Markers of systemic glucocorticoid exposure, such as shorter stature, a greater delay in bone age, and lower bone mineral density in the lumbar spine, are associated with spine fragility and vertebral fractures in patients with Duchenne muscular dystrophy (DMD). This is according to a new study published by Canadian researchers in the journal Osteoporosis International.
“These variables may be useful to identify candidates for primary osteoporosis prevention after glucocorticoid initiation,” wrote Kim Phung, MDCM, of the University of Ottawa in Ontario, Canada, and colleagues.
Glucocorticoids are the gold standard of care for the treatment of DMD, the study team noted. However, they are highly toxic for bones, and their use is associated with loss of bone strength and osteoporosis, often leading to fragility fractures, they added.
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To identify factors associated with vertebral fractures in patients with DMD, the researchers, led by Leanne M. Ward, MD, conducted a cross-sectional study in 60 male patients with DMD. Patients were between 5 and 20 years of age. Of these 60 patients, 19 had 67 vertebral fractures. Of those vertebral fractures, 23 were moderate or severe.
When they analyzed the clinical characteristics of these patients, the researchers found that those who had vertebral fractures were shorter and were exposed to glucocorticoids for longer. Moreover, they had greater bone age delay and lower areal bone mineral density in the lumbar spine.
Using statistical analysis, the researchers calculated that every 0.1 mg/kg increase in the daily dose of glucocorticoid was associated with a 1.4-fold increase in the Spinal Deformity Index (SDI). Moreover, a greater delay in bone age, higher weight, lower height, and lower volumetric bone mineral density in the lumbar spine were also associated with an increase in SDI.
“Readily measurable clinical variables were associated with prevalent [vertebral fracture] in males with glucocorticoid-treated DMD,” the researchers concluded.
Phung K, McAdam L, Ma J, et al. Risk factors associated with prevalent vertebral fractures in Duchenne muscular dystrophy. Osteoporos Int. Published online November 7, 2022. doi:10.1007/s00198-022-06578-6