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Osteoporosis — SCE Rheumatology MCQ

Instant feedback + full explanation. One question, done properly.

ModerateMetabolic Bone DiseaseOsteoporosisSCE Rheumatology

A 70-year-old woman with osteoporosis has received denosumab 60 mg every 6 months for 6 years. Following specialist reassessment, denosumab is to be discontinued and intravenous zoledronic acid is planned as sequential treatment. Her renal function and serum calcium are satisfactory. When should the first zoledronic acid infusion usually be administered?

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Reveal the answer and explanation

Correct answer: E — At the time the next denosumab injection would have been due

The first zoledronic acid infusion should usually be given when the next 6-monthly denosumab injection would have been due—approximately 6 months after the final injection. Denosumab does not remain incorporated within bone; discontinuation can therefore cause rapid rebound bone turnover, loss of bone mineral density and multiple vertebral fractures. Sequential antiresorptive treatment should be planned rather than triggered by later DXA loss, so A is unsafe. No drug holiday is appropriate, excluding C. Waiting 9 or 12 months, as in E or B, leaves an avoidable interval during which rebound bone resorption may become established. Bone turnover markers such as CTX can help assess response and the need for further zoledronate, but should not ordinarily delay the initial infusion.

Reference: Tsourdi E et al. Fracture risk and management of discontinuation of denosumab therapy: a systematic review and position statement by the European Calcified Tissue Society, 2021. https://pubmed.ncbi.nlm.nih.gov/33103722/