Teriparatide is the active fragment (1-34) of human parathyroid hormone and it is one of the few anabolic agents licensed for the treatment of severe postmenopausal osteoporosis. It stimulates both bone formation and bone resorption and so has the potential to cause bone gain or bone loss. Large increases in spine BMD have been reported with this treatment, but its effects on total body BMD and the BMD of its anatomical sub-regions, for instance in the skull, have yet to be described. Women (n=18, age =65.8±5.1 years) with postmenopausal osteoporosis, defined as a BMD T-score of ≤-2.5 at the hip or lumbar spine by dual energy X-ray absorptiometry (DXA) were recruited. They were treated for one year with teriparatide by subcutaneous injection at the licensed dose (Forsteo 20 mcg daily, Lilly, Basingstoke, UK). We measured total body BMD by DXA at baseline and then at 12, 26 and 52 weeks. By 52 weeks, total body BMD had decreased by 1.3% (95% CI: -2.6 to -0.1%, p=0.05). When considering the anatomical sub-regions of the total body, two sites showed a statistically significant change in BMD. There was an increase in BMD at the lumbar spine (mean=9.5%, 95% CI: 6.0 to 12.9%, p<0.001) and a decrease in BMD in the skull (mean =5.2%, 95% CI: -8.1 to -2.3%, p<0.01). We conclude that the BMD response to teriparatide differs by site with an increase at the spine and a decrease at the skull.
Disclosure: The authors declared no competing interests. This work was funded by the National Institute for Health Research (NIHR) with supplemental funding from Lilly and IDS.