The effect of once-yearly zoledronic acid on hip structural and biomechanical properties derived using computed tomography (CT) in Japanese women with osteoporosis.

The effects of zoledronic acid on hip structural and biomechanical properties were evaluated in Japanese patients with osteoporosis by computed tomography (CT). The subjects included in this study were a subset of female subjects (zoledronic acid group, 49 subjects; placebo group, 53 subjects) in the phase 3 trial (ZONE study) who were available for multi-detector row CT (MDCT) scanning. Eligible subjects were those diagnosed with primary osteoporosis based on the Diagnostic Criteria for Primary Osteoporosis (2000) by the Japanese Society for Bone and Mineral Research and who had between one and four fractured vertebrae located between the fourth thoracic vertebra and the fourth lumbar vertebra. The subjects received a once-yearly intravenous infusion of zoledronic acid 5mg or placebo for two years. CT data were obtained at baseline and at 12 and 24months later and analyzed under blinded conditions. The results demonstrated that once-yearly intravenous infusion of zoledronic acid improved volumetric bone mineral density (vBMD), cortical bone geometry parameters, and CT-derived biomechanical parameters at the femoral neck, intertrochanteric region, and shaft; particularly at the intertrochanteric region, significant improvements in cortical bone geometry parameters and CT-derived biomechanical parameters, compared with those in the placebo group, were detectable early, at 12months. The present data suggest that zoledronic acid has a possibility to reduce the risk of hip fractures in Japanese patients with osteoporosis.