The global burden of iron overload. Hepatol Int. 2009;3:434-444. [PMID: 19669241 DOI: 10.1007/s12072-009-9144-z]

Pseudovitelliform maculopathy associated with hereditary hemochromatosis

Background

Hereditary hemochromatosis (HH) is an inherited autosomal recessive iron metabolism disorder resulting from a C282Y mutation in the HFE gene. Mutations in the HFE gene may result in iron accumulation and oxidative stress in the retina, resulting in macular degeneration. This article describes two patients with HH who were treated with erythrocytapheresis or phlebotomy, with no exposure to deferoxamine or any other chelation therapy, and who developed visual symptoms.

Case Presentation

Both patients had known diagnoses of HH. Because of visual symptoms, they were referred to the ophthalmology clinic and underwent a retinal exam, multimodal imaging, and electrodiagnostic studies, which revealed structural and functional degeneration of the central macula. Fundus photography, fluorescein angiography, and fundus autofluorescence revealed changes at the level of the retinal pigment epithelium (RPE) in the central macula. In addition, optical coherence tomography revealed subfoveal accumulation of hyperreflective material at and below the RPE. Multifocal electroretinography confirmed a decreased cone response, whereas the full-field electroretinogram was unremarkable. Genetic testing ruled out Best's vitelliform macular dystrophy and the other known hereditary macular dystrophies. The patients had known diagnoses of HH, homozygous C282Y mutations in the HFE gene, and no comorbidities; thus, we presumed that HH led to the observed morphological and functional disorders of the RPE, which in turn caused structural macular changes in both patients.

Conclusions

Considering the macular findings and the nature of the patients' primary illness, we believe that the accumulation of iron and photoreceptor metabolic products caused dysfunction in the RPE, which led to morphological and functional changes in the macula. Because the patients were not treated using chelating agents, we attribute the macular changes solely to iron accumulation and oxidative stress caused by the pathophysiological processes of HH. Further studies are needed to identify the plausible molecular or cellular insults underlying pseudovitelliform macular degeneration in patients with HH.

Targeting the ferroptosis crosstalk: novel alternative strategies for the treatment of major depressive disorder

Depression is a major contributor to poor global health and disability, with a recently increasing incidence. Although drug therapy is commonly used to treat depression, conventional antidepressant drugs have several disadvantages, including slow onset, low response rates and severe adverse effects. Therefore, developing effective therapies for depression remains challenging. Although various aetiological theories of depression exist, the underlying mechanisms of depression are complex, and further research is crucial. Moreover, oxidative stress (OS)-induced lipid peroxidation has been demonstrated to trigger ferroptosis. Both OS and ferroptosis are pivotal mechanisms implicated in the pathogenesis of neurological disorders, and investigation of the mediators involved in these processes has emerged as a prominent and active research direction. One previous study revealed that regulatory proteins involved in ferroptosis are implicated in the pathogenesis of depression, and antidepressant drugs could reverse depressive symptoms by inhibiting ferroptosis in vivo, suggesting an important role of ferroptosis in the pathogenesis of depression. Hence, our current comprehensive review offers an up-to-date perspective on the intricate mechanisms involved, specifically concerning ferroptosis and OS in the context of depression, along with promising prospects for using molecular mediators to target ferroptosis. We delineate the key targets of molecular mediators involved in OS and ferroptosis implicated in depression, most notably reactive oxygen species and iron overload. Considering the pivotal role of OS-induced ferroptosis in the pathogenesis of neurological disorders, delving deeper into the underlying subsequent mechanisms will contribute significantly to the identification of novel therapeutic targets for depression.

Dithiolethiones D3T and ACDT Protect Against Iron Overload-Induced Cytotoxicity and Serve as Ferroptosis Inhibitors in U-87 MG Cells

Iron overload-induced oxidative stress is implicated in various neurodegenerative disorders. Given the numerous adverse effects associated with current iron chelators, natural antioxidants are being explored as alternative therapeutic options. Dithiolethiones found in cruciferous vegetables have emerged as promising candidates against a wide range of toxicants owing to their lipophilic and cytoprotective properties. Here, we test the dithiolethiones 3H-1,2-dithiole-3-thione (D3T) and 5-amino-3-thioxo-3H-(1,2) dithiole-4-carboxylic acid ethyl ester (ACDT) against ferric ammonium citrate (FAC)-induced toxicity in U-87 MG astrocytoma cells. Exposure to 15 mM FAC for 24 h resulted in 54% cell death. A 24-h pretreatment with 50 μM D3T and ACDT prevented this cytotoxicity. Both dithiolethiones exhibited antioxidant effects by activating the nuclear factor erythroid 2-related factor-2 (Nrf2) transcription factor and upregulating levels of intracellular glutathione (GSH). This resulted in the successful inhibition of FAC-induced reactive oxygen species, lipid peroxidation, and cell death. Additionally, D3T and ACDT upregulated expression of the Nrf2-mediated iron storage protein ferritin which consequently reduced the total labile iron pool. A 24-h pretreatment with D3T and ACDT also prevented cell death induced by the ferroptosis inducer erastin by upregulating the transmembrane cystine/glutamate antiporter (xCT) expression. The resulting increase in intracellular GSH and alleviation of lipid peroxidation was comparable to that caused by ferrostatin-1, a specific ferroptosis inhibitor. Collectively, our findings demonstrate that dithiolethiones may show promise as potential therapeutic options for the treatment of iron overload disorders.

Oral Non-absorbable Polymer-Deferoxamine Conjugates for Reducing Dietary Iron Absorption

Hereditary hemochromatosis (HH) is a non-transfusional genetic iron overload (IO) disease wherein patients are not able to regulate dietary iron absorption, which ultimately leads to excess cellular iron accumulation. Preventative measures for HH mainly include phlebotomy and asking patients to minimize dietary iron intake. To investigate alternative iron reduction strategies, we report on prophylactic non-absorbable polymer-deferoxamine (DFO) conjugates capable of chelating and reducing excessive gut uptake of dietary iron. Three different sizes of the conjugates (56 nm, 256 nm, and 7.4 μm) were prepared, and their physicochemical properties, transit times in the gut under fed/fasted conditions, acute safety, and efficacy at reducing iron absorption in a dietary iron-overload mouse model were investigated. The conjugates were synthesized through reverse phase water-in-oil (w/o) emulsions, followed by conjugation of DFO to the resulting polymer scaffolds. In vitro studies using Caco-2 transwell assays showed that the conjugates could not permeate across the monolayer, were poorly endocytosed, and did not induce cellular toxicity. In vivo mouse studies via oral gavage demonstrated that polymer-DFO conjugates remained in the gastrointestinal (GI) tract for up to 12 h and significantly prevented escalation of serum ferritin levels and excess liver iron accumulation. Ex vivo images of the duodenum suggest that nanometer-sized conjugates (56 and 246 nm) perform better at chelating dietary iron based on longer retention times (i.e., entrapment in the villi of the duodenum) and an overall slower transit from the GI tract compared to larger micron-sized (7.4 μm) conjugates. Overall, nanometer-sized polymer-DFO conjugates were orally non-absorbable, appeared safe, and were more efficacious at reducing dietary iron absorption when taken with non-heme containing food.

Iron Overload and the Risk of Diabetes in the General Population: Results of the Chinese Health and Nutrition Survey Cohort Study

BACKGROUND

Recent studies have found that there are significant associations between body iron status and the development of diabetes. In the present study, we aimed to analyze the association among iron overload (IO), insulin resistance (IR), and diabetes in Chinese adults, and to explore the sex difference.

METHODS

Men and women (age >19 years) who participated in the Chinese Health and Nutrition Survey and did not have diabetes at baseline were followed between 2009 and 2015 (n=5,779). Over a mean of 6 years, 75 participants were diagnosed with incident diabetes. Logistic regression was used to assess the risk factors associated with IO. Cox proportional hazard regression was used to estimate the risk of incident diabetes and to determine whether the risk differed among subgroups. Causal mediation analysis (CMA) was used to explore the mechanism linking IO and diabetes.

RESULTS

According to sex-stratified multivariable-adjusted Cox proportional hazards regression, IO increased the risk of incident diabetes. Women with IO had a higher risk of diabetes than men. Subgroup analysis with respect to age showed that the association between IO and diabetes was stronger in older women and younger men (P<0.001). CMA showed that liver injury (alanine transaminase) and lipid metabolism abnormalities (triglyceride, apolipoprotein B) contributed to the association between IO and diabetes.

CONCLUSION

IO is associated with diabetes and this association is sex-specific. IO may indirectly induce IR via liver injury and lipid metabolism abnormalities, resulting in diabetes.

Free-breathing 3D stack-of-radial MRI quantification of liver fat and R2* in adults with fatty liver disease

PURPOSE

To investigate the agreement, intra-session repeatability, and inter-reader agreement of liver proton-density fat fraction (PDFF) and R₂* quantification using free-breathing 3D stack-of-radial MRI, with and without self-gated motion compensation, compared to reference breath-hold techniques in subjects with fatty liver disease (FLD).

METHODS

In this institutional review board-approved prospective study, thirty-eight adults with FLD and/or iron overload (24 male, 58 ± 12 years) were imaged at 3T using free-breathing stack-of-radial MRI, breath-hold 3D Cartesian MRI, and breath-hold single-voxel MR spectroscopy (SVS). Each sequence was acquired twice in random order. To assess agreement compared to reference breath-hold techniques, the dependency of liver PDFF and/or R₂* quantification on the sequence, radial sampling factor, and radial self-gating temporal resolution was assessed by calculating the Bayesian mean difference (MD_B) of the posteriors. Intra-session repeatability and inter-reader agreement (two independent readers) were assessed by the coefficient of repeatability (CR) and intraclass correlation coefficient (ICC), respectively.

RESULTS

Thirty-five participants (21 male, 57 ± 12 years) were included for analysis. Both free-breathing radial MRI techniques (with and without self-gating) achieved ICC ≥ 0.92 for quantifying PDFF and R₂*, and quantified PDFF with MD_B < 1.2% compared to breath-hold techniques. Free-breathing radial MRI required self-gating to accurately quantify R₂* (MD_B < 10s^-1 with self-gating; MD_B < 50s^-1 without self-gating). The radial sampling factor affected PDFF and R₂* quantification while the radial self-gating temporal resolution only affected R₂* quantification. Repeated self-gated free-breathing radial MRI scans achieved CR < 3% and CR < 27 s^-1 for PDFF and R₂*, respectively.

CONCLUSION

A free-breathing stack-of-radial MRI technique with self-gating demonstrated agreement, repeatability, and inter-reader agreement compared to reference breath-hold techniques for quantification of liver PDFF and R₂* in adults with FLD.

Diagnosis of Systemic Diseases Using Infrared Spectroscopy: Detection of Iron Overload in Plasma-Preliminary Study

Despite the important role of iron in cellular homeostasis, iron overload (IO) is associated with systemic and tissue deposits which damage several organs. In order to reduce the impact caused by IO, invasive diagnosis exams (e.g., biopsies) and minimally invasive methods were developed including computed tomography and magnetic resonance imaging. However, current diagnostic methods are still time-consuming and expensive. A cost-effective solution is using Fourier-transform infrared spectroscopy (FTIR) for real-time and molecular-sensitive biofluid analysis during conventional laboratory exams. In this study, we performed the first evaluation of the accuracy of FTIR for IO diagnosis. The study was performed by collecting FTIR spectra of plasma samples of five rats intravenously injected with iron-dextran and five control rats. We developed a classification model based on principal component analysis and supervised methods including J48, random forest, multilayer perceptron, and radial basis function network. We achieved 100% accuracy for the classification of the IO status and provided a list of possible biomolecules related to the vibrational modes detected. In this preliminary study, we give a first step towards real-time diagnosis for acute IO or intoxication. Furthermore, we have expanded the literature knowledge regarding the pathophysiological changes induced by iron overload.

Hyperferritinemia-A Clinical Overview

Ferritin is one of the most frequently requested laboratory tests in primary and secondary care, and levels often deviate from reference ranges. Serving as an indirect marker for total body iron stores, low ferritin is highly specific for iron deficiency. Hyperferritinemia is, however, a non-specific finding, which is frequently overlooked in general practice. In routine medical practice, only 10% of cases are related to an iron overload, whilst the rest is seen as a result of acute phase reactions and reactive increases in ferritin due to underlying conditions. Differentiation of the presence or absence of an associated iron overload upon hyperferritinemia is essential, although often proves to be complex. In this review, we have performed a review of a selection of the literature based on the authors’ own experiences and assessments in accordance with international recommendations and guidelines. We address the biology, etiology, and epidemiology of hyperferritinemia. Finally, an algorithm for the diagnostic workup and management of hyperferritinemia is proposed, and general principles regarding the treatment of iron overload are discussed.

Iron Deficiency Anemia in Children Residing in High and Low-Income Countries: Risk Factors, Prevention, Diagnosis and Therapy

Iron deficiency and iron-deficiency anemia (IDA) affects approximately two billion people worldwide, and most of them reside in low- and middle-income countries. In these nations, additional causes of anemia include parasitic infections like malaria, other nutritional deficiencies, chronic diseases, hemoglobinopathies, and lead poisoning. Maternal anemia in resource-poor nations is associated with low birth weight, increased perinatal mortality, and decreased work productivity. Maintaining a normal iron balance in these settings is challenging, as iron-rich foods with good bioavailability are of animal origin and either expensive and/or available in short supply. Apart from infrequent consumption of meat, inadequate vitamin C intake, and diets rich in inhibitors of iron absorption are additional important risk factors for IDA in low-income countries. In-home iron fortification of complementary foods with micronutrient powders has been shown to effectively reduce the risk of iron deficiency and IDA in infants and young children in developing countries but is associated with unfavorable changes in gut flora and induction of intestinal inflammation that may lead to diarrhea and hospitalization. In developed countries, iron deficiency is the only frequent micronutrient deficiency. In the industrialized world, IDA is more common in infants beyond the sixth month of life, in adolescent females with heavy menstrual bleeding, in women of childbearing age and older people. Other special at-risk populations for IDA in developed countries are regular blood donors, endurance athletes, and vegetarians. Several medicinal ferrous or ferric oral iron products exist, and their use is not associated with harmful effects on the overall incidence of infectious illnesses in sideropenic and/or anemic subjects. However, further research is needed to clarify the risks and benefits of supplemental iron for children exposed to parasitic infections in low-income countries, and for children genetically predisposed to iron overload.

Health Care Utilization and Economic Burdens of Hemochromatosis in the United States: A Population-Based Claims Study

BACKGROUND

Little is known about the health care burden of hemochromatosis in the United States, despite its increased morbidity and mortality due to associated advanced liver diseases.

OBJECTIVE

To evaluate the health care utilization and economic burdens of hemochromatosis in the United States using real-world claims data.

METHODS

We performed a case-control analysis of adult participants in the Truven Health MarketScan Commercial Claims database from 2010 to 2015. 37,092 hemochromatosis cases were matched 1:1 by demographics and comorbidities to hemochromatosis-free controls with chronic liver disease using propensity scores. Total and service-specific health care parameters were quantified for the 12 months following versus the 12 months before the first date of hemochromatosis diagnosis and over the 12 months following a randomly selected date for controls. Incremental differences in health care burdens between cases and controls were examined using Wilcoxon signed rank tests and McNemar tests for continuous and dichotomous measures, respectively. Adjusted multivariable regression analyses using generalized linear models were used to compare the health care burdens for cases with controls.

RESULTS

In comparison with the year before, the 12 months following first hemochromatosis diagnoses had a higher total number of claims per patient (34.37 vs. 29.99; P < 0.0001) and an increase in the per-patient total health care costs ($20,023 vs. $16,905; P < 0.0001). After hemochromatosis diagnosis, health care costs were 2%, 8%, 23%, and 43% higher for inpatient admissions, emergency department visits, outpatient visits, and pharmaceutical prescriptions, compared respectively with the 12 months before diagnosis. In the 12 months following the index date, hemochromatosis cases incurred $2,732 more in total unadjusted costs compared with controls. Compared with controls, cases had adjusted incident rate ratio (IRR) 1.26 (95% CI = 1.30-1.77) times the total number of claims (IRR = 1.40, 95% CI = 1.38-1.43) more outpatient visits and IRR = 1.10 (95% CI = 1.08-1.11) excess pharmaceutical claims. Compared with controls, cases had significantly higher adjusted mean health care costs for inpatient services ($6,484 vs. $7,854), outpatient services ($7,032 vs. $11,005), and pharmaceutical claims ($2,520 vs. $2,822; all P values < 0.05). The annual health care costs among type 2 diabetes, hypertension, arthritis, and chronic kidney disease (CKD) patients with hemochromatosis were $6,968, $7,424, $2,967, and $43,847, respectively, higher than type 2 diabetes, hypertension, arthritis, and CKD patients without hemochromatosis (P < 0.0001).

CONCLUSIONS

Hemochromatosis in the United States is associated with significant health care utilization and economic burdens driven by outpatient visits, pharmaceutical claims, and a high number of comorbidities DISCLOSURES: No outside funding supported this study. The authors have no relevant financial or other relationships to disclose. An abstract containing some of the results from this study was accepted for the American Association for the Study of Liver Diseases Meeting; November 9-13, 2018; San Francisco, CA.

ACG Clinical Guideline: Hereditary Hemochromatosis

Hereditary hemochromatosis (HH) is one of the most common genetic disorders among persons of northern European descent. There have been recent advances in the diagnosis, management, and treatment of HH. The availability of molecular diagnostic testing for HH has made possible confirmation of the diagnosis for most patients. Several genotype-phenotype correlation studies have clarified the differences in clinical features between patients with the C282Y homozygous genotypes and other HFE mutation patterns. The increasing use of noninvasive tests such as MRI T2* has made quantification of hepatic iron deposition easier and eliminated the need for liver biopsy in most patients. Serum ferritin of <1,000 ng/mL at diagnosis remains an important diagnostic test to identify patients with a low risk of advanced hepatic fibrosis and should be used routinely as part of the initial diagnostic evaluation. Genetic testing for other types of HH is available but is expensive and generally not useful in most clinical settings. Serum ferritin may be elevated among patients with nonalcoholic fatty liver disease and in those with alcoholic liver disease. These diagnoses are more common than HH among patients with elevated serum ferritin who are not C282Y homozygotes or C282Y/H63D compound heterozygotes. A secondary cause for liver disease should be excluded among patients with suspected iron overload who are not C282Y homozygotes. Phlebotomy remains the mainstay of therapy, but emerging novel therapies such as new chelating agents may have a role for selected patients.

The commensal bacterium Bacteroides fragilis down-regulates ferroportin expression and alters iron homeostasis in macrophages

The intestinal microbiota has several effects on host physiology. Previous work from our laboratory demonstrated that the microbiota influences systemic iron homeostasis in mouse colitis models by altering inflammation-induced expression of the iron-regulating hormone hepcidin. In the present study, we examined the impact of the gut commensal bacterium Bacteroides fragilis on the expression of the iron exporter ferroportin, the target of hepcidin action, in macrophages, the cell type that plays a pivotal role in iron recycling. Mouse bone marrow-derived macrophages were exposed to B. fragilis and were analyzed by quantitative real-time polymerase chain reaction and Western blotting. We found that B. fragilis down-regulated ferroportin transcription independently of bacterial viability. Medium conditioned by the bacteria also reduced ferroportin expression, indicating the involvement of soluble factors, possibly Toll-like receptor ligands. Consistent with this idea, several of these ligands were able to down-regulate ferroportin. The B. fragilis-induced decrease in ferroportin was functionally important since it produced a significant increase in intracellular iron concentrations that prevented the effects of the iron chelator deferoxamine on Salmonella-induced IL-6 and IL-1β production. Our results thus reveal that B. fragilis can influence macrophage iron handling and inflammatory responses by modulating ferroportin expression.

Feasibility of the use of a handheld XRF analyzer to measure skin iron to monitor iron levels in critical organs

There exists a need for accurate, non-invasive point-of-care tests to detect body iron burden. This study investigated the use of x-ray fluorescence (XRF) measurements of skin iron as a marker for organ iron content in rats. This study also evaluated a novel application of a commercial XRF device, commonly used in mining and construction, as a rapid, portable, and non-invasive measurement tool. Rats (n = 32) were loaded with iron dextran and the iron signal of each animal's skin, liver, and kidney was measured using a conventional XRF system. A quadratic correlation was observed between liver and skin iron signal (R² = 0.92) and a linear correlation was observed between kidney and skin iron signal (R² = 0.65). As such, it is concluded that skin iron content can act as a marker for both liver and kidney iron content. The same skin samples were measured using the portable XRF device and compared to the liver and kidney samples measured in the conventional XRF system. Again, a quadratic correlation was observed between liver and skin iron signal (R² = 0.91) and a linear correlation was observed between kidney and skin iron signal (R² = 0.83). Thus, the portable XRF device can provide rapid non-invasive, skin XRF measurements. Dosimetry was performed using the portable XRF device to assess the radiological hazard associated with its use. The average skin equivalent dose from this device is 30 ± 10 mSv/min, when the device is collimated and operated at 40 kV. In conclusion, skin iron XRF measurements can act as a surrogate marker for liver iron content, and can be measured using a commercial XRF device for a portable, fast, and non-invasive measurement.

Cost-Effectiveness of Different Population Screening Strategies for Hereditary Haemochromatosis in Australia

INTRODUCTION

Amongst populations of northern European ancestry, HFE-associated haemochromatosis is a common genetic disorder characterised by iron overload. In the absence of treatment, excess iron is stored in parenchymal tissues, causing morbidity and mortality. Population screening programmes may increase early diagnosis and reduce associated disease. No contemporary health economic evaluation has been published for Australia. The objective of this study was to identify cost-effective screening strategies for haemochromatosis in the Australian setting.

METHODS

A Markov model using probabilistic decision analysis was developed comparing four adult screening strategies: the status quo (cascade and incidental screening), genotyping with blood and buccal samples and transferrin saturation followed by genotyping (TfS). Target populations were males (30 years) and females (45 years) of northern European ancestry. Cost-effectiveness was estimated from the government perspective over a lifetime horizon.

RESULTS

All strategies for males were cost-effective compared to the status quo. The incremental costs (standard deviation) associated with genotyping (blood) were AUD7 (56), TfS AUD15 (45) and genotyping (buccal) AUD63 (56), producing ICERs of AUD1673, 4103 and 15,233/quality-adjusted life-year (QALY) gained, respectively. For females, only the TfS strategy was cost-effective, producing an ICER of AUD10,195/QALY gained. Approximately 3% of C282Y homozygotes were estimated to be identified with the status quo approach, compared with 40% with the proposed screening strategies.

CONCLUSION

This model estimated that genotyping and TfS strategies are likely to be more cost-effective screening strategies than the status quo.

Hemochromatosis and blood donation

The voluntary, unpaid, altruistic blood donor is a cornerstone of current transfusion medicine. The complexity of medical and ethical issues related to blood donation and hemochromatosis has led to a large number of studies related to the safety of the hemochromatosis donor and the quality of the blood components produced from these donations. The issue of accepting persons with HC as blood donors is diverting, both in Europe and worldwide and without joint guidelines. A questionnaire-based study was performed and mailed to all 25 blood bank leaders in Norway. Descriptive analysis was used to evaluate the data. Eight of 22 blood banks strictly followed national guidelines concerning persons with hemochromatosis. Other blood banks make local adjustments. 16 of 22 responding blood banks accept hemochromatosis donors and five do not, and one answered partly yes. The reasons the blood bank leaders supported the acceptance of hemochromatosis donors differ. Based on published papers and the present questionnaire, we believe that a clear definition of the "hemochromatosis donor" and guidelines with more detailed information on an acceptable donation regime would be important to overcome the weak points in blood donor eligibility criteria.

Diabetes mellitus caused by secondary hemochromatosis after multiple blood transfusions in 2 patients with severe aplastic anemia

Hemochromatosis is an inherited or secondary disorder caused by excessive iron storage leading to multiple organ damage. We describe 2 patients with diabetes mellitus caused by hemochromatosis secondary to multiple blood transfusions due to severe aplastic anemia. Subject 1, who was diagnosed with severe aplastic anemia at 15 years of age, received multiple red blood cell transfusions before he underwent autologous peripheral blood stem cell transplantation (PBSCT) at 22 years of age. At 21 years of age, hyperglycemia was detected with increased hemoglobin A1c and serum ferritin levels, 9.7% and 12,910 ng/mL (normal range, 20-320 ng/mL), respectively. The 24-hour urine C-peptide level was normal with negative antiglutamic acid decarboxylase antibody. Subsequently, metformin and an iron-chelating agent were administered. However, an intensive insulin regimen was necessary 2 years after the onset of diabetes. Subject 2, who was diagnosed with severe aplastic anemia at 2 years of age, received multiple blood transfusions until she underwent haploidentical PBSCT at 13 years of age. At 11 years of age, she developed diabetes mellitus with a high serum ferritin level (12,559.8 ng/mL). She is currently 18 years old and has been treated with an intensive insulin regimen and estrogen/progesterone replacement therapy because of hypogonadotropic hypogonadism. It is presumed that the loss of insulin secretory capacity and insulin resistance played a role in the pathogenesis of diabetes mellitus due to hemochromatosis in these cases.

Population Screening for Hereditary Haemochromatosis in Australia: Construction and Validation of a State-Transition Cost-Effectiveness Model

INTRODUCTION

HFE-associated haemochromatosis, the most common monogenic disorder amongst populations of northern European ancestry, is characterised by iron overload. Excess iron is stored in parenchymal tissues, leading to morbidity and mortality. Population screening programmes are likely to improve early diagnosis, thereby decreasing associated disease. Our aim was to develop and validate a health economics model of screening using utilities and costs from a haemochromatosis cohort.

METHODS

A state-transition model was developed with Markov states based on disease severity. Australian males (aged 30 years) and females (aged 45 years) of northern European ancestry were the target populations. The screening strategy was the status quo approach in Australia; the model was run over a lifetime horizon. Costs were estimated from the government perspective and reported in 2015 Australian dollars ($A); costs and quality-adjusted life-years (QALYs) were discounted at 5% annually. Model validity was assessed using goodness-of-fit analyses. Second-order Monte-Carlo simulation was used to account for uncertainty in multiple parameters.

RESULTS

For validity, the model reproduced mortality, life expectancy (LE) and prevalence rates in line with published data. LE for C282Y homozygote males and females were 49.9 and 40.2 years, respectively, slightly lower than population rates. Mean (95% confidence interval) QALYS were 15.7 (7.7-23.7) for males and 14.4 (6.7-22.1) for females. Mean discounted lifetime costs for C282Y homozygotes were $A22,737 (3670-85,793) for males and $A13,840 (1335-67,377) for females. Sensitivity analyses revealed discount rates and prevalence had the greatest impacts on outcomes.

CONCLUSION

We have developed a transparent, validated health economics model of C282Y homozygote haemochromatosis. The model will be useful to decision makers to identify cost-effective screening strategies.

Costs associated with hereditary haemochromatosis in Australia: a cost-of-illness study

Objective The aim of the present study was to assess health sector, other sector and time-related (productivity) costs associated with hereditary haemochromatosis from societal, government and patient perspectives for the Australian setting. Methods A national web-based survey of people with haemochromatosis was conducted between November 2013 and February 2015. Participants completed a health survey and resource use diaries. Costs were calculated using a bottom-up approach and calculated in 2015 Australian dollars. Results Cost data were available for 157 participants. From a societal perspective, the estimated annual cost of haemochromatosis was A$274 million. The mean (95% confidence interval) cost for symptomatic patients was almost threefold greater than that of asymptomatic patients (A$10030 (7705–12670) vs A$3701 (2423–5296) respectively). Health sector and productivity-related time loss were the main cost drivers. When extrapolating costs to the Australian population level, asymptomatic haemochromatosis accounted for higher costs than symptomatic haemochromatosis (A$183 million vs A$91 million), reflecting the low clinical penetrance estimate used. Total costs increased when higher clinical penetrance estimates were used. Conclusion The present cost-of-illness study, the first to be published for haemochromatosis, found that although costs were substantial, they could be decreased by reducing clinical penetrance. Development of cost-effective strategies to increase early diagnosis is likely to result in better health outcomes for patients and lower total costs. What is known about the topic? To date, no cost-of-illness study has been conducted for haemochromatosis. Previous economic work in this area has relied on cost estimates based on expert opinion. What does the paper add? This paper provides the first cost estimates for haemochromatosis for the Australian population. These estimates, calculated using a bottom-up approach, were extrapolated to the population level based on the most robust epidemiological estimates available for the Australian population. What are the implications for practitioners? Population screening programs have been widely suggested as an approach to reduce clinical penetrance; however, the lack of high-quality economic analyses has been cited as a barrier to implementation. The present study provides the most robust cost estimates to date, which may be used to populate economic models. In addition, the present study illustrates that reducing clinical penetrance of haemochromatosis is likely to result in substantial reductions in cost.

Management of human factors engineering-associated hemochromatosis: A 2015 update

This review focuses on the management of iron metabolism and iron overload experienced in the hereditary condition, human factors engineering (HFE)-associated hemochromatosis. Hemochromatosis refers to a group of genetic diseases that result in iron overload; the major one globally is HFE-associated hemochromatosis. The evolution in understanding of the most common form of hereditary hemochromatosis, being the substation of cysteine to a tyrosine at position 282 in the HFE gene, has been extensively studied Novel mutations in both HFE and non-HFE genes have been indicated in this disease which hold significance in its application for the Asia-Pacific region. In conditions with iron overload, the storage of excess iron in various body tissues leads to complications and toxic damage. The most common presenting complaint for this disease is malaise, lethargy and other non-specific symptoms. In order to diagnose hereditary hemochromatosis, there are biochemical, imaging and genetic testing options. Currently, cascade screening of affected families is preferred over population-level screening. The mainstay of treatment is venesection and the appropriate approach to treatment has been consolidated over the years. Recently, the indications for venesection therapy of hemochromatosis have been challenged and are the subject of ongoing research.

Quality of life utility values for hereditary haemochromatosis in Australia

Background

Hereditary hemochromatosis (HH) is a common autosomal recessive disorder amongst persons of northern European heritage. If untreated, iron accumulates in parenchymal tissues causing morbidity and mortality. As diagnosis often follows irreversible organ damage, screening programs have been suggested to increase early diagnosis. A lack of economic evidence has been cited as a barrier to establishing such a program. Previous analyses used poorly estimated utility values. This study sought to measure utilities directly from people with HH in Australia.

Methods

Volunteers with HH were recruited to complete a web-based survey. Utility was assessed using the Assessment of Quality of Life 4D (AQOL-4D) instrument. Severity of HH was graded into four categories. Multivariable regression analysis was performed to identify parameters associated with HSUV.

Results

Between November 2013 and November 2014, 221 people completed the survey. Increasing severity of HH was negatively associated with utility. Mean (standard deviation) utilities were 0.76 (0.21), 0.81 (0.18), 0.60 (0.27), and 0.50 (0.27) for categories 1–4 HH respectively. Lower mean utility was found for symptomatic participants (categories 3 and 4) compared with asymptomatic participants (0.583 v. 0.796). Self-reported HH-related symptoms were negatively associated with HSUV (r = −0.685).

Conclusions

Symptomatic stages of HH and presence of multiple self-reported symptoms were associated with decreasing utility. Previous economic analyses have used higher utilities which likely resulted in underestimates of the cost effectiveness of HH interventions. The utilities reported in this paper are the most robust available, and will contribute to improving the validity of future economic models for HH.

A Systematic Review and Narrative Synthesis of Health Economic Studies Conducted for Hereditary Haemochromatosis

BACKGROUND

Hereditary haemochromatosis (HH) is a common genetic condition amongst people of northern European heritage. HH is associated with increased iron absorption leading to parenchymal organ damage and multiple arthropathies. Early diagnosis and treatment prevents complications. Population screening may increase early diagnosis, but no programmes have been introduced internationally: a paucity of health economic data is often cited as a barrier.

OBJECTIVE

To conduct a systematic review of all health economic studies in HH.

METHODS

Studies were identified through electronic searching of economic/biomedical databases. Any study on HH with original economic component was included. Study quality was formally assessed. Health economic data were extracted and analysed through narrative synthesis.

RESULTS

Thirty-eight studies met the inclusion criteria. The majority of papers reported on costs or cost effectiveness of screening programmes. Whilst most concluded screening was cost effective compared with no screening, methodological flaws limit the quality of these findings. Assumptions regarding clinical penetrance, effectiveness of screening, health-state utility values (HSUVs), exclusion of early symptomatology (such as fatigue, lethargy and multiple arthropathies) and quantification of costs associated with HH were identified as key limitations. Treatment studies concluded therapeutic venepuncture was the most cost-effective intervention.

CONCLUSIONS

There is a paucity of high-quality health economic studies relating to HH. The development of a comprehensive HH cost-effectiveness model utilising HSUVs is required to determine whether screening is worthwhile.

Recent advances in hemochromatosis: a 2015 update : a summary of proceedings of the 2014 conference held under the auspices of Hemochromatosis Australia

This review focuses on iron metabolism, the genetics of hemochromatosis, current treatment protocols and various screening methods. Even though the most common form of hereditary hemochromatosis, C282Y gene mutations in the HFE gene, has been extensively studied, novel mutations in both HFE and non-HFE genes have been implicated in this disease. These have important implications for the Asia-Pacific region. In overload, deposition of iron in various body tissues leads to toxic damage. Patients commonly present with non-specific symptoms of malaise and lethargy. Biochemical, imaging and genetic testing can be carried out to confirm diagnosis. Venesection forms the mainstay of treatment and at present cascade screening of affected families is recommended over population-level screening.

Sugars increase non-heme iron bioavailability in human epithelial intestinal and liver cells

Previous studies have suggested that sugars enhance iron bioavailability, possibly through either chelation or altering the oxidation state of the metal, however, results have been inconclusive. Sugar intake in the last 20 years has increased dramatically, and iron status disorders are significant public health problems worldwide; therefore understanding the nutritional implications of iron-sugar interactions is particularly relevant. In this study we measured the effects of sugars on non-heme iron bioavailability in human intestinal Caco-2 cells and HepG2 hepatoma cells using ferritin formation as a surrogate marker for iron uptake. The effect of sugars on iron oxidation state was examined by measuring ferrous iron formation in different sugar-iron solutions with a ferrozine-based assay. Fructose significantly increased iron-induced ferritin formation in both Caco-2 and HepG2 cells. In addition, high-fructose corn syrup (HFCS-55) increased Caco-2 cell iron-induced ferritin; these effects were negated by the addition of either tannic acid or phytic acid. Fructose combined with FeCl3 increased ferrozine-chelatable ferrous iron levels by approximately 300%. In conclusion, fructose increases iron bioavailability in human intestinal Caco-2 and HepG2 cells. Given the large amount of simple and rapidly digestible sugars in the modern diet their effects on iron bioavailability may have important patho-physiological consequences. Further studies are warranted to characterize these interactions.

Diagnostic value of real-time elastography in the assessment of hepatic fibrosis in patients with liver iron overload

OBJECTIVE

The objective of our prospective monocentric work was to determine the diagnostic value of real-time elastography (RTE) in the assessment of liver fibrosis in patients with iron overload, using transient elastography (TE) as reference standard.

METHODS

Sixty-seven consecutive patients with MRI detectable iron overload (T2*<6.3 ms) were enrolled. TE and RTE were performed on the same day as MRI. Elastograms were acquired by an experienced operator and analyzed by calculating the elastic ratio between perihepatic soft tissues and liver parenchyma. An elliptical ROI of 1cm(2) (Z1) was positioned in the liver parenchyma and a smaller elliptical ROI of 2mm(2) (Z2) was positioned in a homogeneously soft (red) region of the diaphragm, which was considered as internal control to calculate the elastic ratio Z2/Z1.

RESULTS

Seven patients were excluded because of invalid TE or RTE examinations. The remaining 60 patients were 57% males and 43% females (mean age: 42 [21-76] years), including 37 homozygous-β-thalassemics, 13 patients with β-thalassemia intermedia, 6 with primary hemochromatosis, and 4 with myelodysplastic syndrome. Increasing elastic ratios were significantly correlated with increasing TE values (r=0.645, 95% CI 0.468-0.772, P<0.0001). The mean elastic ratios for each METAVIR group were as follows: F0/1 = 1.9 ± 0.4; F2 = 2.2 ± 0.4; F3 = 2.9 ± 0.5; F4 = 3.2 ± 0.4. The diagnostic accuracy of RTE for F ≥ 2 evaluated by AUC-ROC analysis was 0.798 (95% CI 0.674-0.890). The diagnostic accuracy of RTE for F ≥ 3 was 0.909 (95% CI 0.806-0.968). At a cut-off ≥ 2.75, RTE showed a sensitivity of 70% (95% CI 45.7-88.1) and a specificity of 97.5% (95% CI 86.8-99.9).

CONCLUSIONS

In patients with MRI-detectable liver iron-overload RTE allows to discriminate between F0/1-F2 and F3-F4 with a reasonable diagnostic accuracy.

Mammalian iron homeostasis in health and disease: uptake, storage, transport, and molecular mechanisms of action

Iron is a crucial factor for life. However, it also has the potential to cause the formation of noxious free radicals. These double-edged sword characteristics demand a tight regulation of cellular iron metabolism. In this review, we discuss the various pathways of cellular iron uptake, cellular iron storage, and transport. Recent advances in understanding the reduction and uptake of non-transferrin-bound iron are discussed. We also discuss the recent progress in the understanding of transcriptional and translational regulation by iron. Furthermore, we discuss recent advances in the understanding of the regulation of cellular and systemic iron homeostasis and several key diseases resulting from iron deficiency and overload. We also discuss the knockout mice available for studying iron metabolism and the related human conditions.

Association between neonatal iron overload and early human brain development in premature infants

BACKGROUND

Emerging evidence suggests that excess iron may be detrimental for brain development. However, little is known regarding the association between neonatal iron overload and subsequent neurodevelopment during infancy in vulnerable premature infants.

AIMS

To evaluate the association between neonatal iron overload and neurodevelopment in premature infants.

STUDY DESIGN

Prospective cohort study.

SUBJECTS

24-32 weeks gestational age infants who had serum ferritin (SF) measured at 34-35 weeks post-menstrual age (PMA) and did not meet exclusion criteria: SF<76 ng/ml, toxoplasmosis, syphilis, rubella, cytomegalovirus, herpes infections, chromosomal disorders, or craniofacial anomalies were eligible. In addition, infants with sepsis or elevated C-reactive protein within 10 days before their SF measurement were excluded.

OUTCOME MEASURES

Infants were evaluated for neurodevelopmental outcome at 8-12 months of age and were deemed to have neurodevelopmental impairment if they had one or more of the following: mental developmental index<70, abnormal neurological examination, bilateral blindness, bilateral deafness, or required occupational, physical, or speech therapy.

RESULTS

95 infants were studied. 70 had normal iron status (SF 76-400 ng/ml) while 25 were deemed to have iron overload (SF >400 ng/ml) at 34-35 weeks PMA. There was a marginal increase in neurodevelopmental impairment among infants with iron overload compared to infants with normal iron status (64% vs. 41%, p=0.05). However, after controlling for confounders, iron overload was not associated with neurodevelopmental impairment (Adjusted OR 0.71, 95% CI, 0.21-2.5).

CONCLUSION

Modest neonatal iron overload is not associated with neurodevelopmental impairment during infancy in premature infants.

Non-invasive methods for liver fibrosis prediction in hemochromatosis: One step beyond

Advances in recent years in the understanding of, and the genetic diagnosis of hereditary hemochromatosis (HH) have changed the approach to iron overload hereditary diseases. The ability to use a radiologic tool (MRI) that accurately provides liver iron concentration determination, and the presence of non-invasive serologic markers for fibrosis prediction (serum ferritin, platelet count, transaminases, etc), have diminished the need for liver biopsy for diagnosis and prognosis of this disease. Consequently, the role of liver biopsy in iron metabolism disorders is changing. Furthermore, the irruption of transient elastography to assess liver stiffness, and, more recently, the ability to determine liver fibrosis by means of MRI elastography will change this role even more, with a potential drastic decline in hepatic biopsies in years to come. This review will provide a brief summary of the different non-invasive methods available nowadays for diagnosis and prognosis in HH, and point out potential new techniques that could come about in the next years for fibrosis prediction, thus avoiding the need for liver biopsy in a greater number of patients. It is possible that liver biopsy will remain useful for the diagnosis of associated diseases, where other non-invasive means are not possible, or for those rare cases displaying discrepancies between radiological and biochemical markers.