IRon Overload screeNing tool (IRON): development of a tool to guide screening in primary care

Haemochromatosis

Haemochromatosis is one of the most common genetic diseases affecting patients of northern European ancestry. It is overdiagnosed in patients without iron overload and is underdiagnosed in many patients. Early diagnosis by genetic testing and therapy by periodic phlebotomy can prevent the most serious complications, which include liver cirrhosis, liver cancer, and death. This Seminar includes an update on the origins of haemochromatosis; and an overview pathophysiology, genetics, natural history, signs and symptoms, differential diagnoses, treatment with phlebotomy, outcomes, and future directions.

A Healthy Diet is Associated with a Lower Risk of Hepatic Fibrosis

BACKGROUND

Higher diet quality is associated with a lower risk of NAFLD.

OBJECTIVES

We examined the relationship between diet quality and hepatic fibrosis.

METHODS

We analyzed cross-sectional associations between 3 a priori diet quality scores-the Dietary Approaches to Stop Hypertension (DASH) score, the Alternative Healthy Eating Index (AHEI), and a modified Mediterranean-style Diet Score (MDS)-and hepatic fat [controlled attenuation parameter (CAP)] and fibrosis [liver stiffness measurement (LSM)] measured by vibration-controlled transient elastography (VCTE) in 2532 Framingham Heart Study (FHS) participants and 3295 participants of the National Health and Nutrition Examination Survey (NHANES).

RESULTS

Higher diet quality scores were associated with lower LSM in both FHS and NHANES after adjustment for demographic and lifestyle factors. Additional adjustment for CAP or BMI attenuated the observed associations. Association strength was similar across all 3 diet quality scores. Fixed-effect meta-analysis demonstrated that, under CAP-adjusted models, the LSM decreases associated with 1-SD increase of the DASH, AHEI, and MDS scores were 2% (95% CI: 0.7%, 3.3%; P = 0.002), 2% (95% CI: 0.7%, 3.3%; P = 0.003), and 1.7% (95% CI: 0.7%, 2.6%; P = 0.001), respectively, whereas in the meta-analysis of BMI-adjusted models, LSM reductions associated with 1-SD increase of the DASH, AHEI, and MDS scores were 2.2% (95% CI: -0.1%, 2.2%; P = 0.07), 1.5% (95% CI: 0.3%, 2.7%; P = 0.02), and 0.9 (95% CI: -0.1%, 1.9%; P = 0.07), respectively.

CONCLUSIONS

We demonstrated associations of higher diet quality with favorable hepatic fat and fibrosis measures. Our data suggest that a healthy diet may reduce the likelihood of obesity and hepatic steatosis as well as the progression of steatosis to fibrosis.

An efficient machine learning-based approach for screening individuals at risk of hereditary haemochromatosis

Hereditary haemochromatosis (HH) is an autosomal recessive disease, where HFE C282Y homozygosity accounts for 80–85% of clinical cases among the Caucasian population. HH is characterised by the accumulation of iron, which, if untreated, can lead to the development of liver cirrhosis and liver cancer. Since iron overload is preventable and treatable if diagnosed early, high-risk individuals can be identified through effective screening employing artificial intelligence-based approaches. However, such tools expose novel challenges associated with the handling and integration of large heterogeneous datasets. We have developed an efficient computational model to screen individuals for HH using the family study data of the Hemochromatosis and Iron Overload Screening (HEIRS) cohort. This dataset, consisting of 254 cases and 701 controls, contains variables extracted from questionnaires and laboratory blood tests. The final model was trained on an extreme gradient boosting classifier using the most relevant risk factors: HFE C282Y homozygosity, age, mean corpuscular volume, iron level, serum ferritin level, transferrin saturation, and unsaturated iron-binding capacity. Hyperparameter optimisation was carried out with multiple runs, resulting in 0.94 ± 0.02 area under the receiving operating characteristic curve (AUCROC) for tenfold stratified cross-validation, demonstrating its outperformance when compared to the iron overload screening (IRON) tool.

HFE mutations in Caucasian participants of the Hemochromatosis and Iron Overload Screening study with serum ferritin level <1000 µg/L

BACKGROUND

Many patients referred for an elevated serum ferritin level <1000 µg⁄L are advised that they likely have iron overload and hemochromatosis.

AIMS

To determine the prevalence of HFE mutations in the hemochromatosis gene for 11 serum ferritin concentration intervals from 200 µg⁄L to 1000 µg⁄L in Caucasian participants in a primary care, population-based study.

METHODS

The Hemochromatosis and Iron Overload Screening study screened 99,711 participants for serum ferritin levels, transferrin saturation and genetic testing for the C282Y and H63D mutations of the HFE gene. This analysis was confined to 17,160 male and 27,465 female Caucasian participants because the HFE C282Y mutation is rare in other races. Post-test likelihood was calculated for prediction of C282Y homozygosity from a ferritin interval. A subgroup analysis was performed in participants with both an elevated serum ferritin level and transferrin saturation.

RESULTS

There were 3359 male and 2416 female participants with an elevated serum ferritin level (200 µg⁄L to 1000 µg⁄L for women, 300 µg⁄L to 1000 µg⁄L for men). There were 69 male (2.1%) and 87 female (3.6%) C282Y homozygotes, and the probability of being a homozygote increased as the ferritin level increased. Post-test likelihood values were 0.3% to 16% in men and 0.3% to 30.4% in women.

CONCLUSIONS

Iron loading HFE mutations are unlikely to be the most common cause of an elevated serum ferritin level in patients with mild hyperferritinemia. Patients should be advised that there are many causes of an elevated serum ferritin level including iron overload.