Anemia and iron deficiency in heart failure: mechanisms and therapeutic approaches

Update in recent clinical trials in heart failure

PURPOSE OF REVIEW

Heart failure represents a major growing health problem in developed world. This article aims to review recent heart failure trials that have significantly impacted the management of heart failure.

RECENT FINDINGS

Despite advances in heart failure, mortality and morbidity remains elevated amongst patients. Recent clinical trials demonstrate promising treatment strategies that likely impact clinical practice; including heart failure prevention with the use of SGLT2-inhibitors in patients with diabetes and cardiovascular risk, new treatments that may abrogate disease progression in cardiac amyloidosis, intravenous iron therapy in iron deficiency anemia in chronic systolic heart failure, predischarge treatment with angiotensin receptor blocker with neprilysin inhibition (ARNi) in patients hospitalized for acute decompensated heart failure, and newer continuous flow left ventricular assist device with increased durability and efficacy in patients with Stage D heart failure.

SUMMARY

Recent clinical trials with SGLT2 inhibitors, therapies targeting transthyretin cardiac amyloidosis, iron, angiotensin receptor blocker with neprilysin inhibition and newer mechanical circulatory support devices are very promising as practice changing new treatment strategies in prevention and treatment of heart failure. This article presents a summary of important trials and should be of practical value to both clinicians and researchers.

Deranged Iron Status Evidenced by Iron Deficiency Characterizes Patients with Hidradenitis Suppurativa

BACKGROUND

Proinflammatory activation and autoimmune processes underlie the pathophysiology of hidradenitis suppurativa (HS). Iron deficiency (ID) is frequently present in inflammation-mediated chronic diseases, irrespective of anemia.

OBJECTIVES

We aimed to characterize iron status in patients with HS.

METHODS

Serum concentrations of ferritin, transferrin saturation (Tsat), soluble transferrin receptor and hepcidin were assessed as the biomarkers of iron status in 74 patients with HS and 44 healthy subjects. ID was defined as ferritin <100 µg/L or ferritin 100-299 µg/L with Tsat <20% (following the definition used in the other studies in chronic disease).

RESULTS

Compared with controls, patients with HS demonstrated a deranged iron status as evidenced by decreased levels of ferritin (91 ± 87 vs. 157 ± 99 µg/L), Tsat (21.5 ± 10.8 vs. 42.2 ± 11.7%) and hepcidin (31.3 ± 25.9 vs. 44.2 ± 22.0 ng/mL) (all p < 0.05 vs. controls). There was also a trend toward higher values of soluble transferrin receptor (1.23 ± 0.35 vs. 1.12 ± 0.19 mg/L) (p = 0.09 vs. controls). Disease severity (assessed with the Hidradenitis Suppurativa Severity Index and the 3-degree Hurley scale) did not differentiate iron status biomarkers. ID was present in 75% of HS patients, and its prevalence was not related with disease severity (Hurley I/II/III - 82 vs. 73 vs. 67%). In HS, none of the iron status biomarkers correlated with the levels of interleukin-6 (a marker of proinflammatory activation).

CONCLUSIONS

The majority of HS patients demonstrate derangements in iron status typical of ID. These abnormalities are neither related to proinflammatory activation nor associated with disease severity. Whether it may have a therapeutic impact needs to be further studied.

[Position Paper. The role of iron deficiency in patients with chronic heart failure and current corrective approaches]

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Iron deficiency in worsening heart failure is associated with reduced estimated protein intake, fluid retention, inflammation, and antiplatelet use

AIMS

Iron deficiency (ID) is common in heart failure (HF) patients and negatively impacts symptoms and prognosis. The aetiology of ID in HF is largely unknown. We studied determinants and the biomarker profile of ID in a large international HF cohort.

METHODS AND RESULTS

We studied 2357 worsening HF patients from the BIOSTAT-CHF cohort. ID was defined as transferrin saturation <20%. Univariable and multivariable logistic regression models were constructed to identify determinants for ID. We measured 92 cardiovascular markers (Olink Cardiovascular III) to establish a biomarker profile of ID. The primary endpoint was the composite of all-cause mortality and first HF rehospitalization. Mean age (±standard deviation) of all patients was 69 ± 12.0 years, 26.1% were female and median N-terminal pro B-type natriuretic peptide levels (+interquartile range) were 4305 (2360-8329) ng/L. Iron deficiency was present in 1453 patients (61.6%), with highest prevalence in females (71.1% vs. 58.3%; P < 0.001). Independent determinants of ID were female sex, lower estimated protein intake, higher heart rate, presence of peripheral oedema and orthopnoea, chronic kidney disease, lower haemoglobin, higher C-reactive protein levels, lower serum albumin levels, and P2Y12 inhibitor use (all P < 0.05). None of these determinants were sex-specific. The biomarker profile of ID largely consisted of pro-inflammatory markers, including paraoxonase 3 (PON3) and tartrate-resistant acid phosphatase type 5. In multivariable Cox proportional hazard regression analyses, ID was associated to worse outcome, independently of predictors of ID (hazard ratio 1.25, 95% confidence interval 1.06-1.46; P = 0.007).

CONCLUSION

Our data suggest that the aetiology of ID in worsening HF is complex, multifactorial and seems to consist of a combination of reduced iron uptake (malnutrition, fluid overload), impaired iron storage (inflammation, chronic kidney disease), and iron loss (antiplatelets).

Prognostic Value of Right Ventricular Dysfunction in Heart Failure With Reduced Ejection Fraction: Superiority of Longitudinal Strain Over Tricuspid Annular Plane Systolic Excursion

BACKGROUND

In heart failure (HF) with reduced ejection fraction, right ventricular (RV) impairment, as defined by reduced tricuspid annular plane systolic excursion, is a predictor of poor outcome. However, peak longitudinal strain of RV free wall (RVFWS) has been recently proposed as a more accurate and sensitive tool to evaluate RV function. Accordingly, we investigated whether RVFWS could help refine prognosis of patients with HF with reduced ejection fraction in whom tricuspid annular plane systolic excursion is still preserved.

METHODS AND RESULTS

A total of 200 patients with HF with reduced ejection fraction (age, 66±11 years; ejection fraction, 30±7%) with preserved tricuspid annular plane systolic excursion (>16 mm) underwent RV function assessment using speckle-tracking echocardiography to measure peak RVFWS. After a median follow-up period of 28 months, 62 (31%) patients reached the primary composite end point of all-cause death/HF rehospitalization. Median RVFWS was -19.3% (interquartile range, -23.3% to -15.0%). By lasso-penalized Cox-hazard model, RVFWS was an independent predictor of outcome, along with Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure-HF score, Echo-HF score, and severe mitral regurgitation. The best cutoff value of RVFWS for prediction of outcome was -15.3% (area under the curve, 0.68; P<0.001; sensitivity, 50%; specificity, 80%). In 50 patients (25%), RVFWS was impaired (ie, ≥-15.3%); event rate (per 100 patients per year) was greater in them than in patients with RVFWS <-15.3% (29.5% [95% confidence interval, 20.4-42.7] versus 9.4% [95% confidence interval, 6.7-13.1]; P<0.001). RVFWS yielded a significant net reclassification improvement (0.584 at 3 years; P<0.001), with 68% of nonevents correctly reclassified.

CONCLUSIONS

In patients with HF with reduced ejection fraction with preserved tricuspid annular plane systolic excursion, RV free-wall strain provides incremental prognostic information and improved risk stratification.

Definition of Iron Deficiency Based on the Gold Standard of Bone Marrow Iron Staining in Heart Failure Patients

BACKGROUND

The most commonly used definition of iron deficiency (ID; ferritin <100 ng/mL or ferritin 100-300 ng/mL and transferrin saturation [TSAT] <20%) has not been validated in patients with heart failure (HF). We aimed to define and validate the biomarker-based definition of ID in HF, using bone marrow iron staining as the gold standard. Second, we aimed to assess the prognostic value of the optimized definition.

METHODS AND RESULTS

Bone marrow aspiration with iron staining was performed in 42 patients with HF and a reduced left ventricular ejection fraction (≤45%) undergoing median sternotomy for coronary artery bypass grafting. Patients were mostly male (76%) with mild-to-moderate HF and a mean age of 68±10 years. Bone marrow ID was found in 17 (40%) of the HF patients. The most commonly used definition of ID had a sensitivity of 82% and a specificity of 72%. A definition solely based on TSAT ≤19.8% or serum iron ≤13 µmol/L had a sensitivity of 94% and specificity of 84% and 88%, respectively (P<0.05 compared with the former definition). Subsequently, we assessed the incidence of all-cause mortality in 387 consecutive outpatient HF patients (left ventricular ejection fraction ≤45%). In these patients, TSAT ≤19.8% and serum iron ≤13 µmol/L, and not ferritin, were independently associated with mortality.

CONCLUSIONS

A TSAT ≤19.8% or a serum iron ≤13 µmol/L shows the best performance in selecting patients with ID and identifies HF patients at the highest risk of death. Our findings validate the currently used TSAT cutoff of <20% for the identification of ID in HF patients, but question the diagnostic value of ferritin.

Hyporesponsiveness to Darbepoetin Alfa in Patients With Heart Failure and Anemia in the RED-HF Study (Reduction of Events by Darbepoetin Alfa in Heart Failure): Clinical and Prognostic Associations

BACKGROUND

A poor response to erythropoiesis-stimulating agents such as darbepoetin alfa has been associated with adverse outcomes in patients with diabetes mellitus, chronic kidney disease, and anemia; whether this is also true in heart failure is unclear.

METHODS AND RESULTS

We performed a post hoc analysis of the RED-HF trial (Reduction of Events by Darbepoetin Alfa in Heart Failure), in which 1008 patients with systolic heart failure and anemia (hemoglobin level, 9.0-12.0 g/dL) were randomized to darbepoetin alfa. We examined the relationship between the hematopoietic response to darbepoetin alfa and the incidence of all-cause death or first heart failure hospitalization during a follow-up of 28 months. For the purposes of the present study, patients in the lowest quartile of hemoglobin change after 4 weeks were considered nonresponders. The median initial hemoglobin change in nonresponders (n=252) was -0.25 g/dL and +1.00 g/dL in the remainder of patients (n=756). Worse renal function, lower sodium levels, and less use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers were independently associated with nonresponse. Although a low endogenous erythropoietin level helped to differentiate responders from nonresponders, its predictive value in a multivariable model was poor (C statistic=0.69). Nonresponders had a higher rate of all-cause death or first heart failure hospitalization (hazard ratio, 1.25; 95% confidence interval, 1.02-1.54) and a higher risk of all-cause mortality (hazard ratio, 1.30; 95% confidence interval, 1.04-1.63) than responders.

CONCLUSIONS

A poor response to darbepoetin alfa was associated with worse outcomes in heart failure patients with anemia. Patients with a poor response were difficult to identify using clinical and biochemical biomarkers.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00358215.

Iron deficiency in long standing type 1 diabetes mellitus and its association with depression and impaired quality of life

AIMS

Iron deficiency (ID) is the most frequent malnutrition worldwide and often associated with reduced quality of life (QoL) and depression. We aimed to investigate the iron status in middle-aged type 1 diabetes in relation to depression and QoL.

METHODS

109 people with type 1 diabetes (54.1% male, mean age 56.2 years) were enrolled in a cross-sectional study at the diabetes clinic of the Goethe University Hospital. Iron, haemoglobin and ferritin levels were measured. Treatment satisfaction, QoL and depression were assessed using standardized questionnaires (Disease Specific Quality of Life scale, CES-D (Center for Epidemiological Studies Depression Scale) and WHO-5 well-being index.

RESULTS

Decreased serum iron (<60 µg/dl) and ferritin levels (<50 pg/nl) were observed in 18 (16.8%) and 28 (26.7%) patients, respectively. Anemia was present in 20 patients (18.34%). A high rate of depression was observed: 42.2% (WHO-5) and 40.7% (CES-D). The personal goals and current diabetes therapy satisfaction score (PWTSS) was significantly better in patients with sufficient iron status (ferritin level > 50 pg/ml, p = 0.018). Multiple regression analysis revealed iron status (p = 0.03) to be an independent predictor for better PWTSS. Insufficient iron status correlated significantly with depression as measured by WHO-5 (p = 0.044) and CES-D (p = 0.029).

CONCLUSIONS

Type 1 diabetes patients in the current study were frequently depressive and reported an impaired QoL that associated with iron insufficiency. If confirmed a better awareness is needed for depression and ID in long standing disease.

Congestive Heart Failure and Upper Digestive Endoscopic Lesions

Objective: To evaluate the impact of congestive heart failure and the most important clinical and pathological factors on severe upper digestive mucosal lesions.

Methods: The study included 749 patients referred for upper digestive endoscopy, divided into two groups: 140 subjects with congestive heart failure (study group) and 609 subjects without heart failure (control group).

Results: Severe endoscopic lesions quantified according to Lanza score (OR = 3.84, 95% IC: 2.62-5.62), active/inactive gastritis (OR = 2.07, 95% CI: 1.36-3.14), intestinal metaplasia and/or gastric atrophy (OR = 2.42, 95% CI: 1.67-3.52) were significant more frequent among patients with heart failure. Anemia (OR = 3.65, 95% IC: 2.48-5.37) and all investigated comorbidities, as well as alcohol consumption (OR = 1.60, 95% IC: 1.10-2.34) and smoking (OR = 1.76, 95% IC: 1.17-2.64) were more frequent in the study-group. Dividing the patients with cardiac insufficiency according to the severity of their endoscopic lesions, the male gender (OR = 2.76, 95% IC: 1.35–5.61) and daily low-dose aspirin consumption were found to be more frequent among patients with severe endoscopic lesions (OR = 7.71, 95% IC: 3.62–16.40), while anticoagulant therapy and alcohol consumption were borderline associated with mucosal lesions (p=0.08).

Conclusions: Male patients and aspirin consumers with heart failure, but not those with H. pylori infection seem to be more prone to develop upper digestive endoscopic lesions, while alcohol consumption or anticoagulant therapy could be other modifiable factors associated with severe endoscopic lesions in a congestive gastro-duodenal mucosa.

Novel Insights and Treatment Strategies for Right Heart Failure

PURPOSE OF REVIEW

The function of the right ventricle (RV) is intimately linked to its preload (systemic volume status) and afterload (pulmonary vasculature). In this review, we explore current knowledge in RV physiology, RV function assessment, causes of right heart failure (RHF), and specific treatment strategies for RHF.

RECENT FINDINGS

We examine the evidence behind new pharmacological therapies available, such as macitentan and riociguat in the treatment of specific etiologies of RHF. We will also focus on RHF in the setting of heart failure with preserved ejection fraction (HFpEF) and in the presence of left ventricular assist devices (LVAD), looking at current treatment recommendations, including mechanical circulatory support. Lastly, we will look to the horizon for the latest research on RHF, including the molecular basis of RHF and potential novel treatment methods for this old yet poorly understood syndrome. Disturbances in this complex relationship result in the clinical syndrome of RHF. Despite advances in the management of left heart diseases, much work remains to be done to understand and manage RHF.

Myocardial iron homeostasis and hepcidin expression in a rat model of heart failure at different levels of dietary iron intake

BACKGROUND

Up to 50% of patients with chronic heart failure (HF) have systemic iron deficiency, which contributes to symptoms and poor prognosis. Myocardial iron deficiency (MID) in HF patients has been recently documented, but its causes and consequences are unknown. The goal of our study was to address these questions in a well-defined rat HF model induced by volume overload due to aorto-caval fistula.

METHODS

Modulation of dietary iron content in a rat model of HF has been used to address how iron status affects cardiac iron levels, heart structure and function, and how the presence of HF affects cardiac expression of hepcidin and other iron-related genes.

RESULTS

MID developed in the rat model of heart failure. Iron supplementation did not normalize the myocardial iron content; however, it improved survival of HF animals compared to animals fed diet with normal iron content. We observed marked upregulation of hepcidin mRNA expression in HF animals, which was not associated with systemic or cardiac iron levels but strongly correlated with markers and parameters of heart injury. Identical iron-independent pattern was observed for expression of several iron-related genes.

CONCLUSIONS

MID is not caused by defective iron absorption or decreased systemic iron levels, but rather by intrinsic myocardial iron deregulation. Altered cardiac expression of hepcidin and other iron-related genes is driven by iron-independent stimuli in the failing heart.

GENERAL SIGNIFICANCE

Understanding of the causes and consequences of MID is critical for finding strategies how to improve cardiac iron stores and in HF patients.

Proteomic signature of circulating extracellular vesicles in dilated cardiomyopathy

Dilated cardiomyopathy (DCM) remains a major cause of heart failure and carries a poor prognosis despite important advances in recent years. Better disease characterization using novel molecular techniques is needed to refine its progression. This study explored the proteomic signature of plasma-derived extracellular vesicles (EVs) obtained from DCM patients and healthy controls using size-exclusion chromatography (SEC). EV-enriched fractions were analyzed by liquid chromatography-mass spectrometry (LC-MS/MS). Raw data obtained from LC-MS/MS were analyzed against the Uniprot human database using MaxQuant software. Additional analyses using Perseus software were based on the Intensity-Based Absolute Quantification (iBAQ) values from MaxQuant analyses. A total of 90.07 ± 21 proteins (227 different proteins) in the DCM group and 96.52 ± 17.91 proteins (183 different proteins) in the control group were identified. A total of 176 proteins (74.6%) were shared by controls and DCM patients, whereas 51 proteins were exclusive for the DCM group and 7 proteins were exclusive for the control group. Fibrinogen (α, β and γ chain), serotransferrin, α-1-antitrypsin, and a variety of apolipoprotein family members (C-I, C-III, D, H or β-2-glycoprotein, and J or clusterin) were clustered in SEC-EVs derived from DCM patients relative to controls (p < 0.05). Regarding Gene Ontology analysis, response to stress and protein activation-related proteins were enriched in DCM-EVs compared with controls. Thus, the present study reports the distinct proteomic signature of circulating DCM-EVs compared with control-EVs. Furthermore, we confirm that SEC obtains highly purified EV fractions from peripheral blood samples for subsequent use in determining disease-specific proteomic signatures.

Incidence and prognostic implications of late bleeding events after percutaneous mitral valve repair

Objectives

MitraClip is an established therapy for patients with mitral regurgitation (MR) that are considered of high-risk or inoperable. However, late bleeding events (BE) after hospital discharge and their impact on prognosis in this cohort of patients have been poorly investigated. Our purpose is to address the incidence, related factors and clinical implications of BE after hospital discharge in patients treated with MitraClip.

Methods

Prospective registry of all consecutive patients (n = 80) who underwent MitraClip implantation in our Institution between June 2014 and December 2017. BE were defined according to MVARC definitions. A combined clinical end-point including admission for heart failure (HF) and all-cause mortality was established to analyze prognostic implications of BE.

Results

During a median follow up of 523.5 days, 41 BE were reported in 21 patients. Atrial fibrillation (AF, HR 4.54, CI95% 1.20–17.10) and combined antithrombotic therapy at discharge (HR 3.52, CI95% 1.03–11.34) were independently associated with BE. In the study period, 15 (18.8%) patients died, 20 (25%) were admitted for HF and 29 (36.3%) presented the combined end-point. After multivariable adjustment BE remained independently associated with an adverse outcome (HR 3.80, CI 95% 1.66–8.72). In the subgroup of patients with AF, HAS-BLED score was higher among subjects with BE (3.1 ± 1.3 vs 2.1 ± 0.9, p = 0.003). HAS-BLED score had a significant discrimination power for the occurrence BE (AUC: 0.677 [0.507–0.848]) in this subgroup.

Conclusions

BE are common after MitraClip and are associated with an impaired outcome. Strategies to reduce bleeding events are paramount in this cohort of patients.

Safety and efficacy of intravenous iron isomaltoside for correction of anaemia in patients with inflammatory bowel disease in everyday clinical practice

AIMS

Iron deficiency anaemia (IDA) is common in patients with inflammatory bowel disease (IBD), who are often treated with intravenous iron. This observational study aimed to investigate the effectiveness and safety of iron isomaltoside in routine practical care of IDA in IBD patients.

METHODS

The study included 197 IBD patients designated for treatment with iron isomaltoside. Treatment was administered according to routine practice. Data were recorded at baseline and after approximately 4, 8, and 16 weeks. Efficacy data included haemoglobin (Hb) levels and haematinics, while safety data included adverse drug reactions and safety laboratory variables.

RESULTS

Patients received a mean (range) cumulative dose of 1304 (100-3500) mg iron isomaltoside. Hb increased from 10.7(±1.6) g/dL at baseline to 13.1(±1.5) g/dL at the final visit. In addition, serum iron, ferritin and transferrin saturation increased and soluble transferrin receptor decreased. Calprotectin decreased, as did IBD symptom scores, Harvey-Bradshaw Index (Crohn's disease) and partial Mayo score (Ulcerative colitis). About 8% of patients reported transient adverse reactions, most commonly skin reactions, nausea and vomiting, and 2% SAEs, most frequently tachycardia.

CONCLUSION

Iron isomaltoside was demonstrated to be effective and had a good safety profile in IBD patients in everyday clinical practice in Germany.

Iron deficiency in patients with heart failure with preserved ejection fraction and its association with reduced exercise capacity, muscle strength and quality of life

BACKGROUND

The prevalence of iron deficiency (ID) in outpatients with heart failure with preserved ejection fraction (HFpEF) and its relation to exercise capacity and quality of life (QoL) is unknown.

METHODS

190 symptomatic outpatients with HFpEF (LVEF 58 ± 7%; age 71 ± 9 years; NYHA 2.4 ± 0.5; BMI 31 ± 6 kg/m²) were enrolled as part of SICA-HF in Germany, England and Slovenia. ID was defined as ferritin < 100 or 100-299 µg/L with transferrin saturation (TSAT) < 20%. Anemia was defined as Hb < 13 g/dL in men, < 12 g/dL in women. Low ferritin-ID was defined as ferritin < 100 µg/L. Patients were divided into 3 groups according to E/e' at echocardiography: E/e' ≤ 8; E/e' 9-14; E/e' ≥ 15. All patients underwent echocardiography, cardiopulmonary exercise test (CPX), 6-min walk test (6-MWT), and QoL assessment using the EQ5D questionnaire.

RESULTS

Overall, 111 patients (58.4%) showed ID with 89 having low ferritin-ID (46.84%). 78 (41.1%) patients had isolated ID without anemia and 54 patients showed anemia (28.4%). ID was more prevalent in patients with more severe diastolic dysfunction: E/e' ≤ 8: 44.8% vs. E/e': 9-14: 53.2% vs. E/e' ≥ 15: 86.5% (p = 0.0004). Patients with ID performed worse during the 6MWT (420 ± 137 vs. 344 ± 124 m; p = 0.008) and had worse exercise time in CPX (645 ± 168 vs. 538 ± 178 s, p = 0.03). Patients with low ferritin-ID had lower QoL compared to those without ID (p = 0.03).

CONCLUSION

ID is a frequent co-morbidity in HFpEF and is associated with reduced exercise capacity and QoL. Its prevalence increases with increasing severity of diastolic dysfunction.

Depleted iron stores are associated with inspiratory muscle weakness independently of skeletal muscle mass in men with systolic chronic heart failure

BACKGROUND

Skeletal and respiratory muscle dysfunction constitutes an important pathophysiological feature of heart failure (HF). We assessed the relationships between respiratory muscle function, skeletal muscle mass, and physical fitness in men with HF with reduced left ventricular ejection fraction (HFrEF), and investigated the hypothesis of whether iron deficiency (ID) contributes to respiratory muscle dysfunction in these patients.

METHODS

We examined 53 male outpatients with stable HFrEF without asthma or chronic obstructive pulmonary disease (age: 64 ± 10 years; New York Heart Association [NYHA] class I/II/III: 36/51/13%; ischaemic aetiology: 83%; all with left ventricular ejection fraction ≤40%) and 10 middle-aged healthy men (control group). We analysed respiratory muscle function (maximal inspiratory and expiratory pressure at the mouth [MIP and MEP, respectively]), appendicular lean mass/body mass index (ALM/BMI; ALM was measured using dual-energy X-ray absorptiometry), physical fitness (components of Functional Fitness Test for Older Adults), and iron status.

RESULTS

MIP, MEP, and ALM/BMI (but not MIP adjusted for ALM/BMI) were lower in men with HFrEF vs. healthy men. MIP, MEP, and MIP adjusted for ALM/BMI (but not ALM/BMI) were lower in men with HFrEF with vs. without ID. In a multivariable linear regression model lower serum ferritin (but not transferrin saturation) was associated with lower MIP independently of ALM/BMI, left ventricular ejection fraction, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and haemoglobin concentration. In multivariable linear regression models, lower MIP was associated with worse results in Functional Fitness Test when adjusted for ALM/BMI or relevant clinical variables (NYHA class, estimated glomerular filtration rate, NT-proBNP, and haemoglobin concentration).

CONCLUSIONS

In men with HFrEF, low ferritin reflecting depleted iron stores is associated with inspiratory muscle weakness independently of skeletal muscle mass. Inspiratory muscle dysfunction correlates with worse physical fitness independently of either skeletal muscle mass or disease severity.

Iron deficiency impairs contractility of human cardiomyocytes through decreased mitochondrial function

AIMS

Iron deficiency is common in patients with heart failure and associated with a poor cardiac function and higher mortality. How iron deficiency impairs cardiac function on a cellular level in the human setting is unknown. This study aims to determine the direct effects of iron deficiency and iron repletion on human cardiomyocytes.

METHODS AND RESULTS

Human embryonic stem cell-derived cardiomyocytes were depleted of iron by incubation with the iron chelator deferoxamine (DFO). Mitochondrial respiration was determined by Seahorse Mito Stress test, and contractility was directly quantified using video analyses according to the BASiC method. The activity of the mitochondrial respiratory chain complexes was examined using spectrophotometric enzyme assays. Four days of iron depletion resulted in an 84% decrease in ferritin (P < 0.0001) and significantly increased gene expression of transferrin receptor 1 and divalent metal transporter 1 (both P < 0.001). Mitochondrial function was reduced in iron-deficient cardiomyocytes, in particular ATP-linked respiration and respiratory reserve were impaired (both P < 0.0001). Iron depletion affected mitochondrial function through reduced activity of the iron-sulfur cluster containing complexes I, II and III, but not complexes IV and V. Iron deficiency reduced cellular ATP levels by 74% (P < 0.0001) and reduced contractile force by 43% (P < 0.05). The maximum velocities during both systole and diastole were reduced by 64% and 85%, respectively (both P < 0.001). Supplementation of transferrin-bound iron recovered functional and morphological abnormalities within 3 days.

CONCLUSION

Iron deficiency directly affects human cardiomyocyte function, impairing mitochondrial respiration, and reducing contractility and relaxation. Restoration of intracellular iron levels can reverse these effects.

Iron Therapy in Heart Failure: Ready for Primetime?

There is an increasing awareness of the prevalence of iron deficiency (ID) in patients with heart failure (HF) and its contributory role in the morbidity and mortality of HF. It is important to note that many HF patients have ID without being anaemic, hence it is vital to screen for ID even in patients with haemoglobin within the normal laboratory range. This review summarises the pathophysiology and epidemiology of ID in HF before discussing the evidence for iron replacement therapy in HF patients. Finally, it discusses the ongoing large outcome trials evaluating iron replacement in HF.

Sex Differences in Heart Failure

Heart failure (HF) represents a global pandemic health problem with a high impact on health-care costs, affecting about 26 million adults worldwide. The overall HF prevalence and incidence are ~2% and ~0.2% per year, respectively, in Western countries, with half of the HF population with reduced ejection fraction (HFpEF) and half with preserved (HFpEF) or mid-range ejection fraction (HFmrEF). Sex differences may exist in HF. More males have HFrEF or HFmrEF and an ischemic etiology, whereas more females have HFpEF and hypertension, diastolic dysfunction, and valvular pathologies as HF etiologies. Females are generally older, have a higher EF, higher frequency of HF-related symptoms, and lower NYHA functional status. Generally, it is observed that female HF patients tend to have more comorbidities such as atrial fibrillation, diabetes, hypertension, anemia, iron deficiency, renal disease, arthritis, frailty, depression, and thyroid abnormalities. However, overall, females have better prognosis in terms of mortality and hospitalization risk compared with men, regardless of EF. Potential sex differences in HF characteristics may be underestimated because of the underrepresentation of females in cardiovascular research and, in particular, the sex imbalance in clinical trial enrollment may avoid to identify sex-specific differences in treatments' benefit.

Iron therapy in heart failure patients without anaemia: possible implications for chronic kidney disease patients

Iron deficiency anaemia is a global health problem that manifests as fatigue and poor physical endurance. Anaemia can be caused by dietary iron deficiency, blood loss or a combination of poor iron absorption and ineffective iron mobilization in patients with chronic disease. Nephrologists caring for patients with impaired renal function understand that iron treatment is necessary to provide adequate iron for erythropoiesis during the treatment of overt anaemia. However, a less well-understood health problem is iron deficiency, which creates symptoms that overlap with those of anaemia and often occurs in concert with chronic disease. Recently, several randomized controlled clinical trials have been conducted to investigate the effects of treatment with intravenous iron in heart failure patients with iron deficiency who may or may not also have anaemia. Given that heart and kidney disease are often comorbid, these clinical trials may have implications for the way nephrologists view their patients with iron deficiency. In this article, we review several clinical studies of intravenous iron therapy for patients with iron deficiency and heart failure and discuss possible implications for the treatment of patients with kidney disease.

Anemia and Iron Deficiency in Heart Failure — Clinical Update

Iron deficiency and anemia affect approximately half of the chronic heart failure patients and they are associated with increased hospitalization rate, lower functional capacity, lower quality of life, and higher mortality. The exact mechanism of iron deficiency in heart failure patients is still not fully understood. Current guidelines recommend ferritin as the most accurate serum biomarker for the diagnosis of iron deficiency. The use of erythropoiesis-stimulating agents is no longer recommended because of the lack of improvement on mortality or hospital readmission rate, and it was associated with a higher rate of thromboembolic events. Intravenous iron replacement therapy is safe and generally well tolerated, with fewer side effects compared to oral administration. Large randomized studies with ferric carboxymaltose demonstrated its effectiveness and superiority to oral administration, and it was associated with a decreased rate of hospitalization rate and worsening heart failure, and improvement of functional capacity and quality of life. Intravenous iron supplementation for chronic heart failure is strongly recommended by European guidelines. Further studies are needed for a better knowledge of this complex pathology and determination of the long-term safety and effectiveness of iron administration in chronic heart failure patients. .

Iron deficiency in heart failure: Efficacy and safety of intravenous iron therapy

AIM

To discuss the pathophysiology of iron metabolism in chronic heart failure (CHF) and the current knowledge of the efficacy of intravenous (IV) iron therapy in patients with CHF and identify points of controversy as well as highlight areas for future research.

DISCUSSION

Iron deficiency is a recognized complication of many chronic conditions. Numerous studies have reported that iron deficiency is highly prevalent in patients with CHF and is associated with exercise intolerance, reduced quality of life, and increased risk of hospitalization and mortality. Several small studies have demonstrated IV iron to be associated with improvements in symptoms, exercise capacity, quality of life, renal function, New York Heart Association (NYHA) functional class and left ventricular ejection fraction (LVEF), and reduction in NT-pro-brain natriuretic peptide (NT-proBNP) in patients with CHF and iron deficiency. Two larger-scale trials confirming these results (FAIR-HF and CONFIRM-HF) have led to guideline recommendations that IV iron therapy should be considered in patients with CHF with reduced ejection fraction and iron deficiency (serum ferritin <100 μg/L, or ferritin between 100 and 299 μg/L with transferrin saturation <20%) to provide symptomatic relief and improve exercise capacity and quality of life.

CONCLUSION

Intravenous iron therapy improves symptoms, exercise capacity, and quality of life, at least in the short-to-intermediate time. However, there are still currently no standardized criteria used to define iron deficiency and the underlying mechanism of iron deficiency in CHF remains incompletely understood. Further work is required to improve the ability to identify iron deficiency in patients with CHF and evaluate the effect of iron repletion on hard endpoints including hospitalization and mortality.

Ferrokinetics is associated with the left ventricular mass index in patients with chronic kidney disease

Background Patients with chronic kidney disease (CKD) often have the complication of anaemia. Usage of an erythropoietin-stimulating agent accelerates iron deficiency because it promotes iron utilization. Recently, iron administration was reported to be effective for patients with cardiac failure. We examined the association between ferrokinetics and cardiac function in patients with CKD. Methods In this cross-sectional study, we examined 558 patients (424 men and 134 women; mean age, 68.9 ± 13.1 years) with CKD who were admitted to our hospital. We assessed cardiac function by ultrasonography and ferrokinetics through transferrin saturation (TSAT) and ferritin levels. Results The primary diseases of CKD were nephrosclerosis (n = 247), diabetic nephropathy (n = 154), chronic glomerulonephritis (n = 73), and others. The mean estimated glomerular filtration rate was 16.9 ± 9.3 mL/min/1.7 m², and the haemoglobin (Hb) level was 11.0 ± 1.7 g/dL. The median of TSAT was 28.05%, and patients were divided into two groups: below (L-Ts) and above (H-Ts) the median. The median of ferritin was 122 ng/mL, and patients were divided into two groups: below (L-f) and above (H-f) the median. We categorized four groups as H-Ts + H-F, H-Ts + L-F, L-Ts + H-F, and L-Ts + L-F. The Hb levels were 11.1 ± 1.8, 11.3 ± 1.4, 10.9 ± 1.6, and 10.8 ± 1.5 g/dL, respectively, and there was no difference between groups. However, the left ventricular mass indices (LVMIs) were 122.6 ± 46.6, 110.8 ± 32.0, 118.3 ± 36.0, 126.7 ± 46.9, respectively (P = 0.0291). This tendency was stronger in patients without cardiovascular events. Conclusion In patients with CKD, there is an association between ferrokinetics and LVMI. We have to be mindful not only of anaemia but also of ferrokinetics.

Proposal of a novel clinical score to predict heart failure incidence in long-term survivors of acute coronary syndromes

INTRODUCTION

HF remains a frequent complication following MI and adversely affects prognosis. The objective of this study was to identify predictors of HF following MI and to design a risk score for its prediction.

METHODS

Retrospective study of all consecutive patients admitted for MI. Primary end point was time to incident HF. Patients with previous history of HF were excluded. Death was modelled as competing risk.

RESULTS

5737 patients were included. Mean age was 66.32±12.80. During a median follow-up of 47.0months (23.0-73.0), 686 patients (12%) developed HF. Age, diabetes mellitus, peripheral artery disease, renal insufficiency, chronic obstructive pulmonary disease, persistent atrial fibrillation, haemoglobin, troponin peak, diuretic at admission, ventricular function, and revascularization were independent predictors for HF development. According to this multivariate regression analysis, we developed a novel score that allows for the identification of patients at high (≥16), medium (9-15) and low risk (<9) for HF development, with an AUC of 0.77 (IC 95%, 0.76-0.78; p=0.008).

CONCLUSIONS

Clinical comorbidities were determinant for the development of HF following MI. A simple score effectively categorize patients into low, intermediate, and high-risk. This could be important in order to intensify medical treatment or consider additional interventions.

Effect of Ferric Carboxymaltose on Exercise Capacity in Patients With Chronic Heart Failure and Iron Deficiency

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Background:

Iron deficiency is common in patients with heart failure (HF) and is associated with reduced exercise capacity and poor outcomes. Whether correction of iron deficiency with (intravenous) ferric carboxymaltose (FCM) affects peak oxygen consumption [peak VO₂], an objective measure of exercise intolerance in HF, has not been examined.

Methods:

We studied patients with systolic HF (left ventricular ejection fraction ≤45%) and mild to moderate symptoms despite optimal HF medication. Patients were randomized 1:1 to treatment with FCM for 24 weeks or standard of care. The primary end point was the change in peak VO₂ from baseline to 24 weeks. Secondary end points included the effect on hematinic and cardiac biomarkers, quality of life, and safety. For the primary analysis, patients who died had a value of 0 imputed for 24-week peak VO₂. Additional sensitivity analyses were performed to determine the impact of imputation of missing peak VO₂ data.

Results:

A total of 172 patients with HF were studied and received FCM (n=86) or standard of care (control group, n=86). At baseline, the groups were well matched; mean age was 64 years, 75% were male, mean left ventricular ejection fraction was 32%, and peak VO₂ was 13.5 mL/min/kg. FCM significantly increased serum ferritin and transferrin saturation. At 24 weeks, peak VO₂ had decreased in the control group (least square means −1.19±0.389 mL/min/kg) but was maintained on FCM (−0.16±0.387 mL/min/kg; P=0.020 between groups). In a sensitivity analysis, in which missing data were not imputed, peak VO₂ at 24 weeks decreased by −0.63±0.375 mL/min/kg in the control group and by −0.16±0.373 mL/min/kg in the FCM group; P=0.23 between groups). Patients’ global assessment and functional class as assessed by the New York Heart Association improved on FCM versus standard of care.

Conclusions:

Treatment with intravenous FCM in patients with HF and iron deficiency improves iron stores. Although a favorable effect on peak VO₂ was observed on FCM, compared with standard of care in the primary analysis, this effect was highly sensitive to the imputation strategy for peak VO₂ among patients who died. Whether FCM is associated with an improved outcome in these high-risk patients needs further study.

Clinical Trial Registration:

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01394562.

Anemia after Continuous-flow Left Ventricular Assist Device Implantation: Characteristics and Implications

Background

Anemia is common in patients with heart failure and is associated with adverse outcomes. Management of anemia in CF-LVAD patients is not well studied. Our purpose is to characterize and identify the etiology of anemia in CF-LVAD patients. Secondary objectives are to describe the effect of CF-LVAD on pre-existing anemia and assess its impact after CF-LVAD support.

Methods

Cross-sectional study from January to July 2015 of ambulatory patients supported with a CF-LVAD for at least 6-months that presented with hemoglobin <12 g/dL and no recent gastrointestinal bleeding. Patients were classified as iron-deficient and non-iron-deficient and compared. Additionally, a retrospective analysis of 116 consecutive patients who underwent CF-LVAD from 2008 to 2013 with reported hemoglobin at 6 months as outpatients were divided into anemic or non-anemic and compared.

Results

In our cross-sectional cohort, iron deficiency was the most common cause of anemia. Notably, 49% of the iron-deficient patients were already on iron supplementation. In our retrospective cohort, 59% of the patients were anemic after 6 months of support. Anemic patients were older, had lower albumin, higher brain natriuretic peptide (BNP), worse renal function and New York Heart Association (NYHA) class. Anemia had a HR of 3.16 (95%CI 1.38–7.26) to predict a composite of 1-year death and HF readmissions, as well as HF-readmissions alone.

Conclusions

The most common cause of anemia in our study was iron-deficiency; almost half of the patients were iron deficient despite treatment, suggesting that oral iron may not be sufficient to reverse anemia. Anemia regardless of etiology was associated with adverse outcomes.

Iron deficiency and red cell indices in patients with heart failure

AIMS

To investigate the prevalence of iron deficiency (ID) in heart failure (HF) patients with normal vs. abnormal red cell indices (RCI), the associations between iron parameters and RCI, and prognostic consequences of ID independently of RCI.

METHODS AND RESULTS

We analysed clinical data of 1821 patients with HF [mean age 66 ± 13 years; 71% men; New York Heart Association class I/II/III/IV (11%/39%/44%/6%); left ventricular ejection fraction >45%: 19%]. Iron deficiency (ferritin <100 µg/L or ferritin 100-299 µg/L with transferrin saturation <20%) was common irrespective of the presence of anaemia (haemoglobin <12 g/dL in women and <13 g/dL in men) or low RCI, from 75% in anaemic subjects with low mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), and MCH concentration (MCHC), to 36% in non-anaemic subjects with MCV, MCH, and MCHC above the lower limit of normal. After adjustment for clinical variables, iron parameters remained independently associated with haemoglobin, MCV, MCH, MCHC, mean reticulocyte haemoglobin content (CHR), and red cell distribution width (RDW). In multivariable Cox proportional hazard regression models there was a trend towards higher mortality in patients with vs. without ID when adjusted for relevant HF prognosticators and MCH or MCHC (but not haemoglobin, CHR or RDW).

CONCLUSIONS

Patients with HF should be routinely screened for ID irrespective of the presence of anaemia or abnormal RCI. The detrimental impact of ID on long-term survival in HF is partially independent of RCI.

Usefulness of Iron Deficiency Correction in Management of Patients With Heart Failure [from the Registry Analysis of Iron Deficiency-Heart Failure (RAID-HF) Registry]

Iron deficiency (ID) has been identified as an important co-morbidity in patients with heart failure (HF). Intravenous iron therapy reduced symptoms and rehospitalizations of iron-deficient patients with HF in randomized trials. The present multicenter study investigated the "real-world" management of iron status in patients with HF. Consecutive patients with HF and ejection fraction ≤40% were recruited and analyzed from December 2010 to October 2015 by 11 centers in Germany and Switzerland. Of 1,484 patients with HF, iron status was determined in only 923 patients (62.2%), despite participation of the centers in a registry focusing on ID and despite guideline recommendation to determine iron status. In patients with determined iron status, a prevalence of 54.7% (505 patients) for ID was observed. Iron therapy was performed in only 8.5% of the iron-deficient patients with HF; 2.6% were treated with intravenous iron therapy. The patients with iron therapy were characterized by a high rate of symptomatic HF and anemia. In conclusion, despite strong evidence of beneficial effects of iron therapy on symptoms and rehospitalizations, diagnostic and therapeutic efforts on ID in HF are low in the actual clinical practice, and the awareness to diagnose and treat ID in HF should be strongly enforced.

Effects of Total Dose Infusion of Iron Intravenously in Patients With Acute Heart Failure and Anemia (Hemoglobin < 13 g/dl)

Iron deficiency is common in heart failure (HF), and intravenous (IV) iron therapy has been associated with improved clinical status in ambulatory patients with HF. There are limited data to support the safety and efficacy of IV iron administration in patients with acute HF. This was a retrospective cohort study of patients admitted to the University of Michigan Health System for HF with low iron studies during admission. Patients were grouped based on the receipt of IV iron therapy. Study outcomes included change in hemoglobin, 30-day readmission, and adverse events. Forty-four patients who received IV iron and 128 control patients were identified. The mean dose of IV iron received was 1,057 (±336) mg. IV iron resulted in a significantly greater increase in hemoglobin over time (p = 0.0001). The mean change in hemoglobin in the iron and control groups was 0.74 g/dl and 0.01 g/dl at day 7 and 2.61 g/dl and 0.23 g/dl at day 28, respectively. Thirty-day readmission rates were 30% and 22% for patients in the iron and control groups, respectively (p = 0.2787). In conclusion, total dose infusion IV iron is well tolerated and associated with significant improvement in hemoglobin in acute HF.

Association of Serum Erythropoietin With Cardiovascular Events, Kidney Function Decline, and Mortality: The Health Aging and Body Composition Study

BACKGROUND

Studies suggest that in patients with heart failure (HF), high serum erythropoietin is associated with risk of recurrent HF and mortality. Trials of erythropoietin-stimulating agents in persons with kidney disease have also suggested an increased incidence of adverse clinical events. No large studies of which we are aware have evaluated the association of endogenous erythropoietin levels with clinical outcomes in the community-living older adults.

METHODS AND RESULTS

Erythropoietin concentration was measured in 2488 participants aged 70-79 years in the Health, Aging and Body Composition Study. Associations of erythropoietin with incident HF, coronary heart disease, stroke, mortality, and ≥ 30% decline in estimated glomerular filtration rate were examined using Cox proportional hazards and logistic regression over 10.7 years of follow-up. Mean (SD) age was 75 (3) years and median (quartile 1, quartile 3) erythropoietin was 12.3 (9.0, 17.2) mIU/mL. There were 503 incident HF events, and each doubling of serum erythropoietin was associated with a 25% increased risk of incident HF 1.25 (95% confidence interval 1.13, 1.48) after adjusting for demographics, prevalent cardiovascular disease, cardiovascular disease risk factors, kidney function, and serum hemoglobin. There was no interaction of serum erythropoietin with chronic kidney disease or anemia (P > 0.50). There were 330 incident coronary heart disease events, 161 strokes, 1112 deaths, and 698 outcomes of ≥ 30% decline in estimated glomerular filtration rate. Serum erythropoietin was not significantly associated with these outcomes.

CONCLUSIONS

Higher levels of endogenous erythropoietin are associated with incident HF in older adults. Studies need to elucidate the mechanisms through which endogenous erythropoietin levels associate with specific outcomes.

The search for efficient diagnostic and prognostic biomarkers of heart failure

Several biomarkers have been tested for screening, diagnosis and prognosis purposes, as well as to guide treatment in heart failure, but only the assay of circulating B-type natriuretic peptides has widely recognized applications for clinical decision-making. Natriuretic peptides are sensitive in detecting the clinically overt or subclinical myocardial damage, but their plasma levels are increased following every generic insult to the cardiovascular system. Novel biomarkers are required to identify specific pathways of disease progression, such as diverse neurohormonal axes activation, inflammation and fibrogenesis, and to act as a tool for therapeutic tailoring. In this view, Gal-3 and ST-2 assays seem very promising, given their involvement in mechanisms of cardiac fibrosis and their prognostic value.

Is cardiac and hepatic iron status assessed by MRI T2* associated with left ventricular function in patients with idiopathic cardiomyopathy?

Excess accumulation of iron in the heart is known to aggravate cardiac function in some cases of genetic and acquired iron overload. We investigated the possible association between cardiac function and iron content in the heart and liver, estimated non-invasively by T2 star (T2*)-weighted magnetic resonance (MR) imaging among patients with cardiomyopathy. MR images were acquired on a 3.0 T MR imaging system using an 8-channel phased-array cardiac coil. Average T2* values of the heart were estimated at regions of interest that were located on short axis mid-ventricular slices positioned at the cardiac septum. In total, 82 patients were enrolled: 48 patients with dilated cardiomyopathy (DCM), 16 patients with hypertrophic cardiomyopathy (HCM), and 18 patients without apparent cardiovascular abnormalities. Cardiac T2* values were lower in the DCM group (median 18.6 ms) than in the HCM (22.0 ms) and control (21.4 ms) groups, although hepatic T2* values did not differ significantly across the groups. Among the whole population, the highest cardiac T2* tertile (≥21.2 ms) was significantly negatively associated with a low left ventricular ejection fraction (LVEF) of <50 %, and this association retained statistical significance after adjustment for sex, age, renal function, hemoglobin and hepatic T2*. Among DCM patients, both hemoglobin and cardiac T2* were selected as parameters that were, respectively, negatively and positively, associated with LVEF (P < 0.05). DCM patients with lower cardiac T2*, and thus higher iron content, were found to have lower LVEF. The possibility that cardiac iron overload may have a role in reducing the systolic cardiac function in DCM patients who do not have systemic iron overload requires further investigation in the future.

Effects of intravenous iron therapy in iron-deficient patients with systolic heart failure: a meta-analysis of randomized controlled trials

AIMS

The aim of this study was to assess the net clinical and prognostic effects of intravenous (i.v.) iron therapy in patients with systolic heart failure (HF) and iron deficiency (ID).

METHODS AND RESULTS

We performed an aggregate data meta-analysis (random effects model) of randomized controlled trials that evaluated the effects of i.v. iron therapy in iron-deficient patients with systolic HF. We searched electronic databases up to September 2014. We identified five trials which fulfilled the inclusion criteria (509 patients received i.v. iron therapy in comparison with 342 controls). Intravenous iron therapy has been shown to reduce the risk of the combined endpoint of all-cause death or cardiovascular hospitalization [odds ratio (OR) 0.44, 95% confidence interval (CI) 0.30-0.64, P < 0.0001], and the combined endpoint of cardiovascular death or hospitalization for worsening HF (OR 0.39, 95% CI 0.24-0.63, P = 0.0001). Intravenous iron therapy resulted in a reduction in NYHA class (data are reported as a mean net effect with 95% CIs for all continuous variables) (-0.54 class, 95% CI -0.87 to -0.21, P = 0.001); an increase in 6-min walking test distance (+31 m, 95% CI 18-43, P < 0.0001); and an improvement in quality of life [Kansas City Cardiomyopathy Questionnaire (KCCQ) score +5.5 points, 95% CI 2.8-8.3, P < 0.0001; European Quality of Life-5 Dimensions (EQ-5D) score +4.1 points, 95% CI 0.8-7.3, P = 0.01; Minnesota Living With Heart Failure Questionnaire (MLHFQ) score -19 points, 95% CI:-23 to -16, P < 0.0001; and Patient Global Assessment (PGA) +0.70 points, 95% CI 0.31-1.09, P = 0004].

CONCLUSION

The evidence indicates that i.v. iron therapy in iron-deficient patients with systolic HF improves outcomes, exercise capacity, and quality of life, and alleviates HF symptoms.

Obesity and iron deficiency: a quantitative meta-analysis

Hypoferraemia (i.e. iron deficiency) was initially reported among obese individuals several decades ago; however, whether obesity and iron deficiency are correlated remains unclear. Here, we evaluated the putative association between obesity and iron deficiency by assessing the concentration of haematological iron markers and the risks associated with iron deficiency in both obese (including overweight) subjects and non-overweight participants. We performed a systematic search in the databases PubMed and Embase for relevant research articles published through December 2014. A total of 26 cross-sectional and case-control studies were analysed, comprising 13,393 overweight/obese individuals and 26,621 non-overweight participants. Weighted or standardized mean differences of blood iron markers and odds ratio (OR) of iron deficiency were compared between the overweight/obese participants and the non-overweight participants using a random-effects model. Compared with the non-overweight participants, the overweight/obese participants had lower serum iron concentrations (weighted mean difference [WMD]: -8.37 μg dL(-1) ; 95% confidence interval [CI]: -11.38 to -5.36 μg dL(-1) ) and lower transferrin saturation percentages (WMD: 2.34%, 95% CI: -3.29% to -1.40%). Consistent with this finding, the overweight/obese participants had a significantly increased risk of iron deficiency (OR: 1.31; 95% CI: 1.01-1.68). Moreover, subgroup analyses revealed that the method used to diagnose iron deficiency can have a critical effect on the results of the association test; specifically, we found a significant correlation between iron deficiency and obesity in studies without a ferritin-based diagnosis, but not in studies that used a ferritin-based diagnosis. Based upon these findings, we concluded that obesity is significantly associated with iron deficiency, and we recommend early monitoring and treatment of iron deficiency in overweight and obese individuals. Future longitudinal studies will help to test whether causal relationship exists between obesity and iron deficiency.

Increased risk of stroke with darbepoetin alfa in anaemic heart failure patients with diabetes and chronic kidney disease

AIMS

The use of an erythropoesis-stimulating agent, darbepoetin alfa (DA), to treat anaemia in patients with diabetes mellitus and chronic kidney disease was associated with a heightened risk of stroke and neutral efficacy in the Trial to Reduce Cardiovascular Events with Aranesp Therapy (TREAT), despite epidemiological data suggesting the contrary. However, this association has not been evaluated in another randomized, placebo-controlled trial.

METHODS AND RESULTS

Reduction of Events by Darbepoetin Alfa in Heart Failure (RED-HF) was a randomized placebo-controlled trial of DA in 2278 patients with systolic heart failure and anaemia, enrolled from 2006 to 2012 and followed for a median of 28 months. Within RED-HF, 816 patients had diabetes mellitus and chronic kidney disease [estimated glomerular filtration rate (eGFR) 20-60 mL/min/1.73 m(2) ] and met inclusion criteria for TREAT. TREAT-like RED-HF patient data were analysed alone and combined at the patient level with the 4038 TREAT patients. In RED-HF, the annualized event rate of stroke was 2.3 in patients on DA and 1.1 in patients randomized to placebo (P = 0.051). Analysis of the combined group (n = 4854) confirmed a nearly two-fold increase in stroke risk [hazard ratio (HR) 1.94, 95% confidence interval (CI) 1.43-2.63] and an overall neutral effect on mortality (HR 1.00, 95% CI 0.89-1.12) of raising haemoglobin with DA.

CONCLUSION

The placebo-controlled cohort of heart failure patients with anaemia, diabetes mellitus, and chronic kidney disease from RED-HF provides confirmation of the increased stroke risk associated with DA use identified in TREAT.

Metabolic serum biomarkers for the prediction of cancer: a follow-up of the studies conducted in the Swedish AMORIS study

The Swedish Apolipoprotein MOrtality RISk study (AMORIS) contains information on more than 500 biomarkers collected from 397,443 men and 414,630 women from the greater Stockholm area during the period 1985–1996. Using a ten-digit personal identification code, this database has been linked to Swedish national registries, which provide data on socioeconomic status, vital status, cancer diagnosis, comorbidity, and emigration. Within AMORIS, 18 studies assessing risk of overall and site-specific cancers have been published, utilising a range of serum markers representing glucose and lipid metabolism, immune system, iron metabolism, liver metabolism, and bone metabolism. This review briefly summarises these findings in relation to more recently published studies and provides an overview of where we are today and the challenges of observational studies when studying cancer risk prediction.

Overall, more recent observational studies supported previous findings obtained in AMORIS, although no new results have been reported for serum fructosamine and inorganic phosphate with respect to cancer risk. A drawback of using serum markers in predicting cancer risk is the potential fluctuations following other pathological conditions, resulting in non-specificity and imprecision of associations observed. Utilisation of multiple combination markers may provide more specificity, as well as give us repeated instead of single measurements. Associations with other diseases may also necessitate further analytical strategies addressing effects of serum markers on competing events in addition to cancer. Finally, delineating the role of serum metabolic markers may generate valuable information to complement emerging clinical studies on preventive effects of drugs and supplements targeting metabolic disorders against cancer.