title: Evaluating real-world use of cinacalcet and biochemical response to therapy in US hemodialysis patients.
abstract: OBJECTIVE
  Data describing real-world use and effectiveness of cinacalcet are limited. We aimed to characterize predictors of treatment and changes in secondary hyperparathyroidism (SHPT) biochemistry after cinacalcet initiation.
  
  
  METHODS
  We studied 25,250 in-center hemodialysis patients from a large dialysis provider, alive through November 2004, with no prior cinacalcet prescription. Patients were followed until initiation of cinacalcet, censoring, death, or July 31, 2007. Initiators were further followed for dose titration and discontinuation. Predictors of these events were evaluated using Cox proportional hazards modeling. Biochemical parameters and other SHPT medication use were compared between baseline, pre-initiation, and post-initiation time points.
  
  
  RESULTS
  Over an average of 1.25 years of follow-up, 30% of patients initiated cinacalcet therapy. Between baseline and initiation (mean of 386 days), parathyroid hormone (PTH) and phosphorus levels increased 78 and 7%, respectively, in these patients. After adjustment, cinacalcet initiation was associated with higher SHPT severity, younger age, African-American race, higher phosphorus levels, and more comorbidity. Within 1 month of initiation, median PTH was reduced by 15-30% and phosphorus by 3-5%. Reductions were sustained or increased over 12 months, depending on initiating PTH level and whether dose up-titration occurred. Discontinuation was common, although many patients reinitiated.
  
  
  CONCLUSIONS
  A substantial proportion of patients experienced SHPT progression and initiated cinacalcet treatment. Reductions in biochemistry varied by disease severity and whether doses were titrated.
authors.affiliation: Center for Observational Research, Amgen Inc., Thousand Oaks, CA, USA.
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Kilpatrick
authors.forename: Britt B
authors.initials: BB
authors.lastname: Newsome
authors.forename: David
authors.initials: D
authors.lastname: Zaun
authors.forename: Jiannong
authors.initials: J
authors.lastname: Liu
authors.forename: Craig A
authors.initials: CA
authors.lastname: Solid
authors.forename: Kimberly
authors.initials: K
authors.lastname: Nieman
authors.forename: Wendy L
authors.initials: WL
authors.lastname: St Peter
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002118:Calcium / Q000097:blood; D000069449:Cinacalcet; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D009281:Naphthalenes / Q000627:therapeutic use*; D010282:Parathyroid Neoplasms / Q000097:blood; D010758:Phosphorus / Q000097:blood; D006435:Renal Dialysis; D014481:United States; D014807:Vitamin D / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D009281:Naphthalenes; D014807:Vitamin D; D010758:Phosphorus; D002118:Calcium; D000069449:Cinacalcet