The metabolic syndrome: similar deleterious impact on all-cause mortality in hypertensive and normotensive subjects

The Metabolic Syndrome, a Human Disease

This review focuses on the question of metabolic syndrome (MS) being a complex, but essentially monophyletic, galaxy of associated diseases/disorders, or just a syndrome of related but rather independent pathologies. The human nature of MS (its exceptionality in Nature and its close interdependence with human action and evolution) is presented and discussed. The text also describes the close interdependence of its components, with special emphasis on the description of their interrelations (including their syndromic development and recruitment), as well as their consequences upon energy handling and partition. The main theories on MS's origin and development are presented in relation to hepatic steatosis, type 2 diabetes, and obesity, but encompass most of the MS components described so far. The differential effects of sex and its biological consequences are considered under the light of human social needs and evolution, which are also directly related to MS epidemiology, severity, and relations with senescence. The triggering and maintenance factors of MS are discussed, with especial emphasis on inflammation, a complex process affecting different levels of organization and which is a critical element for MS development. Inflammation is also related to the operation of connective tissue (including the adipose organ) and the widely studied and acknowledged influence of diet. The role of diet composition, including the transcendence of the anaplerotic maintenance of the Krebs cycle from dietary amino acid supply (and its timing), is developed in the context of testosterone and β-estradiol control of the insulin-glycaemia hepatic core system of carbohydrate-triacylglycerol energy handling. The high probability of MS acting as a unique complex biological control system (essentially monophyletic) is presented, together with additional perspectives/considerations on the treatment of this 'very' human disease.

Endothelial dysfunction, platelet hyperactivity, hypertension, and the metabolic syndrome: molecular insights and combating strategies

Metabolic syndrome (MetS) is a multifaceted condition that increases the possibility of developing atherosclerotic cardiovascular disease. MetS includes obesity, hypertension, dyslipidemia, hyperglycemia, endothelial dysfunction, and platelet hyperactivity. There is a concerning rise in the occurrence and frequency of MetS globally. The rising incidence and severity of MetS need a proactive, multipronged strategy for identifying and treating those affected. For many MetS patients, achieving recommended goals for healthy fat intake, blood pressure control, and blood glucose management may require a combination of medicine therapy, lifestyles, nutraceuticals, and others. However, it is essential to note that lifestyle modification should be the first-line therapy for MetS. In addition, MetS requires pharmacological, nutraceutical, or other interventions. This review aimed to bring together the etiology, molecular mechanisms, and dietary strategies to combat hypertension, endothelial dysfunction, and platelet dysfunction in individuals with MetS.

Links between Metabolic Syndrome and Hypertension: The Relationship with the Current Antidiabetic Drugs

Hypertension poses a significant burden in the general population, being responsible for increasing cardiovascular morbidity and mortality, leading to adverse outcomes. Moreover, the association of hypertension with dyslipidaemia, obesity, and insulin resistance, also known as metabolic syndrome, further increases the overall cardiovascular risk of an individual. The complex pathophysiological overlap between the components of the metabolic syndrome may in part explain how novel antidiabetic drugs express pleiotropic effects. Taking into consideration that a significant proportion of patients do not achieve target blood pressure values or glucose levels, more efforts need to be undertaken to increase awareness among patients and physicians. Novel drugs, such as incretin-based therapies and renal glucose reuptake inhibitors, show promising results in decreasing cardiovascular events in patients with metabolic syndrome. The effects of sodium-glucose co-transporter-2 inhibitors are expressed at different levels, including renoprotection through glucosuria, natriuresis and decreased intraglomerular pressure, metabolic effects such as enhanced insulin sensitivity, cardiac protection through decreased myocardial oxidative stress and, to a lesser extent, decreased blood pressure values. These pleiotropic effects are also observed after treatment with glucagon-like peptide-1 receptor agonists, positively influencing the cardiovascular outcomes of patients with metabolic syndrome. The initial combination of the two classes may be the best choice in patients with type 2 diabetes mellitus and multiple cardiovascular risk factors because of their complementary mechanisms of action. In addition, the novel mineralocorticoid receptor antagonists show significant cardio-renal benefits, as well as anti-inflammatory and anti-fibrotic effects. Overall, the key to better control of hypertension in patients with metabolic syndrome is to consider targeting multiple pathogenic mechanisms, using a combination of the different therapeutic agents, as well as drastic lifestyle changes. This article will briefly summarize the association of hypertension with metabolic syndrome, as well as take into account the influence of antidiabetic drugs on blood pressure control.

Epigenetic Mechanisms Involved in Inflammaging-Associated Hypertension

PURPOSE OF REVIEW

This review summarizes the involvement of inflammaging in vascular damage with focus on the epigenetic mechanisms by which inflammaging-induced hypertension is triggered.

RECENT FINDINGS

Inflammaging in hypertension is a complex condition associated with the production of inflammatory mediators by the immune cells, enhancement of oxidative stress, and tissue remodeling in vascular smooth muscle cells and endothelial cells. Cellular processes are numerous, including inflammasome assembly and cell senescence which may involve mitochondrial dysfunction, autophagy, DNA damage response, dysbiosis, and many others. More recently, a series of noncoding RNAs, mainly microRNAs, have been described as possessing epigenetic actions on the regulation of inflammasome-related hypertension, emerging as a promising therapeutic strategy. Although there are a variety of pharmacological agents that effectively regulate inflammaging-related hypertension, a deeper understanding of the epigenetic events behind the control of vessel deterioration is needed for the treatment or even to prevent the disease onset.

Association of metabolic syndrome with cardiovascular outcomes in hypertensive patients: a systematic review and meta-analysis

PURPOSE

The association between metabolic syndrome (MetS) and cardiovascular outcomes in patients with hypertension is still controversial. This meta-analysis sought to evaluate the association of MetS with cardiovascular outcomes in hypertensive patients.

METHODS

Two authors comprehensively searched PubMed and Embase databases from their inception to April 18, 2020 for the longitudinal studies that evaluated the association of MetS with cardiovascular outcomes in patients with hypertension. The main outcomes were major adverse cardiovascular events (myocardial infarction, revascularization, stroke, hospitalization due to heart failure, etc.) and stroke.

RESULTS

Eight studies consisting of 36,614 hypertensive patients were identified and analyzed. Meta-analysis indicated that MetS was associated with an increased risk of major adverse cardiovascular events (risk ratio [RR] 1.55; 95% confidence intervals [CI] 1.28-1.87), cardiovascular mortality (RR 1.44; 95%CI 1.13-1.82), and stroke (RR 1.46; 95%CI 1.22-1.75), respectively. Sensitivity analysis further confirmed the robustness of the prognostic value of MetS.

CONCLUSIONS

MetS is associated with higher risk of major adverse cardiovascular events, cardiovascular mortality, and stroke in patients with hypertension. Determination of MetS may contribute to improving cardiovascular risk stratification in hypertension.

A Predictive Model of Metabolic Syndrome by Medical Examination: Evidence from an 8-Year Chinese Cohort

PURPOSE

To develop a predictive model for the risk of metabolic syndrome (MetS).

PATIENTS AND METHODS

Totally, 1556 residents without MetS were finally included in 2006 and they were observed for 8 years to check who developed MetS. Univariate and multivariate logistic regression analyses was adopted to explore the risk factors of MetS and develop the predictive model that used the medical examination information of MetS risk after 8 years. The receiver operating characteristic (ROC) curve was drawn to assess the predictive capacity of the model.

RESULTS

The risk of MetS in overweight, prehypertension, hypertension subjects were 4.610 [95% confidence interval (CI): 2.415 to 8.800], 2.759 (95% CI: 1.519 to 5.011) and 3.589 (95% CI: 1.672 to 7.706) times higher than that in controls, respectively. The risk of MetS in people with high-density lipoprotein (HDL) <1.10 mmol/L was 3.716-fold in comparison with HDL ≥1.55 mmol/L [odds risk (OR) = 3.716, 95% CI: 1.483 to 9.313]. Individuals with fatty liver had a higher risk of MetS (OR = 2.577, 95% CI: 1.472 to 4.512). The AUC of the predictive model was 0.831 (95% CI: 0.798 to 0.865), with the sensitivity of 0.898 (95% CI: 0.831 to 0.941) and the specificity of 0.676 (95% CI: 0.651 to 0.700).

CONCLUSION

The model performed well predictive power for the risk of MetS, which may provide a reference for clinicians to identify high-risk groups early.

Hypertension in Metabolic Syndrome: Novel Insights

BACKGROUND

Metabolic syndrome (MetS) is characterized by the simultaneous presence of obesity, hypertension, dyslipidemia and hyperglycemia in an individual, leading to increased cardiovascular disease (CVD) risk. It affects almost 35% of the US adult population, while its prevalence increases with age. Elevated blood pressure is the most frequent component of the syndrome; however, until now, the optimal antihypertensive regiment has not been defined.

OBJECTIVE

The purpose of this review is to present the proposed definitions for the metabolic syndrome, as well as the prevalence of hypertension in this condition. Moreover, evidence regarding the metabolic properties of the different antihypertensive drug classes and their effect on MetS will be displayed.

METHODS

A comprehensive review of the literature was performed to identify data from clinical studies for the prevalence, pathophysiology and treatment of hypertension in the metabolic syndrome.

RESULTS

Hypertension is present in almost 80% of patients with metabolic syndrome. The use of thiazide diuretics and b-blockers has been discouraged in this population; however, new evidence suggests their use under specific conditions. Calcium channel blockers seem to exert a neutral effect on MetS, while renin-angiotensin system inhibitors are believed to be of the most benefit, although differences exist between the different agents of this category.

CONCLUSION

Controversy still exists regarding the optimal antihypertensive treatment for hypertension in MetS. Due to the high prevalence of hypertension in this population, more data from clinical trials are needed in the future.

Association of metabolic syndrome and its components with all-cause and cardiovascular mortality in the elderly: A meta-analysis of prospective cohort studies

There is increasing evidence regarding the relationship between metabolic syndrome and mortality. However, previous research examining metabolic syndrome and mortality in older populations has produced mixed results. In addition, there is a clear need to identify and manage individual components of metabolic syndrome to decrease cardiovascular disease (CVD) mortality. In this meta-analysis, we searched the MEDLINE databases using PubMed, Cochrane Library, and EMBASE databases. Based on 20 prospective cohort studies, metabolic syndrome was associated with a higher risk of all-cause mortality [relative risk (RR), 1.23; 95% confidence interval (CI), 1.15-1.32; I = 55.9%] and CVD mortality (RR, 1.24; 95% CI, 1.11-1.39; I = 58.1%). The risk estimates of all-cause mortality for single components of metabolic syndrome were significant for higher values of waist circumference or body mass index (RR, 0.94; 95% CI, 0.88-1.00), higher values of blood glucose (RR, 1.19; 95% CI, 1.05-1.34), and lower values of high-density lipoprotein (HDL) cholesterol (RR, 1.11; 95% CI, 1.02-1.21). In the elderly population, metabolic syndrome was associated with an increased risk of all-cause and CVD mortality. Among the individual components of metabolic syndrome, increased blood glucose and HDL cholesterol levels were significantly associated with increased mortality. However, older obese or overweight individuals may have a decreased mortality risk. Thus, the findings of the current meta-analysis raise questions about the utility of the definition of metabolic syndrome in predicting all-cause mortality and CVD mortality in the elderly population.

Metabolic syndrome, independent of its components, affects adversely cardiovascular morbidity in essential hypertensives

BACKGROUND

The metabolic syndrome (MS) is widespread among hypertensive patients. However, the net impact of MS on major atherosclerotic events beyond the cardiovascular risk imposed by its individual components remains controversial in this group. We sought to assess both the independent and incremental prognostic role of MS for unfavorable cardiovascular events in a cohort of essential hypertensives.

METHODS

We followed up 2176 essential hypertensives free of cardiovascular disease for a median period of 40 months. All subjects had at least one annual visit. MS was defined according to the updated NCEP III criteria. Endpoint of interest was the incidence of stroke, coronary artery disease (CAD) and their composite.

RESULTS

MS was present at baseline in 819 hypertensives (37.6%). MS group presented increased prevalence of resistant hypertension in comparison to MS free group (18.4% versus 10.6%, p < 0.001). The incidence of the composite end-point was 3.1% (69 events) across the follow-up period. Patients with MS were more likely to experience major adverse cardiovascular events (MACE) in comparison to reference category (3.7% versus 1.9%, log rank p = 0.024). While MS was an independent predictor for MACE, none of the individual components of the syndrome was associated independently with the endpoint. MS provided incremental discriminative value (Harrell's c, p < 0.05 for all) over individual risk factors for the incidence of MACE.

CONCLUSIONS

MS predicts adverse cardiovascular events in hypertensives incrementally of its individual components. Early identification of MS in this population may enable more accurate prediction of future cardiovascular risk and could implement more efficient strategies in terms of primary prevention.

Metabolic syndrome in hypertensive patients: An unholy alliance

For many years, it has been recognized that hypertension tends to cluster with various anthropometric and metabolic abnormalities including abdominal obesity, elevated triglycerides, reduced high-density lipoprotein cholesterol, glucose intolerance, insulin resistance and hyperuricemia. This constellation of various conditions has been transformed from a pathophysiological concept to a clinical entity, which has been defined metabolic syndrome (MetS). The consequences of the MetS have been difficult to assess without commonly accepted criteria to diagnose it. For this reason, on 2009 the International Diabetes Federation, the American Heart Association and other scientific organizations proposed a unified MetS definition. The incidence of the MetS has been increasing worldwide in parallel with an increase in overweight and obesity. The epidemic proportion reached by the MetS represents a major public health challenge, because several lines of evidence showed that the MetS, even without type 2 diabetes, confers an increased risk of cardiovascular morbidity and mortality in different populations including also hypertensive patients. It is likely that the enhanced cardiovascular risk associated with MetS in patients with high blood pressure may be largely mediated through an increased prevalence of preclinical cardiovascular and renal changes, such as left ventricular hypertrophy, early carotid atherosclerosis, impaired aortic elasticity, hypertensive retinopathy and microalbuminuria. Indeed, many reports support this notion, showing that hypertensive patients with MetS exhibit, more often than those without it, these early signs of end organ damage, most of which are recognized as significant independent predictors of adverse cardiovascular outcomes.

Work economic sectors and cardiovascular risk factors: cross-sectional analysis based on the RECORD Study

Background

Little is known on the comparative effect of work economic sectors on multiple cardiovascular risk factors. Such information may be useful to target Public health interventions, e.g., through the occupational medicine. We investigated whether and how a large panel of cardiovascular risk factors varied between 11 work economic sectors.

Methods

Data on 4360 participants from the French RECORD Study geolocated at their residence were analyzed. Ten outcomes were assessed: body mass index (BMI), waist circumference, systolic and diastolic blood pressure (BP), pulse pressure, total cholesterol, glycaemia, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and resting heart rate. Multilevel linear regression models stratified by sex and adjusted for individual and neighborhood sociodemographic characteristics were estimated.

Results

Among men, the Health and social work sector was found to be the most protective sector for BMI, waist circumference, and glycaemia (while the Construction sector and the Transport and communications sector tended to be unfavorable for these outcomes). The Health and social work sector was also associated with higher HDL cholesterol among men. However, men working in the Health and social work sector showed the highest systolic BP and pulse pressure. Women working in the Health and social work sector had the highest BMI, the largest waist circumference, and the most elevated systolic and diastolic BP. The Commercial and repair of vehicles sector, the Transport and communication sector, and the Collective, social, and personal services sector were associated with a more favorable profile for these risk factors among women.

Conclusion

Work economic sectors contribute to shape metabolic and cardiovascular parameters after adjustment for individual/neighborhood sociodemographic characteristics. However, patterns of associations varied strikingly according to the risk factor examined and between men and women. Such findings may be useful to target interventions for reducing cardiovascular risk, e.g., through the occupational medicine.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2458-14-750) contains supplementary material, which is available to authorized users.

Comparison of different metabolic syndrome definitions and risks of incident cardiovascular events in the elderly

The metabolic syndrome is associated with increased cardiovascular risk, and its prevalence increases with age. Various definitions of the metabolic syndrome exist, but whether some definitions are more predictive of future cardiovascular events in the elderly is unclear. We compared the risk of incident cardiovascular events in elderly individuals at least 65 years old from the Cardiovascular Health Study with and without the metabolic syndrome as defined by the European Group for the Study of Insulin Resistance (EGIR), National Cholesterol Education Program (NCEP)/American Heart Association (AHA), American Association of Clinical Endocrinologists, International Diabetes Federation (IDF), and modified World Health Organization (WHO) criteria (n = 3390). Participants were without baseline diabetes or cardiovascular disease. Except for EGIR, all definitions of the metabolic syndrome were significantly associated with increased risk of incident cardiovascular (coronary or cerebrovascular) events. Adjusted hazard ratios (HRs) for risk of incident cardiovascular events as defined by the modified WHO, NCEP/AHA, American Association of Clinical Endocrinologists, and IDF criteria ranged from 1.153 (P = .045) for NCEP/AHA to 1.314 (P < .001) for IDF, with 95% confidence interval (CI) ranging from 1.003 to 1.503. Adjusted HR for EGIR was 1.087 (95% CI, 0.908-1.301; P = .362). Similarly, all definitions of the metabolic syndrome were significantly associated with incident coronary events except for the EGIR definition. Only the modified WHO definition was associated with increased risk for cerebrovascular events (adjusted HR, 1.301; 95% CI, 1.038-1.631; P = .022). Although all metabolic syndrome definitions except EGIR were associated with total cardiovascular events and coronary events, only the modified WHO definition was also associated with risk of cerebrovascular events.

Association between metabolic syndrome and carotid atherosclerosis in individuals without diabetes based on the oral glucose tolerance test

INTRODUCTION

Whether or not metabolic syndrome is predictive of atherosclerotic disorders may depend on the population studied. We investigated whether metabolic syndrome is associated with carotid atherosclerosis in individuals who were shown not to have diabetes mellitus based on results of the 75-g oral glucose tolerance test (OGTT).

METHODS AND RESULTS

Between 1994 and 2003, 3904 individuals underwent general health screening that included the OGTT. Among these 3904 individuals, 3679 had a fasting plasma glucose of <126 mg/dL (subgroup 1), and 3488 had a 2-h post-OGTT glucose value of <200mg/dL (subgroup 2). In both subgroups, metabolic syndrome was found to be a risk factor for carotid plaque and for carotid intima-media thickening in men, and tended to be a risk factor for carotid plaque in women after adjustment for age. Among 3473 individuals who had both a fasting plasma glucose value of <126 mg/dL and a 2-h post-OGTT glucose of <200mg/dL, 2440 did not have hypertension, which was defined as systolic and diastolic blood pressure of <140/90 mmHg and absence of use of anti-hypertensive medication. In these non-diabetic non-hypertensive individuals, the association between metabolic syndrome and carotid plaque or carotid intima-media thickening was not statistically significant even with adjustment only for age.

CONCLUSIONS

In men who did not have impaired fasting glycemia and/or in those without impaired glucose tolerance, metabolic syndrome was a predictor of carotid atherosclerosis after age adjustment, although metabolic syndrome was not found to be a predictor of carotid atherosclerosis when hypertensive individuals were excluded from the study population.

Recent advances in metabolic syndrome and cardiovascular disease

Metabolic syndrome is defined as an association of central obesity and several other cardiometabolic risk factors. Dysfunctional visceral adipose tissue and inflammatory status appear to be involved in its genesis. New definitions have decreased the threshold for glycaemia and one has lowered the threshold for waist circumference, leading to an increase in the prevalence of metabolic syndrome. However, the impact on mortality with these new definitions is lower than with the National Cholesterol Education Program-Adult Treatment Panel III 2001 definition. An increase in waist circumference, along with increased glycaemia, triglycerides and/or blood pressure is more highly associated with an increased risk of mortality than are other associations, while a decrease in high density lipoprotein cholesterol increases risk of coronary heart disease. The risk of sudden death and stroke is particularly notable with metabolic syndrome. Metabolic syndrome is associated with an increase in heart rate, pulse pressure, arterial stiffness and left ventricular hypertrophy, impairment of diastolic function, enlargement of the left atrium and atrial fibrillation. In the 2007 European recommendations for the management of high blood pressure, metabolic syndrome is now taken into consideration for both risk stratification and in selecting the optimal therapeutic strategy for arterial hypertension.