Role of Prednisone and 25( OH ) Vitamin D on Bone Mineral Density and Osteoporosis in Systemic Lupus Erythematosus

Objective We evaluated the role of 25‐hydroxy vitamin D, prednisone and other risk factors for bone mineral density (BMD) loss and osteoporosis in systemic lupus erythematosus (SLE). Methods We calculated the association between 25‐hydroxy vitamin D [25(OH)D] levels and other potential risk factors with BMD measures (spine T‐scores) and osteoporosis (defined as a T‐score ≤ ‐2.5) in a lupus cohort of 1003 patients. Generalized estimating equations were used to assess the statistical significance of observed differences, accounting for patients with multiple BMD measures. Results Univariate analysis showed that older age, lower body mass index (BMI), mean past SLE activity (SELENA‐SLEDAI >2), mean daily prednisone dose at any level, and a history of low C3 or C4 were associated with osteoporosis. Older age, lower BMI, mean 25(OH)D, mean daily prednisone dose (again at any dose), and prior low C3 were associated with lower spine T‐scores. In the multivariate analysis for osteoporosis, older age, lower BMI, low mean 25(OH)D, and prednisone dose >5 mg/d remained predictors. Discontinuation of prednisone within one year prior to the next BMD measurement led to higher mean spine T‐scores. Conclusion Prednisone dose, even at 5 mg/d, and low mean 25(OH)D were found to be modifiable predictors of osteoporosis. Mean (reflecting supplementation), rather than initial, 25(OH)D was significantly associated with bone mineral density. Some of the bone loss from prior prednisone use appears to be reversible.