Long-Term Bone Density Changes and Fracture Risk in Myasthenia Gravis: Implications for FRAX^® Tool Application

Myasthenia gravis (MG) patients often require long-term glucocorticoid therapy, which may affect bone health. This study aimed to assess long-term changes in bone mineral density (BMD), evaluate osteoporotic fracture incidence, and examine the relationship between MG-specific factors and bone health outcomes over a 10-year period. This single-center, prospective cohort study included 28 MG patients. BMD, T-scores, Z-scores, and bone turnover markers were measured at baseline. FRAX^® scores were calculated and adjusted for glucocorticoid dose. Fracture occurrence was monitored for over 10 years. Five (17.9%) patients experienced major osteoporotic fractures during follow-up. The fracture group had significantly lower baseline BMD and T-scores than the no-fracture group. Baseline FRAX^® scores for major osteoporotic fracture risk were significantly higher in the fracture group (median 19.0% vs. 5.7%, p = 0.001). The fracture group progressed from osteopenia at baseline to osteoporosis by the end of this study. This study highlights the importance of early and regular bone health assessments in MG patients, particularly those receiving long-term glucocorticoid therapy. The FRAX^® tool may be valuable for fracture risk stratification in this population. These findings can inform clinical practice and improve long-term management strategies for MG patients who are at risk of osteoporotic fractures.