Effects of intermittent corticosteroids on scoliosis, bone density, and vertebral fractures in duchenne muscular dystrophy

IntroductionSpinal involvement is common in Duchenne muscular dystrophy (DMD), specifically scoliosis and vertebral fractures. Treatment with corticosteroids (CS) delays scoliosis onset, but also induces low bone mineral density, increasing fracture risk.ObjectiveAssess long-term effects of intermittent CS on scoliosis development, bone mineral density and vertebral fractures in DMD.MethodWe retrospectively analysed real-world data from a single national reference center in the Netherlands. Spinal imaging was obtained by yearly anteroposterior radiographs. Scoliosis was defined as lateral spinal curvature with a Cobb angle of >10°. Yearly lumbar spine bone mineral density (LSBMD) Z-scores were measured with dual-energy X-ray absorptiometry (DXA) scans of the lumbar spine. Vertebral fractures were evaluated using yearly vertebral fractures assessments (VFA).ResultsWe included 86 individuals with DMD who visited the outpatient clinic between 2002 and 2022, aged 4-18 years. Seventy-five patients (87.2%) developed scoliosis (median age 11.0 years), mostly after loss of ambulation. Scoliosis progressed to >20° in 40 (46.5%) and to >30° in 29 (33.7%) of all patients. Spinal fusion was performed in 20 (23.3%) of all patients (median age 18.5 years). Cobb angles significantly increased after loss of ambulation (LoA) (p<0.001).Mean height SDS was -0.8. LSBMD Z-score declined below -2.0 in 27 (31.4%) patients and was significantly lower after LoA (p<0.001). Of 86 patients, 64 underwent VFAs, with 16 (25%) developing vertebral fractures during follow-up, mostly asymptomatic (87.5%).ConclusionIndividuals with DMD on intermittent CS experience a higher incidence of scoliosis, fewer vertebral fractures, and generally maintain higher LSBMD Z-scores compared to published data on patients receiving daily CS.