Cinacalcet Decreases Bone Formation Rate in Hypercalcemic Hyperparathyroidism after Kidney Transplantation

Abstract

Background/Aims: Cinacalcet reduces serum calcium in kidney transplant recipients with hypercalcemic hyperparathyroidism. Its effect on bone, however, has not been investigated in this population. Methods: We prospectively examined bone turnover, histomorphometry and density as well as serum bone biomarkers in 10 transplant recipients before and after treatment with cinacalcet. Results: After 18–24 months of treatment with cinacalcet, bone formation decreased in 7, increased in 2, and remained zero in 1 patient (p = 0.11). Trabecular bone volume was maintained. Trabecular number decreased (p = 0.03), but trabecular thickness was unchanged (p = 0.17). Osteoid decreased (p = 0.02) and osteoblast surface increased (p = 0.02). Bone mineral density of the femur remained stable in 1 patient, decreased in 2 patients, but increased in 7 patients (p = 0.153). Serum calcium concentration (p = 0.005), iPTH (p = 0.01) and calcitonin concentration decreased (p = 0.03), while 25(OH) vitamin D₃ increased (p = 0.02). No fractures were reported. Graft function remained stable. Conclusion: Whilecinacalcet might decrease bone formation rate, it did not change bone volume, and bone mineral density of the femur increased. Therefore, the use of cinacalcet in hypercalcemic hyperparathyroidism might be safe with regard to the bone disease present after kidney transplantation.

Bone Disease after Kidney Transplantation

“…The direct effect of cinacalcet on the bone histomorphometry in kidney transplant recipients has not been studied in detail. In a small study of kidney transplant recipients who underwent bone biopsy before and after starting cinacalcet, Borchhardt et al (38) found that, although bone formation rates fell in seven of 10 patients, five of 10 patients had undetectable bone turnover after 18-24 months of cinacalcet therapy. Notwithstanding the risk of ABD associated with cinacalcet, one needs to recognize the risks associated with parathyroidectomy in kidney transplant recipients.…”

A Randomized Study Evaluating Cinacalcet to Treat Hypercalcemia in Renal Transplant Recipients With Persistent Hyperparathyroidism

“…This heterogeneity is likely due to indication bias and variable time interval since transplantation (36). It should be acknowledged that in a recent bone biopsy study in 10 renal transplant recipients with hypercalcemic HPT a high proportion of low bone disease was observed (56). Additional bone biopsy studies are required to evaluate the impact of cinacalcet on bone histomorphometry.…”

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“…However, its use in kidney transplant recipients remains off-label. Several prospective [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] and retrospective [31][32][33][34][35][36][37][38][39][40][41] observational cohort studies have examined the potential effects of cinacalcet in kidney transplant recipients. Most of these studies have included small cohorts with short follow-up periods, whereas only 4 studies have reported follow-up of greater than 3 years.…”