Influence of atherosclerosis on the relationship between anaemia and mortality risk in haemodialysis patients

Abstract

Background. Full, as compared with partial, correction of anaemia did not reduce the mortality risk in patients with chronic kidney disease (CKD), although the underlying mechanisms are unknown. Since CKD is a high-risk population for cardiovascular disease (CVD), we tested a hypothesis that the presence of atherosclerosis affects the relationship between anaemia and mortality risk. Methods. We performed a single-centre 10-year follow-up study with an observational cohort of 505 haemodialysis patients to analyse the relationship between haematocrit and all-cause mortality. Baseline haematocrit levels did not differ between the 153 patients with CVD and the 352 patients without CVD. Results. During the follow-up, 268 patients died. Both Kaplan-Meier and univariate Cox analyses showed that higher haematocrit levels were a significant predictor of lower risk of death in the CVD (-) group, whereas haematocrit did not predict death in the CVD (+) group. In multivariate Cox analyses, the inverse relationship between haematocrit and mortality in the CVD (-) group remained significant and independent of 14 covariates including the use of erythropoietin. In contrast, using the same Cox models, the CVD (+) group did not show such a beneficial effect of higher haematocrit. Similar observations were made when the subjects were divided based on carotid artery intima-media thickness instead of the presence of CVD. Conclusions. These results support the hypothesis that the presence of atherosclerosis alters the relationship between anaemia and mortality risk in haemodialysis patients. © The Author [2008]. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.