Asymptomatic individuals at genetic risk of haemochromatosis take appropriate steps to prevent disease related to iron overload

Barriers and Facilitators for Population Genetic Screening in Healthy Populations: A Systematic Review

Studies suggest that 1-3% of the general population in the United States unknowingly carry a genetic risk factor for a common hereditary disease. Population genetic screening is the process of offering otherwise healthy patients in the general population testing for genomic variants that predispose them to diseases that are clinically actionable, meaning that they can be prevented or mitigated if they are detected early. Population genetic screening may significantly reduce morbidity and mortality from these diseases by informing risk-specific prevention or treatment strategies and facilitating appropriate participation in early detection. To better understand current barriers, facilitators, perceptions, and outcomes related to the implementation of population genetic screening, we conducted a systematic review and searched PubMed, Embase, and Scopus for articles published from date of database inception to May 2020. We included articles that 1) detailed the perspectives of participants in population genetic screening programs and 2) described the barriers, facilitators, perceptions, and outcomes related to population genetic screening programs among patients, healthcare providers, and the public. We excluded articles that 1) focused on direct-to-consumer or risk-based genetic testing and 2) were published before January 2000. Thirty articles met these criteria. Barriers and facilitators to population genetic screening were organized by the Social Ecological Model and further categorized by themes. We found that research in population genetic screening has focused on stakeholder attitudes with all included studies designed to elucidate individuals' perceptions. Additionally, inadequate knowledge and perceived limited clinical utility presented a barrier for healthcare provider uptake. There were very few studies that conducted long-term follow-up and evaluation of population genetic screening. Our findings suggest that these and other factors, such as prescreen counseling and education, may play a role in the adoption and implementation of population genetic screening. Future studies to investigate macro-level determinants, strategies to increase provider buy-in and knowledge, delivery models for prescreen counseling, and long-term outcomes of population genetic screening are needed for the effective design and implementation of such programs. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020198198.

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.

Latin American Association for the Study of the Liver (LAASL) clinical practice guidelines: management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world and the third most common cause of cancer death, and accounts for 5.6% of all cancers. Nearly 82% of the approximately 550,000 liver cancer deaths each year occur in Asia. In some regions, cancer-related death from HCC is second only to lung cancer. The incidence and mortality of HCC are increasing in America countries as a result of an ageing cohort infected with chronic hepatitis C, and are expected to continue to rise as a consequence of the obesity epidemic. Clinical care and survival for patients with HCC has advanced considerably during the last two decades, thanks to improvements in patient stratification, an enhanced understanding of the pathophysiology of the disease, and because of developments in diagnostic procedures and the introduction of novel therapies and strategies in prevention. Nevertheless, HCC remains the third most common cause of cancer-related deaths worldwide. These LAASL recommendations on treatment of hepatocellular carcinoma are intended to assist physicians and other healthcare providers, as well as patients and other interested individuals, in the clinical decision-making process by describing the optimal management of patients with liver cancer.

Hemochromatosis: the new blood donor

Hereditary hemochromatosis (HH) due to homozygosity for the C282Y mutation in the HFE gene is a common inherited iron overload disorder in whites of northern European descent. Hepcidin deficiency, the hallmark of the disorder, leads to dysregulated intestinal iron absorption and progressive iron deposition in the liver, heart, skin, endocrine glands, and joints. Survival is normal if organ damage is prevented by early institution of phlebotomy therapy. HH arthropathy is the symptom most affecting quality of life and can be debilitating. Genotype screening in large population studies has shown that the clinical penetrance of C282Y homozygosity is highly variable and can be very low, with up to 50% of women and 20% of men showing a silent phenotype. Targeted population screening for the HFE C282Y mutation is not recommended at present, but might be reconsidered as a cost-effective approach to management if counseling and care were better organized and standardized. Referral of patients to the blood center for phlebotomy therapy and use of HH donor blood for transfusion standardizes treatment, minimizes treatment costs, and may benefit society as a whole. Physician practices should be amended such that HH subjects are more frequently referred to the blood center for therapy.

Patient compliance based on genetic medicine: a literature review

For this literature review, medical literature data bases were searched for studies on patient compliance after genetic risk assessment. The review focused on conditions where secondary or tertiary preventive options exist, namely cancer syndromes (BRCA-related cancer, HNPCC/colon cancer), hemochromatosis, thrombophilia, smoking cessation, and obesity. As a counterpart, patient compliance was assessed regarding medication adherence and medical advice in some of the most epidemiologically important conditions (including high blood pressure, metabolic syndrome, and coronary heart disease) after receiving medical advice based on nongenetic risk information or a combination of genetic and nongenetic risk information. In the majority of studies based on genetic risk assessments, patients were confronted with predictive rather than diagnostic genetic profiles. Most of the studies started from a knowledge base around 10 years ago when DNA testing was at an early stage, limited in scope and specificity, and costly. The major result is that overall compliance of patients after receiving a high-risk estimate from genetic testing for a given condition is high. However, significant behavior change does not take place just because the analyte is "genetic." Many more factors play a role in the complex process of behavioral tuning. Without adequate counseling and guidance, patients may interpret risk estimates of predictive genetic testing with an increase in fear and anxiety.

How I treat hemochromatosis

Hemochromatosis is a common genetic disorder in which iron may progressively accumulate in the liver, heart, and other organs. The primary goal of therapy is iron depletion to normalize body iron stores and to prevent or decrease organ dysfunction. The primary therapy to normalize iron stores is phlebotomy. In this opinion article, we discuss the indications for and monitoring of phlebotomy therapy to achieve iron depletion, maintenance therapy, dietary and pharmacologic maneuvers that could reduce iron absorption, and the role of voluntary blood donation.

Prevention of hepatocellular carcinoma in the Asia-Pacific region: consensus statements

Among approximately 650,000 people who die from hepatocellular carcinoma (HCC) each year, at least two-thirds live in Asia. Efforts to improve early diagnosis and treatment have not yet impacted mortality. An Asia-Pacific Working Party convened in Hong Kong in June 2008 to consider ways to prevent HCC in this region. Separate reviews have summarized epidemiology of HCC, preventive approaches related to hepatitis B virus (HBV), hepatitis C virus (HCV) and non-viral liver diseases, and the role of surveillance to detect HCC at a curative stage. We now present Consensus Statements from these deliberations and reviews. As chronic hepatitis B is the most common cause of HCC in Asia, effective hepatitis B vaccination programs are the most important strategy to reduce HCC incidence. Prevention of HCV by screening blood donors, universal precautions against blood contamination in health-care settings and reducing HCV transmission from injection drug use are also vital. There is strong evidence that effective antiviral therapy to control HBV infection or eradicate HCV substantially reduces (but does not abolish) HCC risk. With hemochromatosis, family screening, early diagnosis and correcting iron overload to prevent liver fibrosis prevents HCC. There is currently insufficient evidence to give firm recommendations on alcohol, obesity/metabolic risk factors and other liver diseases. HCC surveillance for high-risk groups is recommended in individual cases but cost-effectiveness is not as high as infant hepatitis B vaccination and screening blood for HCV. Widespread application of HCC surveillance in Asia-Pacific countries depends on economic factors and health-care priorities.

The global burden of iron overload

There have been major developments in the field of iron metabolism in the past decade following the identification of the HFE gene and the mutation responsible for the C282Y substitution in the HFE protein. While HFE-associated hemochromatosis occurs predominantly in people of northern European extraction, other less-common mutations can lead to the same clinical syndrome and these may occur in other populations in the Asian-Pacific region. The most common of these is the mutation that leads to changes in the ferroportin molecule, the protein responsible for the transport of iron across the basolateral membrane of the enterocyte and from macrophages. Recent research has unraveled the molecular processes of iron transport and regulation of how these are disturbed in hemochromatosis and other iron-loading disorders. At the same time, at least one new oral iron chelating agent has been developed that shows promise in the therapy of hemochromatosis as well as thalassemia and other secondary causes of iron overload. It is pertinent therefore to examine the developments in the global field of iron overload that have provided insights into the pathogenesis, disease penetrance, comorbid factors, and management.

Prevention of hepatocellular carcinoma in nonviral-related liver diseases

Although chronic infection with hepatitis B virus and/or hepatitis C virus are the most important risk factors for hepatocellular carcinoma (HCC) worldwide, other causes of cirrhosis can also lead to HCC. Given the high prevalence of alcoholism and the worldwide obesity epidemic, the relevant importance of nonviral liver disease-related HCC is expected to increase in the future. Some evidence supports mechanistic interactions between host or environmental factors and chronic viral hepatitis in the development of HCC. For example, food- and water-borne carcinogens have contributed to unusually high rates of HCC in parts of China and sub-Saharan Africa. With some of these conditions, appropriate public health measures to reduce the population's exposure to known etiologic agents, or early therapeutic intervention for 'at-risk' individuals before development of cirrhosis (e.g. hereditary hemochromatosis) can prevent HCC. Community-based programs to discourage and deal with excessive alcohol intake, to promote tobacco smoking awareness, to avoid exposure to aflatoxin and other food toxins, and measures to reduce the pandemic of obesity and diabetes are vital for effective interruption of the rising tide of HCC from nonviral liver disease.

The natural history of serum iron indices for HFE C282Y homozygosity associated with hereditary hemochromatosis

BACKGROUND & AIMS

There are few longitudinal studies of serum ferritin (SF) and transferrin saturation (TS) levels in individuals homozygous for the C282Y mutation. We characterized the development of elevated iron measures in C282Y homozygotes followed for 12 years.

METHODS

From 31,192 people aged 40-69 years at baseline, we identified 203 C282Y homozygotes (95 males), of whom 116 had SF and fasting TS levels measured at baseline (mean age, 55 years) and 86 were untreated and had iron measures at follow-up (mean, 12 years later). The probabilities of SF at follow-up exceeding clinical thresholds were predicted from baseline SF and TS under a multivariate normal model.

RESULTS

For C282Y homozygotes, at baseline, 84% of males and 65% of females had elevated SF and 37% of males and 3% of females had SF >1000 microg/L. For males with SF 300-1000 microg/L at baseline, the predicted probability of progressing to SF >1000 microg/L at follow-up was between 13% and 35% and, for females, between 16% and 22%. For C282Y homozygotes with normal baseline SF, <15% were predicted to develop SF >1000 microg/L if left untreated.

CONCLUSIONS

The majority of C282Y homozygotes who are likely to develop SF levels sufficient to place them at risk of iron overload-related disease will have done so by mean age 55 years. TS >95% at mean age 55 years in males increases the likelihood that SF levels will be elevated at mean age 65 years, but this effect is absent in females, most likely because of physiologic blood loss associated with menstruation.