Association of nodular hyperplasia with resistance to cinacalcet therapy for secondary hyperparathyroidism in hemodialysis patients.

There have been few long-term prospective studies investigating the effect of cinacalcet on secondary hyperparathyroidism with or without nodular hyperplasia. We examined whether the effect of cinacalcet on secondary hyperparathyroidism differed between patients with or without nodular hyperplasia. Stable hemodialysis patients with secondary hyperparathyroidism resistant to conventional treatment received cinacalcet for 12 months. Based on ultrasonography findings, patients were divided into group S (gland < 500 mm(3) without nodular hyperplasia) and group L (gland ≥ 500 mm(3) with nodular hyperplasia). Serum levels of intact parathyroid hormone, bone-specific alkaline phosphatase, osteocalcin, and cross-linked N-terminal telopeptide of type 1 collagen were measured. Thirty-one patients completed the study. The changes of parameters from the baseline did not differ significantly between the two groups after 6 months. However, the percentage reduction of each parameter was significantly smaller in group L compared with group S after 12 months. Nodular hyperplasia is associated with resistance to cinacalcet therapy in patients on chronic dialysis with secondary hyperparathyroidism.