Long-term effectiveness and safety of denosumab for osteoporosis in patients with rheumatic diseases

Objective The long-term effectiveness of denosumab, an anti-RANKL monoclonal antibody, for increasing bone mineral density (BMD) and reducing fracture risk in postmenopausal women with osteoporosis has been demonstrated. However, its long-term effectiveness and safety in patients with rheumatic diseases remain unclear. Therefore, the present study investigated the long-term effectiveness and safety of denosumab for osteoporosis in patients with rheumatic diseases. Methods This retrospective study included patients who received denosumab between August 2013 and August 2022. We evaluated BMD at the lumbar spine for up to 7 years and at the femur for up to 3 years. The effects of glucocorticoid (GC) usage, age, and renal function on BMD in patients receiving denosumab were assessed. The retention rate and adverse events were also evaluated. Results One hundred and sixty-five patients with rheumatic diseases were enrolled (median age 66.5 years, 92.1% female, and 68.5% on GC therapy). Lumbar spine BMD significantly increased over 7 years (p < 0.001), while femoral neck, trochanter, and total hip BMD significantly increased for up to 3 years (p < 0.001). Lumbar spine BMD significantly increased regardless of the GC dose, age, or renal dysfunction. The retention rate of denosumab at 7 years was 68.1%. The most common serious adverse event was infection. Two cases of osteonecrosis of the jaw and 10 new fractures were observed during treatment with denosumab. Conclusion The present study suggests that the long-term use of denosumab is an effective and generally safe option for increasing BMD in patients with rheumatic diseases.