Once-yearly zoledronic acid for treatment of postmenopausal osteoporosis.

BACKGROUND: A single infusion of intravenous zoledronic acid decreases bone turnover and improves bone density at 12 months in postmenopausal women with osteoporosis. We assessed the effects of annual infusions of zoledronic acid on fracture risk during a 3-year period. METHODS: In this double-blind, placebo-controlled trial, 3889 patients (mean age, 73 years) were randomly assigned to receive a single 15-minute infusion of zoledronic acid (5 mg) and 3876 were assigned to receive placebo at baseline, at 12 months, and at 24 months; the patients were followed until 36 months. Primary end points were new vertebral fracture (in patients not taking concomitant osteoporosis medications) and hip fracture (in all patients). Secondary end points included bone mineral density, bone turnover markers, and safety outcomes. RESULTS: Treatment with zoledronic acid reduced the risk of morphometric vertebral fracture by 70% during a 3-year period, as compared with placebo (3.3% in the zoledronic-acid group vs. 10.9% in the placebo group; relative risk, 0.30; 95% confidence interval [CI], 0.24 to 0.38) and reduced the risk of hip fracture by 41% (1.4% in the zoledronic-acid group vs. 2.5% in the placebo group; hazard ratio, 0.59; 95% CI, 0.42 to 0.83). Nonvertebral fractures, clinical fractures, and clinical vertebral fractures were reduced by 25%, 33%, and 77%, respectively (P<0.001 for all comparisons). Zoledronic acid was also associated with a significant improvement in bone mineral density and bone metabolism markers. Adverse events, including change in renal function, were similar in the two study groups. However, serious atrial fibrillation occurred more frequently in the zoledronic acid group (in 50 vs. 20 patients, P<0.001). CONCLUSIONS: A once-yearly infusion of zoledronic acid during a 3-year period significantly reduced the risk of vertebral, hip, and other fractures. (ClinicalTrials.gov number, NCT00049829.)

The HORIZON Recurrent Fracture Trial: design of a clinical trial in the prevention of subsequent fractures after low trauma hip fracture repair.

OBJECTIVE: To present the novel design of a trial testing the safety and efficacy of a yearly bisphosponate, zoledronic acid, in preventing new clinical fractures in patients with recent low trauma hip fracture repair. RESEARCH DESIGN AND METHODS: Randomized, placebo-controlled, triple-blind study. One hundred and fifteen clinical centers worldwide are recruiting approximately 1714 subjects aged 50 years and over (no upper age limit, median age of enrolled subjects to date 79 years) who have undergone surgical repair of a low trauma hip fracture in the preceding 90 days. Patients will be assigned at random to an intervention group (5 mg zoledronic acid intravenously yearly) or a control group (placebo infusion yearly). Both groups receive a loading dose of Vitamin D2 or D3 IM or orally, followed by 800-1200 IU Vitamin D and 1000-1500 mg elemental calcium orally on a daily basis. Concomitant therapy with calcitonin, hormone replacement therapy, selective estrogen receptor modulators, tibolone, and external hip protectors are allowed. MAIN OUTCOME MEASURES: The primary endpoint is subsequent skeletal fractures as adjudicated by a clinical endpoints committee blinded to intervention status. Secondary outcomes include delayed hip fracture healing, changes in bone mineral density, and health resource utilization. Subjects will be recruited over a 3-4 year period and will be followed until 211 primary endpoints are accrued and adjudicated. CONCLUSIONS: This randomized clinical trial is novel among osteoporosis therapies as it (1). targets hip fracture patients, a previously understudied group, and (2). uses only clinically evident fractures as the primary outcome. Ethical and practical considerations in studying this frail population are discussed.