[Heterozygous familial hypercholesterolemia in Spain. Description of 819 non related cases]

Prevalence of familial hypercholesterolemia phenotype and ten-year risk of cardiovascular events in a working population in primary prevention: The ICARIA study

BACKGROUND AND AIMS

We aimed to assess the prevalence of familial hypercholesterolaemia (FH) and to determine the incidence of cardiovascular events during a 10-year follow up in individuals with FH, compared to unaffected individuals in a working, middle-aged/young population.

METHODS AND RESULTS

576,724 active workers (36 ± 10 years-old, 70% men) without cardiovascular disease were given regular health check-ups and followed for a median of 8.5 years (i.e., 4,123,927 person-years). The FH phenotype was defined according to validated low-density lipoprotein-cholesterol thresholds, adjusted for age and sex. The primary outcome was a first cardiovascular event, whether fatal or non-fatal. We found that 707 workers (0.12% or 1 in 816 individuals) met the criteria for a heterozygous FH phenotype. During the follow-up, cardiovascular events occurred in 23 of 707 (3.25%) subjects with the FH phenotype and in 3297 of 576,017 (0.57%) subjects without the FH phenotype (p<0.001). The hazard ratio (HR, assessed with a Cox regression model) for the primary outcome was 5.7 (99% CI 3.33-9.78), before adjustments, and 4.7 (99% CI 2.62-8.58) after adjusting for sex, age, smoking, blood pressure, and diabetes. The HRs were significant for both men and women, but the magnitude of the effect was greater for men than for women.

CONCLUSIONS

Our findings confirmed the high incidence of cardiovascular disease in individuals with untreated FH. We showed that regular health check-ups in an active, and mostly young, working population could contribute to the early identification of FH. Therefore, this approach may provide an opportunity for early treatment.

Barriers to Early Diagnosis and Treatment of Familial Hypercholesterolemia: Current Perspectives on Improving Patient Care

Familial hypercholesterolemia (FH) is a frequent disorder associated with premature atherosclerotic cardiovascular disease. Different clinical diagnosis criteria are available, and cost of genetic testing has been reduced in the last years; however, most cases are not diagnosed worldwide. Patients with FH are at high cardiovascular risk and the risk can be reduced with lifelong lifestyle and pharmacological treatment. Statins and ezetimibe are available as generic drugs in most countries reducing the cost of treatment. However, the use of high-intensity statins combined with ezetimibe and PCSK9 inhibitors, if necessary, is low for different reasons that contribute to a high number of patients not reaching LDL-C targets according to guidelines. On the other hand, cardiovascular risk varies greatly in families with FH; therefore, risk stratification strategies including cardiovascular imaging is another element to consider for improving care and management of FH. There are numerous barriers depending on the awareness, knowledge, perception of risk, management and care of patients living with FH that impact in the diagnosis and treatment of the disorder. In this contemporary review, we analyze different barriers in the diagnosis and care of patients to improve patients’ care and prevention of atherosclerotic cardiovascular disease and describe recent advances and strategies to improve the gaps in the care of FH, including global collaboration and advocacy.

Familial Hypercholesterolaemia Diagnosis and Management

Familial hypercholesterolaemia is the most common monogenic disorder associated with premature coronary artery disease. Mutations are most frequently found in the LDL receptor gene. Clinical criteria can be used to make the diagnosis; however, genetic testing will confirm the disorder and is very useful for cascade screening. Early identification and adequate treatment can improve prognosis, reducing negative clinical cardiovascular outcomes. Patients with familial hypercholesterolaemia are considered at high cardiovascular risk and the treatment target is LDL cholesterol <2.6 mmol/l or at least a 50 % reduction in LDL cholesterol. Patients require intensive treatment with statins and ezetimibe and/or colesevelam. Recently, proprotein convertase subtilisin/kexin type 9 inhibitors have been approved for the management of familial hypercholesterolaemia on top of statins.

[Diagnosis and treatment of familial hypercholesterolemia in Spain: consensus document]

La hipercolesterolemia familiar (HF) es un trastorno genético frecuente que se manifiesta desde el nacimiento y que causa un aumento en los niveles plasmáticos de colesterol-LDL (cLDL), xantomas y enfermedad coronaria prematura. Su detección y tratamiento precoz reduce la morbimortalidad coronaria. A pesar de la disponibilidad de un tratamiento eficaz, la HF está poco diagnosticada y tratada. La identificación de los casos índices y la posterior detección en cascada familiar utilizando los niveles de cLDL y la detección genética es la estrategia más coste-efectiva para la detección de nuevos casos. El tratamiento crónico con estatinas ha disminuido el riesgo cardiovascular a los niveles de la población general. Los objetivos en cLDL son < 130 mg/dl en los niños y adultos jóvenes, < 100 mg/dl en los adultos y < 70 mg/dl en los adultos con enfermedad coronaria conocida o diabetes. En la mayoría de los pacientes es difícil conseguir estos objetivos, por lo que puede ser necesario el tratamiento combinado con ezetimiba u otros fármacos. Cuando no se alcanzan los objetivos con el máximo tratamiento farmacológico tolerado, una reducción de cLDL ≥ 50% puede ser aceptable. La LDL-aféresis es útil en los pacientes homocigotos y en los heterocigotos graves resistentes al tratamiento. Este documento proporciona recomendaciones para el diagnóstico, cribado y tratamiento de la HF en niños y adultos, así como consejos específicos para los especialistas clínicos y médicos de atención primaria con el objetivo de mejorar el cuidado de los pacientes y reducir su carga de enfermedad cardiovascular.

Validation of a food frequency questionnaire in Spanish patients with familial hypercholesterolaemia

BACKGROUND AND AIMS

The aim of this study is to validate a semi-quantitative Food Frequency Questionnaire (FFQ) used for general population in Spain, in patients with familial hypercholesterolaemia (FH).

SUBJECTS AND METHODS

Subjects with genetic diagnosis of FH were randomly selected from the Spanish FH Registry. They completed an FFQ based in 113 food items at inclusion (FFQ1) and after 1 year (FFQ2), and a 3-day dietary records (DR) every 3 months. Detailed instruction about how to register foods and beverages was given by a trained nutritionist. Each DR and FFQ was systematically coded, and the daily nutrients intake in absolute, percentage and nutrient density terms were estimated using a software system based on food composition tables. Pearson correlation coefficient was calculated with correction-repeated measurements to assess the reproducibility of both FFQ and the four 3-day DRs, as well as the validity of FFQ comparing to the mean of 3 days' DR.

RESULTS

A total of 112 subjects (58 females and 54 males, aged 43 ± 16 years) finished the study. There were no differences between FFQ1, FFQ2 and mean FFQ (FFQa) in mean absolute and percentage values of selected daily nutrients' intake. Comparison between FFQ1, FFQ2, FFQa and the mean of four 3-day DRs was statistically significant in all absolute values, but not in percentage or nutrient density terms. Corrected Pearson correlation coefficient ranged from 0.470 to 0.952 for mean values of all nutrients, except alcohol.

CONCLUSION

This study demonstrated that FFQ is a reliable tool to assess the dietary pattern in FH patients.

Basal plasma concentrations of plant sterols can predict LDL-C response to sitosterol in patients with familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH) is associated with a high risk of coronary heart disease. Pharmacological treatment and diet are both essential for the management of FH. Foods rich in plant sterols (PS) may play an important role in the treatment of patients with these disorders.

OBJECTIVE

To test the effect of the intake of PS on low-density lipoprotein (LDL) concentration, endothelial function (EF) and LDL particle size in 30 patients with FH.

DESIGN

Randomized and crossover dietary intervention study.

SETTING

Tertiary outpatient care.

SUBJECTS

Thirty-eight were recruited, but only 30 were subjected to four low-fat dietary intervention periods, each of 4 weeks.

METHODS

Each intervention had a different content of cholesterol (<150 or 300 mg/day) and sitosterol (<1 or 2 g/day). Lipid response, EF and LDL particle size were analysed after the intervention.

RESULTS

Plasma sitosterol/cholesterol ratio was higher during both plant sterol-rich periods than during the low plant sterols periods. Basal sitosterol concentrations predicted the LDL-cholesterol response during the intake of plant sterol-enriched diets. The change in LDL-cholesterol was significantly greater in subjects in the upper and intermediate tertiles of basal plasma sitosterol concentrations (-21+/-8 mg/dl, P=0.03; -19+/-7 mg/dl, P=0.04, respectively) than in subjects in the lower tertile (8+/-5 mg/dl) when they changed from a low cholesterol diet to a low cholesterol plus plant sterol diet.

CONCLUSION

Our study demonstrates that basal sitosterol values can predict hypolipidemic response in patients with FH.

Tendon Xanthomas in Familial Hypercholesterolemia Are Associated With Cardiovascular Risk Independently of the Low-Density Lipoprotein Receptor Gene Mutation

OBJECTIVE

To investigate the significance of tendon xanthomas (TX) in heterozygous subjects with familial hypercholesterolemia (hFH).

METHODS AND RESULTS

951 men and women with genetic diagnosis of hFH were studied, of whom 278 (29.2%) presented TX. TX frequency increased with age from 6.9% in subjects 20 to 30 years to 38.3% at 51 to 60 years, with a decrease in those older than 60 years. Total and low-density lipoprotein (LDL) cholesterol were higher in TX+ than in TX- subjects (439.0+/-78.5 mg/dL and 363.1+/-76.5 mg/dL versus 400.6+/-73.4 and 323.3+/-71.0, respectively; P=0.001). High-density lipoprotein (HDL) cholesterol was lower in TX+ than in TX- subjects (50.4+/-15.0 mg/dL versus 53.1+/-14.8 mg/dL; P=0.005). Lp(a), apolipoprotein E genotype, and type of LDL receptor gene mutation showed no differences between groups. 102 TX+ reported premature cardiovascular disease (CVD) (36.7%) versus 93 TX- (13.8%) (P=0.001). The relative odds for premature CVD were higher in women (4.49 versus 2.26), and increased in hFH younger than 51 years to 3.60 (95% CI, 1.703 to 7.608) in men and to 17.1 (95% CI, 2.697 to 108.920) in women. In the multivariate analysis, age, male sex, LDL cholesterol, and hypertension showed significant positive association with TX, whereas body mass index showed negative association with TX.

CONCLUSIONS

TX are associated with cardiovascular risk factors and higher CVD, indicating that their detection indicates the need for more aggressive lipid-lowering intervention.

The use of Achilles tendon sonography to distinguish familial hypercholesterolemia from other genetic dyslipidemias

OBJECTIVE

Achilles tendon (AT) xanthomas, specific for familial hypercholesterolemia (FH), may be clinically undetectable. We assessed the usefulness of AT sonography in the diagnosis of FH.

METHODS AND RESULTS

Sonographic AT characteristics were evaluated in 127 subjects with FH (81 genetically ascertained), 84 familial combined hyperlipidemia, 79 polygenic hypercholesterolemia, and 88 normolipidemic controls. Abnormal echostructure (sonographic xanthoma) was noted only in FH. AT thickness was higher (P<0.001) in FH men and women compared with all of the other groups and, in FH mutation carriers but not in others, correlated positively with low-density lipoprotein cholesterol (r=0.345; P<0.001) and negatively with high-density lipoprotein cholesterol (r=-0.265, P=0.015). Thickness thresholds for the diagnosis of FH with specificity >80%, as were derived from receiver operating curves, were 5.3 and 5.7 mm in men < and >45 years, and 4.8 and 4.9 mm in women < and >50 years, respectively. In FH mutation carriers, sonographic findings increased the clinical diagnosis of xanthomas from 35 (43%) to 55 (68%). Using thresholds in validation sets of 70 genetically identified FH and 54 dyslipidemic non-FH correctly classified 80% and 88%, respectively.

CONCLUSIONS

Sonographic AT characteristics are normal in non-FH dyslipidemias. Identification of suspected FH by ultrasound using sex- and age-specific AT thickness thresholds is recommended.

Tendon xanthomas in familial hypercholesterolemia are associated with a differential inflammatory response of macrophages to oxidized LDL

Tendon xanthomas (TX) are pathognomonic lipid deposits commonly found in familial hypercholesterolemia (FH) patients. The aim of this study was to determine whether macrophages from FH patients with TX (TX+) have higher predisposition to foam cells formation after oxidized LDL (oxLDL) overload than those from FH patients without TX (TX-), and if their differential gene expression profile could explain these different phenotypes. Total RNA pools from macrophages from FH patients TX+ and TX- were analyzed using Affymetrix oligonucleotide arrays to evaluate the gene expression profile in presence and absence of oxLDL. Also, the intracellular lipid content was measured by fluorescence flow cytometry. Results of these studies suggest that macrophages from FH subjects TX+ compared to those TX- have a differential response to oxLDL, since they show higher intracellular cholesterol ester accumulation and a differential gene expression profile. The gene array data were validated by relative quantitative real-time RT-PCR and quantitative ELISA in culture media and plasma samples. FH subjects TX+ showed increased plasma tryptase, TNF-alpha, IL-8 and IL-6 concentrations. We propose that TX formation are associated with higher intracellular lipid content, and higher inflammatory response of macrophages in response to oxLDL.

Benefits and risks assessment of simvastatin in familial hypercholesterolaemia

Familial hypercholesterolaemia (FH) is a frequent inherited monogenic disorder, associated with premature coronary artery disease. Life expectancy of FH patients is reduced by 15 - 30 years unless they are adequately treated with lipid-lowering therapy. Patients with this disorder need long-term drug therapy and the selection of treatment should be strongly based on its long-term safety and tolerability. The introduction of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors has changed the treatment of FH. Simvastatin 40 - 80 mg/day effectively reduces serum low-density lipoprotein cholesterol levels, and also reduces triglycerides with a modest rise in high-density lipoprotein cholesterol levels. Other potentially important effects, such as improvement of endothelial function, reduction of LDL oxidation and vascular inflammation, have been associated with simvastatin therapy in FH. In addition, simvastatin has been shown to abolish the progression, and even facilitate the regression of existing human atherosclerotic lesions. The safety and tolerability of simvastatin is clearly highlighted by the low rate of therapy discontinuation observed in several population-based clinical trials. Asymptomatic elevations in liver transaminase levels and myopathy are uncommon. The efficacy and tolerability of simvastatin at doses up to 80 mg/day are well-established, as well as its cost-effectiveness in the management of FH patients.

Guidelines for the diagnosis and management of heterozygous familial hypercholesterolemia

Familial hypercholesterolemia (FH) is a genetic disorder of lipoprotein metabolism characterized by very high plasma concentrations of low density lipoprotein cholesterol (LDLc), tendon xanthomas and increased risk of premature coronary heart disease (CHD). FH is a public health problem throughout the world. There are 10,000,000 people with FH worldwide, mainly heterozygotes, and approximately 85% of males and 50% of females with FH will suffer a coronary event before 65 years old if appropriate preventive efforts are not implemented. Early identification of persons with FH and their relatives, and the early start of treatment are essential issues in the prevention of premature cardiovascular disease (CVD) and death in this population. However, guidelines for the general population formally exclude FH from their diagnostic and treatment recommendations. These guidelines have been elaborated by a group of international experts with the intention to answer the main questions about heterozygous FH (heFH) subjects that physicians worldwide face in the diagnosis and management of these patients.

Benefits and risks of simvastatin in patients with familial hypercholesterolaemia

Familial hypercholesterolaemia is a frequent, inherited, monogenic disorder, associated with accelerated development of atherosclerotic disease leading to coronary artery disease. Life expectancy of patients with familial hypercholesterolaemia is reduced by 15-30 years unless they are adequately treated with lipid-lowering therapy. Given the chronic nature of this disease, the selection of a therapeutic approach should be strongly based on its long-term safety and tolerability. The introduction of HMG-CoA reductase inhibitors has revolutionised the treatment of familial hypercholesterolaemia. Simvastatin 40-80 mg/day effectively reduces serum low density lipoprotein (LDL)-cholesterol levels. Furthermore, simvastatin reduces triglycerides and mildly raises high density lipoprotein-cholesterol levels. In addition to the hypolipidaemic effect, other potentially important effects, such as improvement of endothelial function and reduction of LDL oxidation and vascular inflammation, have been associated with HMG-CoA reductase inhibitor therapy. Simvastatin has also been shown to abolish the progression, and even facilitate the regression, of existing human atherosclerotic lesions. The good safety and tolerability profile of simvastatin is clearly highlighted by the low rate of therapy discontinuation observed in several population-based clinical trials. The most common adverse events leading to the discontinuation of therapy are gastrointestinal upset and headache. Asymptomatic elevations in liver transaminase levels and myopathy are uncommon. The overwhelming clinical evidence regarding the long-term use of HMG-CoA reductase inhibitor therapy in patients with familial hypercholesterolaemia together with the long-term safety data (particularly relating to simvastatin) provide support for the use of this drug as a first-line agent when pharmacological treatment is indicated. Early intervention with simvastatin treatment can be successfully implemented with favourable economic benefits.

[Differences in clinical presentation between subjects with a phenotype of familial hypercholesterolemia determined by defects in the LDL-receptor and defects in Apo B-100]

INTRODUCTION AND OBJECTIVES

Familial hypercholesterolemia and familial defective Apo B-100 are phenotypically indistinguishable. At present they can be distinguished by genetic analysis. PATIENTS AND METHODç We compared the clinical features of 13 subjects with familial defective Apo B-100 and 39 subjects with familial hypercholesterolemia. We used data from first degree relatives to compare morbidity and mortality between the two groups.

RESULTS

We found statistically significant differences in total cholesterol and LDL cholesterol, which were lower in the familial defective Apo B-100 group (TC = 357 37.3 mg/dl vs 415 79.7 mg/dl and LDLc = 270 34.2 mg/dl vs 355 72.4 mg/dl). We found no differences in xanthomas, corneal arcus, smoking status, vascular events, blood pressure, BMI or waist/hip ratio. There were no differences between the two groups in the proportions of patients with cardiovascular disease or patients who died. We found statistically significant differences between the groups (p = 0.023) in the mean age at first vascular event (familial hypercholesterolemia and first degree relatives: 45.3 19.9 years; familial defective Apo B-100 and first degree relatives: 51.5 20.8 years).

CONCLUSIONS

We conclude that familial defective Apo B-100 results in clinically milder hypercholesterolemia than familial hypercholesterolemia, and that discerning between them could be helpful to stratify the risk in persons with hereditary hypercholesterolemia.

A common variant in the ABCA1 gene is associated with a lower risk for premature coronary heart disease in familial hypercholesterolaemia

Familial hypercholesterolaemia (FH) is a common autosomal codominant hereditary disease caused by defects in the LDL receptor (LDLR) gene, and one of the most common characteristics of affected subjects is premature coronary heart disease (CHD). In heterozygous FH patients, the clinical expression of FH is highly variable in terms of the severity of hypercholesterolaemia and the age of onset and severity of CHD. Identification of mutations in the ATP binding cassette transporter 1 (ABCA1) gene in patients with Tangier disease, who exhibit reduced HDL cholesterol and apolipoprotein A1 concentrations and premature coronary atherosclerosis, has led us to hypothesise that ABCA1 could play a key role in the onset of premature CHD in FH. In order to know if the presence of the R219K variant in the ABCA1 gene could be a protective factor for premature CHD in FH, we have determined the presence of this genetic variant by amplification by PCR and restriction analysis in a group of 374 FH subjects, with and without premature CHD. The K allele of the R219K variant was significantly more frequent in FH subjects without premature CHD (0.32, 95% CI 0.27 to 0.37) than in FH subjects with premature CHD (0.25, 95% CI 0.21 to 0.29) (p<0.05), suggesting that the genetic variant R219K in ABCA1 could influence the development and progression of atherosclerosis in FH subjects. Moreover, the K allele of the R219K polymorphism seems to modify CHD risk without important modification of plasma HDL-C levels, and it appears to be more protective for smokers than non-smokers.