The effect of cinacalcet on bone remodeling and renal function in transplant patients with persistent hyperparathyroidism.

Background. Parathyroidectomy is associated with renal functional losses in transplant patients; cinacalcet offers an attractive alternative. Methods. We performed a prospective observational study in 58 patients with persisting hyperparathyroidism after renal transplantation (Ca2+≥2.6 mmol/L) and impaired renal transplant function (estimated glomerular filtration rate [eGFR] Results. At inclusion, creatinine was 181±70 μmol/L, eGFR 43±19 mL/min, PTH 371±279 pg/mL, and Ca2+ 2.73±0.22 mmol/L. We observed nephrocalcinosis in 58% of biopsied patients at enrollment. After cinacalcet, Ca2+ decreased significantly and normalized at nearly any measurement. Phosphorus increased significantly at months 1, 9, and 12. PTH decreased significantly, but only at months 9 and 12 and did not normalize. Bone-specific alkaline phosphatase increased significantly (>normal) by month 12. eGFR decreased and serum creatinine increased at all time points. The Δ(creatinine) % increase correlated significantly with the Δ(PTH) % decrease at month 1 and 12. Telopeptide and alkaline phosphatase correlated with PTH and telopeptide also correlated with serum creatinine. Conclusion. Calcium-phosphorus homeostasis in hypercalcemic renal transplant patients normalizes under cinacalcet and PTH decreases, albeit not to normal. The renal functional decline could be PTH mediated, analogous to the effects observed after parathyroidectomy.