Differences in Clinical Profile and Outcomes of Low Iron Storage vs Defective Iron Utilization in Patients With Heart Failure: Results From the DEFINE-HF and BIOSTAT-CHF Studies

Identification of three mechanistic pathways for iron-deficient heart failure

Current understanding of iron-deficient heart failure is based on blood tests that are thought to reflect systemic iron stores, but the available evidence suggests greater complexity. The entry and egress of circulating iron is controlled by erythroblasts, which (in severe iron deficiency) will sacrifice erythropoiesis to supply iron to other organs, e.g. the heart. Marked hypoferraemia (typically with anaemia) can drive the depletion of cardiomyocyte iron, impairing contractile performance and explaining why a transferrin saturation < ≈15%-16% predicts the ability of intravenous iron to reduce the risk of major heart failure events in long-term trials (Type 1 iron-deficient heart failure). However, heart failure may be accompanied by intracellular iron depletion within skeletal muscle and cardiomyocytes, which is disproportionate to the findings of systemic iron biomarkers. Inflammation- and deconditioning-mediated skeletal muscle dysfunction-a primary cause of dyspnoea and exercise intolerance in patients with heart failure-is accompanied by intracellular skeletal myocyte iron depletion, which can be exacerbated by even mild hypoferraemia, explaining why symptoms and functional capacity improve following intravenous iron, regardless of baseline haemoglobin or changes in haemoglobin (Type 2 iron-deficient heart failure). Additionally, patients with advanced heart failure show myocardial iron depletion due to both diminished entry into and enhanced egress of iron from the myocardium; the changes in iron proteins in the cardiomyocytes of these patients are opposite to those expected from systemic iron deficiency. Nevertheless, iron supplementation can prevent ventricular remodelling and cardiomyopathy produced by experimental injury in the absence of systemic iron deficiency (Type 3 iron-deficient heart failure). These observations, taken collectively, support the possibility of three different mechanistic pathways for the development of iron-deficient heart failure: one that is driven through systemic iron depletion and impaired erythropoiesis and two that are characterized by disproportionate depletion of intracellular iron in skeletal and cardiac muscle. These mechanisms are not mutually exclusive, and all pathways may be operative at the same time or may occur sequentially in the same patients.

Intravenous iron in patients with iron deficiency and heart failure: a review of modern evidence

PURPOSE OF REVIEW

Iron deficiency is common in patients with heart failure, affecting up to half of ambulatory patients and an even greater percentage of patients admitted for acute decompensation. Iron deficiency in this population is also associated with poor outcomes, including worse quality of life in addition to increased hospitalizations for heart failure and mortality. Evidence suggests that patients with iron deficiency in heart failure may benefit from repletion with IV iron.

RECENT FINDINGS

In this review, we outline the etiology and pathophysiology of iron deficiency in heart failure as well as various iron formulations available. We discuss evidence for intravenous iron repletion with a particular focus on recent studies that have evaluated its effects on hospitalizations and mortality. Finally, we discuss areas of uncertainty and future study and provide practical guidance for iron repletion.

SUMMARY

In summary, there is overwhelming evidence that intravenous iron repletion in patients with iron deficiency in heart failure is both beneficial and safe. However, further evidence is needed to better identify which patients would most benefit from iron repletion as well as the ideal repletion strategy.

Intravenous iron for heart failure, iron deficiency definitions, and clinical response: the IRONMAN trial

BACKGROUND AND AIMS

What is the relationship between blood tests for iron deficiency, including anaemia, and the response to intravenous iron in patients with heart failure?

METHODS

In the IRONMAN trial, 1137 patients with heart failure, ejection fraction ≤ 45%, and either serum ferritin < 100 µg/L or transferrin saturation (TSAT) < 20% were randomized to intravenous ferric derisomaltose (FDI) or usual care. Relationships were investigated between baseline anaemia severity, ferritin and TSAT, to changes in haemoglobin from baseline to 4 months, Minnesota Living with Heart Failure (MLwHF) score and 6-minute walk distance achieved at 4 months, and clinical events, including heart failure hospitalization (recurrent) or cardiovascular death.

RESULTS

The rise in haemoglobin after administering FDI, adjusted for usual care, was greater for lower baseline TSAT (Pinteraction < .0001) and ferritin (Pinteraction = .028) and more severe anaemia (Pinteraction = .014). MLwHF scores at 4 months were somewhat lower (better) with FDI for more anaemic patients (overall Pinteraction = .14; physical Pinteraction = .085; emotional Pinteraction = .043) but were not related to baseline TSAT or ferritin. Blood tests did not predict difference in achieved walking distance for those randomized to FDI compared to control. The absence of anaemia or a TSAT ≥ 20% was associated with lower event rates and little evidence of benefit from FDI. More severe anaemia or TSAT < 20%, especially when ferritin was ≥100 µg/L, was associated with higher event rates and greater absolute reductions in events with FDI, albeit not statistically significant.

CONCLUSIONS

This hypothesis-generating analysis suggests that anaemia or TSAT < 20% with ferritin > 100 µg/L might identify patients with heart failure who obtain greater benefit from intravenous iron. This interpretation requires confirmation.

Biomarker and transcriptomics profiles of serum selenium concentrations in patients with heart failure are associated with immunoregulatory processes

BACKGROUND

Low selenium concentrations are associated with worse outcomes in heart failure (HF). However, the underlying pathophysiologic mechanisms remain incompletely understood. Therefore, we aimed to contrast serum selenium concentrations to blood biomarker and transcriptomic profiles in patients with HF.

METHODS

Circulating biomarkers, whole blood transcriptomics and serum selenium measurements in a cohort of 2328 patients with HF were utilized. Penalized linear regression and gene expression analysis were used to assess biomarker and transcriptomics profiles, respectively. As a proof-of-principle, potential causal effects of selenium on excreted cytokines concentrations were investigated using human peripheral blood mononuclear cells (PBMCs).

RESULTS

Mean selenium levels were 60.6 μg/L in Q1 and 122.0 μg/L in Q4. From 356 biomarkers and 20 clinical features, the penalized linear regression model yielded 44 variables with <5 % marginal false discovery rate as predictors of serum selenium. Biomarkers associated positively with selenium concentrations included: epidermal growth factor receptor (EGFR), IFN-gamma-R1, CD4, GDF15, and IL10. Biomarkers associated negatively with selenium concentrations included: PCSK9, TNFSF13, FGF21 and PAI. Additionally, 148 RNA transcripts were found differentially expressed between high and low selenium status (Padj.<0.05; log-fold-change<|0.25|). Enrichment analyses of the selected biomarkers and RNA transcripts identified similar enriched processes, including regulation processes of leukocyte differentiation and activation, as well as cytokines production. The mRNA expression of two selenoproteins (MSRB1 and GPX4) were strongly correlated with serum selenium, while GPX4, SELENOK, and SELENOS were associated with prognosis. In the in-vitro setting, PBMCs supplemented with selenium showed significantly lower abundance of several (pro-)inflammatory cytokines.

CONCLUSION

These data suggest that immunoregulation is an important mechanism through which selenium might have beneficial roles in HF. The beneficial effects of higher serum selenium concentrations are likely because of global immunomodulatory effects on the abundance of cytokines. MSRB1 and GPX4 are potential modulators of and should be pursued in future research.

Associations of iron metabolism and inflammation with all-cause and cardiovascular mortality in a large NHANES community sample: Moderating and mediating effects

BACKGROUND AND AIMS

This study aimed to assess the associations between serum iron concentration, C-reactive protein (CRP) concentration and the risk of all-cause mortality and cardiovascular mortality in the general population and to explore potential mediating and moderating effects.

METHODS AND RESULTS

This study analyzed data from the National Health and Nutrition Examination Survey spanning the years 1999-2010, encompassing 23,634 participants. Cox proportional hazards regression models were employed to investigate the independent associations of serum iron and CRP with all-cause and cardiovascular mortality. Moderation and mediation analyses explored the moderating effect of CRP on the association between the serum iron concentration and all-cause and cardiovascular mortality, and the mediating role of the serum iron concentration in the association between the CRP concentration and all-cause and cardiovascular mortality. After multivariate adjustments in the Cox model, serum iron and CRP levels were independently correlated with both all-cause and cardiovascular mortality risk. Moderation analyses revealed a more pronounced correlation between the serum iron concentration and both all-cause and cardiovascular mortality in participants with higher CRP levels. Mediation analysis indicated that the serum iron concentration partly mediated the impact of CRP on the risk of all-cause mortality (13.79%) and cardiovascular mortality (24.12%).

CONCLUSION

Serum iron and CRP are independently associated with all-cause and cardiovascular mortality. Moreover, the associations between serum iron concentrations and both all-cause and cardiovascular mortality are more pronounced in individuals with elevated CRP. Serum iron partially mediates the effect of CRP on all-cause and cardiovascular mortality.

Iron deficiency and anemia in pediatric dilated cardiomyopathy are associated with clinical, biochemical, and hematological markers of severe disease and adverse outcomes

BACKGROUND

There is limited evidence regarding the prevalence and impact of iron deficiency (ID) in children with dilated cardiomyopathy (DCM).

METHODS

Retrospective single-center review of all children between 2010 and 2020 with a diagnosis of DCM and complete iron studies. ID was defined as ≥2 of ferritin <20 μg/liter, iron <9 μmol/liter, transferrin >3 g/liter, or transferrin saturation (TSat) <15%. Clinical and laboratory indices and freedom from a composite adverse event (CAE) of mechanical circulatory support (MCS), heart transplant, or death were compared between children with and without ID.

RESULTS

Of 138 patients with DCM, 47 had available iron studies. Twenty-nine (62%) were iron deficient. Children with ID were more likely to be receiving inotropes (17, 59%, p = 0.005) or invasive/noninvasive ventilation (13, 45%, p = 0.016) than those who were iron replete. They had a higher incidence of anemia (22, 76%, p = 0.004) and higher NT-proBNP (1,590 pmol/liter, IQR 456-3,447, p = 0.001). Children with ID had significantly less freedom from the CAE at 1-year (54% ± 10%), 2-years (45 ± 10), and 5-years (37% ± 11%) than those without (p = 0.011). ID and anemia were the only significant predictors of the CAE on univariate Cox regression.

CONCLUSIONS

ID is highly prevalent in children with DCM. Iron studies are undermeasured in clinical practice, but ID is associated with severe heart failure (HF) and an increased risk of the CAE. The need for iron replacement therapy should be considered in children who present in HF with DCM.

The effect of the four pharmacological pillars of heart failure on haemoglobin level

Anaemia, a condition characterized by low levels of haemoglobin, is frequently observed in patients with heart failure (HF). Guideline-directed medical therapy improves HF outcomes by using medications like beta blockers, angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers, along with mineralocorticoid receptor antagonists and sodium-glucose cotransporter 2 inhibitors. In this study, we aimed to review the pathophysiology of anaemia in patients with HF and present the current evidence regarding the relationship between the main recommended medications for these patients and haemoglobin levels. The authors conducted a comprehensive search in the medical literature for relevant original clinical articles in which the four pharmacological pillars of HF were given to the patients; we, then, assessed whether the association of use of these medications and haemoglobin level or development of anaemia was provided. These common medications have been shown in the literature that may exacerbate or ameliorate anaemia. Besides, it has been shown that even in the case that they result in the development of anaemia, their use is associated with positive effects that outweigh this potential harm. The literature also suggests that among patients receiving medications with negative effects on the level of haemoglobin, there was no difference in the rate of mortality between anaemic and non-anaemic patients when both were on treatment for anaemia; this point highlights the importance of the detection and treatment of anaemia in these patients. Further research is needed to explore these relationships and identify additional strategies to mitigate the risk of anaemia in this population.

Relationship between serum iron level and physical function in heart failure patients is lost by presence of diabetes

AIMS

Iron deficiency (ID) is common in patients with heart failure (HF) and is reportedly associated with exercise intolerance and impaired quality of life. Iron supplementation therapy in HF patients with ID improves exercise capacity. Conversely, protective roles of iron depletion in the development of diabetes mellitus (DM) and its complications have been proposed. This study aimed to determine the impact of ID on physical function in HF patients with and without DM.

METHODS AND RESULTS

We enrolled consecutive patients who were admitted to our institute for HF diagnosis and management. The short physical performance battery (SPPB) was used to evaluate physical function, and low physical function was defined as an SPPB score of <10 points as individuals with SPPB scores of <10 points are most likely to be classified as frail and are at high risk for disability and future adverse events, including death. ID was defined as serum ferritin < 100 or 100-299 ng/mL when transferrin saturation (TSAT) was <20% according to the HF guidelines. Among the 562 HF patients (72 ± 14 years old; 56% male), 329 patients (58%) and 191 patients (34%) had ID and low physical function, respectively. Multivariate logistic regression analysis showed that TSAT as a continuous variable, but not ID, was a predictor of low physical function (odds ratio: 0.980, P = 0.024). Subgroup analysis showed that a significant association between low TSAT and low physical function was lost in HF patients with DM (P for interaction < 0.001). A spline dose-response curve for the relationship between TSAT and risk of low physical function with adjustments for covariates associated with low physical function in non-DM patients was almost linear with an increase in the risk of low physical function as the TSAT increased, but such a relationship was not found in the analyses of DM patients. A lack of close TSAT-SPPB relationship in HF patients with DM was confirmed also in a propensity-score-matched cohort.

CONCLUSIONS

TSAT as a continuous variable, but not ID, was independently associated with physical function in HF patients, and a significant association was lost in patients with HF and DM, suggesting a limited impact of iron supplementation therapy in HF patients with DM.

The influence of iron on bone metabolism disorders

Iron is a necessary trace element in the human body, and it participates in many physiological processes. Disorders of iron metabolism can cause lesions in many tissues and organs, including bone. Recently, iron has gained attention as an independent factor influencing bone metabolism disorders, especially the involvement of iron overload in osteoporosis. The aim of this review was to summarize the findings from clinical and animal model research regarding the involvement of iron in bone metabolism disorders and to elucidate the mechanisms behind iron overload and osteoporosis. Lastly, we aimed to describe the association between bone loss and iron overload. We believe that a reduction in iron accumulation can be used as an alternative treatment to assist in the treatment of osteoporosis, to improve bone mass, and to improve the quality of life of patients.

Iron Deficiency: A Silent Threat in Patients With Heart Failure With Reduced Ejection Fraction

Background Iron deficiency is a prevalent and clinically significant comorbidity in patients with heart failure with reduced ejection fraction (HFrEF). Despite its high prevalence, its impact on clinical outcomes, mortality, and various physiological parameters remains a subject of ongoing investigation. The findings of this study are anticipated to contribute valuable insights into the management and prognosis of patients with HFrEF, potentially informing future interventions and improving patient outcomes. This study aimed to assess the clinical profile of iron deficiency and its implications on morbidity and mortality in patients with HFrEF. Methodology A prospective cohort study was conducted at King Edward Memorial Hospital, India, involving 371 patients with HFrEF. Participants underwent comprehensive clinical and laboratory assessments, evaluating iron deficiency with signs, symptoms, comorbidities, dyspnea, elevated jugular venous pressure (JVP), past medical history, and various hematological and biochemical parameters. Results Overall, 50% of HFrEF participants were iron deficient (n = 185), of whom 80% (n = 148) had anemia against 43% (n = 81) anemics in iron repletes (n = 186). Of the 185 iron-deficient patients, 44 (11.86%) had absolute iron deficiency and 141 (38%) had functional iron deficiency. Iron deficiency significantly correlated with increased mortality in HFrEF patients (χ2 (1, N = 371) = 3.88, p = 0.048). A large positive correlation was observed between absolute iron deficiency and dyspnea severity (r2 = 0.949, p = 0.026). Statistically significant differences were found in hemoglobin (anemia), serum iron, serum ferritin, total iron-binding capacity, and transferrin saturation between iron-deficient and iron-replete patients (p < 0.05). However, no statistically significant difference in left ventricular ejection fraction between iron-deficient and replete patients was noted. Conclusions Iron deficiency emerges as more than a mere comorbidity in heart failure, becoming a prognostic factor with multifaceted outcomes. Its impact extends beyond cardiovascular consequences, encompassing adverse manifestations such as anemia, ascites, edema, dyspnea, elevated JVP, and a heightened risk of mortality. This intricate interplay positions iron deficiency as a critical determinant, significantly influencing the clinical trajectory and outcomes for patients with HFrEF.

Physiology of exercise and heart failure treatments: cardiopulmonary exercise testing as a tool for choosing the optimal therapeutic strategy

In the last decades, the pharmacological treatment of heart failure (HF) become more complex due to the availability of new highly effective drugs. Although the cardiovascular effects of HF therapies have been extensively described, less known are their effects on cardiopulmonary function considered as a whole, both at rest and in response to exercise. This is a 'holistic' approach to disease treatment that can be accurately evaluated by a cardiopulmonary exercise test. The aim of this paper is to assess the main differences in the effects of different drugs [angiotensin-converting enzyme (ACE)-inhibitors, Angiotensin II receptor blockers, β-blockers, Angiotensin receptor-neprilysin inhibitors, renal sodium-glucose co-transporter 2 inhibitors, iron supplementation] on cardiopulmonary function in patients with HF, both at rest and during exercise, and to understand how these differences can be taken into account when choosing the most appropriate treatment protocol for each individual patient leading to a precision medicine approach.

The anaemia treatment journey of CKD patients: from epoetins to hypoxia-inducible factor-prolyl hydroxylase inhibitors

The discovery and development of erythropoiesis-stimulating agents was a journey lasting more than a century, leading to the cloning and approval of recombinant human erythropoietin (rHuEpo). This was an impressive clinical advance, providing the possibility of correcting the symptoms associated with anaemia in chronic kidney disease. Associated iron use was needed to produce new haemoglobin-containing blood red cells. Partial anaemia correction became the standard of care since trials aiming for near-normal haemoglobin levels showed a higher risk of adverse cardiovascular events. Hoping to reduce the cardiovascular risks, a new category of drugs was developed and tested. Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) are small molecules than can be formulated into orally active pills. They simulate reduced tissue oxygen pressure, thus stimulating the production of endogenous erythropoietin (Epo) by the kidneys and liver. Clinical trials with these compounds demonstrated that HIF-PHIs are at least as effective as rHuEpo in treating or correcting anaemia in non-dialysis and dialysis patients. Trials with HIF-PHIs did not demonstrate superiority in safety outcomes and in some trials, outcomes were worse. There was also a focus on oral delivery, a possible beneficial iron-sparing effect and the ability to overcome Epo resistance in inflamed patients. A negative effect is possible iron depletion, which may explain adverse outcomes.

Colorectal Cancer Screening and Iron Deficiency Anemia

In the United States, colorectal cancer has the fourth highest amount of annual new cancer cases per year between 2014 and 2018. In this article, the authors review the data and guidelines supporting effective direct visualization and stool-based testing methods of colon cancer screening along with work-up and management of Iron Deficiency Anemia.

How I treat anemia with red blood cell transfusion and iron

Severe anemia is commonly treated with red blood cell transfusion. Clinical trials have demonstrated that a restrictive transfusion strategy of 7 to 8 g/dL is as safe as a liberal transfusion strategy of 9 to 10 g/dL in many clinical settings. Evidence is lacking for subgroups of patients, including those with preexisting coronary artery disease, acute myocardial infarction, congestive heart failure, and myelodysplastic neoplasms. We present 3 clinical vignettes that highlight the clinical challenges in caring for patients with coronary artery disease with gastrointestinal bleeding, congestive heart failure, or myelodysplastic neoplasms. We emphasize that transfusion practice should be guided by patient symptoms and preferences in conjunction with the patient's hemoglobin concentration. Along with the transfusion decision, evaluation and management of the etiology of the anemia is essential. Iron-restricted erythropoiesis is a common cause of anemia severe enough to be considered for red blood cell transfusion but diagnosis and management of absolute iron deficiency anemia, the anemia of inflammation with functional iron deficiency, or their combination may be problematic. Intravenous iron therapy is generally the treatment of choice for absolute iron deficiency in patients with complex medical disorders, with or without coexisting functional iron deficiency.

Iron deficiency is related to lower muscle mass in community-dwelling individuals and impairs myoblast proliferation

BACKGROUND

Loss of muscle mass is linked with impaired quality of life and an increased risk of morbidity and premature mortality. Iron is essential for cellular processes such as energy metabolism, nucleotide synthesis and numerous enzymatic reactions. As the effects of iron deficiency (ID) on muscle mass and function are largely unknown, we aimed to assess the relation between ID and muscle mass in a large population-based cohort, and subsequently studied effects of ID on cultured skeletal myoblasts and differentiated myocytes.

METHODS

In a population-based cohort of 8592 adults, iron status was assessed by plasma ferritin and transferrin saturation, and muscle mass was estimated using 24-h urinary creatinine excretion rate (CER). The relationships of ferritin and transferrin saturation with CER were assessed by multivariable logistic regression. Furthermore, mouse C2C12 skeletal myoblasts and differentiated myocytes were subjected to deferoxamine with or without ferric citrate. Myoblast proliferation was measured with a colorimetric 5-bromo-2'-deoxy-uridine ELISA assay. Myocyte differentiation was assessed using Myh7-stainings. Myocyte energy metabolism, oxygen consumption rate and extracellular acidification rate were assessed using Seahorse mitochondrial flux analysis, and apoptosis rate with fluorescence-activated cell sorting. RNA sequencing (RNAseq) was used to identify ID-related gene and pathway enrichment in myoblasts and myocytes.

RESULTS

Participants in the lowest age- and sex-specific quintile of plasma ferritin (OR vs middle quintile 1.62, 95% CI 1.25-2.10, P < 0.001) or transferrin saturation (OR 1.34, 95% CI 1.03-1.75, P = 0.03) had a significantly higher risk of being in the lowest age- and sex-specific quintile of CER, independent of body mass index, estimated GFR, haemoglobin, hs-CRP, urinary urea excretion, alcohol consumption and smoking status. In C2C12 myoblasts, deferoxamine-induced ID reduced myoblast proliferation rate (P-trend <0.001) but did not affect differentiation. In myocytes, deferoxamine reduced myoglobin protein expression (-52%, P < 0.001) and tended to reduce mitochondrial oxygen consumption capacity (-28%, P = 0.10). Deferoxamine induced gene expression of cellular atrophy markers Trim63 (+20%, P = 0.002) and Fbxo32 (+27%, P = 0.048), which was reversed by ferric citrate (-31%, P = 0.04 and -26%, P = 0.004, respectively). RNAseq indicated that both in myoblasts and myocytes, ID predominantly affected genes involved in glycolytic energy metabolism, cell cycle regulation and apoptosis; co-treatment with ferric citrate reversed these effects.

CONCLUSIONS

In population-dwelling individuals, ID is related to lower muscle mass, independent of haemoglobin levels and potential confounders. ID impaired myoblast proliferation and aerobic glycolytic capacity, and induced markers of myocyte atrophy and apoptosis. These findings suggest that ID contributes to loss of muscle mass.

Iron Deficiency in Heart Failure: A Scientific Statement from the Heart Failure Society of America

Iron deficiency is present in approximately 50% of patients with symptomatic heart failure and is independently associated with worse functional capacity, lower quality of, life and increased mortality. The purpose of this document is to summarize current knowledge of how iron deficiency is defined in heart failure and its epidemiology and pathophysiology, as well as pharmacological considerations for repletion strategies. This document also summarizes the rapidly expanding array of clinical trial evidence informing when, how, and in whom to consider iron repletion.

Effect of Intravenous Ferric Carboxymaltose on Exercise Capacity After Kidney Transplantation (EFFECT-KTx): rationale and study protocol for a double-blind, randomised, placebo-controlled trial

INTRODUCTION

Iron deficiency (ID) is common and has been associated with an excess mortality risk in kidney transplant recipients (KTRs). In patients with chronic heart failure and ID, intravenous iron improves exercise capacity and quality of life. Whether these beneficial effects also occur in KTRs is unknown. The main objective of this trial is to address whether intravenous iron improves exercise tolerance in iron-deficient KTRs.

METHODS AND ANALYSIS

The Effect of Ferric Carboxymaltose on Exercise Capacity after Kidney Transplantation study is a multicentre, double-blind, randomised, placebo-controlled clinical trial that will include 158 iron-deficient KTRs. ID is defined as plasma ferritin <100 µg/L or plasma ferritin 100-299 µg/L with transferrin saturation <20%. Patients are randomised to receive 10 mL of ferric carboxymaltose (50 mg Fe³⁺/mL, intravenously) or placebo (0.9% sodium chloride solution) every 6 weeks, four dosages in total. The primary endpoint is change in exercise capacity, as quantified by the 6 min walk test, between the first study visit and the end of follow-up, 24 weeks later. Secondary endpoints include changes in haemoglobin levels and iron status, quality of life, systolic and diastolic heart function, skeletal muscle strength, bone and mineral parameters, neurocognitive function and safety endpoints. Tertiary (explorative) outcomes are changes in gut microbiota and lymphocyte proliferation and function.

ETHICS AND DISSEMINATION

The protocol of this study has been approved by the medical ethical committee of the University Medical Centre Groningen (METc 2018/482;) and is being conducted in accordance with the principles of the Declaration of Helsinki, the Standard Protocol Items: Recommendations for Interventional Trials checklist and the Good Clinical Practice guidelines provided by the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use. Study results will be disseminated through publications in peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

NCT03769441.

Emerging Biomarkers for Predicting Clinical Outcomes in Patients with Heart Disease

Cardiovascular disease is most frequently caused by the development and progression of atherosclerosis. When coronary arteries are afflicted, and the stenoses caused by atherosclerotic plaques are severe enough, the metabolic supply-and-offer balance is disturbed, leading to myocardial ischemia. If atherosclerotic plaques become unstable and local thrombosis develops, a myocardial infarction occurs. Sometimes, myocardial ischemia and infarction may result in significant and irreversible heart failure. To prevent severe complications, such as acute coronary syndromes and ischemia-related heart failure, extensive efforts have been made for developing biomarkers that would help identify patients at increased risk for cardiovascular events. In this two-part study, we attempted to provide a review of existing knowledge of blood biomarkers that may be used in this setting. The first part of this work was dedicated to conventional biomarkers, which are already used in clinical practice. In the second part, here presented, we discuss emerging biomarkers which have not yet become mainstream.

How to diagnose iron deficiency in chronic disease: A review of current methods and potential marker for the outcome

Iron deficiency (ID) is the most common nutritional disorder worldwide. It is often observed in patients with chronic diseases, such as heart failure (HF), chronic kidney disease (CKD), inflammatory bowel disease (IBD) and cancer. ID is associated with poor clinical outcome, including poor performance, reduced quality of life, as well as increased hospitalization and mortality. The aim of this review is to provide an overview about the role of ID in chronic diseases (HF, CKD, IBD, cancer) regarding their current definitions and clinical relevance; diagnostic accuracy of iron parameters in chronic inflammatory conditions and its potential as prognostic markers. Due to different definitions and guideline recommendations of ID, various laboratory parameters for ID diagnostic exist and there is no general consensus about the definition of ID and its treatment. Still, a general trend can be observed across all investigated indications of this review (HF, CKD, IBD, cancer) that serum ferritin and transferrin saturation (TSAT) are the two parameters mentioned most often and emphasized in all guidelines to define ID and guide treatment. The most commonly used threshold values for the diagnosis of ID are TSAT of < 20% and serum ferritin of < 100-300 µg/L. Noteworthy, both TSAT and particularly ferritin are frequently applied, but both may vary due to inflammatory conditions. Studies showed that TSAT is less affected by inflammatory processes and may therefore be more accurate and reliable than serum ferritin, particularly in conditions with elevated inflammatory state. A low iron status and particularly a low TSAT value was associated with a poor outcome in all investigated indications, with the strongest evidence in HF patients. Routine surveillance of iron status in these groups of patients with chronic conditions is advisable to detect ID early. Depending on the inflammatory state, TSAT < 20% may be the more accurate diagnostic marker of ID than ferritin. Moreover, TSAT may also be the more reliable estimate for the prognosis, particularly in HF.

Iron deficiency and cardiovascular disease

Iron deficiency (ID) is common in patients with cardiovascular disease. Up to 60% of patients with coronary artery disease, and an even higher proportion of those with heart failure (HF) or pulmonary hypertension have ID; the evidence for cerebrovascular disease, aortic stenosis and atrial fibrillation is less robust. The prevalence of ID increases with the severity of cardiac and renal dysfunction and is probably more common amongst women. Insufficient dietary iron, reduced iron absorption due to increases in hepcidin secondary to the low-grade inflammation associated with atherosclerosis and congestion or reduced gastric acidity, and increased blood loss due to anti-thrombotic therapy or gastro-intestinal or renal disease may all cause ID. For older people in the general population and patients with HF with reduced ejection fraction (HFrEF), both anaemia and ID are associated with a poor prognosis; each may confer independent risk. There is growing evidence that ID is an important therapeutic target for patients with HFrEF, even if they do not have anaemia. Whether this is also true for other HF phenotypes or patients with cardiovascular disease in general is currently unknown. Randomized trials showed that intravenous ferric carboxymaltose improved symptoms, health-related quality of life and exercise capacity and reduced hospitalizations for worsening HF in patients with HFrEF and mildly reduced ejection fraction (<50%). Since ID is easy to treat and is effective for patients with HFrEF, such patients should be investigated for possible ID. This recommendation may extend to other populations in the light of evidence from future trials.

Iron deficiency screening is a key issue in chronic inflammatory diseases: A call to action

Iron deficiency is frequent in patients with chronic inflammatory conditions (e.g., chronic heart failure, chronic kidney disease, cancers, and bowel inflammatory diseases). Indeed, high concentrations of inflammatory cytokines increase hepcidin concentrations that lead to the sequestration of iron in cells of the reticuloendothelial system (functional iron deficiency). Iron parameters are often assessed only in the context of anemia, but iron deficiency, even without anemia, is present in about half of patients with inflammatory conditions. Iron deficiency worsens underlying chronic diseases and is an independent factor of morbidity and mortality. In daily practice, the most effective biomarkers of iron status are serum ferritin, which reflects iron storage, and transferrin saturation, which reflects the transport of iron. Serum ferritin is increased in an inflammatory context, and there is still no consensus on the threshold to be used in chronic inflammatory conditions. Nevertheless, recent recommendations of international guidelines agreed to define iron deficiency by serum ferritin &lt;100 µg/L and/or transferrin saturation &lt;20%. Iron parameters remain, however, insufficiently assessed in patients with chronic inflammatory conditions. Indeed, clinical symptoms of iron deficiency, such as fatigue, are not specific and often confused with those of the primary disease. Iron repletion, preferably by the intravenous route to bypass tissue sequestration, improves clinical signs and quality of life. Because of the negative impact of iron deficiency on chronic inflammatory diseases and the efficacy of intravenous iron repletion, screening of iron parameters should be part of the routine examination of all patients with chronic inflammatory diseases.

Myocardial Iron Deficiency and Mitochondrial Dysfunction in Advanced Heart Failure in Humans

Background

Myocardial iron deficiency (MID) in heart failure (HF) remains largely unexplored. We aim to establish defining criterion for MID, evaluate its pathophysiological role, and evaluate the applicability of monitoring it non‐invasively in human explanted hearts.

Methods and Results

Biventricular tissue iron levels were measured in both failing (n=138) and non‐failing control (NFC, n=46) explanted human hearts. Clinical phenotyping was complemented with comprehensive assessment of myocardial remodeling and mitochondrial functional profiles, including metabolic and oxidative stress. Myocardial iron status was further investigated by cardiac magnetic resonance imaging. Myocardial iron content in the left ventricle was lower in HF versus NFC (121.4 [88.1–150.3] versus 137.4 [109.2–165.9] μg/g dry weight), which was absent in the right ventricle. With a priori cutoff of 86.1 μg/g d.w. in left ventricle, we identified 23% of HF patients with MID (HF‐MID) associated with higher NYHA class and worsened left ventricle function. Respiratory chain and Krebs cycle enzymatic activities were suppressed and strongly correlated with depleted iron stores in HF‐MID hearts. Defenses against oxidative stress were severely impaired in association with worsened adverse remodeling in iron‐deficient hearts. Mechanistically, iron uptake pathways were impeded in HF‐MID including decreased translocation to the sarcolemma, while transmembrane fraction of ferroportin positively correlated with MID. Cardiac magnetic resonance with T2* effectively captured myocardial iron levels in failing hearts.

Conclusions

MID is highly prevalent in advanced human HF and exacerbates pathological remodeling in HF driven primarily by dysfunctional mitochondria and increased oxidative stress in the left ventricle. Cardiac magnetic resonance demonstrates clinical potential to non‐invasively monitor MID.

Preparation and related properties of melanin iron supplement

In this study, BM-Fe (black sesame melanin-iron complex) was prepared and characterized. The results showed that the carboxyl hydroxyl group of BSM (black sesame melanin) participated in the chelation of iron ions. EDS (energy dispersive spectroscopy) and XPS (X-ray photoelectron spectroscopy) results confirmed the presence of iron ions in BM-Fe. The results of DLS (dynamic light scattering) showed that the average particle sizes of BSM and BM-Fe were 844.9 nm and 294.3 nm, respectively, indicating that the structure of BM-Fe with a smaller particle size was formed after the binding of iron ions with the active group on BSM. Finally, the in vitro iron dissolution, iron ion identification, in vitro iron ion reduction, antioxidant activity, cytotoxicity and moisture resistance properties of BM-Fe and FST (ferrous sulfate tablets, a commonly used iron supplement) were comprehensively compared. The results showed that BSM combined with iron instead of physically mixing, and BM-Fe was easily reduced in the gastrointestinal environment. BM-Fe had good bioavailability and retained the excellent characteristics (such as oxidation resistance and biocompatibility) of BSM, and had the potential to be applied in the treatment of iron-deficiency-related diseases. In summary, BM-Fe prepared in this study not only retained the excellent characteristics of BSM but also had a good effect on iron supplementation, high bioavailability and low side effects. Comprehensive analysis showed that the performance of BM-Fe prepared in this study was similar to or even better than that of the control (FST). Thus, BM-Fe is expected to become a new comprehensive multi-functional iron supplement and has a broad developmental prospect.

Iron deficiency in heart failure patients: the French CARENFER prospective study

Aims

Iron deficiency (ID) is reported as one of the main co‐morbidities in patients with chronic heart failure (CHF), which then influences quality of life and prognosis. The CARENFER study aimed to assess the prevalence of ID in a large panel of heart failure (HF) patients at different stages of the disease.

Methods and results

This prospective cross‐sectional nationwide study was conducted in 48 medical units in France in 2019. Serum ferritin concentration and transferrin saturation (TSAT) index were determined in all eligible patients with a diagnosis of HF. ID diagnosis was based on the European Society of Cardiology (ESC) 2016 guidelines. Patients were classified as having either a decompensated HF or a CHF. Left ventricular ejection fraction (LVEF) was categorized as preserved (≥50%), mildly reduced (40–49%), or reduced (<40%). ID diagnosis was determined in 1661 patients, of whom 1475 could be classified as having a decompensated HF or a CHF. Patients' median age was 78 years. Decompensated HF represented 60.1% of cases. The overall prevalence of ID was 49.6% (47.1–52.1). In CHF and decompensated HF patients, respectively, ID prevalence was 39.0% (35.1–43.1) and 58.1% (54.7–61.4), P < 0.001; TSAT < 20% was respectively reported in 34.7% and 70.0% of patients (P < 0.001). Patients with preserved LVEF were more likely to have an ID (57.5%) compared with patients with mildly reduced (47.4%) or reduced LVEF (44.3%) (P < 0.001).

Conclusions

Iron deficiency was highly prevalent in patients with decompensated HF or CHF with preserved LVEF. ID prevalence defined by TSAT was higher than by the ESC criteria in decompensated HF patients, questioning the importance of ID definition to assess its prevalence.

Role of impaired iron transport on exercise performance in heart failure patients

AIMS

Impaired iron transport (IIT) occurs frequently in heart failure (HF) patients, even in the absence of anaemia and it is associated with a poor quality of life and prognosis. The impact of IIT on exercise capacity, as assessed by the cardiopulmonary exercise test (CPET), in HF is at present unknown. The aim of this article is to evaluate in HF patients the impact on exercise performance of IIT, defined as transferrin saturation (TSAT) <20%.

METHODS AND RESULTS

We collected data of 676 patients hospitalized for HF. All underwent laboratory analysis, cardiac ultrasound, and CPET. Patients were grouped by the presence/absence of IIT and anaemia (haemoglobin <13 and <12 g/dL in male and female, respectively): Group 1 (G1) no anaemia, no IIT; Group 2 (G2) anaemia, no IIT; Group 3 (G3) no anaemia, IIT; Group 4 (G4) anaemia and IIT. Peak oxygen uptake (peakVO2) reduced from G1 to G3 and from G2 to G4 (G1: 1266 ± 497 mL/min, G2: 1011 ± 385 mL/min, G3: 1041 ± 395 mL/min, G4: 833 ± 241 mL/min), whereas the ventilation to carbon dioxide relationship slope (VE/VCO2 slope) increased (G1: 31.8 ± 7.5, G2: 34.5 ± 7.4, G3: 36.1 ± 10.2, G4: 37.5 ± 8.4). At multivariate regression analysis, peakVO2 independent predictors were anaemia, brain natriuretic peptide (BNP), and left ventricular ejection fraction, whereas VE/VCO2 slope independent predictors were IIT and BNP.

CONCLUSION

In HF IIT is associated with exercise performance impairment independently from anaemia, and it is a predictor of elevated VE/VCO2 slope, a pivotal index of HF prognosis.

Iron Deficiency in Heart Failure: Mechanisms and Pathophysiology

Iron is an essential micronutrient for a myriad of physiological processes in the body beyond erythropoiesis. Iron deficiency (ID) is a common comorbidity in patients with heart failure (HF), with a prevalence reaching up to 59% even in non-anaemic patients. ID impairs exercise capacity, reduces the quality of life, increases hospitalisation rate and mortality risk regardless of anaemia. Intravenously correcting ID has emerged as a promising treatment in HF as it has been shown to alleviate symptoms, improve quality of life and exercise capacity and reduce hospitalisations. However, the pathophysiology of ID in HF remains poorly characterised. Recognition of ID in HF triggered more research with the aim to explain how correcting ID improves HF status as well as the underlying causes of ID in the first place. In the past few years, significant progress has been made in understanding iron homeostasis by characterising the role of the iron-regulating hormone hepcidin, the effects of ID on skeletal and cardiac myocytes, kidneys and the immune system. In this review, we summarise the current knowledge and recent advances in the pathophysiology of ID in heart failure, the deleterious systemic and cellular consequences of ID.

Iron Deficiency: A New Target for Patients With Heart Failure

Iron deficiency (ID) is one of the most frequent comorbidities in patients with heart failure (HF). ID is estimated to be present in up to 50% of outpatients and is a strong independent predictor of HF outcomes. ID has been shown to reduce quality of life, exercise capacity and survival, in both the presence and absence of anemia. The most recent 2016 guidelines recommend starting replacement treatment at ferritin cutoff value <100 mcg/l or between 100 and 299 mcg/l when the transferrin saturation is <20%. Beyond its effect on hemoglobin, iron plays an important role in oxygen transport and in the metabolism of cardiac and skeletal muscles. Mitochondria are the most important sites of iron utilization and energy production. These factors clearly have roles in the diminished exercise capacity in HF. Oral iron administration is usually the first route used for iron repletion in patients. However, the data from the IRONOUT HF study do not support the use of oral iron supplementation in patients with HF and a reduced ejection fraction, because this treatment does not affect peak VO₂ (the primary endpoint of the study) or increase serum ferritin levels. The FAIR-HF and CONFIRM-HF studies have shown improvements in symptoms, quality of life and functional capacity in patients with stable, symptomatic, iron-deficient HF after the administration of intravenous iron (i.e., FCM). Moreover, they have shown a decreased risk of first hospitalization for worsening of HF, as later confirmed in a subsequent meta-analysis. In addition, the EFFECT-HF study has shown an improvement in peak oxygen consumption at CPET (a parameter generally considered the gold standard of exercise capacity and a predictor of outcome in HF) in patients randomized to receive ferric carboxymaltose. Finally, the AFFIRM AHF trial evaluating the effects of FCM administration on the outcomes of patients hospitalized for acute HF has found significantly fewer hospital readmissions due to HF among patients treated with FCM rather than placebo.

Eisen und Digitalis bei Herzinsuffizienz

Neben der medikamentösen Standardtherapie der Herzinsuffizienz (HI) gilt es, Patienten zu identifizieren, die von einer Eisensupplementation oder Therapie mit Digitalis profitieren können. Wir haben die aktuelle Evidenz für diese Therapien zusammengestellt und beschreiben, wie die HI-Therapie mit Eisen und Digitalis individualisiert werden kann. Eine Eisensupplementation verbessert Leistungsfähigkeit, Symptome und Lebensqualität bei Patienten mit symptomatischer Herzinsuffizienz und Eisenmangel. Die Daten aus der unlängst publizierten AFFIRM-AHF-Studie zeigen, dass eine Eisentherapie mit Eisencarboxymaltose zudem HI-Hospitalisationen verhindert. Die Therapie mit Digitalis sollte bei fortgeschrittenen Stadien der Herzinsuffizienz mit reduzierter systolischer Funktion trotz leitliniengerechter Pharmako- und Devicetherapie in Erwägung gezogen werden, insbesondere, wenn diese aufgrund von Komorbiditäten nur eingeschränkt möglich ist. Auch bei koexistentem Vorhofflimmern ist Digitalis zur Herzfrequenzkontrolle von großem Wert. Serumkonzentrationen von Digitalis im niedrigen therapeutischen Bereich sind anzustreben.

How I treat anemia in heart failure

Anemia is a very common comorbidity in patients with heart failure (HF), affecting ∼30% of stable ambulatory patients and 50% patients with acute decompensated HF. Absolute or functional iron deficiency (ID) is seen in ∼50% patients with HF. Both of these comorbidities often coexist and are independently associated with increased mortality and hospitalizations. These findings led several investigators to test the hypotheses that treatment of anemia and ID in HF would improve symptoms and long-term outcomes. Small studies showed that erythropoiesis-stimulating agents (ESAs) improve subjective measures of HF. However, a large pivotal outcome trial found that the ESA darbepoetin alfa did not improve long-term outcomes in patients with HF with reduced ejection fraction and instead was associated with adverse effects. Studies using IV iron have had somewhat greater success, showing improvements in subjective and some objective measures of HF. However, more research is needed to establish the best treatment options for these high-risk patients. We present 5 common scenarios of patients with HF and anemia and describe our personal approach on how we might treat them based on objective evidence where available. An algorithm that offers guidance in regard to personalized therapy for such patients is also presented.

Iron deficiency impacts prognosis but less exercise capacity in heart failure with preserved ejection fraction

Aims

Whether and how iron deficiency (ID) impacts patients with heart failure (HF) with preserved ejection fraction (HFpEF) remain unclear. The aim of our study was to investigate the impact of ID on functional status, exercise capacity, and prognosis in HFpEF.

Methods and results

The study population consisted of 300 HFpEF patients. ID was defined as serum ferritin <100 μg/L or 100–300 μg/L and transferrin‐saturation <20%. Baseline functional status, quality of life (HADS score and EQ 5D index), 6 min walking test, echocardiography, and outcome (all‐cause mortality and combined all cause‐mortality and HF hospitalization) were evaluated. ID was found in 159 (53%) patients. Patients with ID had a worse prognosis with a higher combined endpoint of all‐cause mortality and HF hospitalization after 4 years of follow‐up (log rank = 0.008). Pulmonary hypertension, depression, and thyroid disease were more prevalent in the ID group. Multivariable analysis showed that ID was independently associated with body mass index (P = 0.003), pulmonary hypertension (P = 0.008), and thyroid disease (P = 0.01). Although patients with ID had a lower exercise capacity compared with patients without ID (393 m [294–455] vs. 344 m [260–441], P = 0.008), there was no significant correlation after multivariable correction for age, BMI, NT‐proBNP, DM, and depression.

Conclusions

Heart failure with preserved ejection fraction patients with ID have a worse prognosis and impaired exercise capacity compared with those without ID. However, although a trend was observed, after multivariable correction ID was no longer significantly associated with a reduced exercise capacity. This reflects that impaired exercise capacity in HFpEF is complex and seems multifactorial. Interestingly, pulmonary hypertension was an independent predictor of both ID and exercise capacity.

Iron deficiency

Iron deficiency is one of the leading contributors to the global burden of disease, and particularly affects children, premenopausal women, and people in low-income and middle-income countries. Anaemia is one of many consequences of iron deficiency, and clinical and functional impairments can occur in the absence of anaemia. Iron deprivation from erythroblasts and other tissues occurs when total body stores of iron are low or when inflammation causes withholding of iron from the plasma, particularly through the action of hepcidin, the main regulator of systemic iron homoeostasis. Oral iron therapy is the first line of treatment in most cases. Hepcidin upregulation by oral iron supplementation limits the absorption efficiency of high-dose oral iron supplementation, and of oral iron during inflammation. Modern parenteral iron formulations have substantially altered iron treatment and enable rapid, safe total-dose iron replacement. An underlying cause should be sought in all patients presenting with iron deficiency: screening for coeliac disease should be considered routinely, and endoscopic investigation to exclude bleeding gastrointestinal lesions is warranted in men and postmenopausal women presenting with iron deficiency anaemia. Iron supplementation programmes in low-income countries comprise part of the solution to meeting WHO Global Nutrition Targets.

Right ventricular function and iron deficiency in acute heart failure

AIMS

Iron deficiency (ID) is a frequent finding in patients with chronic and acute heart failure (AHF) along the full spectrum of left ventricular ejection fraction (LVEF). Iron deficiency has been related to ventricular systolic dysfunction, but its role in right ventricular function has not been evaluated. We sought to evaluate whether ID identifies patients with greater right ventricular dysfunction in the setting of AHF.

METHODS AND RESULTS

We prospectively included 903 patients admitted with AHF. Right systolic function was evaluated by tricuspid annular plane systolic excursion (TAPSE) and the ratio TAPSE/pulmonary artery systolic pressure (TAPSE/PASP). Iron deficiency was defined, according to European Society of Cardiology criteria, as serum ferritin <100 mg/dL (absolute ID) or ferritin 100-299 mg/dL and transferrin saturation (TSAT) <20% (functional ID). The relationships among the exposures with right ventricular systolic function were evaluated by multivariate linear regression analyses. The mean age of the sample was 74.3 ± 10.6 years, 441 (48.8%) were female, 471 (52.2%) exhibited heart failure with preserved ejection fraction, and 677 (75.0%) showed ID. The mean LVEF, TAPSE, and TAPSE/PASP were 49 ± 15%, 18.6 ± 3.9 mm, and 0.45 ± 0.18, respectively. The median (interquartile range) amino-terminal pro-brain natriuretic peptide was 4015 (1807-8775) pg/mL. In a multivariable setting, lower TSAT and ferritin were independently associated with lower TAPSE (P < 0.05 for both comparisons). Transferrin saturation (P = 0.017), and not ferritin (P = 0.633), was independently associated with TAPSE/PASP.

CONCLUSION

In AHF, proxies of ID were associated with right ventricular dysfunction. Further studies should confirm these findings and evaluate the pathophysiological facts behind this association.

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.

A Clinical Tool to Predict Low Serum Selenium in Patients with Worsening Heart Failure

Selenium is an essential micronutrient, and a low selenium concentration (<100 µg/L) is associated with a poorer quality of life and exercise capacity, and an impaired prognosis in patients with worsening heart failure. Measuring selenium concentrations routinely is laborious and costly, and although its clinical utility is yet to be proven, an easy implemented model to predict selenium status is desirable. A stepwise multivariable logistic regression analysis was performed using routinely measured clinical factors. Low selenium was independently predicted by: older age, lower serum albumin, higher N-terminal pro-B-type natriuretic peptide levels, worse kidney function, and the presence of orthopnea and iron deficiency. A 10-points risk-model was developed, and a score of ≥6 points identified >80% of patients with low selenium (sensitivity of 44%, specificity of 80%). Given that selenium and iron overlap in their physiological roles, we evaluated the shared determinants and prognostic associates. Both deficiencies shared similar clinical characteristics, including the model risk factors and, in addition, a low protein intake and high levels of C-reactive protein. Low selenium was associated with a similar or worse prognosis compared to iron deficiency. In conclusion, although it is difficult to exclude low selenium based on clinical characteristics alone, we provide a prediction tool which identifies heart failure patients at higher risk of having a low selenium status.

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.

Anaemia, iron status, and gender predict the outcome in patients with chronic heart failure

Aims

Anaemia and iron deficiency (ID) are frequently found in patients with chronic heart failure (CHF) and associated with adverse outcome. However, it is unclear whether absolute [transferrin saturation (TSAT) <20%, ferritin <100 μg/L] or inflammation‐driven functional ID (TSAT <20%, ferritin >100 μg/L) with and without anaemia had similar or different consequences for such patients.

Methods and results

Within this retrospective cohort study, 2223 patients (1601 men and 622 women) with CHF, referred to our department, between 2000 and 2018, were followed for a median time of 84 months. Anaemia was found in 393 patients and was an independent predictor for an adverse outcome [HR 2.164 (95% CI 1.865–2.512), P < 0.001]. In 674 patients with available parameters of iron metabolism, ID was present in 228 patients and was associated with an unfavourable outcome [HR 1.499 (95% CI 1.158–1.940), P = 0.002]. ID was best predicting an adverse outcome in men ≤59 years, with heart failure with reduced ejection fraction, preserved kidney function, no inflammation, and a body mass index (BMI) ≥25.5 kg/m². Functional ID in women and absolute ID in men were associated with poor prognosis. Of note, TSAT <20% but not low ferritin levels were predictive for an adverse outcome. Anaemic patients with high ferritin levels, advanced inflammation, older age, low BMI, male gender, and reduced glomerular filtration rate had the worst prognosis.

Conclusions

Anaemia and low tissue iron availability as reflected by TSAT <20% are negative predictors of outcome in patients with CHF. Systemic inflammation, renal function, BMI, age, and gender are important contributors for the clinical course.

The changing landscape of iron deficiency

Iron deficiency (ID) with or without anemia is common worldwide. ID is a broad definition encompassing decreased total body iron (absolute deficiency) as well as reduced iron supply to erythropoietic and/or other organs with preserved stores (functional iron deficiency, FID), as it occurs in inflammation. Increased iron needs unbalanced by iron supply, low iron intake, reduced absorption and chronic blood loss, often in combination, are the main causes of absolute ID, easily diagnosed by low ferritin levels. In all these cases hepcidin synthesis is repressed, while in FID is augmented by inflammatory cytokines, causing iron sequestration in stores. Because of increased ferritin levels diagnosis of ID in the latter condition may be tricky: global clinical evaluation, accepted threshold of iron tests together with response to iron treatment may be of help. Search and removal of the responsible cause(s) is as important as diagnosing ID or FID. The response to oral iron treatment is suboptimal when hepcidin levels are high. Future research is needed to establish/validate markers for improved diagnosis of complex cases and to test the therapeutic value of drugs under development aimed at interfering with the altered iron trafficking.