Introduction: Denosumab is a human monoclonal antibody against the receptor activator of nuclear factor-kB ligand, to reduce bone resorption by limiting maturation of osteoclasts. It has been approved for use in Scotland in patients with a bone mineral density (BMD) T-score of between −4 to 2.5 who are unable to take bisphosphonates. We aimed to analyze the effects of denosumab on BMD and fracture rate in a cohort of patients who have completed a 3-year cycle of therapy. We also aimed to review the underlying indication to therapy and discontinuation rates.
Methods: Ninety-one patients were identified through the mineral metabolism service who were receiving denosumab within the Queen Elizabeth University Hospital in Glasgow. Baseline demographics and BMD pre- and post-treatment was obtained through clinical notes.
Results: The mean age of patients receiving denosumab therapy was 71.5 years. The indications for treatment were poor result with previous therapy (n=41), bisphosphonate intolerance (20), renal impairment (17), fractures during bisphosphonate holiday (7), learning difficulties (3) and others (3). Thirty-five patients did not have a post-treatment dual-energy X-ray absorptiometry (DXA) scan, of these 28 stopped denosumab therapy prematurely due death, non-compliance or declined further treatment. Of those where we had post-treatment data, we divided the change in BMD into those whose BMD had deteriorated, increased by 05%, 510% and more than 10% improvements. Fifteen patients sustained a new fracture during denosumab therapy. 13 additional patients sustained a new fracture but had not completed a full course of treatment.
|<0% (i.e. worsening)||05%||510%||>10%|
Conclusion: The majority of patients had a >10% improvement in vertebral BMD while hip BMDs did not change as markedly. The drawbacks to the study include the small number of patients and the inherent frailty of our population which is reflected in the high mortality. We also have a proportion of patients who did have follow-up DXA testing and may influence the overall results.