Iron deficiency in chronic heart failure: an international pooled analysis

Abstract

Background: Iron deficiency (ID) is an emerging problem in patients with chronic heart failure (HF) and can be a potential therapeutic target. However, not much is known about the prevalence, predictors, and prognosis of ID in patients with chronic HF.

Methods: In an international pooled cohort comprising 1,506 patients with chronic HF, we studied the clinical associates of ID and its prognostic consequences.

Results: Iron deficiency (defined as a ferritin level <100 μg/L or ferritin 100-299 μg/L with a transferrin saturation <20%) was present in 753 patients (50%). Anemic patients were more often iron deficient than nonanemic patients (61.2% vs 45.6%, P < .001). Other independent predictors of ID were higher New York Heart Association class, higher N-terminal pro-brain-type natriuretic peptide levels, lower mean corpuscular volume levels, and female sex (all P < .05). During follow-up (median 1.92 years, interquartile range 1.18-3.26 years), 440 patients died (29.2%). Kaplan-Meier survival analysis revealed ID as a strong predictor for mortality (log rank χ(2) 10.2, P = .001). In multivariable hazard models, ID (but not anemia) remained a strong and independent predictor of mortality (hazard ratio 1.42, 95% confidence interval 1.14-1.77, P = .002). Finally, the presence of ID significantly enhanced risk classification and integrated discrimination improvement when added to a prediction model with established risk factors.

Conclusions: Iron deficiency is common in patients with chronic HF, relates to disease severity, and is a strong and independent predictor of outcome. In this study, ID appears to have greater predictive power than anemia.