title: Association between serum albumin and mortality in dialysis patients is partly explained by inflammation, and not by malnutrition.
abstract: OBJECTIVE
  We investigated the effects of inflammatory and nutritional status on the association between serum albumin and mortality in hemodialysis (HD) and peritoneal dialysis (PD) patients.
  
  
  METHODS
  This was a prospective cohort study of incident dialysis patients starting HD or PD. Inflammation (C-reactive protein >or=5 or >or=10 mg/L), malnutrition (1 to 5 on the 7-point subjective global assessment [SGA]), and low protein intake (normalized protein equivalent of nitrogen appearance [nPNA] <0.99 g/kg/day) were measured at 3 months after the start of dialysis.
  
  
  METHODS
  The study involved 38 dialysis centers in The Netherlands.
  
  
  METHODS
  We ascertained all-cause mortality during the first 2 years after the start of dialysis.
  
  
  RESULTS
  In total, 700 patients were included (mean SD age, 59 [+/-15] years; serum albumin, 3.3 (0.7) g/dL; 60% men; 454 starting HD, and 246 starting PD). The 2-year mortality was 21%. In HD patients, the mortality (hazard ratio [HR], with 95% confidence interval [95% CI]) per unit decrease in serum albumin (g/dL) was 1.47 (95% CI, 1.07 to 2.00). Adjustment for SGA did not decrease this risk, whereas adjustment for nPNA decreased the HR to 1.45 (95% CI, 1.06 to 1.97). The mortality risk decreased to 1.30 (95% CI, 0.95 to 1.78) after adjustment for inflammation, and did not further decrease after additional adjustment for SGA and nPNA. Additional adjustments for age, sex, and comorbidity decreased the HR to 1.09 (95% CI, 0.79 to 1.51). In PD patients, the effects of adjustments on the mortality risk of serum albumin (1.38; 95% CI, 0.87 to 2.20) were similar.
  
  
  CONCLUSIONS
  In dialysis patients, a 1-g/dL decrease in serum albumin was associated with an increased mortality risk of 47% in HD patients and 38% in PD patients. These mortality risks were in part explained by the inflammatory pathway. The mortality risks associated with serum albumin were not a consequence of malnutrition, as measured with SGA and nPNA. These findings imply that nutritional status cannot be assessed with precision by the measurement of serum albumin in dialysis patients.
authors.affiliation: Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands. R.de_Mutsert@lumc.nl
authors.forename: Renée
authors.initials: R
authors.lastname: de Mutsert
authors.forename: Diana C
authors.initials: DC
authors.lastname: Grootendorst
authors.forename: Fleur
authors.initials: F
authors.lastname: Indemans
authors.forename: Elisabeth W
authors.initials: EW
authors.lastname: Boeschoten
authors.forename: Raymond T
authors.initials: RT
authors.lastname: Krediet
authors.forename: Friedo W
authors.initials: FW
authors.lastname: Dekker
mesh_terms: D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis / Q000378:metabolism; D002423:Cause of Death; D015331:Cohort Studies; D004044:Dietary Proteins / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000209:etiology / Q000401:mortality*; D007676:Kidney Failure, Chronic / Q000097:blood / Q000401:mortality* / Q000628:therapy; D008297:Male; D044342:Malnutrition / Q000097:blood / Q000401:mortality; D008875:Middle Aged; D015596:Nutrition Assessment; D009752:Nutritional Status; D010530:Peritoneal Dialysis / Q000401:mortality*; D011446:Prospective Studies; D006435:Renal Dialysis / Q000401:mortality*; D012307:Risk Factors; D012709:Serum Albumin / Q000032:analysis* / Q000378:metabolism
chemical_list: D015415:Biomarkers; D004044:Dietary Proteins; D012709:Serum Albumin; D002097:C-Reactive Protein