Although there was only a borderline significant increase in erythropoietin, other studies suggest that an earlier peak may have been missed because this measurement was only repeated 12 months after starting treatment in DAPA-HF.16,17 However, erythropoiesis, leading to increased mobilization and use of iron, would be expected to cause an increase in soluble transferrin receptor levels and iron-binding capacity, coupled with a decrease in ferritin, TSAT, and hepcidin, all of which were observed in DAPA-HF. The gene discussed is HAMP; the disease is hydrops fetalis.