Cardiovascular mortality and morbidity in type-2 diabetes mellitus

Impact of SGLT-2 inhibitors on modifiable cardiovascular risk factors in Romanian patients with type 2 diabetes mellitus

BACKGROUND

Modifiable cardiovascular risk factors are high blood pressure, smoking, diabetes, sedentary lifestyle, obesity, and hypercholesterolemia.

AIM

To investigate the impact of sodium-glucose 2 co-transporter inhibitors (SGLT-2i) on modifiable cardiovascular risk factors in Romanian patients diagnosed with type 2 diabetes mellitus (T2DM).

METHOD

A retrospective study was conducted on 200 Romanian patients with T2DM who were being treated with SGLT-2i, either Dapagliflozin or Empagliflozin. Collected data included demographic characteristics, such as weight, body mass index (BMI), fasting blood glucose (FBG), creatinine, glycated hemoglobin (HbA1c), abdominal circumference (AC), urine albumin-to-creatinine ratio (UACR), systolic blood pressure (SBP), diastolic blood pressure (DBP), C-reactive protein (CRP) and N-terminal pro b-type natriuretic peptide (NT-proBNP). The patients were observed for one year after being treated with SGLT-2i.

RESULTS

The mean value of FBG decreased from 180.00 mg% (IQR: 154.50-207.00) to 130.00 mg% (IQR: 117.50-150.00) (p < 0.001), and the mean of HbA1c values decreased from 8.40% (IQR: 7.98-9.15%) to 7.30% (IQR: 6.90-7.95%) (p < 0.001). We also obtained significant positive effects on body weight, i.e., the weight decreased from 90.50 kg (82.00-106.50) to 89.00 kg (77.50-100.00) (p = 0.018), BMI from 32.87 kg/m2 (29.24-36.45) to 31.00 kg/m2 (27.74-34.71) (p < 0.001) and AC from 107.05 (± 16.39) to 102.50 (± 15.11) (p = 0.042). The UACR decreased from 23.98 mg/g (19.76-36.85) to 19.39 mg/g (1.30-24.29) (p < 0.001). Initially, the median value for SBP was 140.00mmgHg (130.00-160.00), and for DBP was 80.00 mmgHg (72.00-90.00), and one year after treatment, the medium value was 120.00 mmgHg (115.50-130.00) for SBP (p < 0.001), and 72.00 mmgHg (70.00-78.00) for DBP (p < 0.001) The mean CRP values decreased from 68.00 mg/dL (56.25-80.25) to 34.00 mg/dL (28.12-40.12) (p < 0.001), and the mean NT-proBNP decreased from 146.00pg/mL (122.50-170.50) to 136.00 pg/mL (112.50-160.50) (p = 0.005).

CONCLUSION

Treatment with SGLT-2i in Romanian patients with T2DM has beneficial effects on modifiable cardiovascular risk factors.

Impact of Patient-Centered and Self-Care Education on Diabetes Control in a Family Practice Setting in Saudi Arabia

Background: Diabetes mellitus is a chronic and complex medical disease that leads to significant morbidity and mortality. Patient-centered diabetes education that emphasizes active patient involvement, self, and shared care constitutes a substantial and essential component of the comprehensive diabetes management approach. Objectives: To assess the impact of patient-centered diabetes education sessions on the prescribed treatment plan in controlling diabetes and other related cardiovascular risk factors. Methods: In a pre-experimental pretest-posttest one group study design, all referred patients with type 2 diabetes (T2DM) to the diabetes educator clinic (n = 130 patients) during the period of 6 months from January to July 2021 were subjected to multiple and consecutive patient-centered diabetes education sessions, based on the framework published by the Association of Diabetes Care and Education Specialties (ADCES), in addition to their usual treatment plan. Demographic, social, and biological data were obtained at the baseline, three months, and six months after the intervention. Nonparametric Friedman and Cochran’s Q tests for related samples were applied to examine the impact of this educational intervention on glycosylated hemoglobin (HbA1c) and other associated cardiovascular risks. The results of 130 patients with T2DM showed a significant reduction of mean systolic blood pressure “SBP” (p = 0.015), glycosylated hemoglobin (HbA1c) (p < 0.001), fasting blood sugar “FBS” (p < 0.001), total cholesterol (p < 0.001), low-density lipoprotein (p < 0.001), and triglyceride (p < 0.001), and significant rise of mean high-density lipoprotein (p = 0.011). At three and six months after the intervention, 43% and 58% of patients showed improved HbA1c levels. The mean HbA1c was reduced from 10.2% at the beginning of the study to 8.7% (p < 0.001) after six months. Moreover, a significant reduction in the prevalence of obesity (p = 0.018), high FBS (p = 0.011), and high SBP (p = 0.022) was detected. Conclusions: This study showed a considerable positive impact of diabetes education and patient-centered care on optimizing glycemic and other cardiovascular risk control. The needs of certain patients with T2DM should be addressed individually to achieve the best possible outcomes. Further research is needed to explore the long-term benefits of this intervention.

Retinopathy among Chinese subjects with type 2 diabetes mellitus in Shanghai: A community-based follow-up study

OBJECTIVE

To determine the incidence, progression, and regression rates of diabetic retinopathy (DR), as well as their associated factors, in Chinese type 2 diabetic patients.

METHODS

Diabetic patients who participated in a previous survey were recruited for a 1-year follow-up study. Nonmydriatic fundus photographs were acquired to assess the severity of DR as per the International Clinical Diabetic Retinopathy Disease Severity Scale (2002). Factors that potentially influence DR outcomes, including its incidence, progression, and regression, were identified via statistical analyses.

RESULTS

We initially recruited 2453 subjects, among whom 2331 were followed and included in the final analysis. The incidences of new and progressed (ie, ≥2 scale steps) DR were 10.6% and 6.1%, respectively. Moreover, 7.3% of patients with established DR at baseline experienced complete regression. Multivariate logistic regression analysis revealed that high glycosylated haemoglobin (HbA1c) (odds ratio [OR] = 1.50, P = .021) and hyperlipidaemia (OR = 1.46, P = .025) were independent predictors of DR development, high HbA1c (OR = 4.16, P = .027) and macroalbuminuria (OR = 5.60, P = .010) predicted DR progression, and low HbA1c (OR = 0.20, P = .001) and low triglyceride levels (OR = 0.34, P = .026) were associated with DR regression.

CONCLUSIONS

Albumin and HbA1c levels should be closely monitored as signs of progressive retinal damage in diabetic subjects. Optimized control of glucose and triglyceride levels is vital for reducing the incidence of DR or promoting its regression in afflicted patients.

Cardiovascular mortality and oral antidiabetic drugs: protocol for a systematic review and network meta-analysis

INTRODUCTION

Cardiovascular diseases are the leading cause of morbidity and mortality among individuals with diabetes. Despite the beneficial effects of antidiabetic drugs (ADDs) in terms of lowering haemoglobin A1c, several ADDs have been shown to increase the risk of cardiovascular events. Given the high prevalence of cardiovascular disease among individuals with diabetes, it is important to weigh the benefits of ADDs against their cardiovascular safety. Therefore, the objective of the current study is to conduct a systematic review with network meta-analysis to compare the effects of different oral pharmacological classes of ADDs on cardiovascular safety.

METHODS AND ANALYSIS

Randomised clinical trials (RCTs) and observational studies published in English up to 31 January 2017, and which include direct and/or indirect evidence, will be included. Studies will be retrieved by searching four electronic databases and cross-referencing. Dual selection and abstraction of data will occur. The primary outcome will be cardiovascular mortality. Secondary outcomes will include all-cause mortality, new event of acute myocardial infarction, stroke (haemorrhagic and ischaemic), hospitalisation for acute coronary syndrome and urgent revascularisation procedures. Risk of bias will be assessed using the Cochrane Risk of Bias assessment instrument for RCTs and the Strengthening the Reporting of Observational Studies in Epidemiology instrument for observational studies. Network meta-analysis will be performed using multivariate random-effects meta-regression models. The surface under the cumulative ranking curve will be used to provide a hierarchy of ADDs that increase cardiovascular mortality.

DISSEMINATION

The results of this study will be presented at a professional conference and submitted to a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42017051220.

Pioglitazone — current profile

Ploglitazone is a thiazolidinedione that specifically reduces insulin resistance in type 2 diabetes. It has been thoroughly investigated in clinical trials and since its market introduction in 1999 has been prescribed to many patients worldwide. In both monotherapy and combination therapy controlled trials, pioglitazone has proved to be an effective anti-hyperglycaemic agent, reducing fasting plasma glucose and displaying dose-dependent, long-term reductions in glycosylated haemoglobin (HbA1C) compared with placebo. Furthermore, in combination studies, insulin resistance and beta-cell function were significantly improved over baseline and placebo, as measured by HOMA. Pioglitazone also significantly reduced the levels of circulating triglycerides and increased high-density lipoprotein cholesterol without affecting total or low-density lipoprotein cholesterol. In all clinical trials, pioglitazone has been well-tolerated. It may be that the effects of pioglitazone on diabetic dyslipidaemia are at least as important as its effects on lowering blood glucose.

Pioglitazone — an oral antidiabetic agent and metabolic syndrome modulator. Can theory translate into practice?

The metabolic syndrome, associated with insulin resistance, is a cluster of cardiovascular risk factors which results in premature morbidity and mortality from atherosclerotic vascular disease. Pioglitazone, a peroxisome-proliferator-activated receptor gamma (PPARγ) agonist, is an insulin sensitiser with the ability to address key features of the metabolic syndrome: glucose intolerance including type 2 diabetes, hypertension, dyslipidaemia, the pro-coagulant state, endothelial dysfunction, inflammation and atherosclerosis. The greatest potential benefit of pioglitazone is to influence atherogenesis itself through its pleiotrophic effects on vascular risk factors. This has been tested by the PROactive study, results of which are published in September 2005.

Review: Vascular protective effects of peroxisome proliferator-activated receptor agonists

ardiovascular disease is significantly increased in patients with the metabolic syndrome and type 2 diabetes. A clustering of risk factors, including dyslipidaemia, insulin resistance, hypertension, inflammation and coagulation disorders are acting in concert to promote cardiovascular events in these patients. Peroxisome proliferator-activated receptors (PPARs) are transcription factors that influence vascular function by altering gene expression in vascular tissue and indirectly via effects on other tissues. Indeed, PPAR activation displays beneficial effects on glucose homeostasis and lipid metabolism, and also on endothelial function and vessel wall inflammation. Clinically used PPARα agonists, such as fibrates, and PPARγ agonists, such as insulin-sensitising thiazolidinediones, may consequently alter the process of atherosclerosis, especially in subjects with the metabolic syndrome and type 2 diabetes. The present review highlights emerging evidence for beneficial effects of PPAR α and PPARγ in the prevention and treatment of atherosclerosis in such high-risk patients.

Microvascular Changes in the Diabetic Foot

Impairment of the microcirculation of diabetic patients may contribute to secondary complications in the lower extremity, such as foot infections and ulcerations. These microcirculatory changes, which are mainly functional rather than structural, are responsible for the impaired ability of the microvasculature to vasodilate in response to injury. Dysfunction of vascular endothelial cells and vascular smooth muscle cells both contribute to the reduction in vasodilation that is observed in diabetic patients. Nerve-axon reflex related microvascular vasodilation is also impaired in the diabetic population, and there is a growing belief that both the failure of the vessels to dilate and the impairment of the nerve axon reflex are major causes for impaired wound healing in diabetic patients. Further studies are necessary to clarify the precise etiology of endothelial and smooth muscle dysfunction in diabetic patients so that potential therapeutic interventions may be identified.

Effect of Dipeptidyl Peptidase-4 Inhibitor on All-Cause Mortality and Coronary Revascularization in Diabetic Patients

BACKGROUND

Anti-atherosclerotic effect of dipeptidyl peptidase-4 (DPP-4) inhibitors has been suggested from previous studies, and yet, its association with cardiovascular outcome has not been demonstrated. We aimed to evaluate the effect of DPP-4 inhibitors in reducing mortality and coronary revascularization, in association with baseline coronary computed tomography (CT).

METHODS

The current study was performed as a multi-center, retrospective observational cohort study. All subjects with diabetes mellitus who had diagnostic CT during 2007-2011 were included, and 1866 DPP-4 inhibitor users and 5179 non-users were compared for outcome. The primary outcome was all-cause mortality and secondary outcome included any coronary revascularization therapy after 90 days of CT in addition to all-cause mortality.

RESULTS

DPP-4 inhibitors users had significantly less adverse events [0.8% vs. 4.4% in users vs. non-users, adjusted hazard ratios (HR) 0.220, 95% confidence interval (CI) 0.102-0.474, p = 0.0001 for primary outcome, 4.1% vs. 7.6% in users vs. non-users, HR 0.517, 95% CI 0.363-0.735, p = 0.0002 for secondary outcome, adjusted variables were age, sex, presence of hypertension, high sensitivity C-reactive protein, glycated hemoglobin, statin use, coronary artery calcium score and degree of stenosis]. Interestingly, DPP-4 inhibitor seemed to be beneficial only in subjects without significant stenosis (adjusted HR 0.148, p = 0.0013 and adjusted HR 0.525, p = 0.0081 for primary and secondary outcome).

CONCLUSION

DPP-4 inhibitor is associated with reduced all-cause mortality and coronary revascularization in diabetic patients. Such beneficial effect was significant only in those without significant coronary stenosis, which implies that DPP-4 inhibitor may have beneficial effect in earlier stage of atherosclerosis.

Bone mineral density and cardiovascular risk factors in postmenopausal women with coronary artery disease

It has been suggested that osteoporosis and coronary artery disease (CAD) have overlapping pathophysiological mechanisms and related risk factors. The aim of this study was to investigate the association between several traditional cardiovascular risk factors and measures of bone mineral density (BMD) in postmenopausal women with and without clinically significant CAD defined angiographically. A case-control study was undertaken of 180 postmenopausal women (aged between 48 and 88 years) who were recruited from King Abdulaziz University Hospital, Saudi Arabia. Study subjects underwent dual-energy x-ray absorptiometry and coronary angiography. The presence of hypertension, diabetes, dyslipidemia, obesity, smoking and physical activity was identified from clinical examination and history. Demographic, anthropometric and biochemical characteristics were measured. Univariate and multivariate analyses were employed to explore the relationships between cardiovascular risk factors, including BMD, and the presence of CAD. CAD patients were more likely to have a lower BMD and T-score at the femoral neck than those without CAD (P<0.05). Significant differences were found between the groups for fasting lipid profile, fasting blood glucose and anthropometric measures (P<0.05). Conditional logistic regression showed that 3 risk factors were significantly related with the presence of CAD: high-density lipoprotein-cholesterol (odds ratio, OR: 0.226, 95% confidence interval, CI: 0.062-0.826), fasting plasma glucose (OR: 1.154, 95% CI: 1.042-1.278) and femoral neck T-score (OR: 0.545, 95% CI: 0.374-0.794). This study suggests an association of low BMD and elevated CAD risk. Nevertheless, additional longitudinal studies are needed to determine the temporal sequence of this association.

Preanesthetic mortality prediction in diabetics undergoing major lower limb amputation at a tertiary referral hospital: Implications of preoperative echocardiographic and laboratory values

PURPOSE

Cardiac comorbidities in patients undergoing amputation due to diabetic foot ulcer are associated with high mortality rates. The authors investigated whether preanesthetic echocardiographic and laboratory values can predict inhospital mortality in type II diabetes patients undergoing major lower limb amputation under spinal anesthesia.

METHODS

The archived medical records of 215 patients were retrospectively reviewed. Demographic data and preoperative laboratory and transthoracic echocardiographic values were analyzed by multivariate logistic regression for factors independently associated with inhospital mortality.

RESULTS

Of the 215 patients, 12 died in hospital after amputation. Preoperative hemoglobin level (hazard ratio, 0.082; 95% confidence interval, 0.013-0.509; P = .007) and left ventricular ejection fraction (hazard ratio, 0.874; 95% confidence interval, 0.779- 0.981; P = .023) were found to be significant predictors of inhospital mortality.

CONCLUSIONS

Preoperative hemoglobin level and left ventricular ejection fraction are highly correlated with inhospital mortality in type II diabetes patients undergoing major lower extremity amputation under spinal anesthesia.

A device for performing automated balloon catheter inflation ischemia studies

Coronary collateral growth (arteriogenesis) is a physiological adaptive response to transient and repetitive occlusion of major coronary arteries in which small arterioles (native collaterals) with minimal to no blood flow remodel into larger conduit arteries capable of supplying adequate perfusion to tissue distal to the site of occlusion. The ability to reliably and reproducibly mimic transient, repetitive coronary artery occlusion (ischemia) in animal models is critical to the development of therapies to restore coronary collateral development in type II diabetes and the metabolic syndrome. Current animal models for repetitive coronary artery occlusion implement a pneumatic occluder (balloon) that is secured onto the surface of the heart with the suture, which is inflated manually, via a catheter connected to syringe, to effect occlusion of the left anterior descending coronary artery (LAD). This method, although effective, presents complications in terms of reproducibility and practicality. To address these limitations, we have designed a device for automated, transient inflation of balloon catheters in coronary artery occlusion models. This device allows repeated, consistent inflation (to either specified pressure or volume) and the capability for implementing very complex, month-long protocols. This system has significantly increased the reproducibility of coronary collateral growth studies in our laboratory, resulting in a significant decrease in the numbers of animals needed to complete each study while relieving laboratory personnel from the burden of extra working hours and enabling us to continue studies over periods when we previously could not. In this paper, we present all details necessary for construction and operation of the inflator. In addition, all of the components for this device are commercially available and economical (Table S1). It is our hope that the adoption of automated balloon catheter inflation protocols will improve the experimental reliability of transient ischemia studies at many research institutions.

The metabolic syndrome, oxidative stress, environment, and cardiovascular disease: the great exploration

The metabolic syndrome affects 30% of the US population with increasing prevalence. In this paper, we explore the relationship between the metabolic syndrome and the incidence and severity of cardiovascular disease in general and coronary artery disease (CAD) in particular. Furthermore, we look at the impact of metabolic syndrome on outcomes of coronary revascularization therapies including CABG, PTCA, and coronary collateral development. We also examine the association between the metabolic syndrome and its individual component pathologies and oxidative stress. Related, we explore the interaction between the main external sources of oxidative stress, cigarette smoke and air pollution, and metabolic syndrome and the effect of this interaction on CAD. We discuss the apparent lack of positive effect of antioxidants on cardiovascular outcomes in large clinical trials with emphasis on some of the limitations of these trials. Finally, we present evidence for successful use of antioxidant properties of pharmacological agents, including metformin, statins, angiotensin II type I receptor blockers (ARBs), and angiotensin II converting enzyme (ACE) inhibitors, for prevention and treatment of the cardiovascular complications of the metabolic syndrome.

Why is coronary collateral growth impaired in type II diabetes and the metabolic syndrome?

Type II diabetes and the metabolic syndrome are strong predictors of severity of occlusive coronary disease and poorer outcomes of coronary revascularization therapies. Coronary collateral growth can provide an alternative or accessory pathway of revascularization. However, collateral growth is impaired in type II diabetes and the metabolic syndrome. Although many factors necessary for collateral growth are known and many interventions have shown promising results in animal studies, not a single attempt to induce coronary collateral growth in human clinical trials has led to satisfactory results. Accordingly, the first part of this review outlines the known deleterious effects of diabetes and the metabolic syndrome on factors necessary for collateral growth, including pro-angiogenic growth factors, endothelial function, the redox state of the coronary circulation, intracellular signaling, leukocytes and bone marrow-derived progenitors cells. The second section highlights the gaps in our current knowledge of how these factors interact with the radically altered environment of the coronary circulation in diabetes and the metabolic syndrome. The interplay between these pathologies and inadequately explored areas related to the temporal regulation of collateral remodeling and the roles of the extracellular matrix, vascular cell phenotype and pro-inflammatory cytokines are emphasized with implications to development of efficient therapies.

Post-load hyperglycemia as an important predictor of long-term adverse cardiac events after acute myocardial infarction: a scientific study

Background

Diabetes mellitus (DM) and impaired glucose tolerance (IGT) are risk factors for acute myocardial infarction (AMI). However, it is unknown whether hyperglycemic state is associated with increased major adverse cardiovascular events (MACE) after AMI. In this study, we evaluated the relationship between glucometabolic status and MACE in patients after AMI, and determined the critical level of 2 h post-load plasma glucose that may be used to predict MACE.

Methods

AMI patients (n = 422) were divided into 4 groups as follows: normal glucose tolerance (NGT) group, IGT group, newly diagnosed DM (NDM) group, and previously known DM (PDM) group. MACE of the 4 groups were compared for 2 years from AMI onset.

Results

The NDM group had a significantly higher event rate than the IGT and NGT groups and had a similar event rate curve to PDM group. The logistic models analyses revealed that 2 h post-load plasma glucose values of ≥160 mg/dL was the only independent predictor of long-term MACE after AMI (p = 0.028, OR: 1.85, 95% CI: 1.07-3.21). The 2-year cardiac event rate of patients with a 2 h post-load hyperglycemia of ≥160 mg/dL was significantly higher than that of patients with 2 h post-load glucose of <160 mg/dL (32.2% vs. 19.8%, p < 0.05) and was similar to that of PDM group (37.4%, p = 0.513).

Conclusions

NDM increases the risk of MACE after AMI as does PDM. Particularly, post-AMI patients with a 2 h post-load hyperglycemia ≥160 mg/dL may need adjunctive therapy after AMI.

Diabetes and Cardiovascular Disease: Is intensive glucose control beneficial or deadly? Lessons from ACCORD, ADVANCE, VADT, UKPDS, PROactive, and NICE-SUGAR

Type 2 diabetes is a rather complex metabolic disorder still associated with a 2-fold increased cardiovascular (CV) mortality despite a dramatic improvement in CV risk reduction by multifactorial intervention strategies. Intensive glucose control can also reduce CV morbidity, but this effect seems to be limited to younger patients with shorter duration of disease and no CV disease. Intensive glucose control--in particular when complex insulin strategies are used--is associated with a 5-fold increased risk for severe hypoglycemia, which could induce harm in some patients. In contrast to blood pressure and lipid-lowering interventions a reduction of CV mortality cannot be seen before 10-20 years after the start of the glucose-lowering intervention (metabolic memory, legacy effect). Future ongoing outcome studies in more than 50,000 patients will clarify whether new antidiabetic drugs--not inducing hypoglycemia or weight gain--will further improve the prognosis of T2DM patients.

Insulin Resistance and Inflammation in the Early Phase of Type 2 Diabetes: Potential for Therapeutic Intervention

Prospective studies of prediabetic subjects have shown that obesity and its duration are major risk factors for type 2 diabetes. Longitudinal studies are consistent with an etiologic role of subclinical inflammation in the pathogenesis of type 2 diabetes, primarily as a mediator of obesity-induced insulin resistance. Inflammation is closely associated with endothelial dysfunction and is recognized as one of the cardiovascular risk factors clustering in the Insulin Resistance Syndrome or Metabolic Syndrome. The adipose tissue has been recognized as an important source of metabolically active secretory products (adipocytokines), free fatty acids, leptin, TNF-alpha, Iinterleucin-6, plasminogen activator inhibitor-1, adiponectin and resistin. Prevention of insulin resistance by weight loss, diet and exercise is very effective in reducing the progression from glucose intolerance to type 2 diabetes in obese subjects. Since insulin resistance is a key disturbance in early type 2 diabetes additional drug treatment with insulin-sensitizing drugs might be helpful to reduce the progression to both beta-cell failure and macrovascular late complications. The PROACTIVE study will determine if the effects of improving insulin sensitivity and reducing inflammation will translate into clinical benefits and reduce the cardiovascular morbidity and mortality associated with insulin resistance and Type 2 diabetes.

Long-term pioglitazone therapy improves arterial stiffness in patients with type 2 diabetes mellitus

Pioglitazone, a peroxisome proliferator-activated receptor gamma agonist, not only improves insulin resistance and glycemic control, but may also have additional beneficial vascular effects in patients with type 2 diabetes mellitus. We investigated whether pioglitazone had an influence on arterial stiffness, which is an independent predictor of cardiovascular events, in 204 patients with type 2 diabetes mellitus. A prospective, nonrandomized, open-label trial was performed that involved 41 patients treated with pioglitazone, 46 patients receiving sulfonylureas, 67 patients on insulin, and 50 patients on diet/exercise only. The follow-up period was 56 +/- 3 months. Arterial stiffness was evaluated by using the arterial stiffness index (ASI), which was based on analysis of the pulse wave amplitude pattern obtained during automated blood pressure measurement in the upper limb. The 4 groups had a similar baseline ASI, which was greater than the reference range in each group. Although antidiabetic therapies improved hemoglobin A(1c) and low-density lipoprotein cholesterol, ASI only decreased significantly in the pioglitazone group. Thus, pioglitazone improved abnormal arterial stiffness in patients with type 2 diabetes mellitus via a mechanism beyond the metabolic improvement. These findings may have important clinical implications in the use of pioglitazone in patients with type 2 diabetes mellitus.

How safe is the use of thiazolidinediones in clinical practice?

BACKGROUND

Thiazolidinediones (TZDs) are widely used antidiabetic drugs with proven efficacy regarding mainly surrogate markers of diabetes management. However, efficacy on surrogate markers may not always translate into benefits in clinical outcomes. Thiazolidinediones are usually well tolerated; however, their use may be associated with several adverse effects. The first TZD, troglitazone, was withdrawn from the market owing to serious hepatotoxicity. However, this does not seem to be the case with newer TZDs.

OBJECTIVE

The aim of the present review is to discuss the safety profile of this drug class.

METHODS

We searched PubMed up to July 2008 using relevant keywords.

CONCLUSIONS

Common side effects associated with TZDs include edema, weight gain, macular edema and heart failure. Moreover, they may cause hypoglycemia when combined with other antidiabetic drugs as well as decrease hematocrit and hemoglobin levels. Increased bone fracture risk is another TZD-related side effect. Thiazolidinediones tend to increase serum low density lipoprotein cholesterol levels, with rosiglitazone having a more pronounced effect compared with pioglitazone. Moreover, rosiglitazone increases low density lipoprotein particle concentration in contrast to pioglitazone where a decrease is observed. Rosiglitazone has been associated with an increase in myocardial infarction incidence. On the other hand, pioglitazone may reduce cardiovascular events. Overall, TZDs are valuable drugs for diabetes management but physicians should keep in mind that they are associated with several adverse events, the most prominent of which is heart failure.

Myocardial steatosis is an independent predictor of diastolic dysfunction in type 2 diabetes mellitus

OBJECTIVES

The purpose of this study was to compare myocardial triglyceride content and function between patients with uncomplicated type 2 diabetes mellitus (T2DM) and healthy subjects within the same range of age and body mass index (BMI), and to study the associations between myocardial triglyceride content and function.

BACKGROUND

T2DM is a major risk factor for cardiovascular disease. Increasing evidence is emerging that lipid oversupply to cardiomyocytes plays a role in the development of diabetic cardiomyopathy, by causing lipotoxic injury and myocardial steatosis.

METHODS

Myocardial triglyceride content and myocardial function were measured in 38 T2DM patients and 28 healthy volunteers in the same range of age and BMI by proton magnetic resonance (MR) spectroscopy and MR imaging, respectively. Myocardial triglyceride content was calculated as a percentage relative to the signal of myocardial water.

RESULTS

Myocardial triglyceride content was significantly higher in T2DM patients compared with healthy volunteers (0.96 +/- 0.07% vs. 0.65 +/- 0.05%, p < 0.05). Systolic function did not significantly differ between both groups. Indexes of diastolic function, including the ratio of maximal left ventricular early peak filling rate and the maximal left ventricular atrial peak filling rate (E/A) and E peak deceleration, were significantly impaired in T2DM compared with those in healthy subjects (1.08 +/- 0.04 ml/s(2) x 10(-3) vs. 1.24 +/- 0.06 ml/s(2) x 10(-3) and 3.6 +/- 0.2 ml/s(2) x 10(-3) vs. 4.4 +/- 0.3 ml/s(2) x 10(-3), respectively, p < 0.05). Multivariable analysis indicated that myocardial triglyceride content was associated with E/A and E peak deceleration, independently of diabetic state, age, BMI, heart rate, visceral fat, and diastolic blood pressure.

CONCLUSIONS

Myocardial triglyceride content is increased in uncomplicated T2DM and is associated with impaired left ventricular diastolic function, independently of age, BMI, heart rate, visceral fat, and diastolic blood pressure.

Combining insulins with oral antidiabetic agents: effect on hyperglycemic control, markers of cardiovascular risk and disease

Patients with type 2 diabetes mellitus (T2DM) have an increased risk of cardiovascular disease (CVD). Unfortunately, several potential barriers exist for CVD risk management in diabetes, including the need for significant lifestyle changes, potential problems with hypoglycemia, weight gain, injection tolerability, treatment complexity with current diabetes therapies and other, unmodifiable factors. Improving glycemic control may impact CVD risk. Treatment of T2DM usually starts with lifestyle changes such as diet and exercise. When these become insufficient, pharmacotherapy is required. Various oral antidiabetic drugs (OADs) are available that reduce hyperglycemia. The first line of therapy is usually metformin, since it does not increase weight and seems to have a beneficial effect on CVD mortality and risk factors. As T2DM progresses, insulin treatment becomes necessary for the majority of patients. The last few years have seen the development of long-acting, rapid-acting, and premixed insulin analog formulations. The treat-to-target algorithms of recent studies combining OADs plus insulin analogs have demonstrated that patients can reach glycemic treatment targets with low risk of hypoglycemia, greater convenience, and – with some analogs – limited weight gain vs conventional insulins. These factors may possibly have a positive influence on CVD risk. Future studies will hopefully elucidate the benefits of this approach.

Economic evaluation of screening for diabetic retinopathy among Chinese type 2 diabetics: a community-based study in Kinmen, Taiwan

BACKGROUND

This community-based study conducted in Kinmen aimed to discover whether screening for diabetic retinopathy (DR) among Chinese with type 2 diabetes was economically feasible and clinically effective.

METHODS

A total of 971 community-dwelling adults previously diagnosed with type 2 diabetes in 1991-1993 underwent DR screening in 1999-2002 by a panel of ophthalmologists, who used on-site indirect ophthalmoscopy and 45-degree color fundus retinal photographs. Economic evaluation included estimates for cost effectiveness and the cost utility of screening for DR.

RESULTS

For each DR case, screening efficacy and utility decreased, while cost increased with the length of the screening interval. The cost per sight year gained in the annual screening, biennial screening, 3-year screening, 4-year screening, 5-year screening, and control groups were New Taiwan dollars (NT dollars) 20962, NT dollars 24990, NT dollars 30847, NT dollars 37435, NT dollars 44449, and NT dollars 83411, respectively. The cost per quality-adjusted life year gained by the annual screening, biennial screening, 3-year screening, 4-year screening, 5-year screening, and control groups were NT dollars 21924, NT dollars 25319, NT dollars 30098, NT dollars 35106, NT dollars 40037, and NT dollars 61542, respectively. Threshold values indicate that the screening programs are highly sensitive to screening cost in the plausible range.

CONCLUSION

Screening for DR is both medically and economically worthwhile. Annual screening for DR among Chinese with type 2 diabetes should be conducted. Prevention programs aimed at improving eye care for patients with type 2 diabetes result in both substantial federal budgetary savings and highly cost-effective health care.

The diabetes-cardiovascular risk paradox: results from a Finnish population-based prospective study

AIMS

To assess changes in coronary heart disease (CHD) event rates and CHD mortality rates among diabetic and non-diabetic individuals between two large study cohorts with baseline assessments 10 years apart and followed up for 10 years.

METHODS AND RESULTS

Four population surveys were carried out in 1972, 1977, 1982, and 1987 in a randomly selected independent population in Finland. For the analyses, we combined the 1972 and 1977 cohorts (cohort 1) and similarly also the 1982 and 1987 cohorts (cohort 2). A total of 16 779 men and 18 235 women were followed up for 10 years. Whereas the risk of first cardiovascular disease event in women did not change between the two cohorts, the risk in diabetic men aged 25-49 years and men of all age groups with incidence diabetes during the follow-up decreased compared with the earlier cohort. The relative risk of CHD mortality in men with baseline diabetes or incident diabetes compared with non-diabetic individuals increased (from 1.67 to 1.75 and 1.00 to 1.92, respectively). CHD event rates and CHD mortality rates decreased among non-diabetic individuals between the two study cohorts.

CONCLUSION

Special attention should be given to prevent the onset of diabetes in the population and to intensify the management of patients with diabetes.

Left ventricular diastolic dysfunction in normotensive diabetic patients in various age strata

Although patients with type 2 diabetes demonstrate cardiac diastolic dysfunction, it is well known that cardiac diastolic dysfunction is produced by hypertension and aging. The purpose of the present study was to elucidate the cardiac structure and function in normotensive patients with type 2 diabetes in various age strata in order to assess the effect of diabetes mellitus itself on cardiac function. Echocardiographic examination was performed in 77 normotensive patients with type 2 diabetes (age: 63+/-11 years) and 76 healthy control subjects (age: 60+/-11 years) who were in their forties, fifties, sixties, and seventies. The left ventricular (LV) wall thickness and dimension were measured by M-mode echocardiography. The relative wall thickness, LV mass index, and LV ejection fraction (LVEF) were calculated. LV diastolic function was assessed by the peak velocity of early rapid filling (E velocity) and the peak velocity of atrial filling (A velocity), and the ratio of E to A (E/A) using the transmitral flow velocity, which were obtained by Doppler echocardiography. No difference was observed in the relative wall thickness, LV mass index, or LVEF between the diabetic patients and control subjects in any of the age strata. The E/A ratio in the patients with type 2 diabetes was not different from that in the control subjects in their 40s (1.17+/-0.35 versus 1.20+/-0.36). However, E/A was significantly lower in the diabetic patients than in the control subjects in their 50s (0.87+/-0.28 versus 1.14+/-0.24), 60s (0.78+/-0.22 versus 0.97+/-0.27), and 70s (0.66+/-0.19 versus 0.84+/-0.21) (p<0.05). The duration of type 2 diabetes was significantly longer in patients in their 50s (7.0+/-2.5 years), 60s (8.0+/-3.2 years), and 70s (10.4+/-3.2 years) than in patients in their 40s (3.3+/-1.9 years) (p<0.001). The value of E/A in the diabetic patients correlated with the duration of type 2 diabetes (r=-0.62, p<0.001). These results indicate that cardiac diastolic dysfunction without LV systolic dysfunction in patients with well-controlled type 2 diabetes is related neither to hypertension nor LV hypertrophy, but rather to aging and the duration of type 2 diabetes.

Impact of diabetes on cardiomyocyte apoptosis and connexin43 gap junction integrity: role of pharmacological modulation

The integrity of myocardial structures plays a crucial role in signal transductions and cardiac function. The aim of this study was to test the hypothesis that diabetes mellitus (DM) exerts adverse effects on the integrity of gap junctions (GJs) and induces cellular apoptosis in rat cardiomyocytes that can be abolished by simvastatin or losartan therapy. An experimental model of DM (induced by streptozocin 60 mg/kg body weight) in adult male rats (n = 24) was utilized to investigate the integrity of GJs containing connexin43 (Cx43) and the incidence of cellular apoptosis in the left ventricular myocardium. These rats were divided into 3 groups; group I (insulin therapy only), group II (insulin plus simvastatin 20 mg/kg/day), and group III (insulin plus losartan 20 mg/kg/day). Diabetic rats and 8 healthy rats (group IV) were sacrificed at 3 weeks following DM induction for immunofluorescence analysis. The experimental results demonstrated that the number of intact Cx43 GJs and the integrated area (mum(2)) constituted by clusters of Cx43 spots were significantly higher in groups II and IV than in group III, and in groups II-IV than in group I (all P values < 0.05). Additionally, the number of apoptotic bodies was remarkably higher in group I than in groups II-IV, and notably higher in groups II-III than in group IV (all P values < 0.05). Simvastatin is more effective than losartan at inhibiting the effects of DM on the integrity of myocardial ultrastructures. Both drugs effectively prevent cellular apoptosis in diabetic rat heart.

Rosiglitazone treatment improves cardiac efficiency in hearts from diabetic mice

Isolated perfused hearts from type 2 diabetic (db/db) mice show impaired ventricular function, as well as altered cardiac metabolism. Assessment of the relationship between myocardial oxygen consumption (MVO(2)) and ventricular pressure-volume area (PVA) has also demonstrated reduced cardiac efficiency in db/db hearts. We hypothesized that lowering the plasma fatty acid supply and subsequent normalization of altered cardiac metabolism by chronic treatment with a peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist will improve cardiac efficiency in db/db hearts. Rosiglitazone (23 mg/kg body weight/day) was administered as a food admixture to db/db mice for five weeks. Ventricular function and PVA were assessed using a miniaturized (1.4 Fr) pressure-volume catheter; MVO(2) was measured using a fibre-optic oxygen sensor. Chronic rosiglitazone treatment of db/db mice normalized plasma glucose and lipid concentrations, restored rates of cardiac glucose and fatty acid oxidation, and improved cardiac efficiency. The improved cardiac efficiency was due to a significant decrease in unloaded MVO(2), while contractile efficiency was unchanged. Rosiglitazone treatment also improved functional recovery after low-flow ischemia. In conclusion, the present study demonstrates that in vivo PPARgamma-treatment restores cardiac efficiency and improves ventricular function in perfused hearts from type 2 diabetic mice.

Abnormal left ventricular energy metabolism in obese men with preserved systolic and diastolic functions is associated with insulin resistance

OBJECTIVE

Perturbations in cardiac energy metabolism might represent early alterations in diabetes preceding functional and pathological changes. We evaluated left ventricular (LV) structure/geometry and function in relation to energy metabolism and cardiovascular risk factors in overweight/obese men using magnetic resonance techniques.

RESEARCH DESIGN AND METHODS

We studied 81 healthy men (aged 22-55 years, with BMI between 19 and 35 kg/m2) by means of cardiac magnetic resonance imaging and 31P-magnetic resonance spectroscopy in the resting and fasted conditions and stratified them in quartiles of BMI (cut offs: 23.2, 25.5 and 29.0 kg/m2).

RESULTS

LV mass increased across quartiles of BMI; meanwhile, the volumes did not differ. Parameters of LV systolic and diastolic function were not different among quartiles. The phosphocreatine-to-ATP ratio was reduced across increasing quartiles of mean +/- SD BMI (2.25 +/- 0.52, 1.89 +/- 0.26, 1.99 +/- 0.38, and 1.79 +/- 0.29; P < 0.006) in association with insulin sensitivity (computer homeostasis model assessment 2 model); this relation was independent of age, BMI, blood pressure, wall mass, HDL cholesterol, triglycerides, smoking habits, and metabolic syndrome.

CONCLUSIONS

Abnormal LV energy metabolism was detectable in obese men in the presence of normal function, supporting the hypothesis that metabolic remodeling in insulin resistant states precedes functional and structural/geometrical remodeling of the heart regardless of the onset of overt hyperglycemia.

Differential effects of oral hypoglycemic agents on glucose control and cardiovascular risk

Cardiovascular disease (CVD) burden remains the predominant cause of mortality and morbidity in the United States and in most of the developed world. The ongoing twin epidemics of obesity and type 2 diabetes mellitus provide a groundswell source for sustaining this trend for the foreseeable future (increasing the prevalence of CVD by 2-4 times), unless radical changes are made in public health policy. Oral hypoglycemic agents (OHAs) remain a mainstay for management of type 2 diabetes in most practice settings. Although these agents are primarily prescribed to achieve better glycemic control, it is important to evaluate what effects they have on cardiovascular risk and whether there are significant differences in effects among the different OHAs. This review presents the available data on the effects of the various OHAs on cardiovascular risk surrogates and actual events in retrospective and prospective study design settings.

Oral antidiabetic agents as cardiovascular drugs

The increased risk of cardiovascular disease associated with type 2 diabetes is well documented. Lesser degrees of abnormal glucose metabolism including impaired fasting glycaemia and impaired glucose tolerance are also associated with increased cardiovascular risk. Studies showing improved cardiovascular outcomes with oral antidiabetic agents are limited, with the UKPDS demonstrating improved macrovascular outcomes only in a subgroup of obese patients with type 2 diabetes treated with metformin, and the heavily criticized STOP NIDDM trial showing a reduction in the number of cardiovascular events with the alpha glucosidase inhibitor acarbose. In recent years there has been an increase in the number of oral antidiabetic drugs available to treat the hyperglycaemia of diabetes. Some of these drugs have complex metabolic properties, additional to their antihyperglycaemic effect, improving endothelial function and markers of atherogenesis, with the potential to reduce cardiovascular morbidity and mortality, as supported by the recently published results of the PROACTIVE study. The results of further long-term cardiovascular outcome studies with these newer agents are awaited.

Difficulties of smoking cessation in diabetic inpatients benefiting from a systematic consultation to help them to give up smoking

AIM

To assess the value of systematic smoking cessation consultations for diabetic smokers admitted to hospital.

METHODS

All diabetic smokers admitted to the Diabetes Department of Georges Pompidou European Hospital between February 2003 and February 2004 were systematically offered a consultation with a physician specialised in tobacco cessation. Follow-up visits at three, six and nine months were planned.

RESULTS

Of the 306 diabetic patients admitted, 38 (12.4%) were smokers. There were more men than women in the group of smokers and the diabetic smokers were younger than the non-smokers. The smokers had fewer micro-angiopathic complications than the non-smokers, but there was no difference in the frequency of macro-angiopathic complications. The level of nicotine physical dependence was moderate or high for 60% of the smokers. Although all the smokers agreed to the consultation, less than half agreed to drug-based treatments to help them to give up smoking and only 15% returned for the six-month visit. Only one patient had stopped smoking at the six-month visit.

CONCLUSION

This study demonstrates the difficulties in systematic interventions to help diabetic patients to stop smoking. Diabetic smokers probably constitute a specific population for which the barriers to giving up smoking should be explored.

Prevalence of diabetes and other cardiovascular risk factors in an Iranian population with acute coronary syndrome

Background

Coronary artery disease is the leading cause of death in industrialized countries and most patients with diabetes die from complications of atherosclerosis. The objective of this study was to determine the presence of diabetes mellitus and other conventional coronary heart disease risk factors (cigarette smoking, hypertension and hyperlipidemia) in patients with acute coronary events in an Iranian population.

Methods

The study included 514 patients with unstable angina or myocardial infarction (MI) out of 720 patients admitted to CCU ward of a general hospital from March 2003 to March 2005. History of diabetes, hypertension and cigarette smoking, demographic indices, coronary heart disease and diabetes mellitus treatment, myocardial enzymes, serum triglycerides (TG) and cholesterol and fasting and non fasting blood glucose levels and HbA1C of diabetics were recorded of admission sheets. The data were structured to appropriate one way ANOVA, T tests, and chi square test with SPSS 13 product for windows.

Results

Out of all patients 35.8% were female, 30% were diabetics (Duration 13.4 ± 8.7 years), 42% were smoker and 91% were hypertensive. Twenty four percent had MI and 76% had unstable angina. MI was significantly higher in diabetic patients (36.4% vs. 19.2%, P < 0.001). Location and extension of MI and myocardial enzymes did not differ between diabetics and non-diabetic patients. Diabetic patients were older than non diabetics (65 ± 11.6 vs. 59.7 ± 12.5 years, p < 0.05). Five (66.7%) out of 9 patients with fatal MI were diabetics (Odds Ratio = 2.98). Age, duration of diabetes and HbA1c levels, did not differ between diabetic patients with or without MI. Hypertension and current smoking was significantly higher in patients with MI compared to patients with unstable angina (p < 0.05). Serum TG, HDL-C, LDL-C and total cholesterol level did not differ between patients with MI and unstable angina. Diabetic patients compare to non diabetic patients were more hypertensive (96% vs. 88.7%, p < 0.005) and had higher serum triglyceride (TG over 200 mg/dl, 35.1% vs. 26.4, p <0.05). Diabetes was more frequent among women than men (36.4% vs. 26.4%, p < 0.05). Women were older than men (65 ± 11.6 vs. 59.2 ± 13 years, p < 0.005) and had higher total serum cholesterol (200 ± 41.8 vs. 192 ± 42.5 mg/dl, p < 0.05) and HDL-C levels (49.7 ± 22 vs. 40 ± 13 mg/dl, p < 0.005). Ninety seven percent of all patients had at least one of cardiovascular risk factors (hypertension, smoking, diabetes, high cholesterol and low HDL-cholesterol levels).

Conclusion

In this study 19 out of 20 patients with acute coronary event have at least one of conventional cardiac risk factors. Diabetes and hypertension are leading risk factors, which may directly or indirectly interfere and predict more serious complications of coronary heart disease.

Type 2 diabetes mellitus: a cardiovascular perspective

Diabetes mellitus is a disease, which is at the epitome of cardiovascular risk factors causing considerable morbidity and mortality. In addition to microvascular complications, there is two- to six-fold increased risk of macrovascular diseases, such as coronary artery disease, peripheral artery disease and stroke. While the mortality from coronary artery disease in patients without diabetes has declined over the past 20 years, the mortality in men with type 2 diabetes mellitus has not changed. Furthermore, the prevalence of diabetes in the UK has increased by 30% since 1991 and the same among the world population in 2010 is expected to be twice in 1990. This dramatic increase has serious implications from a cardiovascular perspective and thus the aggressive management of blood pressure, dyslipidaemia and blood glucose in diabetes is of vital importance. The aim of this review is to evaluate the current evidence and to discuss the implications of type 2 diabetes and its relevance to clinical practice in cardiology. We address this broad subject in discussing (i) the pathophysiology of cardiovascular disease in the setting of type 2 diabetes and (ii) the prevalence of cardiovascular risk, complications and prognostic implications in type 2 diabetes, with a discussion of current therapeutic interventions for the prevention or delay of these consequences where relevant.

Cardiovascular protection in patients with type 2 diabetes mellitus: Considerations about the tightness of blood pressure control and the choice of treatment

Diabetes mellitus is rapidly evolving as the epidemic of the 21st century. The presently estimated number of 190 million is predicted to grow to over 300 million by the year 2025. Cardiovascular (CVD) morbidity and mortality is two to five times higher in diabetics, while the microvascular complications considerably compromise the quality of life. The main risk factors for CVD, as well as for microangiopathy, are hypertension, dyslipidemia, insulin resistance, hyperglycemia, endothelial dysfunction, and an inflammatory vascular reaction. This review will focus on hypertension, which develops in most patients within the first 10-15 years of their diabetes. The discussion will encompass the criteria for treatment, the target values of blood pressure, and the choice of antihypertensive drugs as primary agents and in various combinations. The special role of angiotensin-receptor blockers will be highlighted, with an emphasis on cardioprotection, risk reduction of stroke, and attenuation of the course of nephropathy.

A community-based follow-up study on diabetic retinopathy among type 2 diabetics in Kinmen

The purpose of this follow-up study was conducted to assess the incidence and risk factors of diabetic retinopathy (DR) among type 2 diabetics in Kinmen, Taiwan. A penal of eye screening regimes were performed yearly for 971 type 2 diabetics by two senior ophthalmologists using indirect ophthalmoscopy and 45-degree color fundus photography to examine fundus after dilating pupils from 1999 to 2002. 74.7% (725/971) of diabetics had been screened at least two times during this period. Among the 548 type 2 diabetics who had no DR at first screening, 93 subjects developed any type of DR. The 3-year 18.2% cumulative incidence was (95% CI: 14.8-21.5%) and incidence density was 6.62% per year (95% CI: 5.36-8.06% per year). Using Cox regression model, HbAlc revealed the significantly dose response relationship to the development of DR (chi2-test for trend = 9.41, p < 0.05) after controlling for confounding factors. Other independent predictors related to the development of DR included duration of diabetes (RR: 1.09, 95% CI: 1.05-1.13), higher systolic blood pressure (>140 vs. < 140 mm Hg, RR: 1.96, 95% CI: 1.23-3.12), and higher triglyceride (> 200 vs. < 200 mg/dl, RR: 1.60, 95% CI: 1.01-2.54). In conclusion, in addition to poor glycemic control of which is the most significant risk factor for the development of DR, longer duration of diabetes, higher systolic blood pressure, and elevated serum triglyceride levels were also associated with the development of DR among type 2 diabetics in Kinmen.

The prospective pioglitazone clinical trial in macrovascular events (PROactive): can pioglitazone reduce cardiovascular events in diabetes? Study design and baseline characteristics of 5238 patients

OBJECTIVE

The PROspective pioglitAzone Clinical Trial In macroVascular Events (PROactive) assesses the effect of pioglitazone, a peroxisome proliferator-activated receptor agonist, with anti-inflammatory and vascular properties, on the secondary prevention of macrovascular events in type 2 diabetes.

RESEARCH DESIGN AND METHODS

PROactive is an on-going randomized, double-blind outcome study in patients with type 2 diabetes managed with diet and/or oral blood glucose-lowering drugs (combination of oral agents with insulin is permitted) who have a history of macrovascular disease. Patients are randomized to receive pioglitazone (forced titration from 15 to 30 to 45 mg, depending on tolerability) or placebo in addition to existing therapy. The primary end point is the time from randomization to occurrence of a new macrovascular event or death. Follow-up is estimated to span 4 years.

RESULTS

A total of 5238 patients have been randomized from 19 countries. At entry into the study, patients enrolled are a mean age of 61.8 years, with type 2 diabetes for a mean of 9.5 years; 60.9 and 61.5% are taking metformin or a sulfonylurea, respectively; and 33.6% are using insulin in addition to oral glucose-lowering drugs. The majority of patients are men (66.1%). Patients are required to meet one or more of entry criteria, as follows: >6 months' history of myocardial infarction (46.7%); coronary artery revascularization (30.8%), stroke (18.8%), or acute coronary syndrome for >3 months (13.7%); other evidence of coronary artery disease (48.1%); or peripheral arterial occlusive disease (19.9%). One-half (48.5%) of the patients have two or more of these risk factors. Three-quarters (75.4%) have hypertension, and 58.8% are current or previous smokers.

CONCLUSIONS

The cohort of patients enrolled in PROactive is a typical type 2 diabetic population at high risk of further macrovascular events. The characteristics of this population are ideal for assessing the ability of pioglitazone to reduce the cardiovascular risk of patients with type 2 diabetes.

Diabetic patients who smoke: are they different?

BACKGROUND

We wanted to identify differences between diabetic patients who smoke and those who do not smoke to design more effective strategies to improve their diabetes care and encourage smoking cessation.

METHODS

A random sample of adult health plan members with diabetes were mailed a survey questionnaire, with telephone follow-up, asking about their attitudes and behaviors regarding diabetes care and smoking. Among the 1,352 respondents (response rate 82.4%), we found 188 current smokers whose answers we compared with those of 1,264 nonsmokers, with statistical adjustment for demographic characteristics and duration of diabetes.

RESULTS

Smokers with diabetes were more likely to report fair or poor health (odds ratio [OR] = 1.5, P = .03) and often feeling depressed (OR = 1.7, P = .004). Relative to nonsmokers, smokers had lower rates of checking blood glucose levels, were less physically active, and had fewer diabetes care visits, glycated hemoglobin (A1c) tests, foot examinations, eye examinations, and dental checkups (P < or = .01). Smokers also reported receiving and desiring less support from family and friends for specific diabetic self-management activities and had lower readiness to quit smoking than has been observed in other population groups.

CONCLUSIONS

Clinicians should be aware that diabetic patients who smoke are more likely to report often feeling depressed and, even after adjusting for depression, are less likely to be active in self-care or to comply with diabetes care recommendations. Diabetic patients who smoke are special clinical challenges and are likely to require more creative and consistent clinical interventions and support.

Effects of dietary supplementation with isoflavones from red clover on ambulatory blood pressure and endothelial function in postmenopausal type 2 diabetes

OBJECTIVE

The aim of this study was to determine whether dietary supplementation with isoflavones from red clover affected ambulatory blood pressure and forearm vascular endothelial function in postmenopausal type 2 diabetic women.

DESIGN

Sixteen postmenopausal type 2 diabetics treated with diet or oral hypoglycaemic therapy completed a randomized double-blind crossover trial of dietary supplementation with isoflavones from red clover (approximately 50 mg/day) for 4 weeks compared to placebo. Twenty-four-hour ambulatory blood pressure recordings and forearm vascular responses to acetylcholine, nitroprusside and L-nitromonomethylarginine (L-NMMA) were measured at the end of each treatment period.

RESULTS

Mean daytime systolic and diastolic blood pressures were significantly lower during isoflavone therapy compared to placebo (-8.0 +/- 3.4 and -4.3 +/- 1.9 mmHg respectively, p < 0.05). The increase in forearm vascular resistance following L-NMMA was significantly greater during isoflavone supplementation (20.9 +/- 6.5) than placebo (3.7 +/- 2.9 arbitrary units, p < 0.05), suggesting an improvement in basal endothelial function. Plasma lipoproteins, glycated haemoglobin and forearm vascular responses to acetylcholine and nitroprusside did not differ significantly between isoflavone and placebo therapy.

CONCLUSION

Isoflavone supplementation from red clover may favourably influence blood pressure and endothelial function in postmenopausal type 2 diabetic women.

Abnormal cardiac and skeletal muscle energy metabolism in patients with type 2 diabetes

BACKGROUND

It is well known that patients with type 2 diabetes have increased risk of cardiovascular disease, but it is not known whether they have underlying abnormalities in cardiac or skeletal muscle high-energy phosphate metabolism.

METHODS AND RESULTS

We studied 21 patients with type 2 diabetes with no evidence of coronary artery disease or impaired cardiac function, as determined by echocardiography, and 15 age-, sex-, and body mass index-matched control subjects. Cardiac high-energy phosphate metabolites were measured at rest using 31P nuclear magnetic resonance spectroscopy (MRS). Skeletal muscle high-energy phosphate metabolites, intracellular pH, and oxygenation were measured using 31P MRS and near infrared spectrophotometry, respectively, before, during, and after exercise. Although their cardiac morphology, mass, and function appeared to be normal, the patients with diabetes had significantly lower phosphocreatine (PCr)/ATP ratios, at 1.50+/-0.11, than the healthy volunteers, at 2.30+/-0.12. The cardiac PCr/ATP ratios correlated negatively with the fasting plasma free fatty acid concentrations. Although skeletal muscle energetics and pH were normal at rest, PCr loss and pH decrease were significantly faster during exercise in the patients with diabetes, who had lower exercise tolerance. After exercise, PCr recovery was slower in the patients with diabetes and correlated with tissue reoxygenation times. The exercise times correlated negatively with the deoxygenation rates and the hemoglobin (Hb)A1c levels and the reoxygenation times correlated positively with the HbA1c levels.

CONCLUSIONS

Type 2 diabetic patients with apparently normal cardiac function have impaired myocardial and skeletal muscle energy metabolism related to changes in circulating metabolic substrates.

Diabetes mellitus impairs vasodilation to hypoxia in human coronary arterioles: reduced activity of ATP-sensitive potassium channels

ATP-sensitive K+ channels (K(ATP)) contribute to vasomotor regulation in some species. It is not fully understood the extent to which K(ATP) participate in regulating vasomotor tone under physiological and pathophysiological conditions in the human heart. Arterioles dissected from right atrial appendage were studied with video microscopy, membrane potential recordings, reverse transcription-polymerase chain reaction, and immunohistochemistry. Hypoxia produced endothelium-independent vasodilation and membrane hyperpolarization of vascular smooth muscle cells, both of which were attenuated by glibenclamide. Aprikalim, a selective K(ATP) opener, also induced a potent endothelium-independent and glibenclamide-sensitive vasodilation with membrane hyperpolarization. Reverse transcription-polymerase chain reaction detected mRNA expression for K(ATP) subunits, and immunohistochemistry confirmed the localization of the inwardly rectifying Kir6.1 protein in the vasculature. In patients with type 1 or type 2 diabetes mellitus (DM), vasodilation was reduced to both aprikalim (maximum dilation, DM(+) 90+/-2% versus DM(-) 96+/-1%, P<0.05) and hypoxia (maximum dilation, DM(+) 56+/-8% versus DM(-) 85+/-5%, P<0.01) but was not altered to sodium nitroprusside or bradykinin. Baseline myogenic tone and resting membrane potential were not affected by DM. We conclude that DM impairs human coronary arteriolar dilation to K(ATP) opening, leading to reduced dilation to hypoxia. This reduction in K(ATP) function could contribute to the greater cardiovascular mortality and morbidity in DM.

Augmentation of central arterial pressure as a marker of atherosclerosis in patients with type 2 diabetes

Macrovascular disease is the most common cause of morbidity and mortality in diabetic patients. With the increasing numbers of patients with type 2 diabetes, a simple, noninvasive method is needed to detect atherosclerosis. Augmentation represents the difference between the second and first peaks of the central arterial pressure waveform in systole and is a measure of systemic arterial stiffness, which causes the pressure wave to rebound. We investigated whether augmentation could serve as a marker of atherosclerosis in patients with type 2 diabetes. Central arterial pressure and degree of its augmentation by pulse wave rebound were measured sphygmographically in 208 consecutive patients with type 2 diabetes and 117 healthy control subjects. The relationship between augmentation and carotid atherosclerosis detected by carotid ultrasonography was investigated in a subgroup of 81 diabetic patients. Augmentation was greater in diabetic patients than control subjects (13.2+/-6.9 vs. 9.4+/-5.7 mm Hg, P<0.0001). The positive correlation between augmentation and intima-media thickness (r=0.309, P=0.0051) and between augmentation and plaque score (r=0.304, P=0.0059) were found in patients with type 2 diabetes. Augmentation was greater in diabetic patients with cardiovascular disease (n=47) than without (n=161; 15.1+/-8.4 vs. 12.6+/-6.3 mm Hg, P=0.031). Augmentation of central arterial pressure is a reliable marker for atherosclerosis in patients with type 2 diabetes. This simple, noninvasive determination would permit large-scale, early screening for atherosclerosis in patients with type 2 diabetes, who are at increased risk for cardiovascular disease.

Cellular dysfunction in the diabetic fibroblast: impairment in migration, vascular endothelial growth factor production, and response to hypoxia

Although it is known that systemic diseases such as diabetes result in impaired wound healing, the mechanism for this impairment is not understood. Because fibroblasts are essential for wound repair, we compared the in vitro behavior of fibroblasts cultured from diabetic, leptin receptor-deficient (db/db) mice with wild-type fibroblasts from mice of the same genetic background in processes important during tissue repair. Adult diabetic mouse fibroblast migration exhibited a 75% reduction in migration compared to normal fibroblasts (P < 0.001) and was not significantly stimulated by hypoxia (1% O(2)), whereas wild-type fibroblast migration was up-regulated nearly twofold in hypoxic conditions (P < 0.05). Diabetic fibroblasts produced twice the amount of pro-matrix metalloproteinase-9 as normal fibroblasts, as measured by both gelatin zymography and enzyme-linked immunosorbent assay (P < 0.05). Adult diabetic fibroblasts exhibited a sevenfold impairment in vascular endothelial growth factor (VEGF) production (4.5 +/- 1.3 pg/ml versus 34.8 +/- 3.3 pg/ml, P < 0.001) compared to wild-type fibroblasts. Moreover, wild-type fibroblast production of VEGF increased threefold in response to hypoxia, whereas diabetic fibroblast production of VEGF was not up-regulated in hypoxic conditions (P < 0.001). To address the question whether these differences resulted from chronic hyperglycemia or absence of the leptin receptor, fibroblasts were harvested from newborn db/db mice before the onset of diabetes (4 to 5 weeks old). These fibroblasts showed no impairments in VEGF production under basal or hypoxic conditions, confirming that the results from db/db fibroblasts in mature mice resulted from the diabetic state and were not because of alterations in the leptin-leptin receptor axis. Markers of cellular viability including proliferation and senescence were not significantly different between diabetic and wild-type fibroblasts. We conclude that, in vitro, diabetic fibroblasts show selective impairments in discrete cellular processes critical for tissue repair including cellular migration, VEGF production, and the response to hypoxia. The VEGF abnormalities developed concurrently with the onset of hyperglycemia and were not seen in normoglycemic, leptin receptor-deficient db/db mice. These observations support a role for fibroblast dysfunction in the impaired wound healing observed in human diabetics, and also suggest a mechanism for the poor clinical outcomes that occur after ischemic injury in diabetic patients.