Predictive value of triglyceride/glucose index for cardiac outcomes in non-diabetic renal transplant recipients

OBJECTIVES

Insulin resistance (IR) is associated with an increased risk of adverse cardiovascular outcomes. The triglyceride-glucose index (TyG index) is a reliable marker of IR. No study has examined the impact of the TyG index on major adverse cardiac and cerebrovascular events (MACCEs) in RTRs. Therefore, this study aimed to investigate the predictive value of the TyG index for MACCEs in RTRs.

MATERIALS AND METHODS

Non-diabetic patients undergoing renal transplantation were retrospectively enrolled. The patients were divided into two groups according to MACCE development. The cut-off value of the TyG index for MACCE was conducted.

RESULTS

The mean age of 522 patients was 41 (31-51) years, and 349 (66.9%) were male. During the 5.4-year follow-up, 84 (16%) MACCE were recorded. TyG index was significantly higher in the group that developed MACCE (p < 0,001). Cox regression analysis revealed that TyG index [HR: 3.297 (1.228-8.855), p = 0.018], left ventricle ejection fraction [HR: 0.934 (0.900-0.968), p < 0.001], cadaveric transplantation [HR: 8.886 (4.764-16.576), p < 0.001], graft survey [HR: 0.608 (0.542-0.682), p < 0.001)], and smoking [HR: 1.965 (1.117-3.456), p = 0.019] were independent predictors of MACCEs in nondiabetic RTRs.

CONCLUSION

TyG index is an independent predictor of MACCEs in non-diabetic RTRs. The widespread use of the TyG index may positively affect long-term treatment costs and survival.

Relationship between the triglyceride-glucose index and the SYNTAX score 2 in patients with non-ST elevation myocardial infarction

We evaluated if admissiontriglyceride-glucose index (TyG index) correlated with the anatomical synergy between percutaneous coronary intervention with taxus and cardiac surgery (SYNTAX) score 2 in non-ST elevation myocardial infarction (NSTEMI), nondiabetic patients.

Methods

SYNTAX score 2 (SSII) was retrospectively evaluated in 260 nondiabetic patients hospitalized with NSTEMI who underwent coronary angiography. The TyG index was calculated using the following equation: log [fasting triglycerides (mg/dl) × fasting glucose (mg/dl)/2]. We stratified patients according to tertiles of SSII (≤21.5, 21.5-30.6, and ≥30.6). These score ranges were defined as SSII low, SSII mid, and SSII high, respectively.

Results

The average age of the patients was 57.2 ± 10.9 years; 135 patients (52.2%) were males. The average TyG index was 8.68 ± 0.12, and SSII was 18.9 ± 9.9. A moderate correlation was found between TyG index and SSII (r = 0.347; P < 0.001) and TyG index was independent risk factors for SSII high [odds ratio (OR), 6.0; 95% CI, 2.7-17.0; P < 0.001].

Conclusion

In nondiabetic patients with NSTEMI, TyG index correlated with the SSII.

New onset diabetes in adulthood is associated with a substantial risk for mortality at all ages: a population based historical cohort study with a decade-long follow-up

BACKGROUND

Diabetes has been reported to be associated with an increased relative risk for mortality, with estimates ranging from 1.1 to 2.1. Findings are inconsistent regarding modification of the risk by gender and by age. The aim of this study was to estimate the mortality risk associated with new-onset diabetes in adulthood, by age group and gender.

METHODS

From the database of a large health care provider, we identified 31,987 individuals diagnosed with diabetes during 2003-2005; and 162,656 individuals without diabetes, group-matched by age. We used Cox regression to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for overall mortality adjusted for age, gender, socioeconomic (SE) level, obesity, smoking and comorbidities at baseline.

RESULTS

During a median follow-up of 9.5 years, 4464 (14%) of persons with diabetes and 13,327 (8.2%) of those without died. Among persons with incident diabetes, the proportion of men, smokers, obese and patients of low SE level was higher, as was the prevalence of cardiovascular disease and renal impairment at baseline. Incident diabetes was associated with an adjusted HR for mortality of 1.38 (95% CI 1.32-1.43). Mortality HR for DM was comparable with hypertension (1.42; 1.37-1.46), smoking (1.65; 1.58-1.71) and atherosclerosis (1.40; 1.35-1.46). Diabetes associated mortality HR was somewhat higher among women 1.78 (95% CI 1.58-2.08) as compared with men 1.51 (95% CI 1.41-1.62).

CONCLUSIONS

Incident diabetes in adults is associated with a substantial risk for mortality, especially in younger adults. Further efforts should be allocated to diabetes primary prevention.

Associations of MTHFR C677T polymorphism with insulin resistance, results of NURSE Study (Nursing Unacquainted Related Stress Etiologies)

Background

The insulin resistance syndrome is one of the major contributors of metabolic syndrome, diabetes Type 2 and atherosclerotic cardiovascular disease. A common mutation (677C to T; Ala to Val) in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with decreased specific MTHFR activity and elevation of the homocysteine. The aim of this study is investigation of association between MTHFR 677C > T polymorphism with insulin resistance by using HOMA (Homeostasis Model Assessment) index in nurses who are potentially prone to develop insulin resistance because of unfavorable effects of shift work.

Method

Nursing Unacquainted Related Stress Etiologies Study (Nurse Study) was conducted in five different educational hospitals of Tehran University of Medical Science (TUMS). The nurses aged 22–57 who have been referred by the matron were recruited. A self-administered questionnaire was completed. Anthropometric measurements including weight, height, waist and hip circumference in addition to blood pressure were measured. Insulin resistance and Insulin sensitivity were measured using the homeostatic model assessment (HOMA) and quantitative insulin sensitivity check index (QUICKI) respectively. The detection of MTHFR C677T polymorphism in exon four of MTHFR gene was performed by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) analysis using HINFI restriction enzyme digestion.

Result

A total of 273 subjects were recruited in the study. CT genotype were detected in 51.6% (129) subjects and CC and TT genotype were seen in 9.2% (25) and 35.2% (96) subjects respectively. Participants with TT genotype (9.65 ± 4.00) have significantly lower insulin level than participants with CT genotype (14.12 ± 15.34) (p-value: 0.01). The same significant difference was observed for HOMA index (p-value: 0.03). Result showed that HOMA is lower in subjects who are taking supplements.

Conclusion

Result of this study showed subjects with TT genotype had significantly lower HOMA compare to CT genotype and the same pattern was seen for insulin level. We also found subjects taking supplement have lower HOMA compared to others regardless of their genotype.

Increased dementia risk predominantly in diabetes mellitus rather than in hypertension or hyperlipidemia: a population-based cohort study

Background

The pathophysiology of insulin resistance-induced hypertension and hyperlipidemia might entail differences in dementia risk in cases with hypertension and hyperlipidemia without prior diabetes mellitus (DM). This study investigated whether incident hypertension, incident hyperlipidemia, or both, increased the dementia risk in patients with and without DM.

Methods

A nationwide retrospective cohort study was conducted. The study sample was obtained from the National Health Insurance Research Database. We enrolled 10,316 patients with a new diagnosis of DM between 2000 and 2002 in the DM cohort. For the same period, we randomly selected 41,264 patients without DM in the non-DM cohort (matched by age and sex at a 1:4 ratio with the DM cohort). Both cohorts were then separately divided into four groups on the basis of incident hypertension or incident hyperlipidemia status.

Results

In total, 51,580 patients aged between 20 and 99 years were enrolled. The dementia risk was higher in the DM cohort than in the non-DM cohort (adjusted hazard ratio (HR) = 1.47, 95% confidence interval (CI) = 1.30–1.67, p < 0.001). In the DM cohort, the dementia risk in patients with both hypertension and hyperlipidemia did not significantly increase compared with that in those without hypertension and hyperlipidemia (p = 0.529). Similar results were observed in those with either hypertension (p = 0.341) or hyperlipidemia (p = 0.189). In the non-DM cohort, patients with both hypertension and hyperlipidemia had a higher dementia risk (adjusted HR = 1.33, 95% CI = 1.09–1.63, p = 0.006). The results remained largely unchanged in patients with only hypertension (adjusted HR = 1.22, 95% CI = 1.05–1.40, p = 0.008). However, the dementia risk did not increase significantly in patients with only hyperlipidemia (p = 0.187).

Conclusions

The development of hypertension, hyperlipidemia, or both, following a diagnosis of incident diabetes is secondary to diabetes onset and likely mediated through insulin resistance associated with diabetes, which does not further accentuate dementia risk. DM itself (i.e., the systemic influence of hyperglycemia) might be the main driver of increased dementia risk.

Triglyceride glucose index, a marker of insulin resistance, is associated with coronary artery stenosis in asymptomatic subjects with type 2 diabetes

Background

Insulin resistance is one of the most important contributing factors to cardiovascular disease. This study aimed to investigate the association between coronary artery stenosis (CAS) and triglyceride glucose index (TyG index), a simple insulin resistance marker, in asymptomatic subjects with type 2 diabetes.

Methods

We recruited asymptomatic adults with type 2 diabetes but without previous history of coronary heart disease (n = 888). Significant CAS was defined as maximum intraluminal stenosis ≥70 % by coronary CT angiography. TyG index was calculated as log [fasting triglycerides (mg/dl) x fasting glucose (mg/dl)/2].

Results

Mean age was 63.8 ± 9.5 and 58.9 % of the subjects were men. We analyzed the participants according to the tertile of TyG index. The TyG index was correlated with HOMA-IR (r = 0.397, P < 0.001), and subjects with higher tertile of TyG index were younger but showed worse clinical and metabolic parameters. The prevalence of CAS was higher in subjects with higher tertile of TyG compared with those with lower tertile of TyG (14 % vs. 7.8 %, P = 0.022). On multiple regression analysis, the highest tertile of TyG index was an independent risk factor for CAS after adjustment for other confounders (odds ratio, 3.19 [95 % CI, 1.371–7.424]). Subgroup analysis showed that TyG index showed more significant association with CAS in patients with risk factors such as old age, longer duration of diabetes, poor glycemic control, no statin use, and male gender.

Conclusion

Higher TyG index is associated with increased risk of CAS in asymptomatic subjects with type 2 diabetes, particularly when they have risk factors for cardiovascular disease.

Trial registration

This study was retrospectively registered in ClinicalTrials. gov with the registration number of NCT02070926 in Feb 23, 2014.

Metabolic syndrome, or What you will: definitions and epidemiology

The metabolic syndrome is a clustering of risk factors which predispose an individual to cardiovascular morbidity and mortality. There is general consensus regarding the main components of the syndrome (glucose intolerance, obesity, raised blood pressure and dyslipidaemia [elevated triglycerides, low levels of high-density lipoprotein cholesterol]) but different definitions require different cut points and have different mandatory inclusion criteria. Although insulin resistance is considered a major pathological influence, only the World Health Organization (WHO) and European Group for the study of Insulin Resistance (EGIR) definitions include it amongst the diagnostic criteria and only the International Diabetes Federation (IDF) definition has waist circumference as a mandatory component. The prevalence of metabolic syndrome within individual cohorts varies with the definition used. Within each definition, the prevalence of metabolic syndrome increases with age and varies with gender and ethnicity. There is a lack of diagnostic concordance between different definitions. Only about 30% of people could be given the diagnosis of metabolic syndrome using most definitions, and about 3540% of people diagnosed with metabolic syndrome are only classified as such using one definition. There is currently debate regarding the validity of the term metabolic syndrome, but the presence of one cardiovascular risk factor should raise suspicion that additional risk factors may also be present and encourage investigation. Individual risk factors should be treated.

Atherothrombotic risk factor clustering in healthy male relatives of male patients with intermittent claudication

OBJECTIVE

Family history is an independent risk factor for premature acute myocardial infarction; in contrast, familial risk for peripheral arterial disease (PAD) has yet to be determined. Elevated levels of hemostatic proteins are consistently predictive for cardiovascular risk in "healthy" subjects, and may cluster with underlying insulin resistance. Atherothrombotic risk factor clustering occurs in first-degree relatives of subjects with coronary artery disease and type 2 diabetes. These may contribute to the enhanced cardiovascular risk in these subjects, and we hypothesised that familial clustering may occur in PAD. The objective of this study was to measure atherothrombotic risk factors in healthy male first-degree relatives of men with intermittent claudication, with emphasis on thrombotic risk.

METHODS

One hundred sixty-five healthy male first-degree relatives were compared with control subjects matched for age, sex, and race (n = 165), free from a personal or family history of premature cardiovascular disease. Primary outcome measures were fibrinogen, von Willebrand factor, factor VII clotting activity (FVII:C), and factor XIII levels. Atherosclerotic risk factors were measured, and subjects were genotyped for common functional polymorphisms (factor VII r353q and fibrinogen B beta-455).

RESULTS

Relatives had higher mean levels of fibrinogen (3.04 vs 2.89 g/L; P = .021), FVII:C (117% vs 104%; P = .000), factor XIII B subunit (1.11 vs 1.01 IU/mL; P = .000), and complex (A 2 B 2 ; 1.18 vs 1.11 IU/mL; P = .021). At multivariate analysis the association between relative status and fibrinogen, FVII:C, and factor XIII B subunit levels were independent of other variables.

CONCLUSIONS

The healthy male relatives of men with PAD have elevated levels of fibrinogen, factor VII, and factor XIII. Our results support the existence of thrombotic risk factor clustering in this population at "high risk."

Lipoprotein abnormalities and their consequences for patients with type 2 diabetes

Dyslipidaemia is common in patients with Type 2 diabetes and is held to be responsible for considerable CVD-related morbidity and mortality. Patients with Type 2 diabetes are at high risk from complications associated with atherosclerosis and should therefore receive preventive interventions. At the level of the adipocyte, impaired insulin action leads to increased rates of intracellular hydrolysis of triglycerides with the release of NEFA. The rise in NEFA provides substrate for the liver that, in the presence of impaired insulin action and relative insulin deficiency, is associated with complex alterations in plasma lipids: * Plasma VLDL levels are raised. (i). Increased VLDL levels are associated with post-prandial hyperlipidaemia that is compounded by impaired LPL activity. The latter may be independently associated with CAD. (ii). Remnant particles can deliver more cholesterol to macrophages than LDL-C particles. Thrombogenic alterations in the coagulation system also ensue from hypertriglyceridaemia. * Plasma HDL-C levels are reduced. (i). The reduction in cardioprotective HDL-C means a reduction of cholesterol efflux from the tissues--the first step in reverse cholesterol transport to the liver from peripheral tissues. (ii). The antioxidant and antiatherogenic activities of HDL-C are reduced when circulating levels are low. * LDL-C particles become small and dense. Small, dense LDL-C particles are held to be more atherogenic than their larger, buoyant counterparts because they (a) are more liable to oxidation and (b) may more readily adhere to and subsequently invade the arterial wall. The atherogenicity of LDL-C may also be enhanced by nonenzymatic glycation. Metabolic and lipid abnormalities can often be improved with lifestyle changes, including dietary modification, weight loss, smoking cessation and increased exercise. Although attainment of better glycaemic control may improve diabetic dyslipidaemia, pharmacological intervention is usually required. Several large-scale clinical trials, including 4S and more recently HPS, have clearly demonstrated the benefits of statins in reducing cardiovascular events. By virtue of their high absolute risk of CVD, many patients with Type 2 diabetes may achieve a greater risk reduction than their non-diabetic counterparts. For example, in 4S there was a 43% reduction in total mortality risk among patients with diabetes compared with 29% for non-diabetics and a reduced risk of MI by 55% vs. 32% for diabetic and non-diabetics, respectively. In the diabetic subgroup in HPS, there were reductions of approximately 25-30% in the risk of first major vascular events. More recently, the lipid-lowering arm of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) was halted early because of a significant reduction in cardiovascular events compared with placebo. Surprisingly an analysis of subgroups failed to show significance among the diabetic population, although the sample size, shortened follow-up period and higher drop-in statin use among diabetics on placebo may have affected results. The Collaborative Atorvastatin Diabetes Study (CARDS), involving 2800 patients with Type 2 diabetes, was halted 2 years early in June 2003 because patients allocated atorvastatin had significant reductions in MI, stroke and surgical procedures compared with those receiving placebo. The UKPDS demonstrated that the appearance and progression of certain microvascular complications of Type 2 diabetes could be reduced by treatment directed at hyperglycaemia and hypertension. In addition, correction of dyslipidaemia in patients with diabetes is important in reducing the high toll from macrovascular disease. The subjects in the HPS had similar lipid profiles to the participants in UKPDS, suggesting that additional benefit would accrue from a therapeutic assault on the main cardiovascular risk factors simultaneously. We now have firm evidence that appropriate use of statins in patients with Type 2 diabetes can significantly reduce cardiovascular morbidity and mortality.

Insulin resistance--the new goal!

Diabetes mellitus is a well-recognized risk-factor for coronary artery disease (CAD). Epidemiological studies have shown that the risk of CAD increases two to sixfold in patients with type 2 diabetes compared with those without the disease. Furthermore the prevalence of diabetes in the UK has increased by 30% since 1991 and the world population of people with diabetes in 2010 is expected to be twice that of 1990. In addition whilst the mortality from CAD in patients without diabetes has declined over the past 20 years the mortality in men with type 2 diabetes has not changed and in women may have increased. UKPDS and other studies have shown a significant improvement in the onset and course of microvascular complications with good diabetic control. However the same is not true for macrovascular complications for which there is no good evidence of improvement with better diabetic control. This apparent lack of benefit from improved care of diabetic patients has led to many different approaches. These include attempts to achieve even better glycaemic control, greater emphasis on other risk factors particularly hypertension and interestingly attention to the prediabetic state characterized by insulin resistance (IR). The latter is associated with a number of abnormalities which could play a causative role in the development of cardiovascular disease. This article will review the concept of IR and the possible interventions available to tackle it.