Statin Therapy and Risk of Diabetes Mellitus in Aging Patients With Heterozygous Familial Hypercholesterolemia or Familial Combined Hyperlipidemia: A 10-Year Follow-Up

Association of BMI, lipid-lowering medication, and age with prevalence of type 2 diabetes in adults with heterozygous familial hypercholesterolaemia: a worldwide cross-sectional study

BACKGROUND

Statins are the cornerstone treatment for patients with heterozygous familial hypercholesterolaemia but research suggests it could increase the risk of type 2 diabetes in the general population. A low prevalence of type 2 diabetes was reported in some familial hypercholesterolaemia cohorts, raising the question of whether these patients are protected against type 2 diabetes. Obesity is a well known risk factor for the development of type 2 diabetes. We aimed to investigate the associations of known key determinants of type 2 diabetes with its prevalence in people with heterozygous familial hypercholesterolaemia.

METHODS

This worldwide cross-sectional study used individual-level data from the EAS FHSC registry and included adults older than 18 years with a clinical or genetic diagnosis of heterozygous familial hypercholesterolaemia who had data available on age, BMI, and diabetes status. Those with known or suspected homozygous familial hypercholesterolaemia and type 1 diabetes were excluded. The main outcome was prevalence of type 2 diabetes overall and by WHO region, and in relation to obesity (BMI ≥30·0 kg/m2) and lipid-lowering medication as predictors. The study population was divided into 12 risk categories based on age (tertiles), obesity, and receiving statins, and the risk of type 2 diabetes was investigated using logistic regression.

FINDINGS

Among 46 683 adults with individual-level data in the FHSC registry, 24 784 with heterozygous familial hypercholesterolaemia were included in the analysis from 44 countries. 19 818 (80%) had a genetically confirmed diagnosis of heterozygous familial hypercholesterolaemia. Type 2 diabetes prevalence in the total population was 5·7% (1415 of 24 784), with 4·1% (817 of 19 818) in the genetically diagnosed cohort. Higher prevalence of type 2 diabetes was observed in the Eastern Mediterranean (58 [29·9%] of 194), South-East Asia and Western Pacific (214 [12·0%] of 1785), and the Americas (166 [8·5%] of 1955) than in Europe (excluding the Netherlands; 527 [8·0%] of 6579). Advancing age, a higher BMI category (obesity and overweight), and use of lipid-lowering medication were associated with a higher risk of type 2 diabetes, independent of sex and LDL cholesterol. Among the 12 risk categories, the probability of developing type 2 diabetes was higher in people in the highest risk category (aged 55-98 years, with obesity, and receiving statins; OR 74·42 [95% CI 47·04-117·73]) than in those in the lowest risk category (aged 18-38 years, without obesity, and not receiving statins). Those who did not have obesity, even if they were in the upper age tertile and receiving statins, had lower risk of type 2 diabetes (OR 24·42 [15·57-38·31]). The corresponding results in the genetically diagnosed cohort were OR 65·04 (40·67-104·02) for those with obesity in the highest risk category and OR 20·07 (12·73-31·65) for those without obesity.

INTERPRETATION

Adults with heterozygous familial hypercholesterolaemia in most WHO regions have a higher type 2 diabetes prevalence than in Europe. Obesity markedly increases the risk of diabetes associated with age and use of statins in these patients. Our results suggest that heterozygous familial hypercholesterolaemia does not protect against type 2 diabetes, hence managing obesity is essential to reduce type 2 diabetes in this patient population.

FUNDING

Pfizer, Amgen, MSD, Sanofi-Aventis, Daiichi-Sankyo, and Regeneron.

Interaction Between Primary Hyperlipidemias and Type 2 Diabetes: Therapeutic Implications

There is a gap of knowledge about the clinical and pathophysiological implications resulting from the interaction between primary hyperlipidemias and type 2 diabetes (T2D). Most of the existing evidence comes from sub-analyses of cohorts; scant information derives from randomized clinical trials. The expected clinical implications of T2D in patients with primary hyperlipidemias is an escalation of their already high cardiovascular risk. There is a need to accurately identify patients with this dual burden and to adequately prescribe lipid-lowering therapies, with the current advancements in newer therapeutic options. This review provides an update on the interactions of primary hyperlipidemias, such as familial combined hyperlipidemia, familial hypercholesterolemia, multifactorial chylomicronemia, lipoprotein (a), and type 2 diabetes.

Inhibiting cholesterol de novo synthesis promotes hepatocellular carcinoma progression by upregulating prostaglandin E synthase 2-mediated arachidonic acid metabolism under high fatty acid conditions

Inhibition of cholesterol de novo synthesis (DNS) by statins has controversial effects on the treatment of hepatocellular carcinoma (HCC). High fatty acid conditions have been reported to limit the effect of statins on metabolism diseases. Whether high fatty acid conditions interfere with the effect of statins on HCC remains unclear. Here, we reported that inhibiting cholesterol DNS with atorvastatin promoted the oncogenic capabilities of diethylnitrosamine (DEN) in mice fed high fatty acid diets (HFD). The combined analysis of metabolomics and transcriptomics revealed that arachidonic acid (AA) metabolism was the most significant changed pathway between mice with and without atorvastatin treatment. In vitro, in the presence of AA precursor linoleic acid (LA), atorvastatin promoted the proliferation and migration ability of HCC cell lines. However, in the absence of LA, these phenomena disappeared. TCGA and tissue microarray examination revealed that prostaglandin e synthase 2 (PTGES2), a key enzyme in AA metabolism, was associated with the poor outcome of HCC patients. Overexpression of PTGES2 promoted the proliferation and migration of HCC cell lines, and knockdown of PTGES2 inhibited the proliferation and migration of cells. Additionally, atorvastatin upregulated PTGES2 expression by enhancing Sterol-regulatory element binding protein 2 (SREBP2)-mediated transcription. Knockdown of PTGES2 reversed the proliferation and migration ability enhanced by atorvastatin. Overall, our study reveals that a high fatty acid background is one of the possible conditions limiting the application of statins in HCC, under which statins promote the progression of HCC by enhancing SREBP2-mediated PTGES2 transcription.

Statin therapy is not warranted for a person with high LDL-cholesterol on a low-carbohydrate diet

PURPOSE OF REVIEW

Although there is an extensive literature on the efficacy of the low carbohydrate diet (LCD) for weight loss and in the management of type 2 diabetes, concerns have been raised that the LCD may increase cardiovascular disease (CVD) risk by increasing the level of low-density lipoprotein cholesterol (LDL-C). We have assessed the value of LDL-C as a CVD risk factor, as well as effects of the LCD on other CVD risk factors. We have also reviewed findings that provide guidance as to whether statin therapy would be beneficial for individuals with high LDL-C on an LCD.

RECENT FINDINGS

Multiple longitudinal trials have demonstrated the safety and effectiveness of the LCD, while also providing evidence of improvements in the most reliable CVD risk factors. Recent findings have also confirmed how ineffective LDL-C is in predicting CVD risk.

SUMMARY

Extensive research has demonstrated the efficacy of the LCD to improve the most robust CVD risk factors, such as hyperglycemia, hypertension, and atherogenic dyslipidemia. Our review of the literature indicates that statin therapy for both primary and secondary prevention of CVD is not warranted for individuals on an LCD with elevated LDL-C who have achieved a low triglyceride/HDL ratio.

Diabetes and Familial Hypercholesterolemia: Interplay between Lipid and Glucose Metabolism

Familial hypercholesterolemia (FH) is a genetic disease characterized by high low-density lipoprotein (LDL) cholesterol (LDL-c) concentrations that increase cardiovascular risk and cause premature death. The most frequent cause of the disease is a mutation in the LDL receptor (LDLR) gene. Diabetes is also associated with an increased risk of cardiovascular disease and mortality. People with FH seem to be protected from developing diabetes, whereas cholesterol-lowering treatments such as statins are associated with an increased risk of the disease. One of the hypotheses to explain this is based on the toxicity of LDL particles on insulin-secreting pancreatic β-cells, and their uptake by the latter, mediated by the LDLR. A healthy lifestyle and a relatively low body mass index in people with FH have also been proposed as explanations. Its association with superimposed diabetes modifies the phenotype of FH, both regarding the lipid profile and cardiovascular risk. However, findings regarding the association and interplay between these two diseases are conflicting. The present review summarizes the existing evidence and discusses knowledge gaps on the matter.

Secondary findings from whole-exome sequencing data in families with familial combined hyperlipidemia (FCHL)

Background

During the interpretation of genome sequencing data, some types of secondary findings are identified that are located in genes that do not appear to be related to the causes of the primary disease. Although these are not the primary targets for evaluation, they have a high risk for some diseases different from the primary disease. Therefore, they can be vital for preventing and intervention from such disease.

Results

Here, we analyzed secondary findings obtained from WES in 6 families with FCHL disease who had an autosomal-dominant pattern based on their pedigrees. These finding are found in CDKAL1, ITGA2, FAM111A, WNK4, PTGIS, SCN10, TBX20, DCHS1, ANK2 and ABCA1 genes.

Conclusions

Secondary findings are very important and must be considered different variants from sequencing results in a diagnostic setting. Although we have considered these variants as secondary findings, some of them may be related to the primary disease.

Incidence of type 2 diabetes in familial combined hyperlipidemia

OBJECTIVE

Familial combined hyperlipidemia (FCHL) is common among survivors of a premature myocardial infarction. FCHL patients are characterized by visceral obesity, fatty liver, and insulin resistance. The aim of the present study was to determine the incidence and determinants of type 2 diabetes (T2D) in a longitudinal cohort of FCHL pedigrees.

RESEARCH DESIGN AND METHODS

FCHL patients, their unaffected relatives and spouses included in our baseline cohort in 1998-2005 (n=596) were re-invited to determine the incidence of self-reported T2D (that was confirmed by medical records), used as the primary outcome measure. The Fatty Liver Index (FLI) and Homeostasis Model Assessment Insulin Resistance (HOMA2-IR) were used as markers of fatty liver and insulin resistance, respectively. A subset of the original cohort underwent ultrasound of the liver, and subcutaneous and visceral fat in 2002-2005 (n=275; 'ultrasound subcohort').

RESULTS

Follow-up data (median: 15 years) was acquired for 76%. The incidence rate of T2D was significantly higher in FCHL patients compared with spouses (19.2 per 1000 person-years vs 2.8 per 1000 person-years; HR : 6.3, 95% CI: 2.4 to 16.8), whereas no differences were observed between unaffected relatives and spouses (HR: 0.9, 95% CI: 0.3 to 2.6). Cox's proportional hazard regression analyses showed that baseline HOMA2-IR and FLI≥60, but not waist circumference, BMI, or the FCHL affected state, were independently associated with incident T2D. Similar results were obtained in the ultrasound subcohort (median follow-up: 11 years), in which baseline HOMA2-IR and fatty liver (assessed by ultrasound) were independently associated with incident T2D.

CONCLUSION

This study further corroborates the suggestion that the liver plays a central role in the pathogenesis of cardiometabolic complications in FCHL. It supports periodical screening for T2D in this high-risk population.

Familial combined hyperlipidemia: An overview of the underlying molecular mechanisms and therapeutic strategies

Among different types of dyslipidemia, familial combined hyperlipidemia (FCHL) is the most common genetic disorder, which is characterized by at least two different forms of lipid abnormalities: hypercholesterolemia and hypertriglyceridemia. FCHL is an important cause of cardiovascular diseases. FCHL is a heterogeneous condition linked with some metabolic defects that are closely associated with FCHL. These metabolic features include dysfunctional adipose tissue, delayed clearance of triglyceride-rich lipoproteins, overproduction of very low-density lipoprotein and hepatic lipids, and defect in the clearance of low-density lipoprotein particles. There are also some genes associated with FCHL such as those affecting the metabolism and clearance of plasma lipoprotein particles. Due to the high prevalence of FCHL especially in cardiovascular patients, targeted treatment is ideal but this necessitates identification of the genetic background of patients. This review describes the metabolic pathways and associated genes that are implicated in FCHL pathogenesis. We also review existing and novel treatment options for FCHL. © 2019 IUBMB Life, 71(9):1221-1229, 2019.

Clinical and genetic characteristics of familial hypercholesterolemia patients with type 2 diabetes

PURPOSE

Though type 2 diabetes mellitus (T2DM) is an important and independent risk factor for coronary artery disease (CAD) in the general population, the impact of T2DM on CAD in patients with familial hypercholesterolemia (FH) is less understood. Thus, the current study aimed to examine the features of FH patients with T2DM and explore the effects of T2DM on CAD in FH.

METHODS

A total of 289 clinical heterozygous FH (HeFH) patients diagnosed with Dutch Lipid Clinic Criteria were consecutively recruited and divided into a T2DM group (n = 58) and non-T2DM group (n = 231). Clinical characteristics and laboratory findings were compared between the two groups. Target exome sequencing was used for gene mutation analysis.

RESULTS

HeFH patients with T2DM had significantly higher levels of triglycerides, body mass index and free fatty acids than did non-T2DM patients; moreover, patients with T2DM more frequently exhibited hypertension. However, the spectrum of FH-causing mutations was not significantly different (p = 0.061). Notably, patients with T2DM had higher prevalence of CAD (p = 0.012) and higher Gensini Score (p = 0.002). The regression analysis confirmed that HbA1c was an independent risk factor for both the presence and severity of CAD [OR 2.321 (1.098-4.904), p = 0.027; OR 1.349 (1.032-1.762), p = 0.028, respectively] in patients with HeFH.

CONCLUSIONS

Although there were not many differences in the clinical, lipid and genetic aspects of HeFH patients with and without T2DM, T2DM and HbA1c were associated with worse coronary lesions, suggesting that diabetes and the degree of blood glucose control are also important determinants of cardiovascular disease in these patients.

The biochemical and genetic diagnosis of lipid disorders

PURPOSE OF REVIEW

To examine recent advances in our knowledge on the diagnosis of lipid disorders.

RECENT FINDINGS

Fasting values above the 99th percentile for direct LDL-cholesterol (LDL-C), lipoprotein(a), and triglycerides are greater than 225 mg/dl, greater than 160 mg/dl, and greater than 500 mg/dl (>5.82, >394, and >5.65 mmol/l), respectively, whereas such values for plasma lathosterol, β-sitosterol, and cholestanol are greater than 8.0, 8.0, and 5.0 mg/l (>0.021, 0.019, and 0.013 mmol/l), respectively. Values below the first percentile for LDL-C are less than 40 mg/dl (<1.03 mmol/l) and for HDL-cholesterol (HDL-C) less than 25 mg/dl (<0.65 mmol/l) in men and less than 30 mg/dl (<0.78 mmol/l) in women, respectively. The above values can predispose to premature CVD, pancreatitis, neurologic disease, and kidney failure, and may be associated with monogenic lipid disorders. In the absence of secondary causes including diabetes or kidney, liver, or thyroid disease, consideration should be given to sequencing the following genes: ABCA1, ABCG5, ABCG8, APOA1, APOA5, APOB, APOC2, APOE, CETP, CYP27A1, GPIHBP1, LCAT, LDLR, LDLRAP1, LIPA, LIPC, LMF1, LPL, MTTP, PCSK9, SCARB1, and STAP1.

SUMMARY

Recent data indicate that secondary causes and a wider range of conditions need to be considered in identifying the underlying causes of hypercholesterolemia, hypertriglyceridemia, hyperalphalipoproteinemia, hypobetalipoproteinemia, and HDL deficiency. Identifying such disorders allows for a more precise assessment of prognosis and the formulation of optimal therapy.

Dyslipidemias in clinical practice

Most dyslipidemic conditions have been linked to an increased risk of cardiovascular disease. Over the past few years major advances have been made regarding the genetic and metabolic basis of dyslipidemias. Detailed characterization of the genetic basis of familial lipid disorders and knowledge concerning the effects of environmental factors on the expression of dyslipidemias have increased substantially, contributing to a better diagnosis in individual patients. In addition to these developments, therapeutic options to lower cholesterol levels in clinical practice have expanded even further in patients with familial hypercholesterolemia and in subjects with cardiovascular disease. Finally, promising upcoming therapeutic lipid lowering strategies will be reviewed. All these advances will be discussed in relation to current clinical practice with special focus on common lipid disorders including familial dyslipidemias.