Iron deficiency contributes to resistance to endogenous erythropoietin in anaemic heart failure patients

Eur J Heart Fail. 2021 Oct;23(10):1677-1686. doi: 10.1002/ejhf.2253. Epub 2021 Jul 11.

Abstract

Aims: Abnormal endogenous erythropoietin (EPO) constitutes an important cause of anaemia in chronic diseases. We analysed the relationships between iron deficiency (ID) and the adequacy of endogenous EPO in anaemic heart failure (HF) patients, and the impact of abnormal EPO on 12-month mortality.

Methods and results: We investigated 435 anaemic HF patients (age: 74 ± 10 years; males: 60%; New York Heart Association class I or II: 39%; left ventricular ejection fraction: 43 ± 17%). Patients with EPO higher than expected for a given haemoglobin were considered EPO-resistant whereas those with EPO lower than expected - EPO-deficient. ID was defined as serum ferritin <100 µg/L or 100-299 µg/L with transferrin saturation <20%. EPO-resistant patients (22%) had more advanced HF whereas those with EPO deficiency (57%) were more frequently females and had worse renal function. Lower serum ferritin (indicating depleted body iron stores) was related to higher EPO observed/predicted ratio when adjusted for significant clinical confounders, including C-reactive protein. One year all-cause mortality was 28% in patients with EPO resistance compared to 17% in patients with EPO deficiency and 10% in patients with adequate EPO (log-rank test for the comparison EPO resistance vs. adequate EPO: P = 0.02). When adjusted for other prognosticators, there was still a trend towards increased 12-month mortality in patients with higher EPO level.

Conclusion: Anaemic HF patients with endogenous EPO deficiency vs. resistance have different clinical and laboratory characteristics. In such patients, ID contributes to EPO resistance independently of inflammation.

Keywords: Anaemia; Erythropoietin; Heart failure; Iron deficiency; Mortality.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Anemia*
  • Anemia, Iron-Deficiency*
  • Erythropoietin*
  • Female
  • Heart Failure*
  • Hemoglobins / metabolism
  • Humans
  • Iron Deficiencies*
  • Male
  • Middle Aged

Substances

  • EPO protein, human
  • Hemoglobins
  • Erythropoietin