Changes in bone density under treatment with parathyroid hormone

Introduction: A new treatment approach for osteoporosis is the intermittent application of the biochemically active part of the parathyroid hormone, teriparatide (hPTH 1–34). Several studies provide evidence that under treatment with teriparatide an increase in bone density and a decrease in fracture incidence is achieved. This paper should reveal just how effective the treatment with teriparatide is in increasing bone density and reducing fracture incidence for those patients who despite treatment with bisphosphonate suffer a progression of the osteoporosis, or for those who due to serious side-effects are forced to abandon the bisphosphonate treatment.

Methods: Included in the study were 30 women with postmenopausal osteoporosis who had been given teriparatide over a period of at least 1–1.5 years. The bone density was measured by the DXA method in the spine and femur neck before and after treatment. In addition the biochemical bone marker osteocalcin, the bone specific alcaline phosphatase and the crosslinks (pyridinoline and desoxypyridinoline) were determined.

Results: The bone density of the spine when measured for the second time revealed an average increase in the t-score form –2.48 (SD) to –1.93 (SD). This increase in bone density is extremely significant. (p<0.001). The improvement in bone density at the femur neck was not quite as significant (from -2.03 SD to -1.91 SD). Moreover, none of the patients suffered any new fractures during treatment. Prior to treatment 59% of patients had suffered at least one fracture. The bone biochemical parameters showed a medial increase (osteocalcin from 21.9 to 24.6µg/l, bone specific alcaline phophatase from 34.9 to 45.3 U/l and the crosslinks from 9.9 to 13.1 nmol/mmol Crea).

Conclusions: These data show that the parathyroid hormone treatment led to a significant increase in bone density in the spinal area and the same time fracture incidence decreased significantly. The rise in the bone function parameters give evidence of increased bone formation and turnover under treatment.