Interleukin-8 Is a Powerful Prognostic Predictor of All-Cause and Cardiovascular Mortality in Dialytic Patients

BACKGROUND: Cohort studies have demonstrated an association between C-reactive protein (CRP) and interleukin-6 (IL-6) and all-cause and cardiovascular mortality in end-stage renal disease (ESRD) patients. Interleukin-8 (IL-8) appears to be not only the plasma expression of the acute-phase response but also a direct pathogenetic mediator of the atherosclerotic process. METHODS: To evaluate the role of IL-8 in predicting outcome, 76 chronic dialytic patients were prospectively followed for 18 months. At baseline, blood samples were taken for analysis of high-sensitivity CRP, IL-6, IL-8 and other standard laboratory analyses. RESULTS: Median IL-8 was 5.2 mg/l, therefore near half of the patients had IL-8 values within the range of 'normal limits'. IL-6 and CRP were significantly correlated (r = 0.45, p < 0.001) and a positive correlation was also found between IL-6 and IL-8 (r = 0.39, p < 0.001). The correlation coefficient between IL-6 and CRP was 0.43 (p < 0.001) and 0.50 (p < 0.001) in patients without and with history and/or clinical signs of cardiovascular disease, respectively. After a follow-up of 1.5 years, 8 patients had died from cardiovascular causes and another 7 patients for other reasons; furthermore 9 major nonfatal cardiovascular events were recorded. Stepwise regression analysis showed IL-8 as the strongest independent predictor of all-cause and cardiovascular events (p = 0.0025) even after adjustment for age and dialytic age, followed by IL-6 and CRP (p < 0.01). CONCLUSION: Despite a small population and a relatively short follow-up period, this study firstly demonstrated that IL-8 is a powerful independent predictive factor for cardiovascular and overall mortality cause in ESRD patients.