Associations of interleukin-6, C-reactive protein and serum amyloid A with mortality in haemodialysis patients

Nephrology (Carlton). 2008 Oct;13(7):593-600. doi: 10.1111/j.1440-1797.2008.01021.x. Epub 2008 Sep 25.


Background: Individuals with end-stage renal disease (ESRD) manifest a chronic inflammatory state. Serum albumin, C-reactive protein (CRP), interleukin-6 (IL-6) and serum amyloid A (SAA) have been associated with mortality in ESRD, although reports vary as to whether they are true independent markers of mortality. We undertook a prospective study to determine whether these markers could predict mortality in ESRD.

Methods: A cohort of individuals on haemodialysis was followed prospectively for a mean of 2.1 years. Albumin, CRP, IL-6 and SAA were drawn at enrollment. Association between mortality and serum markers was assessed using Cox proportional hazards regression. A trend analysis was undertaken to establish the functional form of the association between serum markers and outcome.

Results: After multivariable adjustment, IL-6 was most strongly associated with mortality, followed closely by albumin (P = 0.0002 and P = 0.0005, respectively). CRP was marginally associated with mortality (P = 0.046), and SAA was not independently associated with mortality. In the final model adjusting for the effects of both IL-6 and albumin simultaneously, both markers remained associated with mortality (P = 0.003 and P = 0.011).

Conclusion: IL-6 had the strongest independent association with mortality, followed closely by albumin. CRP and SAA were not associated with mortality when measured at single time points. Increasing levels of IL-6 and decreasing levels of albumin were associated with increased mortality. IL-6 and albumin may be capturing different aspects of the inflammatory burden observed in haemodialysis patients.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Biomarkers
  • C-Reactive Protein / analysis*
  • C-Reactive Protein / physiology
  • Female
  • Humans
  • Interleukin-6 / blood*
  • Male
  • Middle Aged
  • Proportional Hazards Models
  • Renal Dialysis / mortality*
  • Serum Albumin / analysis
  • Serum Amyloid A Protein / analysis*


  • Biomarkers
  • Interleukin-6
  • Serum Albumin
  • Serum Amyloid A Protein
  • C-Reactive Protein