Background: Previous reports have shown that elevated circulating levels of cytokines and/or cytokine receptors predict adverse outcomes in patients with heart failure. However, these studies were limited by small numbers of patients and/or they were performed in a single center. In addition, these studies did not have sufficient size to address the influence of age, race, sex, and cause of heart failure on the circulating levels of these inflammatory mediators in patients with heart failure.
Methods and results: We analyzed circulating levels of cytokines (tumor necrosis factor [TNF] and interleukin-6) and their cognate receptors in 1200 consecutive patients who were enrolled in a multicenter clinical trial of patients with advanced heart failure. This analysis constitutes the largest analysis of cytokines and cytokine receptors to date. Analysis of the patients receiving placebo showed that increasing circulating levels of TNF, interleukin-6, and the soluble TNF receptors were associated with increased mortality. In men, there was a linear increase in circulating levels of TNF with advancing age. Women < or = 50 years of age had relatively low levels of TNF, but TNF levels were disproportionately higher in women >50 years of age. No differences existed in cytokines and/or cytokine receptors in whites versus nonwhites, and circulating levels of cytokines and cytokine receptors were significantly greater in patients with ischemic heart disease.
Conclusions: Cytokines and cytokine receptors are independent predictors of mortality in patients with advanced heart failure. Moreover, circulating levels of cytokines are modified by age, sex, and cause of heart failure.