Differing effects of PTH 1-34, PTH 1-84 and zoledronic acid on bone microarchitecture and estimated strength in postmenopausal women with osteoporosis. An 18 month open-labeled observational study using HR-pQCT

Whereas the beneficial effects of intermittent treatment with parathyroid hormone (PTH) (intact PTH 1-84 or fragment PTH 1-34, teriparatide) on vertebral strength is well documented, treatment may not be equally effective in the peripheral skeleton. We used high resolution peripheral quantitative computed tomography (HR-pQCT) to detail effects on compartmental geometry, density and microarchicture as well as finite element (FE) estimated integral strength at the distal radius and tibia in postmenopausal osteoporotic women treated with PTH 1-34 (20 µg sc. daily, n=18) or PTH 1-84 (100 µg sc. daily, n=20) for 18 month in an open label, non-randomized study. A group of postmenopausal osteoporotic women receiving zoledronic acid (5 mg infusion once yearly, n=33) was also included. Anabolic therapy increased cortical porosity in radius (PTH 1-34 32±37%, PTH 1-84 39±32%, both p