A 40-year-old man with end-stage renal disease comes to the office for routine follow-up. He has been on chronic hemodialysis for the last 3 years. The patient's parathyroid hormone and alkaline phosphatase levels have increased progressively despite efforts to maintain normal serum phosphorus with phosphate binders and oral vitamin D.
Laboratory results are as follows:

Adding cinacalcet to this patient's regimen would most likely contribute to which of the following?

Question

A 40-year-old man with end-stage renal disease comes to the office for routine follow-up.  He has been on chronic hemodialysis for the last 3 years.  The patient's parathyroid hormone and alkaline phosphatase levels have increased progressively despite efforts to maintain normal serum phosphorus with phosphate binders and oral vitamin D.
Laboratory results are as follows:

Adding cinacalcet to this patient's regimen would most likely contribute to which of the following?

Quizplus · Accepted Answer

11ec193a_9907_1bba_853d_a134dfcff76e_MD0002_00 Untreated or inadequately treated hyperphosphatemia and hypocalcemia in chronic kidney disease lead to secondary hyperparathyroidism. Current guidelines recommend the following targets for dialysis patients: Serum total corrected calcium of 8.4-9.5 mg/dLSerum phosphate of 3.5-5.5 mg/dLCalcium-phosphorus product generally maintained at <55 mg²/dL²Intact parathyroid hormone (PTH) level of 150-300 pg/mL Serum total corrected calcium of 8.4-9.5 mg/dL Serum phosphate of 3.5-5.5 mg/dL Calcium-phosphorus product generally maintained at <55 mg²/dL² ² ² Intact parathyroid hormone (PTH) level of 150-300 pg/mL Hyperphosphatemia is corrected initially with dietary phosphate restriction (<900 mg/day). The next step is to add phosphate binders (eg, calcium carbonate/acetate or sevelamer/lanthanum) depending on the serum calcium level. If serum phosphate remains uncontrolled, serum PTH levels should be measured. If serum PTH is elevated (>300 pg/mL), vitamin D analogs or a calcimimetic is added depending on serum phosphate and calcium levels. Calcimimetics increase the calcium sensitivity of calcium-sensing receptors on parathyroid glands and reduce serum PTH, calcium, and phosphate levels. Cinacalcet (Sensipar®) reduces fracture risk and improves symptoms of secondary hyperparathyroidism (eg, pruritus, bone pain, fractures, calciphylaxis, and avascular necrosis). Cinacalcet decreases the need for parathyroidectomy by approximately 50%. However, calcimimetics should not be used in patients with hypocalcemia as they may cause seizures and prolong the QT interval. (Choices B and D) Cinacalcet has been shown to reduce cardiovascular risk in patients age >65 but not in younger individuals. (Choice C) Cinacalcet decreases bone turnover due to secondary hyperparathyroidism and therefore reduces the risk for osteitis fibrosa development. (Choice E) The major side effects of cinacalcet are hypocalcemia and gastrointestinal disturbances. Educational objective: Calcimimetics such as cinacalcet decrease the frequency of fractures and the rate of parathyroidectomy in patients with chronic kidney disease who have hyperphosphatemia and secondary hyperparathyroidism. Calcimimetics also reduce the risk of cardiovascular disease in older patients (age >65). Major side effects are hypocalcemia and gastrointestinal disturbances. __________ References: Cinacalcet HCl, an oral calcimimetic agent for the treatment of secondary hyperparathyroidism in hemodialysis and peritoneal dialysis: a randomized, double-blind, multicenter study. (http://www.ncbi.nlm.nih.gov/pubmed/15689407) Impact of long-term cinacalcet, ibandronate or teriparatide therapy on bone mineral density of hemodialysis patients: a pilot study. (http://www.ncbi.nlm.nih.gov/pubmed/22948280) The Effects of Cinacalcet in Older and Younger Patients on Hemodialysis: The Evaluation of Cinacalcet HCl Therapy to Lower Cardiovascular Events (EVOLVE) Trial. (http://www.ncbi.nlm.nih.gov/pubmed/25710802)

A 40-Year-Old Man with End-Stage Renal Disease Comes to the Office