The effect of intravenous ferric carboxymaltose on red cell distribution width: a subanalysis of the FAIR-HF study
van Craenenbroeck, Emeline M.
Faculty of Medicine and Health Sciences
European journal of heart failure. - Place of publication unknown
, p. 756-762
University of Antwerp
Red cell distribution width (RDW), a measure of variability in red blood cell size, is a novel prognostic marker in chronic heart failure (CHF). Iron deficiency contributes to elevated RDW. In the FAIR-HF trial, i.v. ferric carboxymaltose (FCM) improved the 6 min walk test (6MWT) distance in iron-deficient CHF patients. We studied the effect of FCM on RDW and the relationship between RDW and 6MWT distance. In FAIR-HF, iron-deficient CHF patients were randomized to FCM or placebo in a 2:1 ratio. From the total cohort (n 459), we included 415 patients in whom RDW values and 6MWT distance were available for baseline and at least one follow-up visit (after 4, 12, and 24 weeks). Baseline RDW was higher in anaemic (haemoglobin 12 g/dL) compared with non-anaemic patients [15.2 (14.016.8) vs. 14.2 (13.415.4), P 0.0001, median (interquartile range)]. In multivariate analysis, RDW was significantly associated with transferrin saturation (P 0.001) and C-reactive protein levels (P 0.002). Treatment with FCM led to a biphasic response; RDW increased within 4 weeks (0.54 absolute change from baseline, P 0.01) but fell to values below the placebo group after 24 weeks (1.0 , P 0.03). The 6MWT distance and RDW were inversely related at baseline (r 0.30, P 0.0001). In all patients, the increase in 6MWT distance after 24 weeks was significantly correlated with a decrease in RDW (r 0.25, P 0.0001), even after adjustment for changes in haemoglobin. Iron deficiency in CHF is associated with high RDW, even after adjustment for the presence of anaemia. Treatment with i.v. FCM in iron-deficient CHF patients decreases RDW.