With regard to GDF-15, we believe that its investigation could be profitable since it has not been validated yet by the main Societies [1,20] and given the fact that it has been assessed, essentially, in chronic HF, leading to scarce evidence in ADHF [21]. The most recent studies have related iron deficiency to rehospitalization risk in ADHF (AFFIRM-AHF) [29] and in ambulatory HF patients (IRONMAN) [30]. This evidence concerns the gene GDF15 and hydrops fetalis.