Next, the researchers performed a sensitivity analysis that included all participants enrolled in ACTIVE, even those not enrolled in ACTIVExtend. They found a vertebral fracture rate of 3.15 per 100 patient-years among patients who received placebo during ACTIVE and a fracture rate of 1.66 per 100 patient-years among patients who received alendronate in the placebo/alendronate arm of ACTIVExtend. From this finding, the investigators calculated a 1.48 per 100 patient-years reduction after transition from placebo to alendronate.
The reduction in vertebral fractures in the alendronate group was similar to that seen in previous studies examining the effect of alendronate treatment on postmenopausal women with osteoporosis. The investigators saw no differences in the rates of nonvertebral fractures and clinical fractures.
Lara C. Pullen, PhD, is a medical writer based in the Chicago area.
References
- Miller PD, Hattersley G, Riis BJ, et al. Effect of abaloparatide vs. placebo on new vertebral fractures in postmenopausal women with osteoporosis: A randomized clinical trial. JAMA. 2016 Aug 16;316(7):722–773.
- Bone HG, Cosman F, Miller PD, et al. ACTIVExtend: 24 months of alendronate after 18 months of abaloparatide or placebo for postmenopausal osteoporosis. J Clin Endocrinol Metab. 2018 Aug 1;103(8):2949–2957.
- Leder BZ, Mitlak B, Hu MY, et al. Effect of abaloparatide vs. alendronate on fracture risk reduction in postmenopausal women with osteoporosis. J Clin Endocrinol Metab. 2020 Mar 1;105(3):938–943.