Effect of Empagliflozin on the Mechanisms Driving Erythropoiesis and Iron Mobilization in Patients With Heart Failure

Background
Sodium-glucose cotransporter 2 (SGLT2) inhibitors stimulate erythropoiesis, but the mechanisms and clinical relevance of the effect of SGLT2 inhibitors on systemic iron metabolism in patients with heart failure is not well understood.
Objectives
The authors sought to characterize a comprehensive suite of iron metabolism biomarkers—particularly the erythroblast signaling molecule, erythroferrone—in patients with heart failure before and after short- and long-term treatment with empagliflozin in patients with heart failure and a reduced or preserved ejection fraction.
Methods
We measured serum iron metabolism biomarkers at baseline, 12 weeks, and 52 weeks in 1,139 patients who were treated with placebo or empagliflozin in the EMPEROR (EMPagliflozin outcomE tRial in Patients With chrOnic heaRt Failure) program, and we characterized the inter-relationships of these biomarkers with clinical status and with the effect of empagliflozin on erythropoiesis and heart failure outcomes.
Results
Correlations among iron biomarkers indicated the presence of a functional erythropoietin-erythroferrone–transferrin-receptor-protein-1 (TfR1)–hepcidin axis. As heart failure advanced, patients showed higher levels of erythropoietin, erythroferrone, and TfR1 (P trend <0.01), and levels of these proteins predicted a heightened risk of cardiovascular death or heart failure hospitalization (all P < 0.01). Compared with placebo, at 12 weeks, empagliflozin increased hemoglobin by 0.6 to 0.9 g/dL (P < 0.001), an effect that was accompanied by further activation of the erythropoietin-erythroferrone-TfR1 axis and increased iron use. Empagliflozin increased serum levels of erythroferrone by >40% (along with increases in erythropoietin and TfR1), while simultaneously decreasing hepcidin levels and reducing serum iron concentrations and transferrin saturation (all P < 0.01). When treated with empagliflozin, patients with evidence of iron deficiency at baseline showed attenuation of the erythrocytic response (P trend = 0.04) but no diminution of the heart failure benefits.ConclusionsThe erythropoietin-erythroferrone-TfR1-hepcidin axis is activated in patients with heart failure as the disease advances and is further heightened by SGLT2 inhibitors, in parallel with their effect to enhance erythropoiesis and iron mobilization and use. These changes have important implications for understanding the mechanism of action of SGLT2 inhibitors and for monitoring the response to treatment.