Abstract
Reassessment of fracture risk in women after 3 years of treatment with zoledronic acid: when is it reasonable to discontinue treatment?
Cosman F, Cauley JA, Eastell R, et al.
JCEM. Epub ahead of print 12 September 2014: jc20141971. PMID 25215556.
Yearly infusion with zoledronic acid (ZOL) has previously been shown to reduce fractures in women with postmenopausal osteoporosis. However, bisphosphonates have a long skeletal half-life and there are potential risks associated with prolonged use, including atypical fractures and osteonecrosis of the jaw; the ideal duration of therapy is not clearly defined.
This multicentre randomized double-blinded placebo-controlled extension study involved 1233 postmenopausal women with osteoporosis who, in a previous study, had received three annual infusions of ZOL. They were randomized to receive a further three annual infusions of ZOL or placebo. Risks of non-vertebral fracture and vertebral fracture were the main outcomes. Of note, this study was originally powered to examine changes in bone mineral density (BMD) rather than fractures; the fracture numbers recorded were small.
Discontinuation of ZOL was associated with low fracture risk in the ensuing 3 years in participants with a hip BMD above the osteoporotic range, who had not fractured during initial therapy and had ≤1 other risk factor (prevalent pre-trial vertebral fracture or femoral neck BMD ≤–2.5). The authors conclude that in this low risk population temporary cessation of ZOL may be reasonable.