Seven placebo-controlled trials (n=more than 21,848) were included. One study assessed zoledronic acid, three assessed alendronate, one ibandronate and two risedronate.
There was a 98% probability that zoledronic acid was associated with the greatest reduction in vertebral fractures. Zoledronic acid showed a lower vertebral fracture risk in comparison with placebo (OR 0.28, 95% CrI 0.22 to 0.35), ibandronate (OR 0.57, 95% CrI 0.36 to 0.92), alendronate (OR 0.54, 95% CrI 0.39 to 0.75) and risedronate (OR 0.49, 95% CrI: 0.34 to 0.69). Alendronate, ibandronate and risedronate appeared to have comparable vertebral fracture reductions. The random-effects model showed similar effect sizes, but with wider confidence intervals (90% probability that zoledronic acid was the most effective treatment).