Effect of oral monthly ibandronate on bone microarchitecture in women with osteopenia-a randomized placebo-controlled trial

We have examined the effect of oral monthly ibandronate on distal radius and tibia microarchitecture with high-resolution peripheral quantitative tomography compared with placebo, in women with osteopenia, and found that ibandronate did not significantly affect trabecular bone but improved cortical density and thickness at the tibia. We have examined the effect of ibandronate on bone microarchitecture with peripheral high-resolution quantitative computed tomography (HR-pQCT) in a randomized placebo-controlled trial among 148 women with osteopenia. Patients received either oral 150 mg monthly ibandronate or placebo over 24 months. Bone microarchitecture was assessed at baseline, 6, 12, and 24 months, using HR-pQCT at the distal radius and tibia; areal bone mineral density (aBMD) was measured with DXA at the spine, hip, and radius. At 12 months, there was no significant difference in trabecular bone volume at the radius (the primary end point) between women on ibandronate (10.8 +/- 2.5%) and placebo (10.5 +/- 2.9%), p = 0.25. There was no significant difference in other radius trabecular and cortical microarchitecture parameters at 12 and 24 months. In contrast, at the tibia, cortical vBMD in the ibandronate group was significantly greater than in the placebo group at 6, 12, and 24 months, with better cortical thickness at 6, 12, and 24 months. With ibandronate, aBMD was significantly increased at the hip and spine at 12 and 24 months but at the radius was significantly superior to placebo only at 24 months. Most of the adverse events related to ibandronate were expected with bisphosphonate use, and none of them were serious. We conclude that 12 months of treatment with ibandronate in women with osteopenia did not affect trabecular bone microarchitecture, but improved cortical vBMD at the tibia at 12 and 24 months, and preserved cortical thickness at the tibia.