A comparison of the relationships of the glucose tolerance test and the glycated haemoglobin assay with diabetic vascular disease in the community. The Islington Diabetes Survey

Efficacy of Postprandial Exercise in Mitigating Glycemic Responses in Overweight Individuals and Individuals with Obesity and Type 2 Diabetes-A Systematic Review and Meta-Analysis

Studies investigating the acute effect of postprandial exercise (PPE) on glucose responses exhibit significant heterogeneity in terms of participant demographic, exercise protocol, and exercise timing post-meal. As such, this study aimed to further analyze the existing literature on the impact of PPE on glycemic control in overweight individuals and individuals with obesity and type 2 diabetes (T2DM). A literature search was conducted through databases such as PubMed, CINAHL, and Google Scholar. Thirty-one original research studies that met the inclusion criteria were selected. A random-effect meta-analysis was performed to compare postprandial glucose area under the curve (AUC) and 24 h mean glucose levels between PPE and the time-matched no-exercise control (CON). Subgroup analyses were conducted to explore whether the glucose-lowering effect of PPE could be influenced by exercise duration, exercise timing post-meal, and the disease status of participants. This study revealed a significantly reduced glucose AUC (Hedges' g = -0.317; SE = 0.057; p < 0.05) and 24 h mean glucose levels (Hedges' g = -0.328; SE = 0.062; p < 0.05) following PPE compared to CON. The reduction in glucose AUC was greater (p < 0.05) following PPE lasting >30 min compared to ≤30 min. The reduction in 24 h mean glucose levels was also greater (p < 0.05) following PPE for ≥60 min compared to <60 min post-meal and in those with T2DM compared to those without T2DM. PPE offers a viable approach for glucose management and can be performed in various forms so long as exercise duration is sufficient. The glucose-lowering effect of PPE may be further enhanced by initiating it after the first hour post-meal. PPE is a promising strategy, particularly for patients with T2DM. This manuscript is registered with Research Registry (UIN: reviewregistry1693).

EVALUATION OF HIGH LEVELS OF SPORTS ACTIVITY AND THE BENEFICIAL EFFECT ON POSTPRANDIAL BLOOD GLUCOSE PROFILES

ABSTRACT Introduction: Hyperglycemia is the principal characteristic component of type 2 diabetes. High blood glucose concentrations for long periods can be countered with postprandial exercise by increasing glucose retention involuntary muscles. However, no research is present on the relationship between exercise time and glucose levels. Objective: This study evaluates the relationship between sports activity and postprandial glycemia levels. Methodology: Forty-five individuals were included in the study, 10 males and 35 females with an age of 27.11±2.8 years; a body fat percentage of 25.02% ±5.04%; and a body mass index of 22.74±4.55 kg/m2. Participants were included via WhatsApp for daily information on postprandial activity levels. WhatsApp messages were forwarded to a total of 2,500 people at different colleges and universities. Out of the total 60 active people (2.40%) who responded, 45 individuals participated in the study. They were divided into three categories based on self-reported postprandial activity: not very active (15), quite active (15), highly active (15). All active individuals completed an oral glucose intake test with blood samples obtained for evaluation at 15, 30, 45, 60, 90, and 120 minutes post-rest. On a gender basis, the groups could not be associated (P =.057). Results: All active groups showed a remarkable effect on blood glucose level at one hour (P =.031). A mean increase in blood glucose level in the first hour of 1.50 mmol/L was observed for every extra 1.0 mmol/L of standard glycemic amount, on average, women had a higher blood glucose amount of 1.35 mmol/L than men. Conclusion: It can be concluded that a high amount of postprandial activity generates a good outcome on glycemic parameters. Evidence Level II; Therapeutic Studies – Investigating the results.

Synthesis of novel α-glucans with potential health benefits through controlled glucose release in the human gastrointestinal tract

The glycemic carbohydrates we consume are currently viewed in an unfavorable light in both the consumer and medical research worlds. In significant part, these carbohydrates, mainly starch and sucrose, are looked upon negatively due to their rapid and abrupt glucose delivery to the body which causes a high glycemic response. However, dietary carbohydrates which are digested and release glucose in a slow manner are recognized as providing health benefits. Slow digestion of glycemic carbohydrates can be caused by several factors, including food matrix effect which impedes α-amylase access to substrate, or partial inhibition by plant secondary metabolites such as phenolic compounds. Differences in digestion rate of these carbohydrates may also be due to their specific structures (e.g. variations in degree of branching and/or glycosidic linkages present). In recent years, much has been learned about the synthesis and digestion kinetics of novel α-glucans (i.e. small oligosaccharides or larger polysaccharides based on glucose units linked in different positions by α-bonds). It is the synthesis and digestion of such structures that is the subject of this review.

Adding prandial GLP-1 receptor agonists to basal insulin: a promising option for type 2 diabetes therapy

BACKGROUND

Diabetes mellitus is a serious and increasingly prevalent condition in Canada and around the world. Treatment strategies have become increasingly complex, with a widening array of pharmacological agents available for glycemic management in type 2 diabetes mellitus (T2DM). New therapies that act in concert with available basal insulins may represent alternatives to basal insulin intensification with prandial or pre-mixed insulin. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have recently shown promise as useful additions to basal insulin, with significant reductions in glycated hemoglobin and potentially beneficial effects on body weight. This review will focus on pivotal clinical trials to assess the potential benefits of adding prandial GLP-1 RAs to basal insulin in patients with T2DM.

METHODS

Clinical studies combining prandial GLP-1 RAs and basal insulin (published between 2011 and July 2017) were identified and reviewed in PubMed, the Cochrane Central Register of Clinical Trials (Issue 6, June 2017), and clinicaltrials.gov.

RESULTS

Most of the studies presented in this review show that the addition of a prandial GLP-1 RA to basal insulin results in equal or slightly superior efficacy compared to the addition of prandial insulin, together with weight loss and less hypoglycemia.

CONCLUSIONS

The results of the studies suggest that a prandial GLP-1 RA as an add-on to basal insulin may be a safe and effective treatment intensification option (vs basal-plus or basal-bolus insulin).

A review of glucagon-like peptide-1 receptor agonists and their effects on lowering postprandial plasma glucose and cardiovascular outcomes in the treatment of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is an independent risk factor for cardiovascular (CV) comorbidities, with CV disease being the most common cause of death in adults with T2DM. Although glucocentric therapies may improve glycaemic control (as determined by glycated haemoglobin levels), evidence suggests that this approach alone has limited beneficial effects on CV outcomes relative to improvements in lipid and blood pressure control. This may be explained in part by the fact that current antidiabetic treatment regimens primarily address overall glycaemia and/or fasting plasma glucose, but not the postprandial plasma glucose (PPG) excursions that have a fundamental causative role in increasing CV risk. This literature review evaluates the relationship between PPG and the risk of CV disease, discusses the treatment of T2DM with glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and examines the associated CV outcomes. The literature analysis suggests that exaggerated PPG excursions are a risk factor for CV disease because of their adverse pathophysiologic effects on the vasculature, resulting in increased all-cause and CV-related mortality. Although GLP-1 RAs are well established in the current T2DM treatment paradigm, a subgroup of these compounds has a particularly pronounced, persistent and short-lived effect on gastric emptying and, hence, lower PPG substantially. However, current long-term data on CV outcomes with GLP-1 RAs are contradictory, with both beneficial and adverse effects having been reported. This review explores the opportunity to direct treatment towards controlling PPG excursions, thereby improving not only overall glycaemic control but also CV outcomes.

What next after basal insulin? Treatment intensification with lixisenatide in Asian patients with type 2 diabetes mellitus

There is increasing evidence that the pathophysiology of type 2 diabetes mellitus (T2DM) in Asian patients differs from that in Western patients, with early phase insulin deficiencies, increased postprandial glucose excursions, and increased sensitivity to insulin. Asian patients may also experience higher rates of gastrointestinal adverse events associated with glucagon-like peptide-1 receptor agonists (GLP-1RAs), such as nausea and vomiting, compared with their Western counterparts. These factors should be taken into consideration when selecting therapy for basal insulin treatment intensification in Asian patients. However, the majority of studies to establish various agents for treatment intensification in T2DM have been conducted in predominantly Western populations, and the levels of evidence available in Chinese or Asian patients are limited. This review discusses the different mechanisms of action of short-acting, prandial, and long-acting GLP-1RAs in addressing hyperglycemia, and describes the rationale and available clinical data for basal insulin in combination with the short-acting prandial GLP-1RA lixisenatide, with a focus on treatment of Asian patients with T2DM.

Exercise after You Eat: Hitting the Postprandial Glucose Target

We discuss a novel hypothesis: the effect size of postmeal exercise for attenuating postprandial glucose will be a function of the exercise bout vs. the size of the postprandial glucose response, specifically peak and duration of the postprandial glucose excursion.

Treatment intensification in patients with inadequate glycemic control on basal insulin: rationale and clinical evidence for the use of short-acting and other glucagon-like peptide-1 receptor agonists

A substantial proportion of patients with type 2 diabetes mellitus do not reach glycemic targets, despite treatment with oral anti-diabetic drugs and basal insulin therapy. Several options exist for treatment intensification beyond basal insulin, and the treatment paradigm is complex. In this review, the options for treatment intensification will be explored, focusing on drug classes that act via the incretin system and paying particular attention to the short-acting glucagon-like peptide-1 receptor agonists exenatide and lixisenatide. Current treatment guidelines will be summarized and discussed. © 2016 The Authors. Diabetes/Metabolism Research and Reviews Published by John Wiley & Sons Ltd.

Comparison of the Current Diagnostic Criterion of HbA1c with Fasting and 2-Hour Plasma Glucose Concentration

To determine the effectiveness of hemoglobin A1c (HbA1c) ≥ 6.5% in diagnosing diabetes compared to fasting plasma glucose (FPG) ≥ 126 mg/dL and 2-hour plasma glucose (2hPG) ≥ 200 mg/dL in a previously undiagnosed diabetic cohort, we included 5,764 adult subjects without established diabetes for whom HbA1c, FPG, 2hPG, and BMI measurements were collected. Compared to the FPG criterion, the sensitivity of HbA1c ≥ 6.5% was only 43.3% (106 subjects). Compared to the 2hPG criterion, the sensitivity of HbA1c ≥ 6.5% was only 28.1% (110 subjects). Patients who were diabetic using 2hPG criterion but had HbA1c < 6.5% were more likely to be older (64 ± 15 versus 60 ± 15 years old, P = 0.01, mean ± STD), female (53.2% versus 38.2%, P = 0.008), leaner (29.7 ± 6.1 versus 33.0 ± 6.6 kg/m(2), P = 0.000005), and less likely to be current smokers (18.1% versus 29.1%, P = 0.02) as compared to those with HbA1c ≥ 6.5%. The diagnostic agreement in the clinical setting revealed the current HbA1c ≥ 6.5% is less likely to detect diabetes than those defined by FPG and 2hPG. HbA1c ≥ 6.5% detects less than 50% of diabetic patients defined by FPG and less than 30% of diabetic patients defined by 2hPG. When the diagnosis of diabetes is in doubt by HbA1c, FPG and/or 2hPG should be obtained.

Glycemic targets: what is the evidence?

Hyperglycemia is the unifying metabolic abnormality for all forms of diabetes mellitus, forming the basis for its diagnosis and treatment. The strong epidemiologic associations between hyperglycemia and the complications of diabetes have given rise to the glucose hypothesis-that the complications of diabetes are caused by hyperglycemia and that they can be prevented by normalizing glucose levels. Herein the authors review the epidemiologic relationships between hyperglycemia and the complications of diabetes, the major trials of glucose lowering, and the extent to which the glucose hypothesis is supported by these studies and how this information can be translated into clinical practice.

Exercise lowers postprandial glucose but not fasting glucose in type 2 diabetes: a meta-analysis of studies using continuous glucose monitoring

Exercise has repeatedly been shown to improve glycemic control as assessed by glycated hemoglobin. However, changes in glycated hemoglobin do not provide information regarding which aspects of glycemic control have been altered. The purpose of this systematic review was to examine the effect of exercise as assessed by continuous glucose monitoring systems (CGMS) in type 2 diabetes. Databases (PubMed, Medline, EMBASE) were searched up to February 2013. Eligible studies had participants with type 2 diabetes complete standardized exercise protocols and used CGMS to measure changes in glycemic control. Randomized controlled trials, crossover trials and studies with pre-post designs were included. Average glucose concentration, daily time spent in hyperglycemia or hypoglycemia, and fasting glucose concentration were compared between exercise and control conditions. Eleven studies met the inclusion criteria and were included in the review. Eight studies had short-term (≤2 weeks) exercise interventions, whereas three studies had a longer-term intervention (all >2 months). The types of exercises utilized included aerobic, resistance and a combination of the two. The eight short-term studies were included in quantitative analysis. Exercise significantly decreased average glucose concentrations (-0.8 mmol/L, p < 0.01) and daily time spent in hyperglycemia (-129 minutes, p < 0.01), but did not significantly affect daily time spent in hypoglycemia (-3 minutes, p = 0.47) or fasting glucose (-0.3 mmol/L, p = 0.13). The four randomized crossover trials had similar findings compared to studies with pre-post designs. Exercise consistently reduced average glucose concentrations and time spent in hyperglycemia despite not significantly affecting outcomes such as fasting glucose and hypoglycemia.

Rehabilitative considerations for dental implants in the diabetic patient

Diabetes is a serious illness that affects many people, and there are many new cases diagnosed every year in all populations around the world. Dental implant is one of the restorative methods to replace missing teeth. As implants are directly anchored into bones, they provide stability, a more natural appearance, and minimize the risk of bone resorption. Thus, today, there is a high demand of dental implants and it is inevitable to meet diabetics who request implant treatment. However, Diabetes mellitus patients may pose contraindications to dental implants because of microvascular complications leading to slower healing process after surgery. Studies have shown that dental implantation failure rate in diabetic patients is much higher than that in non-diabetic patients. This article reviews the effect of diabetes on the osseointegration of implants and the soft tissue healing. It presents the factors used in assessing the severity of diabetes and its complications, as well as considerations for rehabilitation planning in these patients. In addition, the role of antibiotic prophylaxis has been reviewed since its effect on wound healing in diabetics is controversial. Integration of these factors by the dentist can dictate whether, as well as what type of implant supported prosthesis should be given to the diabetic patient.

Perception of clinicians and diabetic patients on the importance of postprandial glucose control and diabetes education status: a cross sectional survey

BACKGROUND

Recent studies have shown the importance of postprandial glucose (PPG) in the development of diabetes complications. This study was conducted in order to survey the perceptions of clinicians and diabetic patients with respect to PPG management and the current status of diabetes education.

METHODS

This was a cross-sectional study involving face-to-face interviews and an open questionnaire survey conducted in Korea. A total of 300 patients and 130 clinicians completed questionnaires, which included current education status, self monitoring of blood glucose (SMBG), criteria of diagnosis and management, and perceptions relating to PPG management.

RESULTS

While there was a significantly higher perceived need for diabetes education, the sufficiency of the current education was considered to be severely lacking. Fasting plasma glucose (FPG), PPG, and glycosylated hemoglobin (HbA1c) were all important considerations for clinicians when making a diagnosis of diabetes, although PPG was considered less important than FPG or HbA1c in the treatment of diabetes. Most clinicians and patients were aware of the importance of PPG, but actual education on the importance of PPG was not actively being delivered.

CONCLUSION

Our study showed that the current status of diabetes education is insufficient to meet the needs of the Korean population. A considerable gap was found to exist between awareness and what was actually taught in the current education program in regard to the importance of PPG. These results suggest that clinicians need to be more active in patient education, especially in regard to the importance of PPG.

Blood glucose and subsequent cardiovascular disease: update of a meta-analysis

BACKGROUND/PURPOSE

A 1999 meta-analysis described the relationship between blood glucose and subsequent cardiovascular events (MI, stroke, cardiovascular mortality). More studies have been published; therefore, we updated and refined estimates of this relationship in people without diabetes. ACCEPTABILITY CRITERIA: We accepted prospective studies that reported screening results for blood glucose levels (either fasting, 2-hour postprandial, 1-hour postprandial, or casual) divided into ≥3 quantiles. Required data within each quantile were numbers exposed plus study duration or person-years at risk, and numbers of cardiovascular outcomes (myocardial infarction, stroke, death). No restrictions were placed on language or publication date.

DATA SOURCES

Two reviewers searched Medline, Embase, Scopus, and Cochrane databases from inception until December 2009. Consensus settled discrepancies.

DATA SYNTHESIS

Poisson regression quantified the relationship between glucose quantile and outcomes. Beta values were combined with inverse variance weightings using a random effects meta-analytic model.

RESULTS

We found 36 articles with 141 datasets examining the relationship between blood glucose (32 fasting, 52 2-hour postprandial, 37 1-hour postprandial, 20 casual) in 191,249 patients without diabetes (73% male) for 3 million person-years. There were 12,537 (6.6%) cardiovascular deaths, 14,445 (7.6%) cardiovascular events, 6862 (3.6%) cardiac and 3412 (1.7%) stroke deaths. Relative risks/unit increase in blood glucose were all significant for total cardiovascular events (RRs ranged from 1.09-1.51, all p-values < 0.005) and cardiovascular deaths (RR = 1.05-1.24, p < 0.007), and all for cardiac deaths (p < 0.05) except casual glucose; stroke mortality was less clear. The two strongest relationships were found between fasting levels and all events (RR = 1.51, CI: 1.20-1.89) and with cardiovascular mortality (RR = 1.40, CI: 1.18-1.60). With 2-hour postprandial levels, the respective RRs were 1.22 (1.17-1.28) and 1.24 (1.19-1.30). A limitation is the assumption of a continuous relationship between variables.

CONCLUSIONS

We have provided refined estimates confirming the association between elevated blood glucose and subsequent cardiovascular events.

Initial combination therapy with saxagliptin and metformin provides sustained glycaemic control and is well tolerated for up to 76 weeks

AIM

To assess the efficacy and safety of saxagliptin + metformin initial combination therapy compared with saxagliptin or metformin alone over 76 weeks (24-week short-term + 52-week long-term extension) in treatment-naÏve type 2 diabetes mellitus patients with inadequate glycaemic control.

METHODS

In this phase 3, parallel-group, double-blind, active-controlled study, 1306 patients 18-77 years of age (HbA1c 8.0-12.0%) were randomized to saxagliptin 5 mg + 500 mg metformin, saxagliptin 10 mg + 500 mg metformin, saxagliptin 10 mg + placebo or 500 mg metformin + placebo. Blinded metformin was titrated during weeks 1-5 of the short-term treatment period in 500 mg/day increments to 2000 mg/day maximum in the metformin-based treatment groups. No titration of metformin was permitted during the long-term treatment period. A total of 888 patients completed the study (76 weeks), 613 without being rescued. Changes in HbA1c, fasting plasma glucose, 120-min postprandial glucose (PPG) and PPG-area under the curve (AUC) from baseline to week 76 were analysed using a repeated-measures model.

RESULTS

At 76 weeks, adjusted mean changes from baseline HbA1c (95% CI) for saxagliptin 5 mg + metformin, saxagliptin 10 mg + metformin, saxagliptin 10 mg and metformin were -2.31 (-2.44, -2.18), -2.33 (-2.46, -2.20), -1.55 (-1.70, -1.40) and -1.79% (-1.93, -1.65), respectively (post hoc and nominal p < 0.0001 vs. metformin and saxagliptin monotherapies for saxagliptin 5 mg + metformin and saxagliptin 10 mg + metformin). The proportions of patients requiring rescue or discontinuation for insufficient glycaemic control were lower for saxagliptin + metformin than for either monotherapy. Little or no attenuation in PPG-AUC or 120-min PPG was observed between weeks 24 and 76 for saxagliptin + metformin, indicating persistent efficacy. Adverse event rates were similar across groups; hypoglycaemic events occurred at a low frequency.

CONCLUSION

Saxagliptin + metformin initial combination therapy was well tolerated and produced sustained glycaemic control for up to 76 weeks, with greater improvements in glycaemic parameters compared with either drug alone.

Systemic hemodynamics in relation to glucose tolerance: the Health 2000 Survey

The influence of impaired glucose metabolism--that is, impaired fasting glucose, impaired glucose tolerance (IGT), and type 2 diabetes mellitus diabetes (DM2)--on systemic hemodynamics is largely unknown. Therefore, we investigated the associations of glucose metabolism disturbances with stroke index (SI), cardiac index, systemic vascular resistance index (SVRI), arterial pulse wave velocity (PWV), and heart rate among Finnish adults (N = 389; mean age, 58.3 ± 7.9 years) participating in the Health 2000 Survey. Systemic hemodynamic parameters were measured using the whole-body impedance cardiography device, and an oral glucose tolerance test (OGTT) was performed to evaluate glucose tolerance status. We found a decreasing trend for SI and increasing trends for SVRI and PWV according to the worsening of glucose tolerance (P for trend < .003 for all). In pairwise comparisons, SI was lower in the impaired fasting glucose group (P = .041) and the IGT group (P < .001) as compared with the normal glucose tolerance (NGT) group. Systemic vascular resistance index was higher in the IGT group (P = .045) and the DM2 group (P = .043) than in the NGT group. Subjects with IGT or DM2 had higher arterial PWV (10.7 ± 0.2 m/s, P < .001 and 11.7 ± 0.5 m/s, P = .001, respectively) than subjects with NGT (9.5 ± 0.1 m/s). Moreover, 2-hour glucose in OGTT was an independent determinant of SVRI and PWV (P < .001 and P = .005, respectively) in multivariable linear regression models. In conclusion, the present study demonstrates that glucose intolerance, even without DM2, associates with several adverse changes in systemic hemodynamics and that 2-hour glucose in OGTT is an independent determinant of SVRI and PWV. These findings support the systematic evaluation of glucose tolerance status in the estimation of cardiovascular risk among the middle-aged population.

Influence of abnormal glucose metabolism on coronary microvascular function after a recent myocardial infarction

OBJECTIVES

This study sought to assess the association between abnormal glucose metabolism and abnormal coronary flow reserve (CFR) in patients with a recent acute myocardial infarction (AMI).

BACKGROUND

Mortality and morbidity after AMI is high among patients with abnormal glucose metabolism, which may be related to abnormal microcirculation.

METHODS

We studied 183 patients with a first AMI. In 161 patients with no history of diabetes mellitus (DM), an oral glucose tolerance test was performed, and patients were categorized according to World Health Organization criteria for whole blood glucose into 3 groups. After coronary angiography and revascularization, a comprehensive transthoracic echocardiogram and noninvasive assessment of CFR was performed in the distal part of left descending artery, as an indicator of microvascular function. Adenosine was administered by intravenous infusion (140 microg/kg/min) to obtain the hyperemic flow profiles. The CFR was defined as the ratio of hyperemic to baseline peak diastolic coronary flow velocities.

RESULTS

Median CFR was 1.9 (interquartile range [IQR] 1.4 to 2.4], and 109 (60%) patients had a CFR <or=2. The lowest CFR was seen in patients with a history of DM (1.4 [IQR 1.4 to 1.7], n = 22) and in patients with newly diagnosed DM (1.6 [IQR 1.3 to 2], n = 39), whereas CFR did not differ in patients with abnormal glucose tolerance (2.1 [IQR 1.4 to 2.6], n = 58) and in patients with normal glucose tolerance (2.2 [IQR 1.7 to 2.6], n = 62). In a stepwise logistic regression model adjusting for age, sex, site and size of AMI, heart rate, risk factors of the metabolic syndrome, degree of angiographic evidence of coronary artery disease, and medical therapy, newly diagnosed DM (odds ratio: 3.0) and a history of DM (odds ratio: 9.9) remained significant predictors of CFR <2, whereas impaired glucose tolerance was not.

CONCLUSIONS

CFR is decreased in patients with known or newly diagnosed DM even after adjustment of possible confounders, whereas CFR in patients with impaired glucose tolerance seems less affected. (Coronary Flow Reserve and Glucometabolic State [CFRGS]; NCT00845468).

Importance of postprandial glucose levels as a target for glycemic control in type 2 diabetes

Increasing evidence supports the importance of postprandial glucose (PPG) in glycemic control with regard to the development of complications in patients with diabetes. PPG plays a critical role in determining overall glycemic control, particularly in patients who are close to their glycemic goals. Data also indicate that postprandial hyperglycemia may have a greater effect on the development of cardiovascular complications compared with elevated fasting plasma glucose. Several antidiabetic agents that specifically target PPG are currently available, including glinides, glucagon-like peptide-1 mimetics, dipeptidyl peptidase-4 inhibitors, and rapid-acting insulin analogs. A more intensive approach to managing PPG may improve the care of patients with diabetes and, ultimately, the outcome of these patients.

Cardiovascular effects of acute hyperglycaemia: pathophysiological underpinnings

High admission blood glucose levels after acute myocardial infarction are common and are associated with an increased risk of death in subjects with and without diabetes. In this review, the possible toxic effects of acute hyperglycaemia are discussed as a possible explanation for the worse prognosis in subjects with myocardial infarction and concomitant hyperglycaemia. In particular, evidence supporting the hypothesis that acute hyperglycaemia may favour the appearance of cardiovascular disease through the generation of oxidative stress is presented.

Postprandial dysmetabolism: the missing link between diabetes and cardiovascular events?

OBJECTIVE

To investigate the association of postprandial dysmetabolism, ie, hyperglycemia, and hyperlipidemia with myocardial disease in diabetic, glucose-intolerant, and glucose-tolerant patients.

METHODS

We performed a MEDLINE search of the English-language literature published between January 1979 and April 2007 for studies regarding postprandial dysmetabolism and heart disease.

RESULTS

Postprandial dysmetabolism is associated with increased inflammation, endothelial dysfunction, decreased fibrinolysis, plaque instability, and cardiac events.

CONCLUSION

There is a direct and proportional association between postprandial dysmetabolism and both coronary artery disease and cardiac events.

Serum leptin and its relation to anthropometric measures of obesity in pre-diabetic Saudis

Background

Little information is available on leptin concentrations in individuals with IGT. This study aims to determine and correlate leptin levels to anthropometric measures of obesity in pre-diabetic, (IFG and IGT), type 2 diabetic and normoglycaemic Saudis.

Methods

308 adult Saudis (healthy controls n = 80; pre-diabetes n = 86; Type 2 diabetes n = 142) participated. Anthropometric parameters were measured and fasting blood samples taken. Serum insulin was analysed, using a solid phase enzyme amplified sensitivity immunoassay and also leptin concentrations, using radio-immunoassay. The remaining blood parameters were determined using standard laboratory procedures.

Results

Leptin levels of diabetic and pre-diabetic men were higher than in normoglycaemic men (12.4 [3.2–72] vs 3.9 [0.8–20.0] ng/mL, (median [interquartile range], p = 0.0001). In females, leptin levels were significantly higher in pre-diabetic subjects (14.09 [2.8–44.4] ng/mL) than in normoglycaemic subjects (10.2 [0.25–34.8] ng/mL) (p = 0.046). After adjustment for BMI and gender, hip circumference was associated with log leptin (p = 0.006 with R2 = 0.086) among all subjects.

Conclusion

Leptin is associated with measures of adiposity, hip circumference in particular, in the non-diabetic state among Saudi subjects. The higher leptin level among diabetics and pre-diabetics is not related to differences in anthropometric measures of obesity.

Premeal insulin lispro plus bedtime NPH or twice-daily NPH in patients with type 2 diabetes: acute postprandial and chronic effects on glycemic control and cardiovascular risk factors

OBJECTIVE

Two insulin regimens were used to explore acute and chronic postprandial changes in glycemia, lipemia, and metabolic markers associated with increased risk of cardiovascular disease.

METHODS

An open-label, randomized, two-period crossover study (12 weeks/period) compared a prandial regimen [premeal insulin lispro+bedtime neutral protamine Hagedorn (NPH)] with a basal regimen (twice-daily NPH). There were 30 patients (12 women and 18 men; mean age=61 years) with type 2 diabetes mellitus (mean duration=16 years) who were randomized after a 2-month lead-in with twice-daily NPH treatment. A standard lunch test meal developed according to each patient's caloric needs was administered at the end of each treatment period.

RESULTS

Insulin lispro was associated with significantly lower postprandial glucose (area under the curve0-5 h=43.54 vs. 57.65 mM/h; P<.001), elevated insulin concentrations, and acutely altered lipid fractions that included an early decrease followed by an increase in free fatty acids, lower triglycerides, elevated total cholesterol, elevated low-density lipoprotein cholesterol (LDL), and elevated high-density lipoprotein cholesterol. After 12 weeks of treatment, insulin lispro+bedtime NPH reduced hemoglobin A1c (HbA1c; mean+/-SE=7.6+/-0.2 vs. 8.2+/-0.2%; P<.001) without increasing hypoglycemia or insulin dose as compared with twice-daily NPH. Furthermore, treatment with the prandial insulin regimen resulted in lower total cholesterol, lower LDL cholesterol, and lower oxidized LDL.

CONCLUSION

Improved postprandial glycemic control, as observed in a regimen containing both prandial insulin lispro and NPH as the basal insulin, is associated with significantly lower HbA1c and acute modulation of lipid fractions after a test meal. These biochemical modifications may potentially have a favorable impact on cardiovascular risk in patients with type 2 diabetes mellitus.

The effect of chromium picolinate and biotin supplementation on glycemic control in poorly controlled patients with type 2 diabetes mellitus: a placebo-controlled, double-blinded, randomized trial

BACKGROUND

Preclinical studies have shown that the combination of chromium picolinate and biotin significantly enhances glucose uptake in skeletal muscle cells and enhances glucose disposal. The present pilot study was conducted to determine if supplementation with chromium picolinate and biotin can improve glycemic control in patients with type 2 diabetes mellitus with suboptimal glycemic control despite use of oral antihyperglycemic agents.

METHODS

Forty-three subjects with impaired glycemic control (2-h glucose >200 mg/dL; glycated hemoglobin >or=7%), despite treatments with oral antihyperglycemic agents, were randomized to receive 600 microg of chromium as chromium picolinate and biotin (2 mg/day) (Diachrome(, Nutrition 21, Inc., Purchase, NY) in addition to their prestudy oral antihyperglycemic agent therapy. Measurements of glycemic control and blood lipids were taken at baseline and after 4 weeks.

RESULTS

After 4 weeks, there was a significantly greater reduction in the total area under the curve for glucose during the 2-h oral glucose tolerance test for the treatment group (mean change -9.7%) compared with the placebo group (mean change +5.1%, P < 0.03). Significantly greater reductions were also seen in fructosamine (P < 0.03), triglycerides (P < 0.02), and triglycerides/ high-density lipoprotein cholesterol ratio (P < 0.05) in the treatment group. No significant adverse events were attributed to chromium picolinate and biotin supplementation.

CONCLUSIONS

This pilot study demonstrates that supplementation with a combination of chromium picolinate and biotin in poorly controlled patients with diabetes receiving antidiabetic therapy improved glucose management and several lipid measurements. Chromium picolinate/ biotin supplementation may represent an effective adjunctive nutritional therapy to people with poorly controlled diabetes with the potential for improving lipid metabolism.

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.

Peripheral arterial disease in diabetic patients selected from a primary care setting: Implications for nursing practice

Although the care of patients with diabetes is increasingly provided in primary care, there is relatively little information on the prevalence and long-term progression of asymptomatic peripheral arterial disease (PAD) in diabetic populations selected from primary care settings. The aims of this study were to investigate prevalence and progression of PAD in 146 diabetic patients, and to compare mortality with 113 nondiabetic controls over a 7-year period. The prevalence of PAD in individual pedal arteries varied between 28.6% in the right posterior tibial artery to 48.8% in the left peroneal artery. During the 7-year period, 34.25% of the diabetic subjects died, and 17.5% moved to other locations. Of the remaining 70 patients, 35 (50%) showed no change in ankle-brachial index and 35 (50%) did show change. Comparison of risk factors between those who did and did not show evidence of progression revealed (1) a strong, significant, independent association between hyperglycemia (measured by plasma HbA1c) and progression of PAD among the diabetic population; and (2) a strong association between progression of the disease and family history of diabetes and ischemic vascular disease. There was a high death rate (34.25%) among the diabetic group, which was greater than for the age- and sex-matched nondiabetic controls (13.2%) drawn from the same practice. This high mortality was significantly related (P < .001) to the presence of PAD identified during first-year assessment. Once PAD develops in association with diabetes the long-term prognosis is poor and carries a high mortality rate mainly because of cardiovascular and cerebrovascular diseases. Both progression and mortality were significantly related to poor diabetic control. The role of the primary care nurse in assessing such patients by using Doppler-assisted measurements is one that should be expanded with the massive increase in the number of diabetic patients in the coming years.

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.

Pathogenesis and management of diabetic dyslipidemia

Patients with diabetes mellitus have a 2- to 4-fold increased risk of atherosclerotic cardiovascular, peripheral vascular, and cerebrovascular disease, which are the leading causes of morbidity and mortality in this population. Several epidemiological studies have shown an association between diabetic dyslipidemia, which is characterized by hypertriglyceridemia, low levels of high density lipoprotein-cholesterol, postprandial lipemia and small, dense low density lipoprotein-cholesterol (LDL-C) particles, and the occurrence of cardiovascular disease. Other studies have established the beneficial effects of lipid lowering on the reduction of major coronary events in diabetic patients. The recent National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) guidelines emphasize diabetes as a coronary heart disease risk equivalent. The NCEP ATP III states that elevated LDL-C is a major risk factor for coronary heart disease, and the primary goal of risk-reduction therapy is the reduction of LDL-C levels to 100 mg/dL. This article defines and describes diabetic dyslipidemia and its etiology and pathogenesis, as well as reviewing guidelines and recommendations for treatment of this disorder. Treatment of diabetic dyslipidemia includes 1) lifestyle modifications: physical activity and a diet low in saturated fats and cholesterol and high in complex carbohydrates and fiber; and 2) pharmacological treatment with (i) oral antihyperglycemic agents: metformin and thiazolidinediones; (ii) weight reduction drugs: orlistat and sibutramine and; (iii) lipid-lowering drugs: HMG-CoA reductase inhibitors, fibric acid derivatives, nicotinic acid, and bile acid sequestrants.

Changes in glucose tolerance over time in women with polycystic ovary syndrome: a controlled study

We performed this study to access the changes in glucose tolerance over time in a group of women with polycystic ovary syndrome (PCOS) (n = 71) and control women (n = 23) with regular menstrual cycles and baseline normal glucose tolerance. Mean follow-up was between 2 and 3 yr for both groups (PCOS 2.5 +/- 1.7 yr; controls 2.9 +/- 2.1 yr). Based on World Health Organization glucose tolerance categories, there was no significant difference in the prevalence of glucose intolerance at follow-up in the PCOS group. In the PCOS group, 25 (37%) had impaired glucose tolerance (IGT) and seven (10%) had type 2 diabetes mellitus at baseline, compared with 30 (45%) and 10 (15%), respectively, at follow-up. There were also no differences within groups (PCOS or control) or between groups (PCOS vs. control) in the oral glucose tolerance test-derived measure of insulin sensitivity, but in the women with PCOS who converted to either IGT or type 2 diabetes mellitus, there was a significant decrease (P < 0.0001). At the follow-up visit, the mean glycohemoglobin level was 6.1 +/- 0.9% in women with PCOS vs. 5.3 +/- 0.7% in the control women (P < 0.001). Women with PCOS and baseline IGT had a low conversion risk of 6% to type 2 diabetes over approximately 3 yr, or 2% per year. The effect of PCOS, given normal glucose tolerance (NGT) at baseline, is more pronounced with 16% conversion to IGT per year. Our study supports that women with PCOS (especially with NGT) should be periodically rescreened for diabetes due to worsening glucose intolerance over time, but this interval may be over several years and not annually.

Impact of intensive lifestyle and metformin therapy on cardiovascular disease risk factors in the diabetes prevention program

OBJECTIVE

The Diabetes Prevention Program demonstrated the ability to delay or prevent type 2 diabetes in participants with impaired glucose tolerance (IGT). Participants with IGT are at high risk for cardiovascular disease (CVD), with a marked increase in the number and severity of CVD risk factors. We prospectively assessed the impact of our interventions on hypertension, dyslipidemia, and CVD events.

RESEARCH DESIGN AND METHODS

The study group consisted of 3,234 individuals with IGT randomly assigned to receive intensive lifestyle intervention, metformin, or placebo. Annual assessment of blood pressure, lipids, electrocardiogram, and CVD events was undertaken.

RESULTS

Hypertension was present in 30% of participants at study entry and then increased in the placebo and metformin groups, although it significantly decreased with intensive lifestyle intervention. Triglyceride levels fell in all treatment groups, but fell significantly more with intensive lifestyle intervention. Total cholesterol and LDL cholesterol levels were similar among treatment groups. Intensive lifestyle intervention significantly increased the HDL cholesterol level and reduced the cumulative incidence of the proatherogenic LDL phenotype B. At 3 years of follow-up, the use for pharmacologic therapy to achieve established goals in the intensive lifestyle group was 27-28% less for hypertension and 25% less for hyperlipidemia compared with placebo and metformin groups. Over an average of 3 years, 89 CVD events from 64 participants were positively adjudicated studywide, with no differences among treatment groups.

CONCLUSIONS

Lifestyle intervention improves CVD risk factor status compared with placebo and metformin therapy. Although no differences in CVD events were noted after 3 years, achieved risk factor modifications suggest that longer intervention may reduce CVD event rates.

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.

What does postprandial hyperglycaemia mean?

AIMS

The potential importance of postprandial glucose (PPG) control in the development of complications in Type 2 diabetes is much debated. The recent American Diabetes Association (ADA) consensus statement discussed the role of postprandial hyperglycaemia in the pathogenesis of diabetic complications and concluded that the relationship between PPG excursions and the well-established risk factors for cardiovascular disease (CVD) should be further examined. Using the ADA statement as a starting point and including the more recent American College of Endocrinology guidelines on glycaemic control, a panel of experts in diabetes met to review the role of PPG within the context of the overall metabolic syndrome, in the development of complications in Type 2 diabetes.

RESULTS

Post-prandial hyperglycaemia is a risk indicator for micro- and macrovascular complications, not only in patients with Type 2 diabetes but also in those with impaired glucose tolerance. In addition, the metabolic syndrome confers an increased risk of CVD morbidity and mortality. The debate focused on the relative contributions of postprandial hyperglycaemia, the metabolic syndrome and, in particular, raised triglyceride levels in the postprandial state, to the development of cardiovascular complications of diabetes.

CONCLUSIONS

The panel recommended that in the prevention and management of microvascular complications of Type 2 diabetes, targeting both chronic and acute glucose fluctuations is necessary. Lowering the macrovascular risk also requires control of (postprandial) triglyceride levels and other components of the metabolic syndrome.

Modeling the efficiency of reaching a target intermediate end point: a case study in type 2 diabetes in the United States

OBJECTIVE

The objective of this study was to describe an approach to modeling the efficiency of an intervention by focusing on an established intermediate end point directly. A case study addresses the economic efficiency of obtaining dual glycemic control over time, according to initial choice of treatment.

METHODS

From the perspective of a payer in the United States, instead of the usual approach of basing the model on projecting long-term diabetic complications from glycemic control, this model focuses directly on glycemic control. Treatment changes and associated health-care utilization needed to address postprandial glucose. After assigning each of 10000 drug-naïve patients, HbA1c, age, race, and sex based on distributions from a randomized clinical trial, the model applies the efficacy of nateglinide compared to metformin. Sensitivity analyses were carried out for all parameters. Costs are reported in year 2000 US dollars and discounted at 3%.

RESULTS

In the base case, starting on nateglinide and increasing the time in dual glycemic control over 3 years by 2.4 months led to savings of US dollars 295 compared to starting on metformin. Savings increased with stricter treatment criteria but decreased if glycemic control was better initially.

CONCLUSIONS

This study illustrates the use of an efficiency model that focuses directly on the relevant short-term end point: glycemic control. Starting patients with nateglinide is shown to be an efficient way of obtaining dual glycemic control during the first 3 years of treatment.

Cardiovascular risk in type 2 diabetics and pharmacological regulation of mealtime glucose excursions

In type 2 diabetic patients mealtime glucose fluctuations are important determinants of overall glucose control and overall risk of diabetes cardiovascular complications. In fact, acute elevation of plasma glucose concentrations trigger an array of tissue response that may contribute to development of such vascular complications since it may result in a thrombophilic condition, causes endothelial dysfunction (possibly through a reduction of nitric oxide availability) and is responsible for non-enzymatic glycation and production of free- radicals with ensuing oxidative stress. To keep post-prandial glucose with narrow range, metiglinide analogues drugs have been developed. In particular, repaglinide and nateglinide seem the most useful ones. In fact, both drugs improve 1(st) phase insulin release but they do not affect the total daily amount of insulin released by the pancreas. Due to the mechanism of action and to pharmacokinetic properties, repaglinide and nateglinide allow diabetic patients to get a more tight metabolic glucose control with a contemporary reduction in the cases of severe hypoglycaemia. In conclusions, repaglinide and nateglinide are new and powerful pharmacological tools not only for achieving a better metabolic glucose control but also for preventing the development of diabetes-related cardiovascular complications.

Postprandial Hyperglycemia in Patients with Type 2 Diabetes Mellitus

The role of postprandial hyperglycemia (PPHG) in diabetes mellitus is being increasingly recognized. It is known that PPHG contributes to the increased risk of both micro- and macrovascular complications in patients with diabetes mellitus. This review looks at the clinical significance of PPHG and the currently available therapeutic modalities. The causes of PPHG are influenced by many factors which include a rapid flux of glucose from the gut, impaired insulin release, endogenous glucose production by the liver and peripheral insulin resistance. Knowledge of the pathophysiology of PPHG is essential when adopting treatment options to tackle the problem. Although most oral antihyperglycemic agents and insulins lower both fasting and postprandial blood glucose levels, drugs are now available which specifically act to control PPHG. These drugs may be classified based on the site of their action. alpha-Glucosidase inhibitors like acarbose and miglitol attenuate the rate of absorption of sucrose by acting on the luminal enzymes. Adverse effects of these agents are predominantly gastrointestinal. Newer insulin secretagogues have been developed which attempt to mimic the physiological release of insulin and thus ameliorate PPHG. These include third generation sulfonylureas like glimepiride and nonsulfonylurea secretagogues like repaglinide and nateglinide. Rapid-acting insulin analogs, the amino acid sequences of which have been altered such that they have a faster onset of action, help to specifically target PPHG. Pre-mixed formulations of the analogs have also been developed. Finally, drugs under development which hold promise in the management of patients with PPHG include pramlintide, an amylin analog, and glucagon-like peptide-1 and its analogs.

Recent developments in the management of type 2 diabetes

Type 2 diabetes is a common, chronic disease, with a high risk of macrovascular and microvascular complications that lead to premature death and disability. The disease is managed largely in primary care and its rising prevalence will increase the workload of community nurses. The forthcoming Diabetes National Service Framework will aim to improve the standards of diabetic care, while scientific and technological developments offer new treatments that may also improve the outlook for patients. There is as yet no case for population screening for type 2 diabetes, but community nurses are ideally placed to carry out local screening initiatives based on consensus guidelines.

Pathophysiologic mechanisms of postprandial hyperglycemia

The role of postprandial hyperglycemia in the etiology of diabetes-related complications and outcomes, although still being elucidated, is greater than previously thought. Acute glucose elevations after meal ingestion are associated with a variety of glucose-mediated tissue defects-oxidative stress, glycation, and advanced glycation end product formation-which have far-reaching structural and functional consequences for virtually every human organ system. Lowering glycosylated hemoglobin to levels that prevent or delay these complications can be achieved only by reducing both postprandial and fasting plasma glucose levels. The alpha-glucosidase inhibitors (acarbose, voglibose, miglitol) have been effective in delaying the digestion and absorption of carbohydrates, thus diminishing the postprandial surge in blood glucose levels without loss of calories. However, greater emphasis needs to be placed on the measurement of postprandial glycemia, so that readings can be used to guide treatment.

Impaired glucose tolerance as a disease

Current criteria for diagnosing diabetes, based on fasting plasma glucose levels during administration of the oral glucose tolerance test (OGTT), are poorly sensitive and are only modestly predictive of microvascular risk. The period after administration of OGTT is far more predictive and more closely resembles the postprandial state where microvascular risk is elevated. However, persons who do not yet exhibit symptoms of diabetes may nonetheless have impaired glucose tolerance or dysglycemia, whereby macrovascular disease can develop at a glucose level lower than the threshold for microvascular disease and can progress in a graded fashion. This article reviews the factors that may cause dysglycemia (including insulin resistance and obesity) and how diet, blood pressure control, and the use of statins or glycemic/insulin sensitizing may reduce cardiovascular risk in this prediabetic population.

Usefulness of stable HbA(1c) for supportive marker to diagnose diabetes mellitus in Japanese subjects

To evaluate the adequacy and usefulness of the stable glycated hemoglobin (HbA(1c)) value of 6.5% suggested by the Japan Diabetic Society in 1999 for supportive diagnostic marker of diabetes, we assessed the sensitivity and specificity of an HbA(1c) value of 6.5% in patients who were newly diagnosed by the 75 g oral glucose tolerance test (75g-OGTT). A total of 866 Japanese subjects underwent the 75g-OGTT and HbA(1c) measurement (normal range: 4.3-5.8%). They were divided into three groups [normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and diabetes mellitus (DM)], using the WHO criteria, since no subject with impaired fasting glycemia (IFG) was observed. The cut-off value of HbA(1c) separating DM from NGT or DM from IGT on cumulative distribution curve analysis was 5.9% (sensitivity 0.76 and specificity 0.86) and 5.9% (sensitivity 0.76 and specificity 0.77), respectively. The sensitivity of an HbA(1c) of 6.5% for separation of DM from NGT or IGT by the same analysis was 0.49 and 0.49, respectively. Similarly, the specificity for separation of DM from NGT or IGT was 0.98 and 0.98, respectively. These results mean that 49% of diabetic subjects show an HbA(1c)> or =6.5%, and 51% have an HbA(1c) less than 6.5%, while only 2% of NGT and IGT subjects have an HbA(1c)> or =6.5%, and 98% have a value less than 6.5%. Therefore, the sensitivity of an HbA(1c) value of 6.5% in separating DM from NGT or IGT is low, and thus 6.5% is too high value to use when screening for diabetes. However, the specificity is very high, so an HbA(1c) of 6.5% is a useful supportive marker to diagnose diabetes.

Correlation among fasting plasma glucose, two-hour plasma glucose levels in OGTT and HbA1c

A study was made on the association among 2-h plasma glucose (PG) in oral glucose tolerance test (OGTT), fasting plasma glucose (FPG) using correlation and regression equation. Subjects were 13174 OGTT examinees tested between 1980 and 1998. Blood glucose was determined by the glucose oxidase method and glycated hemoglobin (HbA1c) by the HPLC method. As for correlation between 2-h PG and FPG, regression equation of the <60 year group was y=57.1+0.336x (r=0.866, P<0.0001) and that of the >==60 year group was y=61.5+0.286x (r=0.814, P<0. 0001). FPG was calculated at 124.3 in the <60 year group and 118.7 mg/dl in the >==60 year group for 2-h PG of 200 mg/dl, 2-h PG were calculated at 199.5 and 210.7 mg/dl for FPG of 126 mg/dl, respectively. In the <60 year group, FPG were calculated at 121.7 and 124.4 mg/dl and 2-h PG at 193.2 and 199.3 mg/dl for HbA1c of 6.0 and 6.1%, respectively. As for associations between HbA1c and FPG or 2-h PG being high correlation, it is possible to estimate a prevalence of DM in a group using HbA1c>==6.1%. High correlations were demonstrated among all the three measures; FPG, 2-h PG, HbA1c. If 2-h PG is used in diagnosing diabetes mellitus, an FPG of 126 mg/dl proposed by ADA and World Health Organization (WHO) as a diagnostic level of FPG is an acceptable value for the Japanese.

Coronary artery disease and diabetes

The increased risk of cardiovascular disease in diabetic patients is well documented. A greater appreciation for the importance of this fact and regular use of secondary prevention strategies, including aggressive use of HMG-CoA reductase inhibitors or other lipid-lowering agents to reduce cholesterol levels, are clearly indicated for diabetic patients with CAD. If no contraindications exist, ACE inhibitors, beta blockers, and aspirin also should be considered for these high-risk patients.