A community-based clinical trial of Intra-Venous zOledRonic acid once Yearly in comparison to oral bisphosphonates in postmenopausal women with osteoporosis: The IVORY trial Methodological considerations

BACKGROUND: Zoledronic acid is an intravenous once yearly bisphosphonate that has been shown to be effective and safe in improving BMD (bone mineral density) and reducing fracture risk in controlled clinical trials. IVORY is a Canadian post marketing study aiming at assessing real-life effectiveness, health care resource utilization, safety and compliance to treatment with zoledronic acid in comparison to orally administered bisphosphonates (OBP). METHODS: IVORY is a prospective two cohort observational study of patients treated with zoledronic acid or OBP. Eligible patients are postmenopausal females, >45 years old with osteoporosis for whom initiation of treatment with OBP or zoledronic acid is indicated. Subjects will be followed for four years. Outcomes are the change in lumbar spine, femoral neck and total hip BMD and the incidence of fractures. The study cohort will consist of 920 patients treated with zoledronic acid and 460 treated with OBP. Additional comparisons will be based on external standardization to the population of Quebec patients treated with OBP. DISCUSSION: Post Marketing Observational Studies (PMOS) are essential for the assessment of real-life effectiveness and population based benefit-risk ratios. The effect of access to care, compliance, adherence to guidelines, patient comorbidity and concomitant medication use could only be assessed with observational studies. IVORY will provide information about true life effectiveness, benefit-risk ratios, cost-effectiveness and barriers to the process-outcome optimization. The results will have implications for decision makers and health care stakeholders regarding the management of osteoporosis in Canada.