Criteria for Iron Deficiency in Patients With Heart Failure

Iron deficiency and supplementation in heart failure

Non-anaemic iron deficiency (NAID) is a strategic target in cardiovascular medicine because of its association with a range of adverse effects in various conditions. Endeavours to tackle NAID in heart failure have yielded mixed results, exposing knowledge gaps in how best to define 'iron deficiency' and the handling of iron therapies by the body. To address these gaps, we harness the latest understanding of the mechanisms of iron homeostasis outside the erythron and integrate clinical and preclinical lines of evidence. The emerging picture is that current definitions of iron deficiency do not assimilate the multiple influences at play in patients with heart failure and, consequently, fail to identify those with a truly unmet need for iron. Additionally, current iron supplementation therapies benefit only certain patients with heart failure, reflecting differences in the nature of the unmet need for iron and the modifying effects of anaemia and inflammation on the handling of iron therapies by the body. Building on these insights, we identify untapped opportunities in the management of NAID, including the refinement of current approaches and the development of novel strategies. Lessons learned from NAID in cardiovascular disease could ultimately translate into benefits for patients with other chronic conditions such as chronic kidney disease, chronic obstructive pulmonary disease and cancer.

Intravenous Iron Repletion for Patients With Heart Failure and Iron Deficiency: JACC State-of-the-Art Review

Iron deficiency and heart failure frequently co-occur, sparking clinical research into the role of iron repletion in this condition over the last 20 years. Although early nonrandomized studies and subsequent moderate-sized randomized controlled trials showed an improvement in symptoms and functional metrics with the use of intravenous iron, 3 recent larger trials powered to detect a difference in hard cardiovascular outcomes failed to meet their primary endpoints. Additionally, there are potential concerns related to side effects from intravenous iron, both in the short and long term. This review discusses the basics of iron biology and regulation, the diagnostic criteria for iron deficiency and the clinical evidence for intravenous iron in heart failure, safety concerns, and alternative therapies. We also make practical suggestions for the management of patients with iron deficiency and heart failure and outline key areas in need of future research.

Associations Between Genetically Predicted Iron Status and Cardiovascular Disease Risk: A Mendelian Randomization Study

BACKGROUND

Mendelian randomization (MR) studies suggest a causal effect of iron status on cardiovascular disease (CVD) risk, but it is unknown if these associations are confounded by pleiotropic effects of the instrumental variables on CVD risk factors. We aimed to investigate the effect of iron status on CVD risk controlling for CVD risk factors.

METHODS AND RESULTS

Iron biomarker instrumental variables (total iron-binding capacity [n=208 422], transferrin saturation [n=198 516], serum iron [n=236 612], ferritin [n=257 953]) were selected from a European genome-wide association study meta-analysis. We performed 2-sample univariate MR of each iron trait on CVD outcomes (all-cause ischemic stroke, cardioembolic ischemic stroke, large-artery ischemic stroke, small-vessel ischemic stroke, and coronary heart disease) from MEGASTROKE (n=440 328) and CARDIoGRAMplusC4D (Coronary Artery Disease Genome Wide Replication and Meta-Analysis Plus the Coronary Artery Disease Genetics) (n=183 305). We then implemented multivariate MR conditioning on 7 CVD risk factors from independent European samples to evaluate their potential confounding or mediating effects on the observed iron-CVD associations. With univariate MR analyses, we found higher genetically predicted iron status to be associated with a greater risk of cardioembolic ischemic stroke (transferrin saturation: odds ratio, 1.17 [95% CI, 1.03-1.33]; serum iron: odds ratio, 1.21 [95% CI, 1.02-1.44]; total iron-binding capacity: odds ratio, 0.81 [95% CI, 0.69-0.94]). The detrimental effects of iron status on cardioembolic ischemic stroke risk remained unaffected when adjusting for CVD risk factors (all P<0.05). Additionally, we found diastolic blood pressure to mediate between 7.1 and 8.8% of the total effect of iron status on cardioembolic ischemic stroke incidence. Univariate MR initially suggested a protective effect of iron status on large-artery stroke and coronary heart disease, but controlling for CVD factors using multivariate MR substantially diminished these associations (all P>0.05).

CONCLUSIONS

Higher iron status was associated with a greater risk of cardioembolic ischemic stroke independent of CVD risk factors, and this effect was partly mediated by diastolic blood pressure. These findings support a role of iron status as a modifiable risk factor for cardioembolic ischemic stroke.

Iron deficiency in children with a focus on inflammatory conditions

Iron deficiency (ID) tends to be overlooked compared with anemia. However, its prevalence is estimated to be twice as high as that of ID anemia, and ID without anemia can be accompanied by clinical and functional impairments. The symptoms of ID are nonspecific, such as fatigue and lethargy, but can lead to neurodevelopmental disorders in children, restless legs syndrome, and recurrent infections due to immune system dysregulation. In particular, the risk of ID is high in the context of chronic inflammatory diseases (CIDs) due to the reaction of various cytokines and the resulting increase in hepcidin levels; ID further exacerbates these diseases and increases mortality. Therefore, the diagnosis of ID should not be overlooked through ID screening especially in high-risk groups. Ferritin and transferrin saturation levels are the primary laboratory parameters used to diagnose ID. However, as ferritin levels respond to inflammation, the diagnostic criteria differ among guidelines. Therefore, new tools and criteria for accurately diagnosing ID should be developed. Treatment can be initiated only with an accurate diagnosis. Oral iron is typically the first-line treatment for ID; however, the efficacy and safety of intravenous iron have recently been recognized. Symptoms improve quickly after treatment, and the prognosis of accompanying diseases can also be improved. This review highlights the need to improve global awareness of ID diagnosis and treatment, even in the absence of anemia, to improve the quality of life of affected children, especially those with CIDs.

The findings of a service evaluation on the practice of assessment and treatment of iron deficiency in people admitted to a UK hospital with decompensated Heart Failure

BACKGROUND

Iron Deficiency (ID) is common in Heart Failure (HF) and associated with poor outcomes. Replacement with intravenous (IV) iron can improve functional status, quality of life and risk of unplanned admission. In 2015/16 a local service evaluation was performed which found that of people admitted with HF, only 27.5 % had assessment of iron status, and when identified, replacement occurred in fewer than half. Education strategies were employed to increase awareness of the importance of assessment and correction.

OBJECTIVES

To assess if practice had improved following education strategies.

METHODS

A review of 220 patient records for people admitted with HF in 2020/21 to establish if iron status assessed, presence of ID, and whether if ID identified it was treated, and by which route. Trends in 2020/21 data were explored in sub-groups by age, sex, type of HF, anaemia status, input from HF specialists and type of ID.

RESULTS

Compared to 2015/16, more assessments of iron status were performed (45% vs 27.5 %), ID was corrected more frequently (57% vs 46 %) and increased use of the IV route for replacement (83% vs 58 %) CONCLUSIONS: Despite the impact of COVID-19 on usual care in 2020/21, improvement was seen in proportion of assessment and treatment of ID following simple education strategies for key stakeholders. There may be scope to improve practice further if the findings remain similar post pandemic. If so, a formal Quality Improvement approach may be helpful.

Cardiovascular outcomes and molecular targets for the cardiac effects of Sodium-Glucose Cotransporter 2 Inhibitors: A systematic review

Sodium-glucose cotransporter 2 inhibitors (SGLT2i), a new class of glucose-lowering drugs traditionally used to control blood glucose levels in patients with type 2 diabetes mellitus, have been proven to reduce major adverse cardiovascular events, including cardiovascular death, in patients with heart failure irrespective of ejection fraction and independently of the hypoglycemic effect. Because of their favorable effects on the kidney and cardiovascular outcomes, their use has been expanded in all patients with any combination of diabetes mellitus type 2, chronic kidney disease and heart failure. Although mechanisms explaining the effects of these drugs on the cardiovascular system are not well understood, their effectiveness in all these conditions suggests that they act at the intersection of the metabolic, renal and cardiac axes, thus disrupting maladaptive vicious cycles while contrasting direct organ damage. In this systematic review we provide a state of the art of the randomized controlled trials investigating the effect of SGLT2i on cardiovascular outcomes in patients with chronic kidney disease and/or heart failure irrespective of ejection fraction and diabetes. We also discuss the molecular targets and signaling pathways potentially explaining the cardiac effects of these pharmacological agents, from a clinical and experimental perspective.

Iron deficiency in new onset heart failure: association with clinical factors and quality of life

AIMS

The prevalence of iron deficiency (ID) in newly diagnosed heart failure (HF) and the progression of ID in patients after initiation of HF therapy are unknown. We aimed to describe the natural trajectory of ID in patients with new onset HF during the first year after HF diagnosis, assessing associations between ID, clinical factors, and quality of life (QoL).

METHODS AND RESULTS

A prospective cohort of patients with new onset HF in hospitals or outpatient clinics at five major hospitals in Stockholm, Sweden, during 2015-2018 were analysed with clinical assessment, electrocardiogram, blood samples including iron levels, Minnesota living with heart failure questionnaire (MLHFQ), and echocardiogram at baseline and after 12 months. Of 547 patients with new-onset HF, 482 (88%) had complete iron data at baseline. Mean age was 70 years (interquartile range 61-77) and 311 (65%) were men; 55% of patients had ejection fraction (EF) ≤ 40%, 19% had EF 41-49%, and 26% had HF with preserved EF (HFpEF). At baseline, 163 patients (34%) had ID defined as ferritin <100 μg/L or ferritin 100-299 μg/L and transferrin saturation <20%. After 12 months of follow-up, 119 (32%) had ID of the 368 patients who had complete iron data both at baseline and after 12 months and did not receive intravenous (i.v.) iron during follow-up. During the first year after HF diagnosis, 19% had persistent ID, 13% developed ID, 11% resolved ID, and 57% never had ID, consequently 24% changed their classification. Anaemia at baseline was the strongest independent predictor of ID 1 year after diagnosis [odds ratio (OR) 3.91, 95% confidence interval (CI) 1.88-8.13, P < 0.001], followed by HF hospitalization (OR 2.21, 95% CI 1.24-3.95, P < 0.01), female sex (OR 2.04, 95% CI 1.25-3.32, P < 0.01), HFpEF (OR 1.96, 95% CI 1.13-3.39, P < 0.05), and diabetes mellitus (OR 1.92, 95% CI 1.06-3.48, P < 0.05). ID was associated with low QoL at baseline (MLHFQ score mean difference 7.4 points, 95% CI 3.1-11.7, P < 0.001), but not at follow-up.

CONCLUSIONS

About one third of patients with new onset HF had ID both at the time of HF diagnosis and after 1 year, though a quarter of the patients changed their ID status. Patients with anaemia, HF hospitalization, female gender, HFpEF, or diabetes mellitus at baseline were more likely to have ID after 1 year implying that these should be carefully screened for ID to find those in need of i.v. iron treatment.

Expert recommendations for the management of iron deficiency in patients with heart failure in Asia

BACKGROUND

Iron deficiency is a common comorbidity in heart failure (HF) and is independently associated with a worse quality-of-life and exercise capacity, as well as increased risk of hospitalization, regardless of anemia status. Although international guidelines have provided recommendations for the management of iron deficiency in patients with HF, guidelines in Asia are less established, and practical use of guidelines for management of iron deficiency is limited in the region.

METHODS

A panel comprising cardiologists from China, Hong Kong, India, Japan, Malaysia, Pakistan, Philippines, Singapore, South Korea, Taiwan, and Thailand convened to share insights and provide guidance for the optimal management of iron deficiency in patients with HF, tailored for the Asian community.

RESULTS

Expert opinions were provided for the screening, diagnosis, treatment and monitoring of iron deficiency in patients with HF. It was recommended that all patients with HF with reduced ejection fraction should be screened for iron deficiency, and iron-deficient patients should be treated with intravenous iron. Monitoring of iron levels in patients with HF should be carried out once or twice yearly. Barriers to the management of iron deficiency in patients with HF in the region include low awareness of iron deficiency amongst general physicians, lack of reimbursement for screening and treatment, and lack of proper facilities for administration of intravenous iron.

CONCLUSIONS

These recommendations provide a structured approach to the management of iron deficiency in patients with HF in Asia.

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.

Imbalance of Iron Availability and Demand in Patients With Acute and Chronic Heart Failure

BACKGROUND

Iron deficiency (ID) is a frequent comorbidity in patients with acute (AHF) and chronic heart failure (CHF) associated with morbidity and death. We aimed to better characterize iron homeostasis in patients with heart failure applying different biomarkers and to evaluate the accuracy of current ID definition by the European Society of Cardiology/American College of Cardiology/American Heart Association to indicate tissue iron availability and demand.

METHODS AND RESULTS

We performed a retrospective cohort study investigating 277 patients with AHF and 476 patients with CHF between February 2021 and May 2022. Patients with AHF had more advanced ID than patients with CHF, reflected by increased soluble transferrin receptor and soluble transferrin receptor-ferritin index, and lower ferritin, serum iron, transferrin saturation, hepcidin, and reticulocyte hemoglobin. Decreased iron availability or increased tissue iron demand, reflected by increased soluble transferrin receptor-ferritin index and decreased reticulocyte hemoglobin, was found in 84.1% (AHF) and 28.0% (CHF) with absolute ID and in 50.0% (AHF) and 10.5% (CHF) with combined ID according to the current European Society of Cardiology/American College of Cardiology/American Heart Association-based ID definition. Low hepcidin expression as an indicator of systemic ID was found in 91.1% (AHF) and 80.4% (CHF) of patients with absolute ID and in 32.3% (AHF) and 18.8% (CHF) of patients with combined ID. ID definitions with higher specificity reduce the need for iron supplementation by 25.5% in patients with AHF and by 65.6% in patients with CHF.

CONCLUSIONS

Our results suggest that the current European Society of Cardiology/American College of Cardiology/American Heart Association-based ID definition might overestimate true ID, particularly in CHF. More stringent thresholds for ID could more accurately identify patients with heart failure with reduced tissue iron availability who benefit from intravenous iron supplementation.

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.

Iron deficiency and all-cause mortality after myocardial infarction

BACKGROUND

Data on the clinical significance of iron deficiency (ID) in patients with myocardial infarction (MI) are conflicting. This may be related to the use of various ID criteria. We aimed to compare the association of different ID criteria with all-cause mortality after MI.

METHODS

Consecutive patients hospitalized for their first MI at a large tertiary heart center were included. We evaluated the association of different iron metabolism parameters measured on the first day after hospital admission with all-cause mortality.

RESULTS

From the 1,156 patients included (aged 64±12 years, 25 % women), 194 (16.8 %) patients died during the median follow-up of 3.4 years. After multivariate adjustment, iron level ≤13 µmol/L (HR 1.67, 95 % CI 1.19-2.34) and the combination of iron level ≤12.8 µmol/L and soluble transferrin receptor (sTfR) ≥3 mg/L (HR 2.56, 95 % CI 1.64-3.99) termed as PragueID criteria were associated with increased mortality risk and had additional predictive value to the GRACE score. Compared to the model including iron level, the addition of sTfR improved risk stratification (net reclassification improvement 0.61, 95 % CI 0.52-0.69) by reclassifying patients into a higher-risk group. No association between ferritin level and mortality was found. 51 % of patients had low iron levels, and 58 % fulfilled the PragueID criteria.

CONCLUSION

Iron deficiency is common among patients with the first MI. The PragueID criteria based on iron and soluble transferrin receptor levels provide the best prediction of mortality and should be evaluated in future interventional studies for the identification of patients potentially benefiting from intravenous iron therapy.

Physiological Role of Serum Growth Differentiation Factor-15 (GDF-15) Level and Iron Metabolism in Community-Dwelling Older Adults

Background Anemia is common in older adults and, together with heart failure and chronic kidney disease, forms a vicious cycle, whereas diseases such as chronic inflammation and cancer are associated with the anemia of chronic disease (ACD). Researchers have linked growth differentiation factor-15 (GDF-15) to a variety of conditions such as cardiovascular disease, inflammation, cancer, and kidney disease, and have reported hepcidin as a biomarker for iron regulation in ACD. Therefore, anemia, GDF-15, and hepcidin have significance in aging physiology. Hypothesis GDF-15 and hepcidin play important physiological roles in community-dwelling older adults. This study sought to explore the relationship between these biomarkers and anemia, inflammation, or other health outcomes. Methods This was a prospective study of 73 community-dwelling older adults (six men and 67 women, mean age of 76.3 years). Their serum iron level, percentage transferrin saturation (TSAT), high-sensitivity C-reactive protein (hs-CRP), and estimated glomerular filtration rate (eGFR) were measured. Enzyme-linked immunosorbent assays were used to assess their serum GDF-15, ferritin, and hepcidin levels. The participants' grip strength and walking speed were measured. The skeletal muscle mass index (SMI) of each participant was determined by bioelectrical impedance analysis. Results The GDF-15 level was significantly inversely correlated with serum iron, ferritin, and hepcidin levels; percentage TSAT; the eGFR; and gait speed. Serum hepcidin was positively correlated with levels of ferritin, albumin, and hemoglobin. Handgrip strength, SMI, and hs-CRP were not correlated with either GDF-15 or hepcidin levels. After adjusting for age, sex, and body mass index (BMI), multivariate analysis identified the log GDF-15 and serum iron level (log GDF-15: β=-0.248, iron: β=0.296) as significant factors determining hemoglobin levels, whose findings have significance due to novel results. Multivariate analysis identified eGFR and levels of hemoglobin and hepcidin as significant factors associated with log GDF-15 (eGFR: β=-0.406, hemoglobin: β=-0.269, hepcidin: β=-0.235). Similarly, ferritin and albumin levels were identified as significant factors associated with hepcidin levels (ferritin: β=0.590, Alb: β=0.277). Conclusions Anemia in community-dwelling older adults was determined not only by increasing serum iron levels but also by decreasing GDF-15 levels. Also, the increasing GDF-15 level was determined by a decreasing hepcidin level as well as the presence of anemia and renal dysfunction, and the decreasing hepcidin level was determined by decreasing stored iron and decreasing albumin levels. Serum GDF-15 and hepcidin could potentially inform diagnostic or treatment strategies for anemia or age-related health conditions.

Iron homeostasis in older adults: balancing nutritional requirements and health risks

Iron plays a crucial role in many physiological processes, including oxygen transport, bioenergetics, and immune function. Iron is assimilated from food and also recycled from senescent red blood cells. Iron exists in two dietary forms: heme (animal based) and non-heme (mostly plant based). The body uses iron for metabolic purposes, and stores the excess mainly in splenic and hepatic macrophages. Physiologically, iron excretion in humans is inefficient and not highly regulated, so regulation of intestinal absorption maintains iron homeostasis. Iron losses occur at a steady rate via turnover of the intestinal epithelium, blood loss, and exfoliation of dead skin cells, but overall iron homeostasis is tightly controlled at cellular and systemic levels. Aging can have a profound impact on iron homeostasis and induce a dyshomeostasis where iron deficiency or overload (sometimes both simultaneously) can occur, potentially leading to several disorders and pathologies. To maintain physiologically balanced iron levels, reduce risk of disease, and promote healthy aging, it is advisable for older adults to follow recommended daily intake guidelines and periodically assess iron levels. Clinicians can evaluate body iron status using different techniques but selecting an assessment method primarily depends on the condition being examined. This review provides a comprehensive overview of the forms, sources, and metabolism of dietary iron, associated disorders of iron dyshomeostasis, assessment of iron levels in older adults, and nutritional guidelines and strategies to maintain iron balance in older adults.

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.

Iron deficiency: prevalence, mortality risk, and dietary relationships in general and heart failure populations

Background

Iron deficiency (ID) is the most common nutritional deficiency, with little research on its prevalence and long-term outcomes in the general population and those with heart failure (HF). Both the relationships between dietary iron and ID, as well as dietary folate and ID, are understudied.

Methods

We used data from the National Health and Nutrition Examination Survey from 1999 to 2002 to investigate the prevalence, prognosis, and relationship between dietary and ID defined by different criteria in the general population (n = 6,660) and those with HF (n = 182).

Results

There was no significant difference in the prevalence of ID between HF patients and the general population after propensity score matching. Transferrin saturation (TSAT) <20% was associated with higher 5-year all-cause mortality (HR: 3.49, CI: 1.40-8.72, P = 0.007), while ferritin <30 ng/ml was associated with higher 10-year (HR: 2.70, CI: 1.10-6.67, P = 0.031) and 15-year all-cause mortality (HR: 2.64, CI: 1.40-5.00, P = 0.003) in HF patients. Higher dietary total folate but dietary iron reduced the risk of ID (defined as ferritin <100 ng/ml) in HF patients (OR: 0.80; 95% CI: 0.65-1.00; P = 0.047).

Conclusions

The prevalence of ID was identical in HF and non-HF individuals. Ferritin <30 ng/ml was associated with long-term outcomes whereas TSAT <20% was associated with short-term prognosis in both the general population and HF patients. A diet rich in folate might have the potential for prevention and treatment of ID in HF patients.

Association between CFTR modulators and changes in iron deficiency markers in cystic fibrosis

BACKGROUND

Iron deficiency (ID) is a common extrapulmonary manifestation in cystic fibrosis (CF). CF transmembrane conductance regulator (CFTR) modulator therapies, particularly highly-effective modulator therapy (HEMT), have drastically improved health status in a majority of people with CF. We hypothesize that CFTR modulator use is associated with improved markers of ID.

METHODS

In a multicenter retrospective cohort study across 4 United States CF centers 2012-2022, the association between modulator therapies and ID laboratory outcomes was estimated using multivariable linear mixed effects models overall and by key subgroups. Summary statistics describe the prevalence and trends of ID, defined a priori as transferrin saturation (TSAT) <20 % or serum iron <60 μg/dL (<10.7 μmol/L).

RESULTS

A total of 568 patients with 2571 person-years of follow-up were included in analyses. Compared to off modulator therapy, HEMT was associated with +8.4 % TSAT (95 % confidence interval [CI], +6.3-10.6 %; p < 0.0001) and +34.4 μg/dL serum iron (95 % CI, +26.7-42.1 μg/dL; p < 0.0001) overall; +5.4 % TSAT (95 % CI, +2.8-8.0 %; p = 0.0001) and +22.1 μg/dL serum iron (95 % CI, +13.5-30.8 μg/dL; p < 0.0001) in females; and +11.4 % TSAT (95 % CI, +7.9-14.8 %; p < 0.0001) and +46.0 μg/dL serum iron (95 % CI, +33.3-58.8 μg/dL; p < 0.0001) in males. Ferritin was not different in those taking modulator therapy relative to off modulator therapy. Hemoglobin was overall higher with use of modulator therapy. The prevalence of ID was high throughout the study period (32.8 % in those treated with HEMT).

CONCLUSIONS

ID remains a prevalent comorbidity in CF, despite availability of HEMT. Modulator use, particularly of HEMT, is associated with improved markers for ID (TSAT, serum iron) and anemia (hemoglobin).

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.

Meta-Analysis and Metaregression of the Treatment Effect of Intravenous Iron in Iron-Deficient Heart Failure

BACKGROUND

Guidelines recommend that intravenous iron should be considered to improve symptoms of heart failure (HF) and reduce the risk for HF admissions in patients after acute HF.

OBJECTIVES

This study sought to analyze the effect of intravenous iron on cardiovascular (CV) death and HF admissions in a broad population of HF patients with iron deficiency and the relation with baseline transferrin saturation (TSAT).

METHODS

A systematic review of all published randomized controlled trials assessing the effect of intravenous iron in patients with iron deficiency and HF between January 1, 2000, and August 26, 2023, was performed. The overall treatment effect was estimated using a fixed effect model for: 1) CV death; 2) CV death and HF admission; 3) first HF admission; and 4) total HF admissions. Metaregression through a mixed effect model was used to explore the impact of baseline TSAT in case of heterogeneity among trial results.

RESULTS

A total of 14 randomized controlled trials were identified in the systematic review and retained in the meta-analysis. Aggregate-level data were included on 6,624 HF patients, 3,407 of whom were randomized to intravenous iron and 3,217 to placebo. Treatment with intravenous iron resulted in a lower risk for CV death (OR: 0.867 [95% CI: 0.755-0.955]; P = 0.0427), combined CV death and HF admission (OR: 0.838 [95% CI: 0.751-0.936]; P = 0.0015), first HF admission (OR: 0.855 [95% CI: 0.744-0.983]; P = 0.0281), and total HF admissions (rate ratio: 0.739 [95% CI: 0.661-0.827]; P < 0.0001). Significant heterogeneity among trial results was observed for first and total HF admissions. Metaregression suggested that some of the heterogeneity was related to the baseline TSAT of the enrolled population, with trials enrolling patients with lower TSAT exhibiting a large effect size on HF-related events.

CONCLUSIONS

The totality of data suggests that treatment with intravenous iron reduces both CV death and HF-related events in a broad population with HF. A lower baseline TSAT might be important for the effect on HF-related events.

Plasma Ferritin Levels, Incident Heart Failure, and Cardiac Structure and Function: The ARIC Study

BACKGROUND

Whether iron deficiency contributes to incident heart failure (HF) and cardiac dysfunction has important implications given the prevalence of iron deficiency and the availability of several therapeutics for iron repletion.

OBJECTIVES

The aim of this study was to estimate the associations of plasma ferritin level with incident HF overall, HF phenotypes, and cardiac structure and function measures in older adults.

METHODS

Participants in the ongoing, longitudinal ARIC (Atherosclerosis Risk In Communities) study who were free of prevalent HF and anemia were studied. The associations of plasma ferritin levels with incident HF overall and heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF) were estimated using Cox proportional hazards regression models. Linear regression models estimated the cross-sectional associations of plasma ferritin with echocardiographic measures of cardiac structure and function.

RESULTS

The cohort included 3,472 individuals with a mean age of 75 ± 5 years (56% women, 14% Black individuals). In fully adjusted models, lower ferritin was associated with higher risk for incident HF overall (HR: 1.20 [95% CI: 1.08-1.34] per 50% lower ferritin level) and higher risk for incident HFpEF (HR: 1.28 [95% CI: 1.09-1.50]). Associations with incident HFrEF were not statistically significant. Lower ferritin levels were associated with higher E/e' ratio and higher pulmonary artery systolic pressure after adjustment for demographics and HF risk factors but not with measures of left ventricular structure or systolic function.

CONCLUSIONS

Among older adults without prevalent HF or anemia, lower plasma ferritin level is associated with a higher risk for incident HF, HFpEF, and higher measures of left ventricular filling pressure.

Considerations Regarding Management of Heart Failure in Older Adults

Understanding noncardiovascular comorbidities and geriatric syndromes in elderly patients with heart failure (HF) is important as the average age of the population increases. Healthcare professionals need to consider these complex dynamics when managing older adults with HF, especially those older than 80. A number of small studies have described associations between HF and major geriatric domains. With information on patients' cognitive, functional decline, and ability to adhere to therapy, physicians can plan for individualized treatment goals and recommendations for these patients.

Associations between genetically predicted iron status and cardiovascular disease risk: A Mendelian randomization study

Background

Mendelian randomization (MR) studies suggest a causal effect of iron (Fe) status on cardiovascular disease (CVD) risk, but it is unknown if these associations are confounded by pleiotropic effects of the instrumental variables (IV) on CVD risk factors. We aimed to investigate the effect of Fe status on CVD risk controlling for CVD risk factors.

Methods

Fe biomarker IVs (total Fe binding capacity (TIBC, n=208,422), transferrin saturation (TSAT, n=198,516), serum Fe (SI, n=236,612), ferritin (n=257,953)) were selected from a European GWAS meta-analysis. We performed two-sample univariate (UV) MR of each Fe trait on CVD outcomes (all-cause ischemic stroke (IS), cardioembolic IS (CES), large artery IS (LAS), small vessel IS (SVS), and coronary heart disease (CHD)) from MEGASTROKE (n=440,328) and CARDIoGRAMplusC4D (n=183,305). We then implemented multivariate (MV) MR conditioning on six CVD risk factors from independent European samples to evaluate their potential confounding and/or mediating effects on the observed Fe-CVD associations.

Results

With UVMR analyses, we found higher genetically predicted Fe status to be associated with a greater risk of CES (TSAT: OR 1.17 [95%CI 1.03, 1.33], SI: OR 1.21 [ 95%CI 1.02, 1.44]; TIBC: OR 0.81 [95%CI 0.69, 0.94]). The detrimental effects of Fe status on CES risk remained unaffected when adjusting for CVD risk factors (all P<0.05). Additionally, we found diastolic blood pressure (DBP) to mediate between 7.1-8.8% of the total effect of Fe status on CES incidence. While UVMR initially suggested a protective effect of Fe status on LAS and CHD, MVMR analyses factoring CVD risk factors revealed a complete annulment of this perceived protective effect (all P>0.05).

Discussion

Higher Fe status was associated with a greater risk of CES independent of CVD risk factors, and this effect was partly mediated by DBP. These findings support a role of Fe status as a modifiable risk factor for CES.

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.

Interaction between systemic iron parameters and left ventricular structure and function in the preserved ejection fraction population: a two-sample bidirectional Mendelian randomization study

BACKGROUND

Left ventricular (LV) remodeling and diastolic function in people with heart failure (HF) are correlated with iron status; however, the causality is uncertain. This Mendelian randomization (MR) study investigated the bidirectional causal relationship between systemic iron parameters and LV structure and function in a preserved ejection fraction population.

METHODS

Transferrin saturation (TSAT), total iron binding capacity (TIBC), and serum iron and ferritin levels were extracted as instrumental variables for iron parameters from meta-analyses of public genome-wide association studies. Individuals without myocardial infarction history, HF, or LV ejection fraction (LVEF) < 50% (n = 16,923) in the UK Biobank Cardiovascular Magnetic Resonance Imaging Study constituted the outcome dataset. The dataset included LV end-diastolic volume, LV end-systolic volume, LV mass (LVM), and LVM-to-end-diastolic volume ratio (LVMVR). We used a two-sample bidirectional MR study with inverse variance weighting (IVW) as the primary analysis method and estimation methods using different algorithms to improve the robustness of the results.

RESULTS

In the IVW analysis, one standard deviation (SD) increased in TSAT significantly correlated with decreased LVMVR (β = -0.1365; 95% confidence interval [CI]: -0.2092 to -0.0638; P = 0.0002) after Bonferroni adjustment. Conversely, no significant relationships were observed between other iron and LV parameters. After Bonferroni correction, reverse MR analysis showed that one SD increase in LVEF significantly correlated with decreased TSAT (β = -0.0699; 95% CI: -0.1087 to -0.0311; P = 0.0004). No heterogeneity or pleiotropic effects evidence was observed in the analysis.

CONCLUSIONS

We demonstrated a causal relationship between TSAT and LV remodeling and function in a preserved ejection fraction population.

Iron Dyshomeostasis and Mitochondrial Function in the Failing Heart: A Review of the Literature

Cardiac contraction and relaxation require a substantial amount of energy provided by the mitochondria. The failing heart is adenosine triphosphate (ATP)- and creatine-depleted. Studies have found iron is involved in almost every aspect of mitochondrial function, and previous studies have shown myocardial iron deficiency in heart failure (HF). Many clinicians advocated intravenous iron repletion for HF patients meeting the conventional criteria for systemic iron deficiency. While clinical trials showed improved quality of life, iron repletion failed to significantly impact survival or significant cardiovascular adverse events. There is evidence that in HF, labile iron is trapped inside the mitochondria causing oxidative stress and lipid peroxidation. There is also compelling preclinical evidence demonstrating the detrimental effects of both iron overload and depletion on cardiomyocyte function. We reviewed the mechanisms governing myocardial and mitochondrial iron content. Mitochondrial dynamics (i.e., fusion, fission, mitophagy) and the role of iron were also investigated. Ferroptosis, as an important regulated cell death mechanism involved in cardiomyocyte loss, was reviewed along with agents used to manipulate it. The membrane stability and iron content of mitochondria can be altered by many agents. Some studies are showing promising improvement in the cardiomyocyte function after iron chelation by deferiprone; however, whether the in vitro and in vivo findings will be reflected on on clinical grounds is still unclear. Finally, we briefly reviewed the clinical trials on intravenous iron repletion. There is a need for more well-simulated animal studies to shed light on the safety and efficacy of chelation agents and pave the road for clinical studies.

Iron Deficiency in Chronic Pediatric Heart Failure: Overall Assessment and Outcomes in Dilated Cardiomyopathy

OBJECTIVE

To evaluate the frequency of iron status assessment in pediatric heart failure and the prevalence and adverse effects of absolute iron deficiency in dilated cardiomyopathy-induced heart failure.

STUDY DESIGN

We retrospectively reviewed records of children with chronic heart failure at our center between 2010 and 2020. In children with dilated cardiomyopathy, we analyzed baseline cardiac function, hemoglobin level, and subsequent risk of composite adverse events (CAE), including death, heart transplant, ventricular assist device (VAD) placement, and transplant registry listing. Absolute iron deficiency and iron sufficiency were defined as transferrin saturations <20% and ≥30%, respectively; and indeterminant iron status as 20%-29%.

RESULTS

Of 799 patients with chronic heart failure, 471 (59%) had no iron-related laboratory measurements. Of 68 children with dilated cardiomyopathy, baseline transferrin saturation, and quantitative left ventricular ejection fraction (LVEF), 33 (49%) and 14 (21%) were iron deficient and sufficient, respectively, and 21 (31%) indeterminant. LVEF was reduced to 23.6 ± 12.1% from 32.9 ± 16.8% in iron deficiency and sufficiency, respectively (P = .04), without a significant difference in hemoglobin. After stratification by New York Heart Association classification, in advanced class IV, hemoglobin was reduced to 10.9 ± 1.3 g/dL vs 12.7 ± 2.0 g/dL in iron deficiency and sufficiency, respectively (P = .01), without a significant difference in LVEF.

CONCLUSIONS

In this single-center study, iron deficiency was not monitored in most children with chronic heart failure. In pediatric dilated cardiomyopathy-induced heart failure, absolute iron deficiency was prevalent and associated with clinically consequential and possibly correctable decreases in cardiac function and hemoglobin concentration.

Association between serum iron markers, iron supplementation and cardiovascular morbidity in pre-dialysis chronic kidney disease

BACKGROUND

The optimal range of serum iron markers and usefulness of iron supplementation are uncertain in patients with pre-dialysis chronic kidney disease (CKD). We investigated the association between serum iron indices and risk of cardiovascular disease (CVD) events and the effectiveness of iron supplementation using Chronic Kidney Disease Japan Cohort data.

METHODS

We included 1416 patients ages 20-75 years with pre-dialysis CKD. The tested exposures were serum transferrin saturation and serum ferritin levels and the outcome measures were any cardiovascular event. Fine-Gray subdistribution hazard models were used to examine the association between serum iron indices and time to events. The multivariable fractional polynomial interaction approach was used to evaluate whether serum iron indices were effect modifiers of the association between iron supplementation and cardiovascular events.

RESULTS

The overall incidence rate of CVD events for a median of 4.12 years was 26.7 events/1000 person-years. Patients with serum transferrin saturation <20% demonstrated an increased risk of CVD [subdistribution hazard ratio (HR) 2.13] and congestive heart failure (subdistribution HR 2.42). The magnitude of reduction in CVD risk with iron supplementation was greater in patients with lower transferrin saturations (P = .042).

CONCLUSIONS

Maintaining transferrin saturation >20% and adequate iron supplementation may effectively reduce the risk of CVD events in patients with pre-dialysis CKD.

Role of red blood cells in clinically relevant bleeding tendencies and complications

The multiple roles of red blood cells (RBCs) are often neglected as contributors in hemostasis and thrombosis. Proactive opportunities to increase RBC numbers, either acutely or subacutely in the case of iron deficiency, are critical as RBCs are the cellular elements that initiate hemostasis together with platelets and stabilize fibrin and clot structure. RBCs also possess several functional properties to assist hemostasis: releasing platelet agonists, promoting shear force-induced von Willebrand factor unfolding, procoagulant capacity, and binding to fibrin. Additionally, blood clot contraction is important to compress RBCs to form a tightly packed array of polyhedrocytes, making an impermeable seal for hemostasis. All these functions are important for patients having intrinsically poor capacity to cease bleeds (ie, hemostatic disorders) but, conversely, can also play a role in thrombosis if these RBC-mediated reactions overshoot. One acquired example of bleeding with anemia is in patients treated with anticoagulants and/or antithrombotic medication because upon initiation of these drugs, baseline anemia doubles the risk of bleeding complications and mortality. Also, anemia is a risk factor for reoccurring gastrointestinal and urogenital bleeds, pregnancy, and delivery complications. This review summarizes the clinically relevant properties and profiles of RBCs at various steps of platelet adhesion, aggregation, thrombin generation, and fibrin formation, including both structural and functional elements. Regarding patient blood management guidelines, they support minimizing transfusions, but this approach does not deal with severe inherited and acquired bleeding disorders where a poor hemostatic propensity is exacerbated by limited RBC availability, for which future guidance will be needed.

Prognostic value of three iron deficiency definitions in patients with advanced heart failure

AIMS

There is uncertainty about the definition of iron deficiency (ID) and the association between ID and prognosis in patients with advanced heart failure. We evaluated three definitions of ID in patients referred for heart transplantation.

METHODS AND RESULTS

Consecutive patients assessed for heart transplantation at a single UK centre between January 2010 and May 2022 were included. ID was defined as (1) serum ferritin concentration of <100 ng/ml, or 100-299 ng/ml with transferrin saturation <20% (guideline definition), (2) serum iron concentration ≤13 μmol/L, or (3) transferrin saturation <20%. The primary outcome measure was a composite of all-cause mortality, urgent heart transplantation or need for mechanical circulatory support. Overall, 801 patients were included, and the prevalence of ID was 39-55% depending on the definition used. ID, defined by either serum iron or transferrin saturation, was an independent predictor of the primary outcome measure (hazard ratio [HR] 1.532, 95% confidence interval [CI] 1.264-1.944, and HR 1.595, 95% CI 1.323-2.033, respectively), but the same association was not seen with the guideline definition of ID (HR 1.085, 95% CI 0.8827-1.333). These findings were robust in multivariable Cox regression analysis. ID, by all definitions, was associated with lower 6-min walk distance, lower peak oxygen consumption, higher intra-cardiac filling pressures and lower cardiac output.

CONCLUSIONS

Iron deficiency, when defined by serum iron concentration or transferrin saturation, was associated with increased frequency of adverse clinical outcomes in patients with advanced heart failure. The same association was not seen with guideline definition of ID.

Influence of serum transferrin concentration on diagnostic criteria for iron deficiency in chronic heart failure

AIMS

Transferrin saturation (TSAT), a marker of iron deficiency, reflects both serum concentrations of iron (SIC) and transferrin (STC). TSAT is susceptible to changes in each of these biomarkers. Little is known about determinants of STC and its influence on TSAT and mortality in patients with heart failure. Accordingly, we studied the relationship of STC to clinical characteristics, to markers of iron deficiency and inflammation and to mortality in chronic heart failure (CHF).

METHODS AND RESULTS

Prospective cohort of patients with CHF attending a clinic serving a large local population. A total of 4422 patients were included (median age 75 (68-82) years; 40% women; 32% with left ventricular ejection fraction ≤40%). STC ≤ 2.3 g/L (lowest quartile) was associated with older age, lower SIC and haemoglobin and higher high-sensitivity C-reactive protein, ferritin and N-terminal pro-brain natriuretic peptide compared with those with STC > 2.3 g/L. In the lowest STC quartile, 624 (52%) patients had SIC ≤13 μmol/L, of whom 38% had TSAT ≥20%. For patients in the highest STC quartile, TSAT was <20% when SIC was >13 μmol/L in 185 (17%) patients. STC correlated inversely with ferritin (r = -0.52) and high-sensitivity C-reactive protein (r = -0.17) and directly with albumin (r = 0.29); all P < 0.001. In models adjusted for age, N-terminal pro-brain natriuretic peptide and haemoglobin, both higher SIC (hazard ratio 0.87 [95% CI: 0.81-0.95]) and STC (hazard ratio 0.82 [95% CI: 0.73-0.91]) were associated with lower mortality. SIC was more strongly associated with both anaemia and mortality than either STC or TSAT.

CONCLUSIONS

Many patients with CHF and a low STC have low SIC even when TSAT is >20% and serum ferritin >100 μg/L; such patients have a high prevalence of anaemia and a poor prognosis and might have iron deficiency but are currently excluded from clinical trials of iron repletion.

Heart Failure-Related Iron Deficiency Anemia Pathophysiology and Laboratory Diagnosis

PURPOSE OF REVIEW

The goal of the current review is to give an overview regarding the pathophysiology of iron deficiency in heart failure and how different laboratory tests change in the setting of heart failure.

RECENT FINDINGS

Recent studies have questioned the current employed definition of iron deficiency in the field of heart failure, as patients with ferritin < 100ng/ml but TSAT > 20% have a better prognosis, no iron deficiency on bone marrow staining, and altered treatment response to ferric carboxymaltose. This review summarizes changes in iron parameters in the setting of heart failure and underscores the importance of a reduced bioavailability of iron documented by a low serum iron or TSAT, irrespective of the presence of anemia.

Ferric Carboxymaltose in Heart Failure with Iron Deficiency

BACKGROUND

Ferric carboxymaltose therapy reduces symptoms and improves quality of life in patients who have heart failure with a reduced ejection fraction and iron deficiency. Additional evidence about the effects of ferric carboxymaltose on clinical events is needed.

METHODS

In this double-blind, randomized trial, we assigned ambulatory patients with heart failure, a left ventricular ejection fraction of 40% or less, and iron deficiency, in a 1:1 ratio, to receive intravenous ferric carboxymaltose or placebo, in addition to standard therapy for heart failure. Ferric carboxymaltose or placebo was given every 6 months as needed on the basis of iron indexes and hemoglobin levels. The primary outcome was a hierarchical composite of death within 12 months after randomization, hospitalizations for heart failure within 12 months after randomization, or change from baseline to 6 months in the 6-minute walk distance. The significance level was set at 0.01.

RESULTS

We enrolled 3065 patients, of whom 1532 were randomly assigned to the ferric carboxymaltose group and 1533 to the placebo group. Death by month 12 occurred in 131 patients (8.6%) in the ferric carboxymaltose group and 158 (10.3%) in the placebo group; a total of 297 and 332 hospitalizations for heart failure, respectively, occurred by month 12; and the mean (±SD) change from baseline to 6 months in the 6-minute walk distance was 8±60 and 4±59 m, respectively (Wilcoxon-Mann-Whitney P = 0.02; unmatched win ratio, 1.10; 99% confidence interval, 0.99 to 1.23). Repeated dosing of ferric carboxymaltose appeared to be safe with an acceptable adverse-event profile in the majority of patients. The number of patients with serious adverse events occurring during the treatment period was similar in the two groups (413 patients [27.0%] in the ferric carboxymaltose group and 401 [26.2%] in the placebo group).

CONCLUSIONS

Among ambulatory patients who had heart failure with a reduced ejection fraction and iron deficiency, there was no apparent difference between ferric carboxymaltose and placebo with respect to the hierarchical composite of death, hospitalizations for heart failure, or 6-minute walk distance. (Funded by American Regent, a Daiichi Sankyo Group company; HEART-FID ClinicalTrials.gov number, NCT03037931.).

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.

Assessment of haemoglobin and serum markers of iron deficiency in people with cardiovascular disease

BACKGROUND

The prevalence of anaemia and iron deficiency and their prognostic association with cardiovascular disease have rarely been explored at population level.

METHODS

National Health Service records of the Greater Glasgow region for patients aged ≥50 years with a broad range of cardiovascular diagnoses were obtained. During 2013/14, prevalent disease was identified and results of investigations collated. Anaemia was defined as haemoglobin <13 g/dL for men or <12 g/dL for women. Incident heart failure, cancer and death between 2015 and 2018 were identified.

RESULTS

The 2013/14 dataset comprised 197 152 patients, including 14 335 (7%) with heart failure. Most (78%) patients had haemoglobin measured, especially those with heart failure (90%). Of those tested, anaemia was common both in patients without (29%) and with heart failure (prevalent cases in 2013/14: 46%; incident cases during 2013/14: 57%). Ferritin was usually measured only when haemoglobin was markedly depressed; transferrin saturation (TSAT) even less often. Incidence rates for heart failure and cancer during 2015-18 were inversely related to nadir haemoglobin in 2013/14. A haemoglobin of 13-15 g/dL for women and 14-16 g/dL for men was associated with the lowest mortality. Low ferritin was associated with a better prognosis and low TSAT with a worse prognosis.

CONCLUSION

In patients with a broad range of cardiovascular disorders, haemoglobin is often measured but, unless anaemia is severe, markers of iron deficiency are usually not. Low haemoglobin and TSAT, but not low ferritin, are associated with a worse prognosis. The nadir of risk occurs at haemoglobin 1-3 g/dL above the WHO definition of anaemia.

Iron deficiency in heart failure: screening, prevalence, incidence and outcome data from the Swedish Heart Failure Registry and the Stockholm CREAtinine Measurements collaborative project

AIMS

Iron deficiency (ID) is common in heart failure (HF) and linked with poor prognosis regardless of anaemia. We assessed temporal trends in ID testing, ID prevalence, ID incidence, iron need, and outcomes associated with ID in HF across the ejection fraction (EF) spectrum.

METHODS AND RESULTS

From the Swedish HF registry, we enrolled 15 197 patients from Region Stockholm with available EF and collected laboratory tests from routine practice. Iron screening improved since 2016 but remained <25% as of 2018. In 1486 patients with iron biomarkers at baseline, the prevalence of ID was 55% (HF with reduced EF 54%; mildly reduced EF 51%; preserved EF 61%). Iron need was ≥1500 mg in 72% of patients. ID was independently associated with higher risk for HF rehospitalizations (incidence rate ratio [IRR] 1.62, 95% confidence interval [CI] 1.13-2.31) and with cardiovascular (CV) death or repeated HF hospitalizations (IRR 1.63, 95% CI 1.15-2.30) regardless of EF (p-interaction 0.21 and 0.26, respectively), but not with all-cause death, CV death, or first HF hospitalization. Among 96 patients without ID at baseline and with follow-up iron biomarkers, 21% developed ID within 6 months.

CONCLUSIONS

Iron deficiency screening improved over time but is still limitedly implemented, despite being highly prevalent and incident, and independently associated with CV death or HF rehospitalizations regardless of EF. Most patients with ID had an iron need necessitating either repeated administrations of intravenous iron or a preparation permitting >1000 mg doses. These data highlight the need for improved screening for ID in HF.

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.

SGLT2 inhibitors: role in protective reprogramming of cardiac nutrient transport and metabolism

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce heart failure events by direct action on the failing heart that is independent of changes in renal tubular function. In the failing heart, nutrient transport into cardiomyocytes is increased, but nutrient utilization is impaired, leading to deficient ATP production and the cytosolic accumulation of deleterious glucose and lipid by-products. These by-products trigger downregulation of cytoprotective nutrient-deprivation pathways, thereby promoting cellular stress and undermining cellular survival. SGLT2 inhibitors restore cellular homeostasis through three complementary mechanisms: they might bind directly to nutrient-deprivation and nutrient-surplus sensors to promote their cytoprotective actions; they can increase the synthesis of ATP by promoting mitochondrial health (mediated by increasing autophagic flux) and potentially by alleviating the cytosolic deficiency in ferrous iron; and they might directly inhibit glucose transporter type 1, thereby diminishing the cytosolic accumulation of toxic metabolic by-products and promoting the oxidation of long-chain fatty acids. The increase in autophagic flux mediated by SGLT2 inhibitors also promotes the clearance of harmful glucose and lipid by-products and the disposal of dysfunctional mitochondria, allowing for mitochondrial renewal through mitochondrial biogenesis. This Review describes the orchestrated interplay between nutrient transport and metabolism and nutrient-deprivation and nutrient-surplus signalling, to explain how SGLT2 inhibitors reverse the profound nutrient, metabolic and cellular abnormalities observed in heart failure, thereby restoring the myocardium to a healthy molecular and cellular phenotype.

Patient phenotype profiling in heart failure with preserved ejection fraction to guide therapeutic decision making. A scientific statement of the Heart Failure Association, the European Heart Rhythm Association of the European Society of Cardiology, and the European Society of Hypertension

Heart failure with preserved ejection fraction (HFpEF) represents a highly heterogeneous clinical syndrome affected in its development and progression by many comorbidities. The left ventricular diastolic dysfunction may be a manifestation of various combinations of cardiovascular, metabolic, pulmonary, renal, and geriatric conditions. Thus, in addition to treatment with sodium-glucose cotransporter 2 inhibitors in all patients, the most effective method of improving clinical outcomes may be therapy tailored to each patient's clinical profile. To better outline a phenotype-based approach for the treatment of HFpEF, in this joint position paper, the Heart Failure Association of the European Society of Cardiology, the European Heart Rhythm Association and the European Hypertension Society, have developed an algorithm to identify the most common HFpEF phenotypes and identify the evidence-based treatment strategy for each, while taking into account the complexities of multiple comorbidities and polypharmacy.

Mendelian randomization study reveals a causal relationship between serum iron status and coronary heart disease and related cardiovascular diseases

Background

Growing observational studies have shown that abnormal systemic iron status is associated with Coronary heart disease (CHD). However, these results from observational studies was not entirely consistent.It remains unclear whether this relationship represents causality.It is necessary to explore the causal relationship between iron status and CHD and related cardiovascular diseases (CVD).

Objective

We aimed to investigate the potential casual relationship between serum iron status and CHD and related CVD using a two-sample Mendelian randomization (MR) approach.

Methods

Genetic statistics for single nucleotide polymorphisms (SNPs) between four iron status parameters were identified in a large-scale genome-wide association study (GWAS) conducted by the Iron Status Genetics organization. Three independent single nucleotide polymorphisms (SNPs) (rs1800562, rs1799945, and rs855791) aligned with four iron status biomarkers were used as instrumental variables. CHD and related CVD genetic statistics We used publicly available summary-level GWAS data. Five different MR methods random effects inverse variance weighting (IVW), MR Egger, weighted median, weighted mode, and Wald ratio were used to explore the causal relationship between serum iron status and CHD and related CVD.

Results

In the MR analysis, we found that the causal effect of serum iron (OR = 0.995, 95% CI = 0.992-0.998, p = 0.002) was negatively associated with the odds of coronary atherosclerosis (AS). Transferrin saturation (TS) (OR = 0.885, 95% CI = 0.797-0.982, p = 0.02) was negatively associated with the odds of Myocardial infarction (MI).

Conclusion

This MR analysis provides evidence for a causal relationship between whole-body iron status and CHD development. Our study suggests that a high iron status may be associated with a reduced risk of developing CHD.

Iron deficiency in pulmonary vascular disease: pathophysiological and clinical implications

AIMS

Iron deficiency is common in pulmonary hypertension, but its clinical significance and optimal definition remain unclear.

METHODS AND RESULTS

Phenotypic data for 1028 patients enrolled in the Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics study were analyzed. Iron deficiency was defined using the conventional heart failure definition and also based upon optimal cut-points associated with impaired peak oxygen consumption (peakVO2), 6-min walk test distance, and 36-Item Short Form Survey (SF-36) scores. The relationships between iron deficiency and cardiac and pulmonary vascular function and structure and outcomes were assessed. The heart failure definition of iron deficiency endorsed by pulmonary hypertension guidelines did not identify patients with reduced peakVO2, 6-min walk test, and SF-36 (P > 0.208 for all), but defining iron deficiency as transferrin saturation (TSAT) <21% did. Compared to those with TSAT ≥21%, patients with TSAT <21% demonstrated lower peakVO2 [absolute difference: -1.89 (-2.73 to -1.04) mL/kg/min], 6-min walk test distance [absolute difference: -34 (-51 to -17) m], and SF-36 physical component score [absolute difference: -2.5 (-1.3 to -3.8)] after adjusting for age, sex, and hemoglobin (all P < 0.001). Patients with a TSAT <21% had more right ventricular remodeling on cardiac magnetic resonance but similar pulmonary vascular resistance on catheterization. Transferrin saturation <21% was also associated with increased mortality risk (hazard ratio 1.63, 95% confidence interval 1.13-2.34; P = 0.009) after adjusting for sex, age, hemoglobin, and N-terminal pro-B-type natriuretic peptide.

CONCLUSION

The definition of iron deficiency in the 2022 European Society of Cardiology (ESC)/European Respiratory Society (ERS) pulmonary hypertension guidelines does not identify patients with lower exercise capacity or functional status, while a definition of TSAT <21% identifies patients with lower exercise capacity, worse functional status, right heart remodeling, and adverse clinical outcomes.