Lay summary
Fractures are a major health burden for older people. We recently completed a 10-year randomised controlled trial which showed that zoledronate, given as a 5- or 10-yearly infusion, reduced spinal fractures in early postmenopausal women by 40-44% and all fractures by 23-30% over 10 years. Therefore, very infrequent zoledronate offers a new approach to preventing fractures. We wish to see whether the benefits of 5- or 10-yearly zoledronate persist out to 20 years. If they did, the results would provide stronger, practice changing evidence for this new approach, which would be more convenient, less expensive, prevent fractures and improve health, and produce large cost-savings for New Zealand. In this open-label extension, participants from the core study will continue to receive 5- or 10-yearly zoledronate for 10 years, providing 20 years of follow-up. The primary outcomes of the extension study are spinal fractures, as seen on regular spinal x-rays, and total fractures.