Acute heart failure and iron deficiency: a prospective, multicentre, observational study

The prevalence and the natural course of iron deficiency (ID) in acute heart failure (AHF) are still unclear. We investigated the prevalence of ID in unselected patients admitted with AHF on admission, at discharge and up to 3 months thereafter.

Methods and results
In this prospective, multicentre, observational study, 742 patients admitted with AHF were enrolled. The main study outcome was the percentage of patients with ID (ferritin <100 μg/L = absolute ID or ferritin 100–299 μg/L and transferrin saturation <20% = functional ID) at admission (T0), after clinical stabilization prior to discharge (T1), and 10 ± 6 weeks after discharge (T2). At T0, ID was present in 71.8% of the patients (44.1% absolute and 27.7% functional ID). At T1 and T2, ID was present in 56.4% (32.4% absolute and 24% functional ID) and 50.3% (36.8% absolute and 13.5% functional ID), respectively. Absolute ID persisted from T0 to T2 in 66% of the patients, while functional ID resolved in 56% of the patients. Ferritin (median [interquartile range] 124 μg/L [56–247] to 150 μg/L [73–277]), transferrin saturation (15% [10–20] to 18% [12–27]), and iron levels (9 μmol/L [6–13] to 11 μmol/L [8–16]) increased significantly (all P < 0.001) from T0 to T1. Transferrin saturation (to 21% [15–29]) and iron levels (to 13 μmol/L [9–17]) also increased significantly (both P < 0.01) from T1 to T2 without iron supplementation.

Iron deficiency is highly prevalent in patients with AHF, but resolves during treatment in some patients, even without iron supplementation. Absolute ID is more likely to persist over time, whereas functional ID often resolves during treatment of AHF, representing probably a reduced iron availability rather than a true deficiency.