring according to standards of care and to report on radiologically confirmed fractures in adults with DMD.

Methods: Men with DMD aged ≥ 18 years in the adult neuromuscular or respiratory clinics (2013–2018) were included (n,41). Fractures and bone monitoring from 2013 till September 2018 or time of death were evaluated. Results were expressed as median (range).

Results: Median age of the group was 24 years (19, 41). Eight (20%) died by last assessment, median age of death 23 years (20, 29). All were non-ambulant. 12/41(29%) had gastrostomy for feeding, 29/41 (71%) required assisted ventilation. 11/41 (27%) had metal instrumentation for scoliosis.10/41 (24%) were on glucocorticoid whereas 31/41 (76%) were glucocorticoid naïve or had received glucocorticoid < 12 months and had discontinued for longer than five years. 4/41 (10%) sustained new fragility fractures during the study period. 3/10 (30%) of those on glucocorticoid sustained fractures during the study period including a man with progression of pre-existing vertebral fractures presenting with severe back pain. On the other hand, 1/31 (3%) not on glucocorticoid sustained fractures during the study period. None had monitoring of vitamin D levels or screening lateral thoracolumbar spine x-ray. 12/41 (29%) had at least one DXA performed during the period. DXA BMD done in the adult service were not size adjusted. 6/41 (15%) had bisphosphonate therapy.

Conclusion: Fragility fracture may be underestimated in adult men with DMD as routine screening for vertebral fracture was not in place. There is a need to implement bone health monitoring in the adult population accordance with the updated standards of care.

Disclosure: The authors declared no competing interests.