Effects of cinacalcet on bone mineral density and bone markers in hemodialysis patients with secondary hyperparathyroidism.

BACKGROUND: Cinacalcet markedly reduces the serum intact parathyroid hormone (PTH) level of hemodialysis (HD) patients with secondary hyperparathyroidism. Parathyroidectomy also reduces the serum intact PTH level of HD patients and it increases their bone mineral density (BMD). However, there is little information about the effect of cinacalcet on BMD or on the associations between bone markers and BMD in HD patients.
METHODS: We performed a 1-year cohort study of 25 HD patients who had a serum intact PTH level above 300 pg/ml during treatment by conventional therapies, such as with active vitamin D, and cinacalcet was prescribed for 14 of them. BMD of the femoral neck and the serum levels of two circulating bone markers, alkaline phosphatase (ALP) and bone-specific alkaline phosphatase (BSAP), were measured before and after treatment. The other 11 HD patients without cinacalcet treatment were defined as control group.
RESULTS: BMD significantly increased by 7.3 % during the 1 year of treatment in the cinacalcet group and decreased by 6.2 % during the same period in the control group, and cinacalcet therapy was independently associated with the changes in BMD after multiple regression analysis that included intact PTH (β = 7.57, P < 0.01). In the cinacalcet group, the serum ALP levels (R(2) = 0.315, P < 0.05) and BSAP levels (R(2) = 0.682, P < 0.01) levels were significantly negatively correlated with the changes in BMD, but the serum intact PTH levels were not significantly associated with the changes in BMD (R(2) = 0.011, P = 0.72).
CONCLUSIONS: One year of treatment with cinacalcet increased the BMD of the femoral neck in the HD cohort, especially in the patients who had higher serum ALP and BSAP levels at baseline.