Postchallenge hyperglycemia but not hyperinsulinemia is associated with angiographically documented coronary atherosclerosis in Korean subjects

Postprandial Blood Glucose Outweighs Fasting Blood Glucose and HbA1c in screening Coronary Heart Disease

The objective of the present study is to assess the performance of fasting blood glucose (FBG), postprandial blood glucose (PBG), and glycated hemoglobin (HbA1c) as screening for coronary heart disease (CHD) in an inpatient population undergoing coronary angiography. 1852 consecutive patients scheduled for coronary angiography were classified into Normal Glucose Tolerance (NGT), Impaired Glucose Regulation (IGR), and diabetes, based on FBG, PBG, and HbA1c. Correlations of Gensini score with glucose metabolism and insulin resistance were analyzed. The associations between glycemic variables and Gensini score or the presence of CHD were analyzed by multiple linear regression and logistic regression, respectively. CHD was diagnosed in 488, 622, and 414 patients with NGT, IGR, and diabetes, respectively. Gensini score was positively correlated with FBG (r = 0.09, p < 0.01), PBG (r = 0.20, p < 0.01), and HbA1c (r = 0.19, p < 0.01). Gensini score was not correlated with fasting insulin (r = −0.081, p = 0.36), post-prandial insulin (r = −0.02, p = 0.61), or HOMAIR (r = −0.0059, p = 0.13). When FBG, PBG and HbA1c were pooled altogether, only PBG persisted in its association with Gensini score and the prevalence of CHD. The severity of CHD was associated with glucose rather than insulin resistance in this Chinese population. PBG was optimally correlated with the presence and severity of CHD.

Post-challenge insulin concentration is useful for differentiating between coronary artery disease and cardiac syndrome X in subjects without known diabetes mellitus

BACKGROUND

Cardiac syndrome X (CSX) is characterized by angina pectoris but with patent coronary arteries. Our previous study demonstrated that subjects with CSX had a higher fasting insulin-resistance (IR) than the controls. However, few studies have investigated the degree of IR, including oral glucose tolerance test (OGTT)-derived indices and profiles of metabolic abnormalities between CSX and coronary artery disease (CAD).

METHODS

Ninety-two CSX and 145 CAD subjects without known diabetes mellitus (DM) underwent coronary angiogram (CAG) for angina pectoris and also agreed to receive OGTT and glycated hemoglobin (HbA_1C) evaluations for screening abnormal glucose regulation and IR.

RESULTS

CAD group had more subjects with metabolically unhealthy obesity (52.4 vs. 31.5%, p < 0.001) than the CSX group. The CAD group had higher OGTT 2 h glucose and insulin (both p < 0.005) while fasting glucose, insulin and HOMA-IR were similar to those of CSX subjects. In the binary regression analysis, OGTT 2 h insulin and being metabolic unhealthy were significantly different between the CAD and CSX groups, but there were no significant differences in Matsuda index, fasting glucose, insulin, HOMA-IR, or HbA_1C.

CONCLUSIONS

Post challenge OGTT 2 h insulin and being metabolic unhealthy were useful parameters in differentiating between CAD and CSX in subjects without known DM but suffered from angina pectoris and underwent CAG. Different degrees of IR and metabolic abnormalities might be implicated in the pathogenesis of micro vs. macro vascular coronary diseases. Trial registration NCT01198730 at https://clinicaltrials.gov, Registered Sep. 8, 2010.

Fasting plasma glucose correlates with angiographic coronary artery disease prevalence and severity in Chinese patients without known diabetes

Type 2 diabetes mellitus is a risk factor for coronary artery disease (CAD). While there is a clear association of fasting plasma glucose (FPG) with microvascular complications, the risk for CAD conferred by FPG is relatively less clear. Therefore, we investigate the association between different FPG and the prevalence and severity of angiographic CAD in high-risk Chinese patients without known diabetes. Among 1,419 subjects who were to undergo coronary angiography for the confirmation of suspected myocardial ischemia, 906 subjects without known diabetes were included in this study and categorized into four groups according to the level of FPG: group 1, ≤5.5 mmol/l; group 2, 5.6-6.0 mmol/l; group 3, 6.1-6.9 mmol/l; and group 4, ≥7.0 mmol/l. Significant angiographic CAD was defined as ≥50 % lumen diameter reduction in at least one major coronary artery in a given subject. The severity and extent of coronary atherosclerosis were defined as the number of diseased vessels, the proportion of totally occluded vessel and the Gensini score. Associations between FPG and the prevalence and severity of CAD were assessed by logistic and linear stepwise regression analyses. The angiographic CAD prevalence, the number of diseased vessels, the totally occluded vessel, and the Gensini score increased corresponding to increasing FPG levels from ≤5.5 mmol/l to 5.6-6.0 mmol/l to 6.1-6.9 mmol/l to ≥7.0 mmol/l (P < 0.05). The FPG had significant association with angiographic CAD (adjusted OR, 1.53; 95 % CI, 1.19-1.98; P = 0.001) and the Gensini score (standardized regression coefficient = 0.172, P = 0.011). Compared with group 1, group 2, 3 and 4 demonstrated significantly higher CAD prevalence after adjustment (adjusted OR, 1.61 [1.16-2.19]; P = 0.015 for group 2; 1.49 [1.11-2.59]; P = 0.027 for group 3; and 4.19 [2.85-6.16]; P = 0.024 for group 4, respectively). FPG group was also significantly associated with the Gensini score (Standardized coefficients, 0.185; P = 0.007, respectively). FPG was an independent risk factor for the prevalence and severity of significant angiographic CAD in our study population. The severity of angiographic CAD increased along with the increasing FPG levels even in prediabetic state.

Glucometabolic state in Chinese patients undergoing elective coronary angiography

AIM

The aim of this study is to characterize the glucometabolic state of patients undergoing elective coronary angiography (CA) in a subpopulation in China.

METHODS AND RESULTS

This study recruited 896 patients undergoing elective CA for the evaluation of suspected coronary artery disease (CAD). Oral glucose tolerance tests (OGTTs) performed in patients without previously known diabetes revealed that 173 (19.2%) had newly diagnosed diabetes and 281 (31.5%) had impaired glucose regulation. The prevalence of abnormal glucose metabolism (AGM) was significant difference among three groups of CA diagnosis, including normal coronary, nonsignificant stenosis and CAD. Overall, the proportion of patients with type 2 diabetes increased from 22.0% at baseline to 41.2% post-OGTT analysis. In total, 270 (59.5%) patients with AGM would have remained undetected if OGTTs had not been performed. Patients with CAD, hypertension, dyslipidemia, obesity and high C-reactive protein levels were at high risk of AGM.

CONCLUSIONS

AGM is common and underestimated by FPG testing alone in patients undergoing elective CA. OGTTs should be routinely performed to assess the glucometabolic state of patients undergoing elective CA, especially in patients with high risks of AGM. Detecting the state of AGM in CA individuals may provide strategies to reduce the progression of AGM and associated complications.

The Relationship between Glucose Tolerance and Severity of Coronary Artery Disease Using the Gensini Score

Consecutive patients (n = 235) with coronary ischemia were studied; 69 patients (29%) had diabetes. An oral glucose tolerance test (OGTT) was administered to the 166 patients without diabetes; 76 (46%) had normal glucose tolerance (group I = NGT), 68 (41%) had impaired glucose tolerance ([IGT] group II = IGT), and 22 (13%) had diabetic glucose tolerance (DGT). The DGT patients were added to the known diabetics forming (Group III; n = 91). Multivessel disease was significantly more prevalent in group III; 30 patients (43%) in group I, 32 patients (51%) in group II, and 57 patients (69%) in group III ( P = .002). Gensini scores were 43.20 ± 24.92 in group I, 54.22 ± 42.61 in group II, and 60.59 ± 38.21 in group III. ( P = .037) The severity of coronary artery disease is related to abnormal glucose tolerance. Patients with IGT could be neglected in terms of interventions focused to improve risk factors.

Increased carotid IMT in overweight and obese women affected by Hashimoto's thyroiditis: an adiposity and autoimmune linkage?

BACKGROUND

Hashimoto's thyroiditis is the most important cause of hypothyroidism. It is a systemic disease that can even affect the cardiovascular system, by accelerating the atherosclerotic process. Aim of this study was to examine whether autoimmune thyroiditis has an effect on the intima-media thickness of the common carotid artery (IMT-CCT), independently of the thyroid function and well-known cardiovascular risk factors. Hashimoto's thyroiditis is a systemic disease. The aim is to examine whether autoimmune thyroiditis and adiposity can effect carotid IMT independently of thyroid hormones and cardiovascular risk factors.

METHODS

A total of 104 obese women (BMI > or = 25.0 kg/m-2), with FT3 and FT4 serum levels in the normal range and TSH levels < 4.5 microU/ml, were investigated. None of these patients was taking any kind of drug influencing thyroid function. Measurements were made of the IMT-CCT, BMI, waist circumference, blood pressure levels, as well as fasting TSH, FT3, FT4, anti-thyroid antibodies, insulin, fasting glycemia, triglycerides, total and HDL-cholesterol serum concentrations.

RESULTS

Of the 104 women, 30 (28.8%) were affected by autoimmune thyroiditis. Significantly higher values of IMT-CCT (p < 0.05), TSH (p < 0.05), and triglycerides (p < 0.05) were obtained, and significantly lower values of FT4 (p < 0.05), in patients with Hashimoto's thyroiditis as compared to those with a normal thyroid function. When examining the whole group together, at multiple regression analysis Hashimoto's thyroiditis maintained a positive association with the IMT (p < 0.001), independently of age, hypertension, BMI, and the fasting serum levels of TSH, FT3, FT4, insulin, fasting glycemia, triglycerides, total and HDL-cholesterol levels.

CONCLUSIONS

The present study shows that Hashimoto's thyroiditis is associated to an increased IMT only in overweight and obese, independently of the thyroid function, BMI and cardiovascular risk factors. These results suggest that Hashimoto's thyroiditis is a marker of evolution of the atherosclerosis if combined to adiposity.

The comparison of coronary angiographic profiles between diabetic and nondiabetic patients with coronary artery disease in a Chinese population

BACKGROUND

It is well known that diabetes mellitus (DM) is a crucial risk factor for coronary artery disease (CAD). The present study aimed to investigate angiographic profiles of the coronary arteries in diabetic CAD patients in comparison with nondiabetics.

METHODS

A total of 546 Chinese patients were angiographically documented for CAD, 375 of whom were diabetics and 171 were nondiabetics according to the WHO diabetes criteria (1999). The patients in these two groups were matched for age, sex, and body mass index (BMI). The 75 g oral glucose tolerance test (OGTT) was performed in all patients, for whom blood glucose, insulin, glycosylated hemoglobin (HbA1c), triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoprotein A (ApoA), apolipoprotein B (ApoB), and lipoprotein(a) [Lp(a)] were measured. Insulin resistance (Homa-IR) and insulin secretion index (Homa-IS) were determined by the HOMA model. The clinical features and the data from selective coronary angiographies were compared between the diabetic and nondiabetic CAD patients.

RESULTS

Diabetic CAD patients had significantly higher waist to hip ratio (WHR) (p=0.016), fasting plasma glucose (FPG), 2h plasma glucose (2hPG), glycosylated hemoglobin (HbA1c) (p<0.001), insulin resistance index (Homa-IR) (p=0.001), and apolipoprotein A (ApoA) (p=0.008), with a significantly lower insulin secretion index (Homa-IS) level (p<0.001). Diabetic patients had one-vessel disease less frequently (28.8% vs 46.2%, p<0.001), and three-vessel disease more frequently (35.2% vs 24.0%, p=0.009), and they also had significantly higher cumulative coronary atherosclerosis score (CAS) (p=0.003). The right coronary artery was significantly more frequently involved in diabetics (66.4% vs 52.6%, p=0.002), with a clearly higher CAS at the same time (p=0.002).

CONCLUSIONS

Diabetics were presented with more severe and diffuse angiographically documented coronary artery disease compared to nondiabetics. The right coronary artery was significantly more frequently involved in the diabetics. Duration of CAD, Homa-IR, and diabetes mellitus were the independent risk factors for CAD found in the present study, while ApoA was the protective one.

The level of 2-h post-challenge glucose is an independent risk factor of carotid intima-media thickness progression in Korean type 2 diabetic patients

OBJECTIVE

To evaluate the relationship between the metabolic abnormalities commonly associated with diabetes and the changes in carotid intima-media thickness (IMT) in Korean type 2 diabetic patients who do not have clinically manifest cardiovascular disease (CVD).

DESIGN

In a prospective study, a total of 152 type 2 diabetic patients were recruited from a group of outpatients at the Yonsei University Hospital.

MATERIALS AND METHODS

The carotid IMTs of 152 subjects with type 2 diabetes (mean age 63.5+/-7.0 years) were determined at baseline and after a mean follow-up time of 23.7+/-3.7 months. Fasting plasma glucose, serum total cholesterol (TC), serum triglyceride, high-density lipoprotein cholesterol (HDL-C), HbA1c, oral glucose tolerance test (OGTT) results for 2-h post-challenge glucose (2hPG), and blood pressure measurements were collected every 3 months and averaged.

RESULTS

The highest quartiles of baseline C-peptide and homeostatic model assessment (HOMA) index showed more IMT progression than the lowest quartiles. The change in the mean IMT correlated with average values of HbA1c (r=.219, P=.007), the 2-h post-challenge glucose (r=.239, P=.003), HDL-C (r=-.228, P=.005), LDL-C (r=.175, P=.033), and non-HDL-C (r=.194, P=.016). Multiple regression analysis demonstrated that the independent risk factor for the mean IMT change in diabetic patients was the average 2hPG level (P=.004). The change in the mean IMT of those in the lowest quartile of average 2hPG (<11.1 mmol/l) was 823+/-176 to 841+/-146 microm (P=.276). In the highest quartile (2hPG >15.3 mmol/l), however, the mean IMT increased from 794+/-127 to 882+/-153 microm (P<.001).

CONCLUSION

The 2hPG parameter among the various metabolic parameters exerts the greatest influence upon the prevention of carotid IMT progression in type 2 diabetic subjects. The level of 2hPG is an independent risk factor for the progression of carotid IMT in Korean type 2 diabetic patients.

Impact of type 2 diabetes on myocardial insulin sensitivity to glucose uptake and perfusion in patients with coronary artery disease

BACKGROUND AND HYPOTHESIS

Myocardial insulin resistance (IR) is a feature of coronary artery disease (CAD) with reduced left ventricular ejection fraction (LVEF). Whether type 2 diabetes mellitus (T2DM) with CAD and preserved LVEF induces myocardial IR and whether insulin in these patients acts as a myocardial vasodilator is debated.

METHODS

We studied 27 CAD patients (LVEF > 50%): 12 with T2DM (CAD+DM), 15 without T2DM (CAD-NoDM). Regional myocardial and skeletal glucose uptake, myocardial and skeletal muscle perfusion were measured with positron emission tomography. Myocardial muscle perfusion was measured at rest and during hyperemia in nonstenotic and stenotic regions with and without acute hyperinsulinemia.

RESULTS

Myocardial glucose uptake was similar in CAD+DM and CAD-NoDM in both nonstenotic and stenotic regions [0.38 +/- 0.08 and 0.36 +/- 0.11 micromol/g.min; P value nonsignificant (NS)] and (0.35 +/- 0.09 and 0.37 +/- 0.13 micromol/g.min; P = NS). Skeletal glucose uptake was reduced in CAD+DM (0.05 +/- 0.04 vs. 0.10 +/- 0.05 micromol/g.min; P = 0.02), and likewise, whole-body glucose uptake was reduced in CAD+DM (4.0 +/- 2.8 vs. 7.0 +/- 2.4 mg/kg.min; P = 0.01). Insulin did not alter myocardial muscle perfusion at rest or during hyperemia. Insulin increased skeletal muscle perfusion in CAD-NoDM (0.11 +/- 0.03 vs. 0.06 +/- 0.03 ml/g.min; P = 0.02), but not in CAD+DM (0.08 +/- 0.04 and 0.09 +/- 0.05 ml/g.min; P = NS).

CONCLUSION

Myocardial IR to glucose uptake is not an inherent feature in T2DM patients with preserved LVEF. Acute physiological insulin exposure exerts no coronary vasodilation in CAD patients irrespective of T2DM.

Abnormal glucose tolerance--a common risk factor in patients with acute myocardial infarction in comparison with population-based controls

BACKGROUND

A high prevalence of newly detected diabetes and impaired glucose tolerance (abnormal glucose tolerance) was recently reported in patients with acute myocardial infarction. It is important to verify whether this finding is specific for the patients or attributable to the population, from which they were recruited.

OBJECTIVE

To verify whether abnormal glucose tolerance is more prevalent in patients than in controls chosen from the same population and to compare metabolic characteristics between the two groups.

DESIGN AND SUBJECTS

The metabolic state was assessed in patients (n = 181) admitted with acute myocardial infarction and no history of diabetes before discharge and after 3 months. Sex- and age-matched controls (n = 185) without previously known diabetes or cardiovascular disease except hypertension were recruited from the general population.

MAIN OUTCOME MEASURES

Oral glucose tolerance test, glucosylated haemoglobin A1c (HbA1c), insulin, proinsulin, lipid profile, fibrinolytic function and inflammatory markers.

RESULTS

Abnormal glucose tolerance was more common (number/all classified) in patients at discharge 113/168 (67%) and after 3 months 95/145 (66%) than in controls 65/185 (35%) (P < 0.001). Dyslipidaemia (70% vs. 29%; P < 0.001) and previously treated hypertension (32% vs. 18%; P = 0.028) were more frequent amongst patients whilst obesity (18% vs. 24%) did not differ significantly. Blood glucose, HbA1c, proinsulin, proinsulin/insulin ratio, triglycerides, insulin resistance (by HOMA) and fibrinogen were consistently higher in patients than controls (P < 0.01).

CONCLUSIONS

Abnormal glucose tolerance was almost twice as common amongst patients with acute myocardial infarction as in matched controls. Impaired glycaemic control accompanied by insulin resistance, dyslipidaemia, hypertension, together with increased plasma fibrinogen and proinsulin levels were main features characterizing patients.