Plasma interleukin-6 is independently associated with mortality in both hemodialysis and pre-dialysis patients with chronic kidney disease

Chronic inflammation associated with chronic kidney disease predicts all-cause and cardiovascular mortality in hemodialysis patients. Here we sought to evaluate the association between plasma levels of the inflammatory mediator interleukin-6 (IL-6) and mortality and aortic calcification/stiffness in 125 patients at different stages (2-5D) of chronic kidney disease. Using multivariate linear regression, we found that plasma IL-6 was independently associated with C-reactive protein, albumin and the stage of chronic kidney disease, but not the aortic calcification score or pulse wave velocity. During follow-up studies (median of 829 days), 38 patients died, 22 from cardiovascular events. Plasma IL-6 significantly predicted overall and cardiovascular mortality; this association persisted after multiple adjustments or restricting the analysis to pre-dialysis patients. Moreover, IL-6 was a significantly better predictor of mortality than C-reactive protein, albumin or tumor necrosis factor-α. Hence, plasma IL-6 independently predicted overall and cardiovascular mortality in patients at different stages of chronic kidney disease; however, whether lowering plasma IL-6 will affect the outcome of chronic kidney disease will require more direct evaluation.