Monitoring of iron status in patients with heart failure

Role of Iron Deficiency in Heart Failure-Clinical and Treatment Approach: An Overview

BACKGROUND

The association of chronic heart failure (CHF) and iron deficiency (ID) with or without anemia is frequently encountered in current medical practice and has a negative prognostic impact, worsening patients' exercise capacity and increasing hospitalization costs. Moreover, anemia is common in patients with chronic kidney disease (CKD) and CHF, an association known as cardio-renal anemia syndrome (CRAS) possessing a significantly increased risk of death.

AIM

This review aims to provide an illustrative survey on the impact of ID in CHF patients-based on physiopathological traits, clinical features, and the correlation between functional and absolute ID with CHF-and the benefit of iron supplementation in CHF.

METHOD

We selected the most recent publications with important scientific content covering the association of CHF and ID with or without anemia.

DISCUSSIONS

An intricate physiopathological interplay is described in these patients-decrease in erythropoietin levels, activation of the renin-angiotensin-aldosterone system, systemic inflammation, and increases in hepcidin levels. These mechanisms amplify anemia, CHF, and CKD severity and worsen patients' outcomes.

CONCLUSIONS

Anemia is frequently encountered in CHF and represents a negative prognostic factor. Data from randomized controlled trials have underlined the administration of intravenous iron therapy (ferric carboxymaltose) as the only viable treatment option, with beneficial effects on quality of life and exercise capacity in patients with ID and systolic heart failure.

Iron homeostasis in heart transplant recipients randomized to ferric derisomaltose or placebo

Introduction

The randomized IronIC trial evaluated the effect of intravenous ferric derisomaltose on physical capacity in iron‐deficient, maintenance heart transplant (HTx) recipients. Iron deficiency was defined as in heart failure with high cut‐points for ferritin to compensate for inflammation. However, intravenous iron did not improve physical capacity except in patients with ferritin <30 μg/L. We aimed to explore determinants of iron status in the 102 IronIC participants to better define iron deficiency in the HTx population.

Methods

We assessed key governors of iron homeostasis, such as hepcidin, soluble transferrin receptor (sTfR), and interleukin‐6 (IL‐6). We also measured growth factors and inflammatory markers with relevance for iron metabolism. The results were compared to those of 21 healthy controls.

Results

Hepcidin did not differ between HTx recipients and controls, even though markers of inflammation were modestly elevated. However, HTx recipients with ferritin <30 μg/L or sTfR above the reference range had significantly reduced hepcidin levels suggestive of true iron deficiency. In these patients, intravenous iron improved peak oxygen uptake. Hepcidin correlated positively with ferritin and negatively with sTfR.

Conclusion

HTx recipients with iron deficiency as defined in heart failure do not have elevated hepcidin levels, although inflammatory markers are modestly increased. The high ferritin cut‐offs used in heart failure may not be suitable to define iron deficiency in the HTx population. We suggest that hepcidin and sTfR should be measured to identify patients with true iron deficiency, who might benefit from treatment with intravenous iron.

Phenotyping heart failure patients for iron deficiency and use of intravenous iron therapy: data from the Swedish Heart Failure Registry

AIMS

Iron deficiency (ID) is associated with poor prognosis regardless of anaemia. Intravenous iron improves quality of life and outcomes in patients with ID and heart failure (HF) with reduced ejection fraction (HFrEF). In the Swedish HF registry, we assessed (i) frequency and predictors of ID testing; (ii) prevalence and outcomes of ID with/without anaemia; (iii) use of ferric carboxymaltose (FCM) and its predictors in patients with ID.

METHODS AND RESULTS

We used multivariable logistic regressions to assess patient characteristics independently associated with ID testing/FCM use, and Cox regressions to assess risk of outcomes associated with ID. Of 21 496 patients with HF and any ejection fraction enrolled in 2017-2018, ID testing was performed in 27%. Of these, 49% had ID and more specifically 36% had ID-/anaemia-, 15% ID-/anaemia+, 29% ID+/anaemia-, and 20% ID+/anaemia+ (48%, 39%, 13%, 30% and 18% in HFrEF, respectively). Risk of recurrent all-cause hospitalizations was higher in patients with ID regardless of anaemia. Of 1959 patients with ID, 19% received FCM (24% in HFrEF). Important independent predictors of ID testing and FCM use were anaemia, higher New York Heart Association class, having HFrEF, and referral to HF specialty care.

CONCLUSION

In this nationwide HF registry, ID testing occurred in only about a quarter of the patients. Among tested patients, ID was present in one half, but only one in five patients received FCM indicating low adherence to current guidelines on screening and treatment.

Should we use ferritin in the diagnostic criteria of iron deficiency in heart failure patients?

BACKGROUND AND AIMS

Iron deficiency (ID) is a common comorbidity in patients with chronic heart failure (HF) and is associated with worse prognosis. We aimed at comparing the currently European Society of Cardiology (ESC) criterion for diagnosis of ID (ferritin < 100 μg/L or ferritin 100-299 μg/L with transferrin saturation [TSAT] < 20%) with either isolated low TSAT or isolated low ferritin on survival, in a cohort of HF patients.

METHODS

This was an observational prospective study, investigating ambulatory patients with HF and reduced ejection fraction (n = 108). All patients were assessed for clinical aspects and iron indexes. The primary endpoint was all-cause death.

RESULTS

Abnormal iron status was observed in 50 (46%) of patients. During the median follow-up time of 857.5 [647-899] days, 31 patients died (29%). In univariate analyses ESC-criterion (p = 0.022) and isolated TSAT <20% (p = 0.002), but not isolated ferritin <100 μg/L (p = 0.439), were significantly related to an increased risk of all-cause death. However, in multivariate analyses only TSAT <20% (HR = 2.3; [95% CI: 1.11-4.85]; p = 0.026) was independently related to all-cause mortality.

CONCLUSIONS

Our results indicated that diagnosis of ID based on isolated TSAT <20% identifies HF patients with worse prognosis, while ferritin was not associated with mortality risk, suggesting that ferritin should not be taken into account for evaluation of clinical impact of ID in HF patients.

Iron deficiency and iron therapy in heart failure and chronic kidney disease

PURPOSE OF REVIEW

Iron deficiency is common and associated with adverse outcomes in heart failure, regardless of anemia. Iron deficiency, absolute and functional, with and without anemia, is associated with adverse outcomes in chronic kidney disease (CKD). Heart failure and CKD frequently occur together. Intravenous iron therapy has been shown to reduce heart failure symptoms and improve physical function in heart failure with reduced ejection fraction with iron deficiency. In CKD, intravenous or oral iron therapy are often used for management of anemia, along with erythropoiesis stimulating agents, yet the risks and benefits of intravenous iron use is controversial. In this review, we survey available evidence and ongoing studies of iron deficiency and iron supplementation in heart failure, and integrate with recent evidence on effectiveness and safety of intravenous iron therapy in CKD.

RECENT FINDINGS

Intravenous iron therapy improves heart failure symptoms and physical function in heart failure with reduced ejection fraction and iron deficiency, regardless of anemia, and may reduce heart failure hospitalizations and cardiovascular mortality. Sustained intravenous iron therapy regardless of hemoglobin level in selected patients with end-stage kidney disease receiving hemodialysis improves outcomes, and does not appear to cause infectious complications.

SUMMARY

Iron therapy has important effects in heart failure and CKD, and appears safe in the short term. Ongoing trials will provide additional important information.