title: Nonoxidized, biologically active parathyroid hormone determines mortality in hemodialysis patients.
abstract: BACKGROUND
  It was shown that nonoxidized PTH (n-oxPTH) is bioactive, whereas the oxidation of PTH results in a loss of biological activity.
  
  
  METHODS
  In this study we analyzed the association of n-oxPTH on mortality in hemodialysis patients using a recently developed assay system.
  
  
  RESULTS
  Hemodialysis patients (224 men, 116 women) had a median age of 66 years. One hundred seventy patients (50%) died during the follow-up period of 5 years. Median n-oxPTH levels were higher in survivors (7.2 ng/L) compared with deceased patients (5.0 ng/L; P = .002). Survival analysis showed an increased survival in the highest n-oxPTH tertile compared with the lowest n-oxPTH tertile (χ², 14.3; P = .0008). Median survival was 1702 days in the highest n-oxPTH tertile, whereas it was only 453 days in the lowest n-oxPTH tertile. Multivariable-adjusted Cox regression showed that higher age increased odds for death, whereas higher n-oxPTH reduced the odds for death. Another model analyzing a subgroup of patients with intact PTH (iPTH) concentrations at baseline above the upper normal range of the iPTH assay (70 ng/L) revealed that mortality in this subgroup was associated with oxidized PTH but not with n-oxPTH levels.
  
  
  CONCLUSIONS
  The predictive power of n-oxPTH and iPTH on the mortality of hemodialysis patients differs substantially. Measurements of n-oxPTH may reflect the hormone status more precisely. The iPTH-associated mortality is most likely describing oxidative stress-related mortality.
authors.affiliation: MD, PhD, Institute of Nutritional Science, University of Potsdam, 14558 Nuthetal, Potsdam, Germany. hocher@uni-potsdam.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Tepel
authors.forename: Franz Paul
authors.initials: FP
authors.lastname: Armbruster
authors.forename: Hans Jürgen
authors.initials: HJ
authors.lastname: Grön
authors.forename: Alexandra
authors.initials: A
authors.lastname: Scholze
authors.forename: Christoph
authors.initials: C
authors.lastname: Reichetzeder
authors.forename: Heinz Jürgen
authors.initials: HJ
authors.lastname: Roth
authors.forename: Berthold
authors.initials: B
authors.lastname: Hocher
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000737:chemistry / Q000378:metabolism; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006801:Humans; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000378:metabolism / Q000401:mortality / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009026:Mortality; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010281:Parathyroid Hormone / Q000097:blood* / Q000737:chemistry / Q000378:metabolism; D011379:Prognosis; D011446:Prospective Studies; D055550:Protein Stability; D006435:Renal Dialysis / Q000009:adverse effects*; D016019:Survival Analysis
chemical_list: D015415:Biomarkers; C470125:PTH protein, human; D010281:Parathyroid Hormone