181 elderly women with osteoporosis or bone fractures were randomized to receive either one 5-mg dose of zoledronic acid or placebo intravenously. The purpose of this study was to determine whether zoledronic acid was safe and effective for improving bone mineral density in frail elderly women with osteoporosis. Hip and spine bone mineral density were measured at 12 and 24 months post-intervention via dual x-ray absorptiometry. Results demonstrated significantly greater improvement in hip and spine bone mineral density, as well as bio-markers of bone resorption, in the zoledronic acid group compared to the placebo group.