Plasma interleukin-6 predicts cardiovascular mortality in hemodialysis patients

Am J Kidney Dis. 2005 Feb;45(2):324-33. doi: 10.1053/j.ajkd.2004.09.018.


Background: Interleukin-6 (IL-6) is a mediator and marker of the chronic inflammatory process that is responsible for much of the morbidity and mortality seen in hemodialysis (HD) patients. This study evaluated circulating plasma IL-6 as a predictor of all-cause mortality and cardiovascular mortality and studied its relationship to prevalent comorbidity and hypoalbuminemia, in a cohort of stable HD patients enrolled in the HEMO study.

Methods: Clinical data included demographic, medical, and routine laboratory parameters. Comorbidities were graded using the Index of Co-Existing Diseases (ICED). Outcomes of interest were all-cause mortality and cardiovascular mortality. Blood samples were drawn at enrollment and annually, and plasma IL-6 levels measured with high-sensitivity enzyme-linked immunosorbent assay.

Results: Median plasma IL-6 level in 206 patients was 7.9 pg/mL (range, 0.1 to 90.3 pg/mL) and was higher in patients with vascular disease ( P = 0.03), higher ICED scores ( P = 0.01), and lower Karnofsky indices ( P < 0.01). Serum albumin was inversely related to plasma IL-6 levels ( P = 0.03, r = -0.16). Unadjusted median survival time was 1,209 days in the lowest quartile of plasma IL-6 and 806 days in the highest ( P = 0.02, log rank test). A 1-log increase in plasma IL-6 was associated with a 1.19-fold higher adjusted risk for all-cause mortality ( P = 0.04; 95% confidence interval, 1.01 to 1.40) and a 1.43-fold higher adjusted risk of cardiovascular mortality ( P = 0.02; 95% confidence interval, 1.06 to 1.92). Hazard ratio estimates were higher when IL-6 levels over time were incorporated as a time-dependent covariate.

Conclusion: Plasma IL-6 levels are strongly associated with comorbidity in HD patients and are a powerful predictor of cardiovascular and all-cause mortality.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers / blood
  • Cardiovascular Diseases / mortality*
  • Comorbidity / trends
  • Female
  • Humans
  • Interleukin-6 / blood*
  • Kidney Failure, Chronic / blood
  • Kidney Failure, Chronic / mortality
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Prospective Studies
  • Renal Dialysis / methods*
  • Serum Albumin / metabolism
  • Urea / blood
  • Urea / metabolism
  • Urea / urine
  • beta 2-Microglobulin / blood
  • beta 2-Microglobulin / metabolism
  • beta 2-Microglobulin / urine


  • Biomarkers
  • Interleukin-6
  • Serum Albumin
  • beta 2-Microglobulin
  • Urea