SGLT2 inhibitors possess multiple mechanisms of improving HF syndrome, including correction of anemia; and our study aims to determine if elevation of hemoglobin is definitely linked with improved outcome in HF patients receiving placebo or dapagliflozin, if dapagliflozin use is associated with higher incidence of elevation of hemoglobin, and last but not least, if elevation of hemoglobin is accompanied by HF outcome improvement. This evidence concerns the gene SLC5A2 and hydrops fetalis.