title: Mineral metabolism and cardiovascular morbidity and mortality risk: peritoneal dialysis patients compared with haemodialysis patients.
abstract: BACKGROUND
  The K/DOQI guideline for bone metabolism and disease in chronic kidney disease is predominantly based on studies in haemodialysis (HD) patients. However, in clinical practice, this guideline is also applied to peritoneal dialysis (PD) patients. To validate the implementation of this guideline in PD patients, we evaluated the associations between plasma concentrations outside the K/DOQI-targets and the risk of cardiovascular morbidity and mortality in incident PD patients compared with HD patients.
  
  
  METHODS
  In a large prospective multicentre study in the Netherlands (The Netherlands Cooperative Study on the Adequacy of Dialysis, NECOSAD), we included patients starting PD or HD between 1997 and 2004. Relative risk of cardiovascular morbidity and mortality were estimated using time-dependent Cox regression modelling.
  
  
  RESULTS
  We included 586 PD patients with mean age 52 +/- 15 years (66% males) and 1043 HD patients with mean age 63 +/- 14 years (58% males). Cardiovascular disease (CVD) was the reason for hospitalization in 102 PD and 271 HD patients. In HD patients, the relative risk of CVD-related hospitalization increased with elevated plasma calcium concentrations (hazard ratio: 1.4; 95% CI: 1.1-1.9). Cardiovascular mortality was significantly higher for phosphorus concentrations above the K/DOQI-threshold in PD (2.4; 95% CI: 1.3-4.2) and HD patients (1.5; 95% CI: 1.1-2.1), and for elevated Ca x P in PD (2.2; 95% CI: 1.3-3.8) and HD patients (1.5; 95% CI: 1.1-2.1).
  
  
  CONCLUSIONS
  Plasma calcium concentrations above the K/DOQI-threshold increase the relative risk of CVD-related hospitalization in HD patients. Associations with cardiovascular mortality were more pronounced. Both in PD and HD patients with elevated plasma phosphorus and Ca x P concentrations, the cardiovascular mortality risk is increased. Therefore, it seems appropriate to adopt the current guideline in PD patients.
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands. m.noordzij@amc.uva.nl
authors.forename: Marlies
authors.initials: M
authors.lastname: Noordzij
authors.forename: Johanna C
authors.initials: JC
authors.lastname: Korevaar
authors.forename: Willem J
authors.initials: WJ
authors.lastname: Bos
authors.forename: Elisabeth W
authors.initials: EW
authors.lastname: Boeschoten
authors.forename: Friedo W
authors.initials: FW
authors.lastname: Dekker
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Bossuyt
authors.forename: Raymond T
authors.initials: RT
authors.lastname: Krediet
mesh_terms: D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000097:blood*; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009017:Morbidity / Q000639:trends; D009426:Netherlands / Q000453:epidemiology; D010530:Peritoneal Dialysis / Q000009:adverse effects; D010758:Phosphorus / Q000097:blood*; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects*; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends
chemical_list: D015415:Biomarkers; D010758:Phosphorus; D002118:Calcium