title: The association between parathyroid hormone and mortality in dialysis patients is modified by wasting.
abstract: BACKGROUND
  The association between parathyroid hormone (PTH) level and mortality in dialysis patients is controversial. We hypothesized that wasting, a common condition potentially related to adynamic bone disease, modifies the association of PTH with mortality and cardiovascular events (CVE), respectively.
  
  
  METHODS
  We analysed data from 1255 diabetic haemodialysis patients, participating in the German Diabetes and Dialysis Study between 1998 and 2004. The patients were stratified by the presence or absence of wasting (albumin <or=3.8 versus albumin >3.8 g/dL; BMI <or=23 versus BMI >23 kg/m(2)). Using Cox regression analyses, we calculated the risks of (1) all-cause mortality and (2) CVE according to baseline PTH levels. All analyses were adjusted for age, sex, atorvastatin treatment, duration of dialysis, comorbidity, HbA1c, phosphate, calcium, blood pressure, haemoglobin and C-reactive protein.
  
  
  RESULTS
  Patients had a mean age of 66 +/- 8 years, and 54% were male. Among patients without wasting (albumin >3.8 g/dL, n = 586), the risks of death and CVE during 4 years of follow-up significantly increased by 23% and 20% per unit increase in logPTH. Patients in the highest PTH tertile had a 74% higher risk of death (HR(adj) 1.74, 95% CI 1.27-2.40) and a 49% higher risk of CVE (HR(adj) 1.49, 95% CI 1.05-2.11) compared to patients in the lowest PTH tertile. In contrast, no effect was found in patients with wasting. Accordingly, additional analyses in strata of BMI showed that PTH significantly impacted on death and CVE [HR(logPTH)(adj) 1.15 and 1.14, respectively] only in patients without, but not in patients with, wasting.
  
  
  CONCLUSIONS
  Wasting modifies the association of PTH with adverse outcomes in diabetic dialysis patients. High PTH levels are of concern in the patients without wasting, while the effect of PTH on mortality is nullified in the patients with wasting.
authors.affiliation: Division of Nephrology, Department of Medicine, University of Würzburg, Germany. drechsler_c@medizin.uni-wuerzburg.de
authors.forename: Christiane
authors.initials: C
authors.lastname: Drechsler
authors.forename: Vera
authors.initials: V
authors.lastname: Krane
authors.forename: Diana C
authors.initials: DC
authors.lastname: Grootendorst
authors.forename: Eberhard
authors.initials: E
authors.lastname: Ritz
authors.forename: Karl
authors.initials: K
authors.lastname: Winkler
authors.forename: Winfried
authors.initials: W
authors.lastname: März
authors.forename: Friedo
authors.initials: F
authors.lastname: Dekker
authors.forename: Christoph
authors.initials: C
authors.lastname: Wanner
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood*; D006435:Renal Dialysis / Q000401:mortality*; D019282:Wasting Syndrome / Q000097:blood*
chemical_list: D010281:Parathyroid Hormone