Factors associated with osteoporosis and fractures in patients with systemic lupus erythematosus: Kyoto Lupus Cohort

Objectives Osteoporosis and compression fractures of the lumbar spine are some of the major adverse effects of glucocorticoid therapy in patients with systemic lupus erythematosus (SLE). This study examined the association between bone mineral density, bone turnover markers, presence of vertebral fractures, and Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index in SLE patients. Methods This was a cross-sectional study of 246 outpatients with SLE at the Kyoto University Hospital. Lumbar and femoral bone mineral density was measured with dual-energy X-ray absorptiometry, and the presence of vertebral fractures was determined using X-ray, computed tomography, or magnetic resonance imaging. Results On multiple regression analysis, both high lumbar and femoral T-scores were associated with the concomitant use of hydroxychloroquine (P = .018 and P = .037, respectively), no use of bisphosphonate or denosumab (P = .004 and P = .038, respectively), high body mass index (P < .001), and low bone-specific alkaline phosphatase level (P = .014 and P = .002, respectively). Vertebral fractures showed a significant association with Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index score (P < .001) and femoral T-score (P < .001). Conclusion Vertebral fracture was associated with SLE-associated organ damage, and serum bone-specific alkaline phosphatase level is a potentially useful marker for osteoporosis monitoring in SLE patients.