Treatment With Zoledronate Subsequent to Denosumab in Osteoporosis 2 (ZOLARMAB2)

Inclusion Criteria: * Postmenopausal women (postmenopausal for at least two years) * Age ≥ 40 years * Treatment for at least two years with denosumab * Last denosumab injection less than six months ago * At least 2 lumbar vertebrae that can be evaluated by DXA Exclusion Criteria: * Low-energy vertebral fracture within the last ten years * Multiple low-energy vertebral fractures (\> 3) at any time * Low-energy hip fracture within the last 12 months * BMD T-score \< -2.5 (lumbar spine, total hip or femoral neck) * Zoledronate treatment for more than three years prior to denosumab treatment within the last ten years * Alendronate treatment for more than three years prior to denosumab treatment within the last five years or for more than five years within the last 10 the years * Treatment with other bisphosphonates (risedronate, ibandronate) for more than three years prior to denosumab treatment within the last five years * Diabetes Mellitus * Ongoing treatment with systemic glucocorticoids * Metabolic bone disease (for example osteogenesis imperfecta, Paget's disease of bone) * Hormone replacement therapy * Active cancer within the last 5 years with the exception of basal cell skin cancer * Estimated glomerular filtration rate (eGFR) ≤ 35 mL/min * Contraindications for zoledronate according to the SPC * Unable to read and understand Danish * Immobility