I RUDERMAN1,2, E SMITH1,2, N TOUSSAINT1,2,T HEWITSON1,2, S HOLT1,2
1The Royal Melbourne Hospital, Parkville, Australia, 2The University of Melbourne, Parkville, Australia
Aim: To assess changes in novel biochemical biomarkers, calciprotein particles following cessation of cinacalcet in dialysis patients.
Background: The calcimimetic agent cinacalcet is effective for the management of secondary hyperparathyroidism (SHPT) in dialysis patients. Changes to reimbursement of cinacalcet in Australia provided an opportunity to assess effects of medication cessation on biochemical and clinical outcomes in dialysis patients, including changes to novel biomarkers such as calciprotein particles (CPP). CPP are nanoparticles of mineral and protein in the circulation associated with increased vascular calcification in patients with CKD.
Methods: Dialysis patients from a single center who ceased cinacalcet between August 2015 and March 2016 were included in a prospective observational study. Blood tests were taken at time of cessation and at 1, 6 and 12 months. Clinical and biochemical outcomes were compared with an age- and gender-matched cohort of cinacalcet-naïve dialysis patients.
Results: 62 patients participated in the study. Mean age was 69.6 ± 13.2 years. Biochemical changes over 12 months following cessation of cinacalcet included an increase in serum parathyroid hormone (PTH) (42.2 [IQR 27.8-94.6] pmol/L to 114.8 [83.9-159.1] pmol/L [p<0.001]), serum calcium (2.31±0.21mmol/L to 2.46±0.14mmol/L [p<0.001]) and primary CPP (CPP-I) (p=0.002). Changes in CPP were associated with an increase in PTH (p=0.007), calcium (p=0.002) and ferritin (p=0.02) but a reduction in serum albumin (p=0.001). Over the 12-month period, there were two fractures, five cardiovascular events, one episode of calciphylaxis, and one parathyroidectomy, with a mortality rate of 19% (n=13).
Conclusion: Uniquely we report the effects of cinacalcet withdrawal in a real world setting with demonstrated increases in PTH, serum calcium and the novel prognostic marker CPP over a 12-month period.
Irene Ruderman is a Nephrology Fellow at The Royal Melbourne Hospital. She is currently completing a PhD and is in her second year of study. Her interest is in vascular calcification and CKD-MBD