Differences in Prevalence and Severity of Coronary Artery Disease by Three Metabolic Syndrome Definitions

How to Define Pathogenicity, Health, and Disease?

Scientific and clinical communities produce ever increasing amounts of data and details about health and disease. Our ability to understand and utilize this information is limited because of imprecise language and lack of well-defined concepts. This problem involves also the principal concepts of health, disease, and pathogenicity. Here, a systematic model is presented for pathogenicity, as well as for health and disease. It has three components: extent, modulation, and severity, which jointly define the continuum of pathogenicity. The model is population based, and once implemented, it can be used for numerous purposes such as diagnosis, patient stratification, prognosis, finding phenotype-genotype correlations, or explaining adverse drug reactions. The new model has several benefits including health economy by allowing evidence-based personalized/precision medicine.

Establishment and application of a new diagnostic definition of metabolic syndrome in the Shantou region of southern China

The existing definitions of metabolic syndrome (MetS) may not be fully appropriate for the Shantou population because of ethnic and regional differences. We sought to establish a 95% multivariate medical reference range (MMRR) model for diagnosing MetS in Shantou adults and to evaluate the prevalence of MetS by the MMRR, JCDCG (the Chinese Guidelines), and International Diabetes Federation (IDF) criteria. A total of 4,580 participants were recruited in Shantou, southern China. We developed a MMRR model based on the combinatorial indicatrixes method for three categorized indicatrixes. According to the developed MMRR criteria, men (women) in Shantou have MetS by meeting 3 or more of the following: waist circumference ≥89 (81) cm; triglycerides level ≥1.73 (1.64) mmol/L; high-density lipoprotein cholesterol level ≤1.07 (1.05) mmol/L; blood pressure ≥138/89 (136/85) mmHg; and fasting plasma glucose ≥5.8 (5.7) mmol/L. The agreement of the MMRR with JCDCG and IDF criteria was "substantial" (both κ > 0.68), but the recommended reference values and proportion of individual components of MetS defined by the 3 criteria differed. The population-based MMRR criteria may be appropriate for diagnosing MetS in Shantou population and the model might be useful for generalization to other geographic regions.

Effects of the metabolic syndrome on right heart mechanics and function

BACKGROUND

We sought to investigate right ventricular (RV) and right atrial (RA) deformation obtained using 3-dimensional echocardiography (3DE) and 2-dimensional (2DE) strain in subjects with the metabolic syndrome (MS).

METHODS

This cross-sectional study included 108 untreated subjects with the MS and 75 control subjects similar according to sex and age. The MS was defined by the presence ≥ 3 American Heart Association/National Heart, Lung, and Blood Institute criteria. All the subjects underwent adequate laboratory analyses and complete 2DE and 3DE examination.

RESULTS

2DE global longitudinal strain of the RV was significantly decreased in the MS group compared with the control subjects (-24 ± 5 vs -27 ± 5%; P < 0.001). Similar results were obtained for the RA longitudinal strain (40 ± 5 vs 44 ± 7%; P < 0.001). Systolic and early diastolic RV and RA strain rates were decreased, whereas late diastolic strain rates were increased among the MS participants compared with the control subjects. 3DE RV ejection fraction was significantly decreased in the MS subjects (55 ± 4 vs 58 ± 4%; P < 0.001). The multivariate analysis of MS criteria showed that systolic blood pressure, waist circumference, and fasting glucose were independently associated with RV and/or RA myocardial function and deformation.

CONCLUSIONS

RV mechanics and RA mechanics, assessed using 3DE and 2DE strain, were significantly deteriorated in the MS subjects. Among all MS risk factors, systolic blood pressure, abdominal circumference, and fasting glucose were the most responsible for the right heart remodelling.

Metabolic syndrome in the prevention of cardiovascular diseases and diabetes--still a matter of debate?

After metabolic syndrome was first introduced to identify persons at greater cardiovascular disease (CVD) risk, it has been associated with an increased risk of CVD and type 2 diabetes (T2D). Obesity has been considered as the fundamental factor in metabolic syndrome and it is thought to be mediated, at least in part by the role of the adipocyte in controlling circulating free fatty acids and the development of insulin resistance. However, the obese population is not perfectly overlapped with the population with metabolic syndrome. Is metabolic syndrome a better predictor than obesity to prevent CVD and T2D? Has metabolic syndrome been considered as a cluster of risk factors or an additional independent risk factor to assess CVD and T2D risk? The debate on the necessity of metabolic syndrome diagnosis seems not to be ended. Various definitions of metabolic syndrome were advocated by different organizations with emphasis on different components, and these definitions have different abilities to predict CVD and T2D among different populations because of fundamental philosophical differences. In the definitions of metabolic syndrome, only the cutoffs of each component were presented but rather continuous values or the degree of the severity of the syndrome with multiple cutoffs. Moreover, metabolic syndrome did not incorporate all the risk factors as known for CVD and T2D, such as physical activity. Future prospective studies with the measurement of sophisticated metabolic markers and of abdominal visceral and subcutaneous adiposity are needed to examine if the metabolic syndrome is a good CVD and T2D risk predictor over obesity and other risk factors. In practice, prevention action should be taken at the stage of obesity and providers need to pay attention to any components in the definition of metabolic syndrome even if the number of positive components has not achieved three or more.