HORIZON-PFT

Once-yearly zoledronic acid for treatment of postmenopausal osteoporosis.

Black DM, Delmas PD, Eastell R, et al. The New England journal of medicine 2007 · PMID 17476007 · doi:10.1056/nejmoa067312

Question

Does an annual intravenous infusion of zoledronic acid reduce vertebral and hip fractures in postmenopausal osteoporosis?

Design

International multicentre double-blind placebo-controlled RCT over 3 years.

Patients

Postmenopausal women with osteoporosis defined by BMD and/or prevalent vertebral fracture.

Intervention

Zoledronic acid 5 mg IV once yearly

Comparison

Placebo infusion

Primary outcome

New morphometric vertebral fracture and hip fracture at 3 years

Key result

Zoledronic acid markedly and significantly reduced vertebral fractures (around 70%) and significantly reduced hip fractures (around 40%) versus placebo.

Limitations

Acute-phase reactions were common and an excess of serious atrial fibrillation was reported; trial population excluded those with significant renal impairment.

Impact on practice

Provides the evidence for annual IV zoledronate, widely used in UK practice when oral bisphosphonates are not tolerated, not absorbed or adherence is poor.