Role of Prednisone and 25-Hydroxyvitamin D on Bone Mineral Density and Osteoporosis in Systemic Lupus Erythematosus

We evaluated the role of 25-hydroxyvitamin D (25[OH]D), prednisone, and other risk factors for bone mineral density (BMD) loss and osteoporosis in systemic lupus erythematosus (SLE).

We calculated the association between 25(OH)D levels and other potential risk factors and BMD measures (spine T scores) and osteoporosis (defined as a T score ≤ -2.5) in a lupus cohort of 1,003 patients. Generalized estimating equations were used to assess the statistical significance of observed differences, accounting for patients with multiple BMD measures.

Univariate analysis showed that older age, lower body mass index (BMI), mean past SLE activity (Safety of Estrogens in Lupus Erythematosus National Assessment-Systemic Lupus Erythematosus Disease Activity Index > 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 levels, 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 levels, and prednisone dose >5 mg/day remained predictors. Discontinuation of prednisone within one year before the next BMD measurement led to higher mean spine T scores.

Prednisone dose, even at 5 mg/day, and low mean 25(OH)D levels were found to be modifiable predictors of osteoporosis. Mean (reflecting supplementation), rather than initial, 25(OH)D levels were significantly associated with BMD. Some of the bone loss from prior prednisone use appears to be reversible.