New horizons for zoledronic acid: results of the HORIZON trials in postmenopausal women with osteoporosis and after hip fracture

Abstract

Nearly 2 million hip fractures occur each year in the US as a result of osteoporosis. After hip fracture, people are at an increased risk of a further fracture. The HORIZON-PFT (Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly Pivotal Fracture Trial), investigated the effect of zoledronic acid on fractures in women with osteoporosis, whereas the HORIZON-RFT (Recurrent Fracture Trial), studied the effect of zoledronic acid after hip fracture. In the HORIZON-PFT, after 3 years the incidence of new vertebral fractures in postmenopausal women, who were not taking any medication for osteoporosis at randomisation, was 10.9% in the placebo group and this was significantly lower in the once-yearly intravenous zoledronic acid group (3.3%). In the second of the HORIZON trials, the RFT, the effect of a single intravenous injection of zoledronic acid within 90 days of fracture on the recurrence of fracture was tested. The primary endpoint was a new clinical fracture, and after a median follow-up of 1.9 years, there were 139 fractures in the placebo group of 1062 and this was significantly reduced to 92 out of 1065 in the zoledronic acid group. Thus, this second HORIZON trial has demonstrated that zoledronic may have a role in preventing recurrent fractures in those who have a recent hip fracture.

Keywords::

• hip fracture
• HORIZON
• non-vertebral fracture
• osteoporosis
• vertebral fracture
• zoledronic acid