A group of 2,000 women with osteopenia receiving either zolendronate infusion or placebo were followed for 6 years. Zoledronate 5 mg or placebo were provided every 1.5 years. At the end of the study, the intravenous bisphosphonate reduced vertebral and nonvertebral fractions significantly by about 55% and 35% respectively.
Findings are of major significance as bisphosphonates in general and zolendronate specifically have been approved only for osteoporosis and not osteopenia. Would this expand indications for zoledronate? Should patients with osteopenia be treated or monitored?
N E J M
Bisphosphonates prevent fractures in patients with osteoporosis, but their efficacy in women with osteopenia is unknown.
Most fractures in postmenopausal women occur in those with osteopenia, so therapies that are effective in women with osteopenia are needed.
We conducted a 6-year, double-blind trial involving 2000 women with osteopenia (defined by a T score of −1.0 to −2.5 at either the total hip or the femoral neck on either side) who were ≥ 65 years of age.
Participants were randomly assigned to receive four infusions of either zoledronate at a dose of 5 mg (zoledronate group) or normal saline (placebo group) every 1.5 years.
A dietary calcium intake of 1 g per day was advised, but calcium supplements were not provided. Participants who were not already taking vitamin D supplements received cholecalciferol before the trial began (a single dose of 2.5 mg) and during the trial (1.25 mg per month).
Primary endpoint was the time to first occurrence of a nonvertebral or vertebral fragility fracture.
At baseline, the mean age was 71, the T-score at the femoral neck was −1.6, and the median 10-year risk of hip fracture was 2.3%.
A fragility fracture occurred in 190 women in the placebo group and in 122 women in the zoledronate group (HR with zoledronate, 0.63, p<0.001).
The number of women that would need to be treated to prevent the occurrence of a fracture in 1 woman was 15 (1:15).
As compared with the placebo group, women who received zoledronate had a lower risk of:
Nonvertebral fragility fractures (HR 0.66; p=0.001)
Symptomatic fractures (HR 0.73; p=0.003)
Vertebral fractures (OR 0.45; p=0.002)
Height loss (P<0.001).
The risk of nonvertebral or vertebral fragility fractures was significantly lower in women with osteopenia who received zoledronate than in women who received placebo