Prevalence of metabolic syndrome, insulin resistance, and microvascular angina pectoris in 500 consecutive patients referred to coronarography

The obesity paradox and diabetes

BACKGROUND

Obesity has been proven to be a risk factor for type 2 diabetes mellitus (T2DM) through numerous pathogenetic mechanisms. Unexpectedly, some studies suggest that subjects with overweight/obesity and T2DM have better clinical outcome than their normal weight peers. This finding is described as "obesity paradox" and calls into question the importance of weight loss in this specific population.

OBJECTIVE

This article is a narrative overview on the obesity and type 2 diabetes mellitus, particularly regarding the obesity paradox in T2DM patients.

METHODS

We used as sources MEDLINE/PubMed, CINAHL, EMBASE, and Cochrane Library, from inception to March 2020; we chose 30 relevant papers regarding the association of obesity with clinical outcome and mortality of patients affected by T2DM.

RESULTS

Many studies report that in patients with T2DM, overweight and obesity are associated with a better prognosis than underweight or normal weight, suggesting the presence of an obesity paradox. However, these studies have numerous limitations due to their mainly retrospective nature and to numerous confounding factors, such as associated pathologies, antidiabetic treatments, smoking habit, lack of data about distribution of body fat or weight history.

CONCLUSION

Literature data regarding the phenomenon of obesity paradox in T2DM patients are controversial due to the several limitations of the studies; therefore in the management of patients with overweight/obesity and T2DM is recommended referring to the established guidelines, which indicate diet and physical activity as the cornerstone of the treatment.

LEVEL OF EVIDENCE

Level V: narrative review.

Ventricular late potential in cardiac syndrome X compared to coronary artery disease

BACKGROUND

Although ventricular late potential (VLP) was extensively studied in risk stratification of myocardial infarction (MI) patients, comparable researches evaluating presence of VLP in MI-free coronary artery disease (CAD) and cardiac syndrome X (CSX) subjects are scarce. This study aimed to compare presence of VLP between CSX and CAD patients.

METHODS

Signal average ECG (SAECG) was performed to 49 patients with a history of typical cardiac pain before undergoing diagnostic coronary angiography (DCA) in Al-Shaab cardiac center, Khartoum, Sudan. QRS duration, duration of the terminal part of the QRS complex with amplitude less than 40 microvolts (LAS40) and the root mean square voltage of the terminal 40 milliseconds (RMS40) of the filtered QRS complex were identified for each patient. Presence of two or more of QRS duration > 120 ms, RMS40 > 38 ms and LAS40 < 20 μV was considered indicative of VLP. Associations between VLP and patients grouped according to DCA results were assessed using appropriate statistical tests.

RESULTS

VLP was present in 11.11% (3.63%-24.66%) and 15.38% (2.66%-42.23%) of patients with CAD and CSX respectively. Presence of VLP was comparable in patients with CAD and CSX (OR = 0.69, 95% CI = 0.11-6.05, P = 0.692), even after controlling for the possible variations in gender, age, body mass index (BMI), hypertension and diabetes mellitus in the studied groups.

CONCLUSION

Presence of VLP is comparable among CSX and CAD patients.

Anxiety Level and Cardiac Autonomic Modulations in Coronary Artery Disease and Cardiac Syndrome X Patients

BACKGROUND

Anxiety and cardiac autonomic modulations (CAM) were thoroughly investigated in coronary artery disease (CAD) and cardiac syndrome X (CSX) patients worldwide, but not among Sudanese with similar pathology.

AIMS

To compare levels of anxiety and CAM between Sudanese patients with CSX and CAD.

MATERIALS AND METHODS

Anxiety was evaluated in 51 CAD and 26 CSX patients using Taylor Manifest anxiety score (TMAS) questionnaire while heart rate variability derived indices were used to assess CAM, namely natural logarithm of low frequency (LnLF), high frequency (LnHF) and LF/HF ratio (LnLF/HF).

RESULTS

Low anxiety levels were achieved by 6 (23.1%) and 9 (17.6%) patients with CSX and CAD respectively. High anxiety level was achieved by only one (3.8%) patient, who was suffering from CSX. TMAS was significantly higher in CSX (31.27 (21.97)) compared to CAD (21.86 (12.97), P = 0.021). However, abnormally increased anxiety was not associated with higher risk of CSX. LnLF, LnHF and LnLF/HF were comparable in CAD and CSX patients.

CONCLUSION

CSX and CAD patients showed comparable CAM. Although anxiety levels were higher in CSX compared to CAD, TMAS ≥ 35 failed to show significant association with CSX.

Prevalence of Insulin Resistance in Subjects with Nonalcoholic Fatty Liver Disease and Its Predictors in a Chinese Population

OBJECTIVE

Insulin resistance (IR) is a key factor involved in the development and progression of nonalcoholic fatty liver disease (NAFLD). However, the prevalence of IR in NAFLD patients and its risk factors have been rarely reported, especially in China. This prospective study was undertaken to clarify these issues in the Chinese population.

METHODS

A total of 600 NAFLD patients and 300 age- and sex-matched healthy controls were recruited between January 1, 2011, and December 31, 2013. Demographic information and clinical characteristics were collected, and the presence of IR was evaluated using the homeostasis model. Uni- and multivariate analyses were conducted, and receiver operating characteristic (ROC) curves were generated to identify IR predictors.

RESULTS

NAFLD patients had a much higher prevalence of IR than healthy controls (37.8 vs. 2.3 %, P < 0.001). The rates of elevated alanine transferase (ALT) and aspartate transferase (AST) levels were much higher in NAFLD patients with IR than those without (53.7 vs. 41.6 % and 28.6 vs. 18.2 %, respectively, P < 0.001). Uni- and multivariate analyses revealed that female sex, general obesity, abdominal obesity, and hypertension were independent predictors for IR. The area under the ROC curve for fasting plasma insulin (FPI) detecting IR was 0.93 (P < 0.001), and the optimal cutoff was 11.3 μU/ml (sensitivity = 0.86, specificity = 0.92).

CONCLUSION

Chinese NAFLD patients are susceptible to IR. Female sex, general and abdominal obesity, and hypertension were independent predictors for IR in NAFLD patients. FPI is an optimal predictor for IR.

Central obesity, type 2 diabetes and insulin: exploring a pathway full of thorns

The prevalence of type 2 diabetes (T2D) is rapidly increasing. This is strongly related to the contemporary lifestyle changes that have resulted in increased rates of overweight individuals and obesity. Central (intra-abdominal) obesity is observed in the majority of patients with T2D. It is associated with insulin resistance, mainly at the level of skeletal muscle, adipose tissue and liver. The discovery of macrophage infiltration in the abdominal adipose tissue and the unbalanced production of adipocyte cytokines (adipokines) was an essential step towards novel research perspectives for a better understanding of the molecular mechanisms governing the development of insulin resistance. Furthermore, in an obese state, the increased cellular uptake of non-esterified fatty acids is exacerbated without any subsequent β-oxidation. This in turn contributes to the accumulation of intermediate lipid metabolites that cause defects in the insulin signaling pathway. This paper examines the possible cellular mechanisms that connect central obesity with defects in the insulin pathway. It discusses the discrepancies observed from studies organized in cell cultures, animal models and humans. Finally, it emphasizes the need for therapeutic strategies in order to achieve weight reduction in overweight and obese patients with T2D.

Etiopathogenesis of microvascular angina: caveats in our knowledge

Nearly 50% of subjects of coronary artery disease suffer from coronary microvascular dysfunction. Various etiopathogenetic factors have been proposed by different workers but no hypothesis can explain the genesis of microvascular angina in all patients. We have made an attempt to review the literature to find caveats in our knowledge so that future studies can be better designed.

Microvascular dysfunction in the course of metabolic syndrome induced by high-fat diet

Background

Metabolic syndrome (MetS) is associated with increased risk of cardiovascular disease (CVD). One important feature underlying the pathophysiology of many types of CVD is microvascular dysfunction. Although components of MetS are themselves CVD risk factors, the risk is increased when the syndrome is considered as one entity. We aimed to characterize microvascular function and some of its influencing factors in the course of MetS development.

Methods

Development of MetS in C57BL/6 mice on a high-fat diet (HFD, 51% of energy from fat) was studied. The initial phase of MetS (I-MetS) was defined as the first 2 weeks of HFD feeding, with the fully developed phase occurring after 8 weeks of HFD. We characterized these phases by assessing changes in adiposity, blood pressure, and microvascular function. All data are presented as mean ± standard error (SEM). Differences between cumulative dose–response curves of myograph experiments were calculated using non-linear regression analysis. In other experiments, comparisons between two groups were made with Student’s t-test. Comparisons between more than two groups were made using one-way ANOVA with Tukey post-hoc test. A probability value <0.05 was considered statistically significant.

Results

I-MetS mice presented with weight gain, blood pressure elevation, and microvascular dysfunction characterized by augmented vasoconstriction. This finding, contrary to those in mice with fully developed MetS, was not associated with endothelial dysfunction, insulin resistance, or systemic inflammation. In the initial phase, perivascular adipose tissue showed no sign of inflammation and had no influence on the pattern of vasoconstriction. These findings suggest that the onset of hypertension in MetS is strongly influenced by vascular smooth muscle cell dysfunction and independent of important factors known to influence microvascular function and consequently blood pressure levels.

Conclusion

We identified in I-MetS the occurrence of isolated augmented vasoconstriction along with blood pressure elevation, but not the presence of classical MetS components known to influence microvascular function. These findings increase our understanding of the pathophysiology of CVD risk associated with MetS.