A total of 27 randomized controlled trials were included in this network meta-analysis investigating the comparative efficacies of bisphosphonates - including alendronate, ibandronate, risedronate, and zoledronic acid - versus placebo or control in patients with low bone mineral density. All studied drugs demonstrated significant effects on vertebral fracture incidence and bone mineral density of the femoral neck; effects sizes of both outcomes were observed to be greatest with zoledronic acid. Ibandronate was the only drug to not demonstrate a significant effect on nonvertebral fracture incidence; risedronate demonstrated the greatest effect size.