To evaluate the effect of switching from oral bisphosphonates to denosumab on bone mineral density (BMD) in long-term glucocorticoid users.
Adult patients who were receiving long-term prednisolone (≥2.5 mg/day for ≥1 year) and oral bisphosphonates (≥2 years) were recruited. Participants were randomized to either continue oral bisphosphonates or switch to denosumab (60 mg subcutaneously every 6 months) for 12 months. Serial BMD (lumbar spine, hip) and bone turnover markers (serum osteocalcin, P1NP, β-CTX) were measured.
42 women were recruited (age 54.7±12.9 years; 21 shifted to denosumab and 21 continued on bisphosphonates). The duration of prednisolone therapy was 101±66.3 months and the daily dose was 4.4±2.1 mg. Baseline demographic data, osteoporosis risk factors, and BMD at various sites were similar between the two groups of patients. At month 12, BMD of the spine and hip increased by +3.4±0.9% (p=0.002) and +1.4±0.6% (p=0.03), respectively, in the denosumab group; whereas the corresponding change was +1.5±0.4% (p=0.001) and +0.80±0.5% (p=0.12) in the bisphosphonate group. The spinal BMD at month 12 was significantly higher in the denosumab than bisphosphonate group after adjustment for baseline BMD and β-CTX values, and other confounding factors (p=0.01). Bone turnover markers (β-CTX and P1NP) were more strongly suppressed by denosumab than the bisphosphonates. Minor infections were more common in denosumab-treated patients while other adverse events occurred at similar frequencies between the two groups.
In patients receiving long-term glucocorticoids, switching from oral bisphosphonates to denosumab resulted in greater gain of the spinal BMD and suppression of bone turnover markers after 12 months of therapy. The results have to be confirmed by a larger clinical trial with fracture as endpoint.