Cincalcet and Vascular Arterial Stiffness Among Peritoneal Dialysis Patients With Secondary Hyperparathyroidism

• Percent change in the values for parathyroid hormone levels [ Time Frame: within one year of treatment with cinacalcet ] [ Designated as safety issue: No ]
  Blood samples will be stored before and after treatment with cinacalcet for further analysis.
• Change in calcium levels [ Time Frame: within one year of treatment with cinacalcet ] [ Designated as safety issue: No ]
  as before
• Aortic pulse wave velocity after the cinacalcet treatment [ Time Frame: change in aortic pulse wave velocity at 26 weeks from baseline ] [ Designated as safety issue: No ]
  as stated in the description of Primary Outcome Measure
• Change in phosphorus levels [ Time Frame: within one year of cinacalcet treatment ] [ Designated as safety issue: No ]
  as before
• Change in calcium-phosphorus product [ Time Frame: within one year of cinacalcet treatment ] [ Designated as safety issue: No ]
  as before

Active parathyroid glands among renal dialysis patients contribute to calcified and hardened blood vessels. Such damage to the blood vessels, in turn, takes a significant toll in terms of cardiovascular disease. Calcimimetics has been suggested to lower the risk of vascular calcification. Role of cinacalcet was demonstrated in animal model but human data are lacking. The investigators designed an open label pilot study to evaluate the effect of cinacalcet in 20 peritoneal dialysis patients with inadequately controlled secondary hyperparathyroidism despite standard treatment. The primary outcome is the aortic pulse wave velocity at 26 and 52 months after cinacalcet treatment.

Mineral metabolism disturbance and hyperparathyroidism contribute to arterial stiffness and vascular calcification. The vascular damage, in turn, contributes to significant cardiovascular morbidity and mortality of end-stage renal disease patients. Calcimimetics has been suggested to lower the risk of vascular calcification. Role of cinacalcet was demonstrated in animal model but human data are lacking. We design an open label pilot study to evaluate the effect of cinacalcet in 20 peritoneal dialysis patients with inadequately controlled secondary hyperparathyroidism despite standard treatment. The primary outcome is the aortic pulse wave velocity at 26 and 52 months after cinacalcet treatment.

• Hyperparathyroidism
• Arterial Stiffness

Inclusion Criteria:

• plasma parathyroid hormone level of at least 300 pg/ml (31.8 pmol/L)
• aged 18 or older on peritoneal dialysis for at least three months
• willingness to give written consent and comply with the study protocol

Exclusion Criteria:

• evidence of cancer, active infection or diseases with limited life expectancy
• diseases known to cause hypercalcaemia
• adjusted serum calcium level below 2.1 mmol/L (8.4 mg/dL) after correction for albumin
• participation in another interventional study within last 30 days of randomization
• history of a psychological illness or condition that would interfere with the patient's ability to understand the requirement of the study and/or comply with the study procedures
• patients receiving drugs with a narrow therapeutic index and metabolized by cytochrome P-450 2D6 (which is inhibited by cinacalcet): flecainide, thioridazine and most tricyclic antidepressants