Teriparatide's effects on quantitative ultrasound parameters and bone density in women with established osteoporosis

Introduction This study aimed to evaluate the effects of teriparatide [hPTH (1-34)] on quantitative ultrasound (QUS) parameters and bone mineral density (BMD) at the axial and appendicular (hand) skeleton in women with established osteoporosis who had been previously treated with antiresorptive drugs. Methods Sixty postmenopausal women (age 71.1 +/- 6.8 years) were randomly assigned to either receive once-daily 20-mu g subcutaneous teriparatide (n=30) or continue the antiresorptive treatment (n=30). At baseline and at 2-month intervals we measured QUS parameters at the calcaneus using the Achilles Plus (GE, Lunar), measuring speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness index; QUS parameters at the phalanxes using the Bone Profiler (IGEA), measuring amplitude-dependent speed of sound (AD-SoS), bone transmission time (BTT), and fast wave amplitude (FWA); and BMD values at the right hand using dual x-ray absorptiometry. BMD at the lumbar spine, femur, and whole body were measured on a 6-monthly basis. Results After 1 year of teriparatide treatment, the changes in BMD were 7.1% at the lumbar spine, 2.6% at the femoral neck, -0.8% at the total hip, and -0.6% for the whole body. Teriparatide induced a significant and persistent decrease in BMD at the hand (-3.6% at month 6 and -2.7% at month 12). In the teriparatide group at month 12, AD-SoS was slightly increased (0.7%; not significant), whereas BTT significantly decreased (-16.4%, p < 0.001) and FWA significantly increased (17.5%, p < 0.001). The FWA/BTT ratio increased by 26.6% and 32.9% at months 6 and 12, respectively, in the teriparatide group and remained unchanged in the antiresorptive group. Conclusions In women with established osteoporosis who had previously been treated with various antiresorptive drugs, 1 year of teriparatide treatment determined the expected increase in BMD at the axial skeleton and a significant and prolonged decrease in BMD at the hand. Moreover, teriparatide determined important changes in BTT and FWA, two parameters obtained from the analysis of ultrasonographic trace at the phalanxes, which could be considered in monitoring for the early effect of teriparatide on bone.