title: Serum phosphorus reduction in dialysis patients treated with cinacalcet for secondary hyperparathyroidism results mainly from parathyroid hormone reduction.
abstract: The calcimimetic cinacalcet lowers parathyroid hormone (PTH), calcium (Ca) and phosphorus (P) in dialysis patients with secondary hyperparathyroidism (SHPT). We explored serum P changes in dialysis patients treated with cinacalcet, while controlling for vitamin D sterol and phosphate binder (PB) changes, based on data from the pan-European observational study ECHO.
  
  
  
  Patients were categorized by serum P change (decreased/unchanged/increased) at 12 months after starting cinacalcet and subcategorized by vitamin D sterol and PB dose changes (decreased/unchanged/increased). The impact of PTH, Ca and P, and vitamin D sterol, PB and cinacalcet doses (absolute values and/or change) was evaluated. Predictors of P change were explored using univariate and multivariate general linear models (GLM) and logistic regression analysis.
  
  
  
  At Month 12, 661 (41%) of 1607 patients had decreased, 61 (4%) unchanged and 400 (25%) increased serum P, while 485 patients had missing data. In 45% of the patients with serum P reduction, vitamin D was either increased or unchanged and P binders decreased or unchanged. PTH was a key predictor of serum P reduction, with an estimated 3% decrease in P per 10% reduction in PTH. Changes in vitamin D sterol and PB doses were not generally significant factors in GLM and regression analyses.
  
  
  
  The serum P reduction observed in a significant proportion of dialysis patients after adding cinacalcet to an existing therapeutic regimen for SHPT appears to result mainly from PTH reduction, rather than from changes in vitamin D sterol or PB doses. Financial support for the ECHO study was provided by Amgen.
authors.affiliation: Academic Teaching Hospital , Feldkirch , Austria.
authors.forename: Emanuel
authors.initials: E
authors.lastname: Zitt
authors.forename: Denis
authors.initials: D
authors.lastname: Fouque
authors.forename: Stefan H
authors.initials: SH
authors.lastname: Jacobson
authors.forename: Fabio
authors.initials: F
authors.lastname: Malberti
authors.forename: Miroslav
authors.initials: M
authors.lastname: Ryba
authors.forename: Pablo
authors.initials: P
authors.lastname: Ureña
authors.forename: Marianne
authors.initials: M
authors.lastname: Rix
authors.forename: Bastian
authors.initials: B
authors.lastname: Dehmel
authors.forename: Nick
authors.initials: N
authors.lastname: Manamley
authors.forename: Marc
authors.initials: M
authors.lastname: Vervloet
keywords: chronic kidney disease; cinacalcet; secondary hyperparathyroidism; serum phosphorus