Osteoporosis in long-term hospitalized patients with muscular dystrophy: a retrospective cross-sectional study

BACKGROUND: Muscular dystrophy comprises a group of hereditary muscle disorders characterized by progressive muscle weakness and atrophy, ultimately resulting in the loss of ambulation and wheelchair dependence or confinement to a bed. However, the effects of prolonged hospitalization and immobilization on bone health in patients with advanced muscular dystrophy remain poorly characterized. Therefore, this study aimed to assess osteoporotic characteristics in patients with muscular dystrophy who experienced long-term hospitalization. METHODS: Patients with muscular dystrophy undergoing long-term hospitalization were retrospectively reviewed in this cross-sectional study. Bone mineral density (BMD) and bone metabolism markers-including serum albumin, calcium, 25-hydroxy vitamin D [25(OH)D], tartrate-resistant acid phosphatase-5b (TRACP-5b), and bone-specific alkaline phosphatase (BAP)-were evaluated. RESULTS: A total of 32 patients with muscular dystrophy were included (median age, 50 years). The median duration of hospitalization was 2,287 days (range, 707-16,861 days). Regarding BMD assessment, the median T-scores for the lumbar spine and femoral neck were - 2.2 (interquartile range [IQR], - 4.1 to 0) and - 4.1 (IQR, - 4.6 to - 2.1), respectively. The median serum levels of albumin, calcium, 25(OH)D, TRACP-5b, and BAP were 3.5 g/dL (IQR, 3.2-3.9), 9.0 mg/dL (IQR, 8.8-9.3), 18.8 ng/mL (IQR, 8.7-24.9), 341 mU/dL (IQR, 221-403), and 12.8 U/L (IQR, 10.7-16.0), respectively. Patients with muscular dystrophy exhibited markedly reduced femoral neck BMD and low 25(OH)D levels, whereas lumbar spine BMD was less severely reduced. Levels of serum calcium, TRACP-5b, and BAP were within reference ranges. CONCLUSIONS: Patients with muscular dystrophy who required long-term hospitalization and were wheelchair-dependent or bedbound exhibited femoral neck osteoporosis and vitamin D insufficiency/deficiency. These findings may help inform strategies for osteoporotic treatment and nutritional care in this patient population.