Postchallenge hyperglycemia and mortality in a national sample of U.S. adults

Load-dependent effects of duodenal glucose on glycemia, gastrointestinal hormones, antropyloroduodenal motility, and energy intake in healthy men

Gastric emptying is a major determinant of glycemia, gastrointestinal hormone release, and appetite. We determined the effects of different intraduodenal glucose loads on glycemia, insulinemia, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and cholecystokinin (CCK), antropyloroduodenal motility, and energy intake in healthy subjects. Blood glucose, plasma hormone, and antropyloroduodenal motor responses to 120-min intraduodenal infusions of glucose at 1) 1 ("G1"), 2) 2 ("G2"), and 3) 4 ("G4") kcal/min or of 4) saline ("control") were measured in 10 healthy males in double-blind, randomized fashion. Immediately after each infusion, energy intake at a buffet meal was quantified. Blood glucose rose in response to all glucose infusions (P < 0.05 vs. control), with the effect of G4 and G2 being greater than that of G1 (P < 0.05) but with no difference between G2 and G4. The rises in insulin, GLP-1, GIP, and CCK were related to the glucose load (r > 0.82, P < 0.05). All glucose infusions suppressed antral (P < 0.05), but only G4 decreased duodenal, pressure waves (P < 0.01), resulted in a sustained stimulation of basal pyloric pressure (P < 0.01), and decreased energy intake (P < 0.05). In conclusion, variations in duodenal glucose loads have differential effects on blood glucose, plasma insulin, GLP-1, GIP and CCK, antropyloroduodenal motility, and energy intake in healthy subjects. These observations have implications for strategies to minimize postprandial glycemic excursions in type 2 diabetes.

Cardiovascular benefits and safety profile of acarbose therapy in prediabetes and established type 2 diabetes

Dysglycaemic disease is one of the most important health issues facing the world in the 21^st century. Patients with type 2 diabetes and individuals with prediabetes are at risk of developing macrovascular and microvascular complications. Long-term management strategies are therefore required that are effective at controlling dysglycaemia, well tolerated and, ideally, offer additional cardiovascular disease (CVD) risk-reduction benefits. The efficacy, safety and tolerability of the α-glucosidase inhibitor acarbose have been well-established in a wide range of patient populations in both clinical and community trials. In addition, acarbose has been shown to reduce cardiovascular complications in type 2 diabetes and prevent hypertension and CVD in individuals with impaired glucose tolerance (IGT). Acarbose has a very good safety profile and, owing to its straightforward, non-systemic mode of action, avoids most adverse events. The most common side-effects of acarbose are mild-to-moderate gastrointestinal complaints that subside as treatment continues. They can be minimised through the use of an appropriate stepwise dosing regimen and careful choice of diet. Acarbose is therefore a valuable option for the management of type 2 diabetes and, as the only oral antidiabetes agent approved for the treatment of prediabetes, can help to improve clinical management across the dysglycaemic disease continuum.

Normnahe Blutzuckereinstellung beim Typ-2-Diabetes

Patients with type 2 diabetes are at high risk for the development of micro- and macrovascular complications. It is necessary to aim at an early, multifactorial intervention at different levels of metabolic syndrome. Epidemiological data have consistently shown that postprandial hyperglycaemia has strong proatherogenic effects, increasing overall cardiovascular risk. These findings indicate that intensive blood glucose control with the aim of maintaining near normal preprandial (<110 mg/dl) and postprandial levels (<140 mg/dl) is required to minimise the incidence of complications. Antidiabetic therapy should be selected individually by integrating therapeutic goals and the patient's possibilities for self-management. The fact that national recommendations for the treatment of patients with type 2 diabetes are not fully implemented in clinical practice emphasizes the importance of further activities to improve the quality of care.

Soluble CD40 ligand levels in otherwise healthy subjects with impaired fasting glucose

Unlike diabetes mellitus and impaired glucose tolerance, it is not clear whether the subjects with impaired fasting glucose (IFG) are at increased risk of atherosclerosis and cardiovascular diseases. The CD40-CD40 ligand interaction is involved in the mechanism of atherosclerosis. We investigated whether soluble CD40L (sCD40L) as well as high sensitive C-reactive protein (hsCRP) levels are increased in subjects with IFG having no confounding factors for inflammation or atherosclerosis. Twenty four IFG subjects with no additional disorders and 40 appropriate healthy controls were studied. sCD40L and hsCRP levels in the IFG and control groups were similar. Blood pressures, total and LDL-cholesterol, and triglyceride levels were also similar, whereas HDL-cholesterol was lower and HOMA-IR indexes were higher in the IFG group. Though the sample size was small, the present data show that sCD40L seems not to alter in subjects with IFG suggesting that it might not be an independent risk factor for atherosclerosis.

Cardiometabolic risk in impaired fasting glucose and impaired glucose tolerance: the Atherosclerosis Risk in Communities Study

OBJECTIVE

We compared and contrasted cardiovascular disease (CVD) risk factors, subclinical manifestations of CVD, incident coronary heart disease (CHD), and all-cause mortality by categories of impaired glucose regulation in nondiabetic individuals.

RESEARCH DESIGN AND METHODS

The study included 6,888 participants aged 52-75 years who had no history of diabetes or CVD. All-cause mortality and incident CHD were ascertained over a median of 6.3 years of follow-up.

RESULTS

Agreement between fasting and postchallenge glucose impairment was poor: 3,048 subjects (44%) had neither impaired fasting glucose (IFG) nor impaired glucose tolerance (IGT), 1,690 (25%) had isolated IFG, 1,000 (14%) had isolated IGT, and 1,149 (17%) had both IFG and IGT. After adjustment for age, sex, race, and center, subjects with isolated IFG were more likely to smoke, consume alcohol, and had higher mean BMI, waist circumference, LDL cholesterol, and fasting insulin and lower HDL cholesterol than those with isolated IGT, while subjects with isolated IGT had higher mean triglycerides, systolic blood pressure, and white cell counts. Measures of subclinical CVD and rates of all-cause mortality and incident CHD were similar in isolated IFG and isolated IGT.

CONCLUSIONS

Neither isolated IFG nor isolated IGT was associated with a more adverse CVD risk profile.

Aldosterone as a key mediator of the cardiometabolic syndrome in primary aldosteronism: an observational study

OBJECTIVE

Primary aldosteronism (PA) is characterized by the onset of both cardiac and gluco-metabolic alterations. The aim of this study was to evaluate the impact of aldosterone excess on the development of such complications, and the effects of surgical and pharmacological treatment on their long-term outcome.

METHODS

We prospectively re-examined 61 patients: 25 with aldosterone-producing adenoma (APA), after surgery, and 36 patients with idiopathic hyperaldosteronism (IHA) on pharmacological treatment. The lipid, fasting and dynamic glucose profiles and the echocardiographic parameters were evaluated at diagnosis and at follow-up.

RESULTS

After adrenalectomy all patients had normalization of aldosterone levels and were cured of hypokalaemia, and a resolution of hypertension was achieved in 12 of 25 patients. APA patients showed a significant reduction of both plasma glucose (P=0.017) and insulin levels (P=0.001) after 75 g oral glucose tolerance test. Stabilization of glucose metabolism complications was observed in IHA patients. Multiple regression analysis at diagnosis showed a positive correlation between homeostasis model assessment (HOMA) insulin resistance index and HOMA beta cell and serum aldosterone levels in both APA and IHA. Echocardiographic parameters were improved in both APA and IHA at follow-up and the difference was statistically significant for left ventricular mass index (P=0.017) and interventricular septum thickness (P=0.007) in APA patients.

CONCLUSIONS

The removal of aldosterone excess in APA patients induces the regression of both cardiac and gluco-metabolic complications, indicating aldosterone as a main determinant of such alterations. In IHA patients the medical treatment seems to avoid the possible progression of the these alterations that appear to be stable.

Prediction of postprandial glycemic exposure: utility of fasting and 2-h glucose measurements alone and in combination with assessment of body composition, fitness, and strength

OBJECTIVE

To determine the best predictors of total postprandial glycemic exposure and peak glucose concentrations in nondiabetic humans.

RESEARCH DESIGN AND METHODS

Data from 203 nondiabetic volunteers who ingested a carbohydrate-containing mixed meal were analyzed.

RESULTS

Fasting glucose and insulin concentrations were poor predictors of postprandial glucose area above basal (R2 = approximately 0.07, P < 0.001). The correlation was stronger for 2-h glucose concentration (R2 = 0.55, P < 0.001) and improved slightly but significantly (P < 0.001) with the addition of fasting glucose, insulin, age, sex, and body weight to the model (r2 = 0.58). The 2-h glucose concentration also predicted the peak glucose concentration (R2 = 0.37, P < 0.001) with strength of the prediction increasing (P < 0.001) modestly with the addition of fasting glucose, insulin, age, sex, and body weight to the model (R2 = 0.48, P < 0.001). On the other hand, addition of measures of body function and composition did not improve prediction of total glycemic exposure or peak glucose concentration.

CONCLUSIONS

Isolated measures of fasting or 2-h glucose concentrations alone or in combination with more complex measures of body composition and function are poor predictors of postprandial glycemic exposure or peak glucose concentration. This may explain, at least in part, the weak and at times inconsistent relationship between these parameters and cardiovascular risk.

Effects of lipase inhibition on gastric emptying and alcohol absorption in healthy subjects

The rate of alcohol absorption is dependent on gastric emptying (GE). As the slowing of GE by fat is dependent on lipolysis, orlistat may increase the rise in blood alcohol when alcohol is consumed with, or after, fat. The aim of the study was to evaluate the effects of orlistat on GE and blood alcohol after an alcohol-containing drink following a fat 'preload', in healthy subjects. Ten healthy males consumed 120 ml cream with or without 120 mg orlistat, 30 min before an alcohol-containing drink labelled with 20 MBq [(99 m)Tc]sulfur colloid on 2 d. GE, plasma alcohol and blood glucose were measured. GE was slightly faster with orlistat (P<0.05) compared with control. Plasma alcohol at 15 min was slightly higher with orlistat (0.034 (SEM 0.006) g/100 ml) v. control (0.029 (SEM 0.005) g/100 ml) (P<0.05), but there was no effect on the area under the curve 0-240 min. The increase in blood glucose was greater with orlistat, for example, at 15 min (1.07 (SEM 0.2) mmol/l) v. control (0.75 (SEM 0.2) mmol/l) (P=0.05). The rise in blood glucose and plasma alcohol were related (for example, at 15 min r 0.49; P=0.03). In conclusion, lipase inhibition accelerates GE of an alcohol-containing drink following a fat 'preload' with a minor increase in the initial rise in plasma alcohol.

Predicting isolated postchallenge hyperglycaemia: a new approach; Tehran Lipid and Glucose Study (TLGS)

AIMS

To determine factors predicting isolated postchallenge hyperglycaemia (IPH) defined as fasting plasma glucose (FPG) < 7.0 mmol/l and 2-h plasma glucose (2-hPG) >or= 11.1 mmol/l after an oral glucose tolerance test (OGTT) and factors influencing the value of 2-hPG in a population-based study.

MATERIALS AND METHODS

From 15,005 participants in the Tehran Lipid and Glucose Study (TLGS), we analysed the results of OGTTs in 5386 individuals (2909 women and 2437 men) aged >or= 20 years, free of known diabetes and any other disorders influencing glucose metabolism. Logistic and multiple linear regression models were developed to predict IPH and the 2-hPG, respectively.

RESULTS

The overall prevalence of non-diabetic subjects, IPH and undiagnosed Type 2 diabetes mellitus (FPG >or= 7.0 mmol/l) were 94.5% (n = 5088), 2.5% (n = 133) and 3.1% (n = 165), respectively. Of subjects with IPH, 29.3% (n = 39) had FPG levels < 5.6 mmol/l. Factors associated with IPH were FPG (mmol/l) [odds ratio (OR) 11.05, 95% confidence interval (CI) 7.9, 15.4], age >or= 40 years (OR 2.0, 95% CI 1.3, 3.2), abnormal waist circumference (OR 2.1, 95% CI 1.4, 3.1) and serum triglycerides >or= 1.7 mmol/l (OR 2.0, 95% CI 1.3, 3.1). In the multiple linear regression model, six explanatory factors (FPG, age, female sex, triglycerides, systolic blood pressure, waist circumference) were positively related to 2-hPG.

CONCLUSIONS

The model could predict 47.7% of total variance of 2-hPG. Based on our results in this Iranian population, OGTT can be recommended in subjects with FPG < 7.0 mmol/l in the presence of abnormal waist circumference and triglycerides, age >or= 40 years and in particular when FPG is close to 7.0 mmol/l.

Targeting postprandial hyperglycemia

In healthy individuals, blood glucose levels in the fasting state are maintained by the continuous basal-level insulin secretion. After a meal, the rise in postprandial glucose (PPG) is controlled by the rapid pancreatic release of insulin, stimulated by both glucose and the intestinal production of the incretins glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1. In diabetic individuals, postprandial insulin secretion is insufficient to suppress an excessive rise in PPG. There is increasing evidence that elevated PPG exerts a more deleterious effect on the vascular system than elevation of fasting plasma glucose. In particular, individuals with normal fasting plasma glucose but impaired glucose tolerance have significantly increased risk of cardiovascular events. With the recognition of the importance of PPG and the availability of new pharmacologic options, management of diabetes will shift to greater attention to PPG levels. The prototype for such an approach is in the treatment of gestational diabetes and diabetic pregnancies where PPG is the primary target of efforts at glycemic control. These efforts have been extremely successful in improving the outlook for diabetic pregnant women. There are many approaches to reduction of PPG; dietary management and promotion of exercise are very effective. Sulfonylureas, meglitinides, metformin, thiazolidinediones, and disaccharidase inhibitors all counteract PPG elevation. The development of glucagon-like peptide 1 agonists such as exendin and dipeptidyl peptidase IV inhibitors such as vildagliptin offers a new approach to suppression of PPG elevation. New semisynthetic insulin analogues permit a more aggressive response to postprandial glucose elevation, with lower risk of hypoglycemia, than with regular insulin. Inhaled insulin also has a rapid onset of action and offers benefits in PPG control. It is proposed that an aggressive treatment approach focusing on PPG, similar to the current standards for diabetic pregancies, be directed at individuals with diabetes and impaired glucose tolerance.

Seventy-five gram glucose tolerance test to assess carbohydrate malabsorption and small bowel bacterial overgrowth

AIM: To investigate non-invasively the incidence of absorption of carbohydrates in diabetic patients during an oral glucose tolerance test (OGTT) and to determine whether malabsorption may be associated with insulin secretion and insulin resistance.

METHODS: A standard 75-g OGTT was performed in 82 diabetic patients. The patients received 75 g of anhydrous glucose in 225 mL of water after an overnight fasting and breath samples were collected at baseline and up to 120 min after ingestion. Breath hydrogen and methane concentrations were measured. Blood glucose and serum insulin concentrations were measured before ingestion and at 30, 60, 90, 120 min post-ingestion.

RESULTS: When carbohydrate malabsorption was defined as subjects with an increase of at least 10 ppm (parts per million) in hydrogen or methane excretion within a 2-h period, 28 (34%) had carbohydrate malabsorption. According to the result of increased breath test, 21 (75%) patients were classified as small bowel bacterial overgrowth and 7 (25%) as glucose malabsorption. Patients with carbohydrate malabsorption were older and had poor glycemic control as compared with those without carbohydrate malabsorption. The HOMA value, the sum of serum insulin during the test and the Δinsulin/Δglucose ratio were greater in patients with carbohydrate malabsorption.

CONCLUSION: Insulin resistance may be overestimated by using these markers if the patient has carbohydrate malabsorption, or that carbohydrate malabsorption may be present prior to the development of insulin resistance. Hence carbohydrate malabsorption should be taken into account for estimating insulin resistance and β-cell function.

Impaired glucose tolerance, diabetes, and cardiovascular disease

OBJECTIVE

To analyze the association among impaired glucose tolerance (IGT), diabetes, and cardiovascular disease (CVD).

METHODS

We review current studies that have addressed the foregoing relationship and summarize the results of diagnostic and therapeutic interventions.

RESULTS

A major cause of the reduction in life expectancy in patients with diabetes is CVD and cardiovascular complications. Both prediabetes and diabetes predispose to cardiovascular alterations. IGT and even the upper normal values of nondiabetic glucose levels are associated with an increased cardiovascular risk. The risk of heart disease can be increased as early as 15 years before the diagnosis of diabetes. Patients with chronic or acute CVD and no previous diagnosis of diabetes frequently present with either IGT or diabetes. Thus, such patients should undergo screening for diabetes with an oral glucose tolerance test. In acute coronary syndromes, lowering of glucose levels to the near-normal range by administration of insulin is highly beneficial. Early, rigorous interventions to improve metabolic control will yield better cardiovascular outcomes in patients with dysglycemia.

CONCLUSION

Aggressive preventive and treatment strategies, which can include multiple interventions, are needed to minimize the potential effects of CVD in patients with diabetes or IGT.

Epidemiology of the diabetic heart

Diabetes mellitus is a worldwide epidemic. Cardiovascular disease remains the major cause of morbidity and mortality in people with diabetes. Studies have suggested that increased risk of cardiovascular disease is not restricted to type II or type I diabetes mellitus, but extends to prediabetic stages such as impaired fasting glucose, impaired glucose tolerance, metabolic syndrome, and obesity. Insulin resistance, impaired fasting glucose, impaired glucose tolerance, and diabetes mellitus form a continuous sequence of risk for cardiovascular disease. Therefore, cardiovascular disease mortality and morbidity within the diabetes epidemic grow into vast proportions. Evidence also exists that diabetic patients have a high prevalence of heart failure or impaired diastolic and systolic cardiac function subsequent to the combination of coronary artery disease, hypertension, and diabetic cardiomyopathy. In view of the proportions of this new epidemic, prevention of diabetes and its prediabetic states is likely to be the most effective strategy to prevent serious cardiovascular events.

Efficacy and adverse effects of nateglinide in early type 2 diabetes. Comparison with voglibose in a cross-over study

An open-label prospective cross-over trial was performed to compare the efficacy and adverse effects of nateglinide with those of voglibose on Japanese early type 2 diabetes (who were oral hypoglycemic agent naïve and whose HbA(1C) levels were between 7.0 and 7.9% before treatment). Fourteen patients received 270 mg/day of nateglinide and 15 patients received 0.6 mg/day of voglibose. After 12 weeks of either therapy, the drugs were switched and treatment was continued for another 12 weeks. After 3-month treatment with each drug, HbA(1C) value decreased significantly (baseline HbA(1C) 7.24 +/- 0.42%, 6.70 +/- 0.47% with nateglinide: p<0.01, 6.93 +/- 0.62% with voglibose: p<0.05) but the difference in the effect between nateglinide and voglibose was not significant (p = 0.121). Symptoms related to hypoglycemia (e.g., increased appetite, palpitation, sweating, tremor) were scarcely observed with either voglibose or nateglinide treatments. Abdominal fullness/borborygmi was frequently reported, with variable severity, by patients on voglibose but this was absent or mild in those on nateglinide. After completion of both arms of the study, more patients favored nateglinide than voglibose. Our results suggest that nateglinide is an effective and safe drug in the treatment of early type 2 diabetes, similar to voglibose.

Postprandial hyperglycaemia: to treat or not to treat?

Accumulating evidence suggests that the postprandial or the post-75 g glucose load rise in plasma glucose are a contributing factor to the development of atherosclerosis. Many epidemiological studies have shown that post-load hyperglycaemia is a strong and independent risk factor for cardiovascular disease. The few interventional studies available also support a role for postprandial or post-load hyperglycaemia on cardiovascular disease or mortality or on validated surrogates of atherosclerosis. The mechanism through which acute hyperglycaemia could exert its deleterious effects on the vessel wall is very likely multifactorial, but the overproduction of free radicals is probably involved. There is growing evidence that treating postprandial hyperglycaemia should probably be part of the strategies for the prevention and management of cardiovascular diseases in pre-diabetes as well as in diabetes.

Insulin resistance reduces arterial prostacyclin synthase and eNOS activities by increasing endothelial fatty acid oxidation

Insulin resistance markedly increases cardiovascular disease risk in people with normal glucose tolerance, even after adjustment for known risk factors such as LDL, triglycerides, HDL, and systolic blood pressure. In this report, we show that increased oxidation of FFAs in aortic endothelial cells without added insulin causes increased production of superoxide by the mitochondrial electron transport chain. FFA-induced overproduction of superoxide activated a variety of proinflammatory signals previously implicated in hyperglycemia-induced vascular damage and inactivated 2 important antiatherogenic enzymes, prostacyclin synthase and eNOS. In 2 nondiabetic rodent models--insulin-resistant, obese Zucker (fa/fa) rats and high-fat diet-induced insulin-resistant mice--inactivation of prostacyclin synthase and eNOS was prevented by inhibition of FFA release from adipose tissue; by inhibition of the rate-limiting enzyme for fatty acid oxidation in mitochondria, carnitine palmitoyltransferase I; and by reduction of superoxide levels. These studies identify what we believe to be a novel mechanism contributing to the accelerated atherogenesis and increased cardiovascular disease risk occurring in people with insulin resistance.

Therapeutic efficacy of mitiglinide combined with once daily insulin glargine after switching from multiple daily insulin regimen of aspart insulin and glargine in patients with type 2 diabetes mellitus

Mitiglinide is novel class of rapid-acting insulin secretagogues, which have been widely used alone or in combination with other oral hypoglycemic drugs to improve postprandial hyperglycemia in early type 2 diabetes. While mitiglinide enhances postprandial requirement of insulin, the efficacy of mitiglinide combined with insulin has yet to be established. We investigated the efficacy of mitiglinide combined with insulin glargine, the first soluble insulin analog that has a flat and prolonged effect. After control with the intensive regimen (daily aspart insulin and glargine), 30 inpatients with type 2 diabetes were switched to premeal mitiglinide combined with once daily insulin glargine (mitiglinide regimen), and daily profiles of blood glucose level were compared under each regimen. Fifteen patients showed similar control of hyperglycemia with mitiglinide regimen and intensive insulin regimen, assessed by M value (<32), while the remaining 15 showed worsening under the mitiglinide regimen. The patients who were well controlled with mitiglinide regimen were significantly younger (51.9 +/- 16.0 years, p<0.005) and heavier (body mass index: 25.7 +/- 3.3 kg/m(2), p<0.05) than those who were not (67.9 +/- 8.7 and 23.0 +/- 3.1, respectively). Moreover, insulin doses of aspart per body weight were significantly fewer in effective group than in ineffective group. Duration of diabetes was shorter in the effective group, albeit insignificantly. Previous treatment before starting intensive insulin regimen, such as insulin and sulfonylurea, was not different between the two groups. Our results suggest that mitiglinide plus insulin glargine combination therapy is useful for lowering both fasting and postprandial hyperglycemia in a subpopulation of type 2 diabetes. The long-term effects of such treatment need to be established in future studies.

Pioglitazone and reductions in post-challenge glucose levels in patients with type 2 diabetes

AIM

Pioglitazone (PIO) has been shown to decrease insulin resistance in patients with type 2 diabetes, resulting in lowered blood glucose concentrations, lowered plasma insulin levels and lowered haemoglobin A1C (A1C) values. Postprandial glucose control has been recently recognized as an important target for reducing overall glycemic burden in patients with type 2 diabetes. Some authors assert that reductions in postprandial glucose levels may lead to a decrease in cardiovascular risk, one of the major complications associated with diabetes.

METHODS

Data were analysed from a 26-week PIO monotherapy study of 88 patients who underwent a 3-h oral glucose tolerance test (75 g dose) at baseline and last measurement. Change from baseline in area under the curve (AUC) values and hourly glucose concentrations were calculated and analysed at both time points for four medication groups: placebo group and PIO 15, 30 and 45 mg groups. Changes from baseline in fasting plasma glucose (FPG) and A1C also were reported.

RESULTS

Glucose AUC was significantly (p < 0.05) different from baseline at 15, 30 and 45 mg doses of PIO. In addition, when compared to placebo, PIO (15, 30 and 45 mg) significantly decreased post-challenge blood glucose AUC (p < 0.05). The mean hourly blood glucose levels at last measurement for PIO 15, 30 and 45 mg all were significantly lower (p < 0.05) than placebo at all four time points. In addition, PIO significantly (p < 0.05) reduced FPG and A1C from baseline to last measurement in a dose-related fashion.

CONCLUSIONS

PIO significantly reduced post-challenge glucose levels following an oral glucose challenge, leading to improvements in overall glycemic control. Postprandial glucose lowering is one of several metabolic effects of PIO in addition to decreasing insulin resistance and improving some lipids components. Whether these combined metabolic effects can lead to cardiovascular risk reductions may be confirmed by the pending results of cardiovascular outcomes studies with PIO.

Treatment of Impaired Glucose Tolerance with Acarbose and Its Effect on Intima-Media Thickness: A Substudy of The Stop-Niddm Trial (Study to Prevent Non-Insulin-Dependent Diabetes Mellitus)

OBJECTIVE

To discuss the influence of glucose excursions on intima-media thickness (IMT) and the potential benefits of treatment to reduce or reverse its effects on cardiovascular risk.

METHODS

The findings in pertinent reported studies are reviewed, and the efficacy of various interventions for management of impaired glucose tolerance and type 2 diabetes in slowing the progression of IMT is analyzed.

RESULTS

Considerable evidence from published epidemiologic studies provides compelling data regarding the association between postprandial and postchallenge glycemic excursions and cardiovascular risk. IMT has been shown to be a good surrogate marker for symptomatic and coronary atherosclerosis. Acarbose treatment in patients with impaired glucose tolerance has been shown to diminish the progression of IMT in comparison with placebo. In a study of repaglinide or glyburide therapy in patients with type 2 diabetes, a reduction in IMT was noted in the repaglinide group but not in the glyburide group at 1-year follow-up.

CONCLUSION

Measurement of IMT allows direct observation of vascular damage attributable to postprandial and postchallenge hyperglycemia. It also provides a means for direct assessment of the effect of medications used for the control of glucose excursions.

Opposing glucose set points hypothesis of essential hypertension

Understanding of the mechanisms involved in the development of essential hypertension is incomplete. Many studies have demonstrated that sympathetic overactivity is involved in the development of essential hypertension. In addition, hypertensive patients, as a group, are insulin resistant. The relationship of increased sympathetic activity to insulin resistance in essential hypertension has not been adequately explained. Hypertensive subjects have been reported to have rapid gastric emptying compared to control subjects. They also have increased postprandial hypotensive responses to high carbohydrate meals compared with non-hypertensive control subjects. The author hypothesizes that essential hypertension is the result of a metabolic disregulation in which the body's glucose regulatory system splits into two separate glucose control systems with two different homeostatic set points for fasting and postprandial glucose levels. It is proposed that insulin is the principle regulator of the lower glucose set point while counter-regulatory hormones, predominantly catecholamines, as well as the rate of gastric emptying, are regulators of the upper glucose set point. The tension between these two opposing control systems results in increased sympathetic activity, increased fasting and postprandial glucose and insulin levels and an increased rate of gastric emptying in hypertension. It is hypothesized that increased sympathetic activity from these opposing regulatory systems initiates a vicious cycle that eventually leads to the development of essential hypertension. This hypothesis explains the beneficial effects of agents that either slow carbohydrate absorption or delay gastric emptying on essential hypertension and postprandial hypotension. New therapeutic strategies for treatment of hypertension are suggested by this hypothesis.

Impaired glucose metabolism in patients with acute stroke and no previous diagnosis of diabetes mellitus

BACKGROUND

About a third of patients with acute stroke and no prior diagnosis of diabetes have hyperglycaemia during the acute phase of stroke. Whether this is an acute stress response or a reflection of underlying diabetes is controversial.

AIM

To assess whether impaired glucose metabolism in patients with acute ischaemic stroke and no previous diagnosis of diabetes persists after 3 months, and whether such persistence can be predicted.

DESIGN

Prospective observational study.

METHODS

We enrolled 106 patients with acute ischaemic stroke and no history of diabetes. Fasting blood glucose, serum insulin and the insulin resistance index HOMA were recorded during hospital stay. A standard oral glucose tolerance test was performed at discharge and 3 months later.

RESULTS

Ten patients did not complete the study. Eighty-one patients (84.4%) had abnormal glucose metabolism at discharge and 62 (64.6%) after 3 months. Thirty-seven (38.5%) had impaired glucose tolerance at discharge and 26 (27.1%) after 3 months. Forty-four (45.8%) had diabetes at discharge, and 36 (37.5%) at 3 months. Post-load hyperglycaemia at discharge was a predictor of diabetes after 3 months. A plasma glucose cut-off of 11.7 mmol/l (210 mg/dl) had a specificity of 90.0% and a positive predictive value of 81.3%. HOMA increased progressively from patients with normal glucose metabolism to those with newly diagnosed diabetes.

DISCUSSION

Impaired glucose tolerance and previously unrecognized diabetes could be detected early in the stroke course, and persisted after 3 months in more than two-thirds of our patients. Post-load hyperglycaemia during the acute phase of stroke may be useful in identifying patients with abnormal glucose metabolism, which places them at risk for adverse outcomes, including cardiovascular disease.

The Links between Diabetes and Cardiovascular Disease

The aim of this study was to review current studies relevant to the link between impaired glucose tolerance (IGT), diabetes, and cardiovascular disease. Cardiovascular disease is a major cause of the reduction in life expectancy in patients with diabetes. Seventy-five percent of diabetic patients die prematurely of cardiovascular complications. Both prediabetes and diabetes highly pre-dispose to cardiovascular alterations. IGT and even the upper-normal of nondiabetic glucose values are associated with an increased cardiovascular risk. The risk of heart disease is increased up to 15 years prior diagnosis of diabetes. Patients with chronic or acute cardiovascular disease and no previous diagnosis of diabetes frequently present with either IGT or diabetes. Patients with cardiovascular disease and no previous diagnosis of diabetes need to be screened for diabetes with an oral glucose tolerance test. In acute coronary syndromes, lowering glucose levels to the near-normal range with insulin is highly beneficial. Early and rigorous improvement of metabolic control is highly supportive in improving the cardiovascular outcome in patients with dysglycemia. Preventive treatment strategies, which include multiple approaches, are required to overcome the burden of cardiovascular disease in diabetes and IGT.

Increased mortality risks of pre-diabetes (impaired fasting glucose) in Taiwan

OBJECTIVE

The objective of this article was to assess mortality risks at different levels of fasting blood glucose (FBG) in Taiwan, with particular attention to those pre-diabetic subjects with impaired fasting glucose (IFG).

RESEARCH DESIGN AND METHODS

Governmental employees and schoolteachers were followed up for an average of 11 years. With the use of Cox regression analyses, mortality risks were calculated for 36,386 subjects, aged 40-69.

RESULTS

FBG > or =110 mg/dl was associated with increased mortality risks for all causes, cardiovascular diseases (CVD), and diabetes. IFG, when defined as 110-125 mg/dl, was associated with a significant increase for CVD and/or diabetes mortality. These mortality risks remained elevated when known CVD risk factors were adjusted for. The IFG group shared risk factor characteristics more with the FBG > or =126 mg/dl group than with the FBG <110 mg/dl group. When IFG was defined as 100-125 mg/dl, the number of subjects quadrupled, but mortality risks diminished substantially because of the inclusion of 100-109 mg/dl group. The lowest FBG group, 50-75 mg/dl, had a significant 2-fold risk from all causes.

CONCLUSIONS

There was an overall J-shaped relationship between all-cause mortality and FBG. IFG, when defined as 110-125 mg/dl, is an independent risk factor and should be aggressively treated as a disease because its subsequent mortality risks for CVD and diabetes were significantly increased. The newly defined IFG at 100-125 mg/dl did not have the predictive power for later increases in CVD or diabetes mortality.

Post-prandial hyperglycemia is an important predictor of the incidence of diabetic microangiopathy in Japanese type 2 diabetic patients

Diabetic microangiopathy is often observed in diabetic patients, but there is little evidence regarding the relationship between post-prandial glycemia or insulinemia and the incidence of diabetic microangiopathy. In this study, to elucidate the relationship between post-prandial glycemia (or insulinemia) and diabetic microangiopathy, we performed a cross-sectional study of 232 subjects with type 2 diabetes mellitus who were not being treated with insulin injections. A multiple regression analysis showed that post-prandial hyperglycemia independently correlated with the incidence of diabetic retinopathy and neuropathy. Post-prandial hyperglycemia also correlated, although not independently, with the incidence of diabetic nephropathy. In addition, interestingly, post-prandial hypoinsulinemia independently correlated with the incidence of diabetic retinopathy, although not correlated with diabetic neuropathy or nephropathy. In conclusion, post-prandial hyperglycemia, rather than fasting glycemia or hemoglobin A1c levels, is an important predictor of the incidence of diabetic microangiopathy in Japanese type 2 diabetic patients.

Prandial hyperglycemia: is it important to track and treat?

Prandial hyperglycemia comprises 16 to 18 hours in type 2 diabetes. Depending on quality of diabetes control, 30% to 70% of the variance of hemoglobin A(1c) is determined by postprandial glucose excursions. A large amount of evidence now shows that postprandial/postchallenge glucose value is an independent cardiovascular risk factor, especially for coronary heart disease. Excessive postprandial hyperglycemia initiates a cascade of proatherogenic disturbances, which leads to endothelial dysfunction and plaque instability. Measurement of 2-hour postprandial glucose after big meals should be performed once or twice a week in subjects with type 2 diabetes. Measurement of 2-hour glucose after a 75-g oral glucose tolerance test is the only way to detect subjects with impaired glucose tolerance and isolated postchallenge hyperglycemia in the diagnosis for diabetes. a-Glucosidase inhibitors, glinides, and short-acting analogue insulin allow a well-tailored control of type 2 diabetes with excessive postprandial hyperglycemia. Prospective trials have demonstrated that strict control of postprandial hyperglycemia reduces the incidence of cardiovascular events.

Continuous glucose monitoring system signals the occurrence of marked postprandial hyperglycemia in the elderly

BACKGROUND

The aim of this study was to ascertain whether dysglycemic episodes occur in institutionalized elderly persons and, if that is the case, to determine whether such episodes are related to meal patterns. Another objective was to investigate the feasibility of subcutaneous (s.c.) glucose measurements in the elderly using a Medtronic MiniMed (Sylmar, CA) continuous glucose monitoring system (CGMS).

METHODS

Nine nursing home residents (74-95 years old) without known diabetes or other metabolic disorders were included. The s.c. glucose level was measured for 3 days with the Medtronic MiniMed CGMS. Capillary blood glucose was measured four times daily with a Glucometer Elite device (Bayer, Leverkusen, Germany). Body mass index and basal metabolic rate were calculated, and food intake was recorded.

RESULTS

The s.c. glucose level fluctuated noticeably over time; 22.5% of the values recorded during the 3-day period were > or = 8 mmol/L, and values < 3.5 mmol/L were rarely seen. A marked (> 5 mmol/L) and short-term (2-4 h) increase in s.c. glucose was seen after a meal. The mean capillary blood glucose concentration was 7.5 +/- 1.8 mmol/L. Capillary blood glucose > or = 8 mmol/L was recorded on 32.5% of the measurement occasions, and no values were < 3.5 mmol/L. The s.c. glucose values agreed with corresponding capillary blood glucose levels (mean r = 0.75; range 0.43-0.86). Five participants consumed less energy than recommended according to their age, weight, and physical activity level.

CONCLUSIONS

Postprandial hyperglycemia frequently occurs in elderly people living in nursing homes. The CGMS is convenient to use to detect hyperglycemia in this age group.

The beneficial effect of a diet with low glycaemic index on 24 h glucose profiles in healthy young people as assessed by continuous glucose monitoring

Elevated postprandial glycaemia has been linked to CVD in a number of different epidemiological studies involving predominantly non-diabetic volunteers. The MiniMed continuous glucose monitor, which measures blood glucose every 5 min, over a 24 h period, was used to investigate changes in blood glucose readings before and after instigating a diet with low glycaemic index (GI) for 1 week in free-living healthy individuals. Nine healthy people (age 27 (SEM 1.3) years, BMI 23.7 (SEM 0.7) kg/m2, one male, eight females) completed the study. A reduction in GI (59.7 (SEM 2) v. 52.1 (SEM 2), P<0.01) occurred in all nine subjects while energy and other macronutrients remained constant. A significant reduction was also observed in fasting glucose at 06.00 hours (5.4 (SEM 0.2) v. 4.4 (SEM 0.3) mmol/l, P<0.001), mean glucose (5.6 (SEM 0.2) v. 5.1 (SEM 0.2) mmol/l, P=0.004), area under the 24 h glucose curve (8102 (SEM 243) v. 750 (SEM 235) mmol/l per min, P=0.004) and area under the overnight, 8 h glucose curve (2677 (SEM 92) v. 2223 (SEM 121) mmol/l per min, P=0.01). The present study provides important data on how a simple adjustment to the diet can improve glucose profiles that, if sustained in the long term, would be predicted from epidemiological studies to have a favourable influence on CVD.

Effects of lipase inhibition on gastric emptying of, and on the glycaemic, insulin and cardiovascular responses to, a high-fat/carbohydrate meal in type 2 diabetes

AIMS/HYPOTHESES

We examined the effects of lipase inhibition with orlistat on (i) gastric emptying of, and (ii) the glycaemic, glucagon-like peptide-1 (GLP-1) and cardiovascular responses to, a high-fat/carbohydrate meal in type 2 diabetic patients.

METHODS

Eight type 2 diabetic patients, who were aged 62 years (median range: 49-68 years) and managed by diet alone, consumed a meal containing 65 g powdered potato, 20 g glucose reconstituted with 200 ml water (labelled with 20 MBq (99m)Tc-sulphur-colloid) and 45 g margarine. They did this on two separate occasions, with and without 120 mg orlistat, and while in the seated position with their back against a gamma camera. Venous blood samples for measurement of blood glucose, plasma insulin and GLP-1 were obtained immediately before the meal and at regular intervals afterwards. Blood pressure (systolic and diastolic) and heart rate were measured using an automated device.

RESULTS

Gastric emptying of the meal was faster after orlistat than without orlistat (50% emptying time [mean +/- SEM], 61+/-8 min vs 98+/-5 min; p=0.0001). In the first 60 min after the meal blood glucose (p=0.001) and plasma insulin (p=0.01) concentrations were higher in patients who had taken orlistat; between 60 and 180 min plasma GLP-1 (p=0.02) concentrations were lower after orlistat than without orlistat. Between 0 and 30 min systolic blood pressure (p=0.003) was lower, and heart rate (p=0.03) greater in subjects who had taken orlistat than in those who had not.

CONCLUSIONS/INTERPRETATION

Inhibition of fat digestion by orlistat may-as a result of more rapid gastric emptying-exacerbate postprandial glycaemia and the postprandial fall in blood pressure in patients with type 2 diabetes after ingestion of meals containing fat and carbohydrate.

Postprandial hyperglycaemia in type 2 diabetes: pathophysiological aspects, teleological notions and flags for clinical practice

Type 2 diabetes subjects carry an excess risk for micro- and macrovascular disease and a higher cardiovascular morbidity and mortality rate. The beneficial impact of tight glycaemic control-evidenced by the integrated marker of fasting glucose and postprandial glucose values, the HbA1c-for the prevention of microvascular complications is definitely confirmed. Over the past few years, several studies have identified postprandial hyperglycaemia as a better predictor of cardiovascular or even of all-cause mortality, as well as an independent risk factor for atherosclerosis. The continuous glucose monitoring could offer a rationale means for the detection of postprandial hyperglycaemia and ultimately for its effective management. Advances in technology keep a promise for a reliable, convenient and closer to the idea of the artificial endocrine pancreas glucose sensor. Subcutaneous glucose levels charted by one of the new sensors were found to be well correlated with venous glucose measurements. Intervention for a healthy lifestyle is frequently hampered by patients' poor compliance. The availability of diverse antidiabetic agents provides options for targeting the glycaemic goal and a choice more fitted to the particularized pathophysiology of each individual subject. Drugs targeting postprandial glycaemia may prove to represent the 'sine qua non' for the 'return' of postprandial glucose values at a 'non-deleterious' threshold, either as monotherapy for the early stages of the disease or as combination therapy later in the progression of diabetes.

Impaired glucose tolerance and cardiovascular disease: the possible role of post-prandial hyperglycemia

There is increasing evidence that the post-prandial state is an important contributing factor in the development of atherosclerosis. In subjects with impaired glucose tolerance, whereas fasting glycemia is in reference range, the post-prandial phase is characterized by a rapid and large increase in blood glucose levels. The possibility that this post-prandial "hyperglycemic spike" may be relevant to the development of cardiovascular disease in these subjects has received recently much attention. The oral glucose tolerance test, although highly non-physiological, has been used largely as model of the post-prandial state, and epidemiological studies have shown that impaired oral glucose tolerance is associated with an increased risk of cardiovascular disease, because the glycemia level after 2 hours of the glucose challenge is a direct and independent risk factor. Most of the cardiovascular risk factors are modified in the post-prandial phase and are directly affected by an acute increase of glycemia. The mechanisms through which acute hyperglycemia exerts its effects may be identified in the production of free radicals, which favours the development of an endothelial dysfunction, a prothrombotic and proinflammatory condition. Future studies may evaluate whether correcting the post-prandial hyperglycemia in the impaired glucose tolerance state can form part of the strategy for the prevention and management of cardiovascular diseases in these subjects.

Acarbose slows progression of intima-media thickness of the carotid arteries in subjects with impaired glucose tolerance

BACKGROUND AND PURPOSE

Impaired glucose tolerance (IGT)-a prediabetic state-is an important risk factor for atherosclerosis. Acarbose, an alpha-glucosidase inhibitor, was shown in the placebo-controlled prospective study to prevent noninsulin-dependent diabetes mellitus (STOP-NIDDM) trial to reduce the risk of diabetes by 36% in IGT subjects. This article reports on a placebo-controlled subgroup analysis of the STOP-NIDDM study to examine the efficacy of acarbose to slow progression of intima-media thickness (IMT) in subjects with IGT.

METHODS

One hundred thirty-two IGT subjects were randomized to placebo (n=66) or acarbose (n=66) 100 mg 3 times daily; the study duration was at least 3 years, mean follow-up time 3.9 (SD 0.6) years. Carotid IMT was determined at study entry and the end of the trial. The intent-to-treat analysis included 56 subjects in the acarbose and 59 in the control group who had a baseline and endpoint measurement.

RESULTS

A significant reduction of the progression of IMT(mean) was observed in the acarbose group versus placebo. After an average time of 3.9 years, IMT(mean) increased by 0.02 (0.07) mm in the acarbose group versus 0.05 (0.06) mm in the placebo group (P=0.027). The annual increase of IMT(mean) was reduced by approximately 50% in the acarbose group versus placebo. Multiple linear regression revealed IMT progression as significantly related to acarbose intake.

CONCLUSIONS

Acarbose slows progression of IMT in IGT subjects, a high-risk population for diabetes and atherosclerosis. This is the first placebo-controlled prospective subgroup analysis, demonstrating that counterbalancing of postprandial hyperglycemia may be vasoprotective.

Nontraditional risk factors for cardiovascular disease in diabetes

People with type 2 diabetes are disproportionately affected by cardiovascular disease (CVD), compared with those without diabetes. Traditional risk factors do not fully explain this excess risk, and other "nontraditional" risk factors may be important. This review will highlight the importance of nontraditional risk factors for CVD in the setting of type 2 diabetes and discuss their role in the pathogenesis of the excess CVD morbidity and mortality in these patients. We will also discuss the impact of various therapies used in patients with diabetes on nontraditional risk factors.

Intensive lifestyle changes or metformin in patients with impaired glucose tolerance: Modeling the long-term health economic implications of the diabetes prevention program in Australia, France, Germany, Switzerland, and the United Kingdom

BACKGROUND

In the Diabetes Prevention Program (DPP), interventions with metformin (plus standard lifestyle advice) or intensive lifestyle changes (ILC) reduced the risk of developing type 2 diabetes mellitus (DM) by 31% and 58%, respectively, versus control (standard lifestyle advice only) in patients with impaired glucose tolerance (IGT).

OBJECTIVE

The goal of this study was to establish whether implementing the active treatments used in the DPP would be cost-effective in Australia, France, Germany, Switzerland, and the United Kingdom.

METHODS

A Markov model simulated 3 states-IGT, type 2 DM, and deceased-using probabilities from the DPP and published data. Country-specific direct costs were used throughout.

RESULTS

Assuming only within-trial effects and costs of interventions, both metformin and ILC improved life expectancy versus control. Mean improvements in nondiscounted life expectancy were 0.11 and 0.22 years for metformin and ILC, respectively. Both interventions were associated with cost savings versus control in all countries except the United Kingdom, where a small increase in costs was observed in both intervention arms. When a lifetime effect of interventions was assumed, incremental improvements in life expectancy were 0.35 and 0.90 years for metformin and ILC, respectively. Results were sensitive to probabilities of developing type 2 DM, the projected long-term duration of effect of interventions after the 3-year trial period, the relative risk of mortality for type 2 DM compared with IGT, and the costs of implementing the interventions.

CONCLUSIONS

Based on probabilities from the DPP and published data, in this model analysis, incorporation of the DPP interventions into clinical practice in 5 developed countries was projected to lead to an increase in DM-free years of life, improvements in life expectancy, and either cost savings or minor increases in costs compared with standard lifestyle advice in a population with IGT. Thus, financial constraints should not prevent the implementation of DM prevention programs.

The metabolic syndrome in children and adolescents

The metabolic syndrome was recently defined by the Adult Treatment Panel III. Despite a lack of uniform definition of the syndrome in pediatrics, recent studies have shown that the syndrome develops during childhood and is highly prevalent among overweight children and adolescents. The hypothesized central role of insulin resistance and obesity as a common underlying feature of the metabolic syndrome also appears to be already manifested in childhood. In view of the current obesity epidemic in children and adolescents, there is a vital need to provide adequate guidelines for the definition of the metabolic syndrome in pediatrics and for the development of screening and treatment strategies. This article focuses on the above issues, as well as on the impact of the syndrome on two major disease outcomes, type 2 diabetes and cardiovascular disease.

The potential of metformin for diabetes prevention

Well designed intervention trials, such as the Diabetes Prevention Program (DPP), have demonstrated the potential of lifestyle interventions or pharmacologic treatments for the prevention or delay of type 2 diabetes in subjects with impaired glucose tolerance (IGT). Lifestyle interventions are likely to form the cornerstone of the management of IGT in the future, as they do in the management of type 2 diabetes today. However, it remains to be seen whether the intensive lifestyle interventions employed in trials such as the DPP can be transferred successfully from the highly structured environment of a randomised trial to routine, day-to-day management within the primary care sector. Thus, pharmacologic treatment may provide an important additional option where subjects are unwilling or unable to improve their diet and levels of physical activity. Treatment with metformin significantly reduced the incidence of diabetes in subjects with IGT and high-normal fasting plasma glucose in the DPP. Moreover, metformin was well tolerated, and health economic analyses suggest that metformin treatment is cost-effective in the US and Europe. The DPP investigators found that the protective effect of metformin persisted beyond the end of the study, and estimated that only one quarter of the protection arose from a short-lived pharmacological effect. The results of the DPP identify metformin as an effective option for the prevention of diabetes in subjects with IGT and impaired fasting glucose.

Glyburide/metformin tablets: a new therapeutic option for the management of Type 2 diabetes

Oral antidiabetic combination therapy is a proven means of establishing glycaemic control in the hyperglycaemic, Type 2 diabetic patient, but co-administering two oral antidiabetic agents separately may hinder compliance with therapy. A new single-tablet of glyburide/metformin combination therapy (Glucovance), Bristol-Myers Squibb, Inc.) has recently been developed, which addresses the primary defects of Type 2 diabetes: beta-cell dysfunction and insulin resistance. The glyburide/metformin tablet, taken with meals, is designed to optimise the absorption of glyburide and to address the postprandial glucose rise. Glyburide/metformin tablets are more effective in controlling fasting and postprandial glycaemia than its component monotherapies, at lower doses of metformin and glyburide compared with monotherapy because of the synergy between its glyburide and metformin components. Moreover, a double-blind study showed that glyburide/metformin tablets are more effective than a free combination of glyburide co-administered with metformin in controlling postprandial glucose. Retrospective analyses suggested that glyburide/metformin tablets control glycated haemoglobin (A1C) more effectively than a free combination of glyburide co-administered with metformin, at lower mean doses of glyburide and metformin. The incidence of side effects is lower than separate component therapy for any given A1C. Glyburide/metformin tablets are an effective option for optimising the control of blood glucose in Type 2 diabetic patients and appear to enhance adherence to therapy.

Gender difference in all-cause and cardiovascular mortality related to hyperglycaemia and newly-diagnosed diabetes

AIM/HYPOTHESIS

Diabetic women generally have a greater relative risk of cardiovascular diseases than diabetic men in comparison with non-diabetic women and men. Reasons for this excess risk in diabetic women is still unclear. The aim of this study is to evaluate whether the association between different degrees of hyperglycaemia and the risk of all-cause and cardiovascular mortality is different in women and men.

METHODS

We analysed baseline glucose concentrations from 14 prospective European cohorts including 8172 men and 9407 women aged 30 to 89 years without history of diabetes, with a median follow-up of 8.3 years. Hazards ratios for all-cause and cardiovascular mortality were estimated adjusting for other risk factors.

RESULTS

The mortality rates for all-cause and cardiovascular diseases were higher in men than in women in normoglycaemia, impaired glucose regulation and newly-diagnosed diabetes; the largest sex differential for cardiovascular mortality was in normoglycaemic people. The hazards ratios for all-cause and cardiovascular mortality were higher in newly-diagnosed diabetic women than men compared with normoglycaemic women and men, respectively; however, this sex difference was only significant for cardiovascular mortality. For smokers and for subjects with hypertension, hypercholesterolaemia or who where overweight, the hazards ratios for cardiovascular mortality in diabetic patients compared with normoglycaemic people were also higher in women than in men.

CONCLUSIONS/INTERPRETATION

Newly diagnosed diabetic women showed higher relative risks for death from cardiovascular disease than diabetic men. Thus a more aggressive control of hyperglycaemia as well as of other cardiovascular risk factors might be appropriate in women with asymptomatic hyperglycaemia.

Factors responsible for development from normal glucose tolerance to isolated postchallenge hyperglycemia

OBJECTIVE

Isolated postchallenge hyperglycemia (IPH), defined as fasting plasma glucose (FPG) level <7.0 mmol/l and 2-h plasma glucose (PG) level >/=11.1 mmol/l, is a subtype of early-stage diabetes. This study evaluates the metabolic profiles of insulin secretion and insulin sensitivity in IPH to clarify the factors responsible for development of this form of type 2 diabetes.

RESEARCH DESIGN AND METHODS

We conducted cross-sectional analysis of 231 Japanese men aged 20-70 years. The subjects were classified into the following three groups, based on the results of a 75-g oral glucose tolerance test (OGTT): 1) normal glucose tolerance (NGT), defined as FPG level <6.1 mmol/l and 2-h PG level <7.8 mmol/l (n = 89); 2) impaired glucose tolerance (IGT), defined as FPG level <7.0 mmol/l and 2-h PG level of 7.8-11.1 mmol/l (n = 94); and 3) IPH (n = 48). We compared the three groups for insulin secretion (insulinogenic index) and insulin sensitivity (index of insulin resistance using homeostasis model assessment [HOMA-IR]).

RESULTS

The insulinogenic index in IPH was the lowest of the three groups (P < 0.001 versus NGT). The HOMA-IR in the IGT and IPH groups were significantly higher than in the NGT group (P < 0.001), but both were similar. By linear regression analysis, the insulinogenic index rather than fasting insulin or HOMA-IR was the more significant factor in the 2-h PG level in IGT and IPH.

CONCLUSIONS

Subjects with IPH exhibited distinctly impaired early-phase insulin secretion and only mild insulin resistance, indicating that reduced insulin secretion is the primary determinant of deterioration from NGT to IGT and IPH in development of type 2 diabetes in these subjects.

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

Although hyperinsulinemia has attracted considerable attention as a possible risk factor for coronary artery disease (CAD), previous studies have not shown consistent results. Hyperglycemia could be an alternative explanation for the association between type 2 diabetes and atherosclerosis. Since previous studies have been mostly lacking coronary angiographic data, we analyzed the relationship between the presence and severity of coronary atherosclerosis based on angiography and hyperinsulinemia or hyperglycemia. Two hundred and thirty subjects underwent coronary angiography and a 75-g oral glucose tolerance test. Age, sex, waist-to-hip ratio, postchallenge 1-h and 2-h glucose levels, plasma triglyceride and HDL-cholesterol levels were different between those with or without CAD. However, there was no significant difference in the plasma insulin levels, area of insulin under the curve, and the ratio of the insulin- and glucose areas between the groups with and without CAD. Multiple logistic regression analysis including fasting-, 1-h, and 2-h glucose values and a variety of atherosclerosis risk factors showed that age, sex and postchallenge 2-h glucose levels were independent determinants of the presence of CAD. These results suggest that coronary atherosclerosis might be associated with postchallenge hyperglycemia, but not with hyperinsulinemia in Korean subjects.

Isolated post-challenge hyperglycemia in patients with normal fasting glucose concentration exaggerates neointimal hyperplasia after coronary stent implantation

Postprandial hyperglycemia has been shown to increase the risk of cardiovascular disease as much as overt diabetes mellitus does. The aim of this study was to determine whether isolated post-challenge hyperglycemia during an oral glucose tolerance test (OGTT) is related to exaggerated neointimal proliferation after coronary stent implantation. Forty seven coronary lesions treated with stents in 40 patients who had normal fasting glucose levels (<110 mg/dl) were categorized into the following 2 groups according to the results of a 75-g OGTT: 29 lesions in 24 patients with normal glucose tolerance (NGT group) and 18 lesions in 16 patients with abnormal glucose tolerance (AGT group). Although there were no differences in angiographic characteristics before and immediately after stenting between the 2 groups, the minimal lumen diameter was significantly smaller (p=0.04) and the degree of stenosis and late loss were also significantly greater (p=0.01 and p=0.047) in the AGT group than in the NGT group at 6-month follow-up. Multiple regression analysis including the insulin concentrations during an OGTT revealed that the 120-min plasma glucose concentration after glucose load significantly correlated with late loss (p=0.0018) and the degree of stenosis (p=0.0100) at follow-up. It is concluded that isolated post-challenge hyperglycemia exaggerates neointimal hyperplasia after coronary stent implantation.

Nateglinide improves early insulin secretion and controls postprandial glucose excursions in a prediabetic population

OBJECTIVE

The purpose of this study was to evaluate the metabolic effectiveness, safety, and tolerability of nateglinide in subjects with impaired glucose tolerance (IGT) and to identify a dose appropriate for use in a diabetes prevention study.

RESEARCH DESIGN AND METHODS

This multicenter, double-blind, randomized, parallel-group, fixed-dose study of 8 weeks' duration was performed in a total of 288 subjects with IGT using a 2:2:2:1 randomization. Subjects received nateglinide (30, 60, and 120 mg) or placebo before each main meal. Metabolic effectiveness was assessed during a standardized meal challenge performed before and after the 8-week treatment. All adverse events (AEs) were recorded, and confirmed hypoglycemia was defined as symptoms accompanied by a self-monitoring of blood glucose measurement < or =3.3 mmol/l (plasma glucose < or =3.7 mmol/l).

RESULTS

Nateglinide elicited a dose-related increase of insulin and a decrease of glucose during standardized meal challenges, with the predominant effect on early insulin release, leading to a substantial reduction in peak plasma glucose levels. Nateglinide was well tolerated, and symptoms of hypoglycemia were the only treatment-emergent AEs. Confirmed hypoglycemia occurred in 28 subjects receiving nateglinide (30 mg, 0 [0%]; 60 mg, 5 [6.6%]; 120 mg, 23 [26.7%]) and in 1 (2.3%) subject receiving placebo.

CONCLUSIONS

Nateglinide was safe and effective in reducing postprandial hyperglycemia in subjects with IGT. Preprandial doses of 30 or 60 mg nateglinide would be appropriate to use for longer-term studies to determine whether a rapid-onset, rapidly reversible, insulinotropic agent can delay or prevent the development of type 2 diabetes.

Health and economic effects of adding nateglinide to metformin to achieve dual control of glycosylated hemoglobin and postprandial glucose levels in a model of type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus is a common disease whose complications have great costs, both in quality of life and expense of treatment. Improving glycemic control, as measured by monitoring glycosylated hemoglobin (HbA1c) levels, can reduce the rate of such complications.

OBJECTIVES

The aims of this study were to estimate the lifetime costs associated with diabetes-related complications in a theoretical population receiving metformin monotherapy and to predict the health and economic effect of improving glycemic control in this theoretical population by combining metformin with nateglinide.

METHODS

A pharmacoeconomic model was developed to simulate the long-term (30 years) complication rates (microvascular and macrovascular) of a cohort of patients with type 2 diabetes mellitus. The model simulated each year of life for each patient in a theoretical cohort of 10,000 patients until diabetes-related complications were present or death occurred. The mean accumulated costs (direct medical costs for acute care and subsequent care for diabetes-related complications), mean survival time, and the frequency of each type of complication were estimated. Both effectiveness and cost data were discounted at 3%. Sensitivity analyses were conducted on key model input parameters.

RESULTS

Average costs of treating complications in theoretical patients undergoing metformin monotherapy were estimated at $29,565 per patient. Savings of $2,742 were estimated per patient for all complications--particularly, nephropathy ($1,166) and macrovascular disease ($632)--when nateglinide was added. The cost-effectiveness ratio of adding nateglinide to metformin was estimated at $27,131 per undiscounted life-year gained (95% CI, $23,710-$28,577) or $43,024 (95% CI, $37,285-$45,193) per additional discounted life-year gained. In the sensitivity analyses, decreasing HbA1c level at baseline, HbA1c upward drift, and duration of disease improved survival.

CONCLUSIONS

Combination therapy with nateglinide and metformin, compared with metformin alone, was predicted to reduce the frequency of complications and, thus, treatment costs in this theoretical model. The major factor in cost savings was fewer complications due to nephropathy. The increased drug treatment costs were expected to be offset by the long-term savings from reducing complication rates.