Impact of type of preadmission sulfonylureas on mortality and cardiovascular outcomes in diabetic patients with acute myocardial infarction

Beyond metformin: safety considerations in the decision-making process for selecting a second medication for type 2 diabetes management: reflections from a diabetes care editors' expert forum

The trend toward personalized management of diabetes has focused attention on the differences among available pharmacological agents in terms of mechanisms of action, efficacy, and, most important, safety. Clinicians must select from these features to develop individualized therapy regimens. In June 2013, a nine-member Diabetes Care Editors' Expert Forum convened to review safety evidence for six major diabetes drug classes: insulin, sulfonylureas (SUs), thiazolidinediones (TZDs), glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, and sodium glucose cotransporter 2 inhibitors. This article, an outgrowth of the forum, summarizes well-delineated and theoretical safety concerns related to these drug classes, as well as the panelists' opinions regarding their best use in patients with type 2 diabetes. All of the options appear to have reasonably wide safety margins when used appropriately. Those about which we know the most-metformin, SUs, insulin, and perhaps now also TZDs-are efficacious in most patients and can be placed into a basic initial algorithm. However, these agents leave some clinical needs unmet. Selecting next steps is a more formidable process involving newer agents that are understood less well and for which there are unresolved questions regarding risk versus benefit in certain populations. Choosing a specific agent is not as important as implementing some form of early intervention and advancing rapidly to some form of combination therapy as needed. When all options are relatively safe given the benefits they confer, therapeutic decision making must rely on a personalized approach, taking into account patients' clinical circumstances, phenotype, pathophysiological defects, preferences, abilities, and costs.

Association between clinical presentations before myocardial infarction and coronary mortality: a prospective population-based study using linked electronic records

Background

Ischaemia in different arterial territories before acute myocardial infarction (AMI) may influence post-AMI outcomes. No studies have evaluated prospectively collected information on ischaemia and its effect on short- and long-term coronary mortality. The objective of this study was to compare patients with and without prospectively measured ischaemic presentations before AMI in terms of infarct characteristics and coronary mortality.

Methods and results

As part of the CALIBER programme, we linked data from primary care, hospital admissions, the national acute coronary syndrome registry and cause-specific mortality to identify patients with first AMI (n = 16,439). We analysed time from AMI to coronary mortality (n = 5283 deaths) using Cox regression (median 2.6 years follow-up), comparing patients with and without recent ischaemic presentations. Patients with ischaemic presentations in the 90 days before AMI experienced lower coronary mortality in the first 7 days after AMI compared with those with no prior ischaemic presentations, after adjusting for age, sex, smoking, diabetes, blood pressure and cardiovascular medications [HR: 0.64 (95% CI: 0.57–0.73) P < 0.001], but subsequent mortality was higher [HR: 1.42 (1.13–1.77) P = 0.001]. Patients with ischaemic presentations closer in time to AMI had the lowest seven day mortality (P-trend = 0.001).

Conclusion

In the first large prospective study of ischaemic presentations prior to AMI, we have shown that those occurring closest to AMI are associated with lower short-term coronary mortality following AMI, which could represent a natural ischaemic preconditioning effect, observed in a clinical setting.

Clinical trials registration

Clinicaltrials.gov identifier NCT01604486.

[Cardiovascular safety of non-insulin anti-diabetic drugs. Scientific position statement of SEMERGEN]

Diabetes increases the risk of both microvascular and macrovascular complications. Although reducing plasma glucose levels to recommended targets decreases the risk of microvascular outcomes, the effects of anti-diabetic drugs on macrovascular complications and cardiovascular death are of concern. In fact, it has been suggested that some anti-diabetic agents could even be harmful for cardiovascular outcomes. In this context, several health care regulatory agencies have established the need for performing clinical trials specifically designed to assess the cardiovascular safety of anti-diabetic drugs. The results of 2 clinical trials have recently been published that provide important information on the cardiovascular safety of dipeptidyl peptidase 4 (DPP-4) inhibitors. The aim of this document was to review the available evidence on the cardiovascular safety of non-insulin anti-diabetic drugs and provide practical recommendations on their use in this context.

[The use of gliclazide in individualized sulfonylurea therapy]

In addition to the common blood glucose lowering effect, sulfonylurea compounds are different in many aspects from each other. Based on earlier findings the second generation gliclazide has special advantages within this group. Although the number of experimental and clinical observations on gliclazide is continuously increasing, these novel findings are not in the focus anymore due to the appearance of new antidiabetics. This article reviews recent experimental (effect on receptors, the absence of Epac2 activation, antioxidant properties, possible incentive of factors participating in beta-cell differentiation) and pharmacogenomic data, and compares them with clinical observations obtained from gliclazide treatment (hypoglycemias, parameters of cardiovascular outcome). The data underline the advantages of gliclazide, the highly pancreas-selective nature, preservation of the ischemic precondition, favourable hemodynamic properties and potential reduction of the beta-cell loss as compared to other compounds of the group. However, gliclazide is not free from disadvantages characteristic to sulfonylureas in general (blood glucose independent insulin stimulation, beta-cell depletion). Comparing gliclazide with other derivatives of the group, the above data indicate individual benefits for the application when sulfonylurea compound is the drug of choice.

Cardiovascular risks and benefits with oral drugs for Type 2 diabetes mellitus

Type 2 diabetes mellitus affects approximately 321 million people worldwide. It is estimated that about half of these patients will die from cardiovascular complications. In spite of these statistics, medications for diabetes are approved based not on outcomes, but on surrogate markers such as blood glucose or glycosylated hemoglobin. In recent years, however, the safety of diabetes medications has come under scrutiny, and more studies are being undertaken to determine the effect(s) of the medications on actual outcomes. In this review the authors review available study results for all of the currently approved classes of oral medications for Type 2 diabetes, and discuss the possible mechanisms for the findings. More studies are necessary for many of these classes, however, to make definitive recommendations regarding their cardiovascular effects.

Complications of diabetes therapy

Current strategies for the treatment of type 2 diabetes mellitus promote individualized plans to achieve target glucose levels on a patient-by-patient basis while minimizing treatment related risks. Maintaining glycemic control over time is a significant challenge because of the progressive nature of diabetes as a result of declining β-cell function. This article identifies complications of non-insulin treatments for diabetes. The major classes of medications are reviewed with special focus on target population, mechanism of action, effect on weight, cardiovascular outcomes and additional class-specific side effects including effects on bone. Effects on β-cell function are also highlighted.

Association of hypoglycemic treatment regimens with cardiovascular outcomes in overweight and obese subjects with type 2 diabetes: a substudy of the SCOUT trial

OBJECTIVE

To assess the association of hypoglycemic treatment regimens with cardiovascular adverse events and mortality in a large population of type 2 diabetic patients at increased cardiovascular risk.

RESEARCH DESIGN AND METHODS

This analysis included 8,192 overweight patients with type 2 diabetes from the Sibutramine Cardiovascular Outcomes (SCOUT) trial randomized to lifestyle intervention with or without sibutramine for up to 6 years. Patients were grouped according to hypoglycemic treatment at baseline. The primary end point was the time from randomization to the first occurrence of a primary outcome event (POE), nonfatal myocardial infarction, nonfatal stroke, resuscitation after cardiac arrest, or cardiovascular death. Multivariable Cox proportional hazards regression models were used to assess the impact of antiglycemic treatment on POE and all-cause mortality.

RESULTS

Treatments for type 2 diabetes were as follows: diet alone (n = 1,394 subjects), metformin monotherapy (n = 1,631), insulin monotherapy (n = 1,116), sulfonylurea monotherapy (n = 1,083), metformin plus sulfonylurea (n = 1,565), and metformin plus insulin (n = 1,000); 905 subjects experienced a POE and 708 died. Metformin monotherapy was associated with lower risk of POE than insulin (hazard ratio [HR], 0.74; 95% CI, 0.57-0.95; P = 0.02). Diet alone also was associated with lower risk of POE (HR, 0.65; 95% CI, 0.48-0.87; P = 0.004). Metformin monotherapy also was associated with lower mortality (HR, 0.73; 95% CI, 0.54-0.99; P < 0.05), whereas no other monotherapies or combination therapies were significantly associated with POE or all-cause mortality compared with insulin as monotherapy.

CONCLUSIONS

In obese patients with type 2 diabetes and high risk of cardiovascular disease, monotherapy with metformin or diet-only treatment was associated with lower risk of cardiovascular events than treatment with insulin.

Oral hypoglycaemic agents and the development of non-fatal cardiovascular events in patients with type 2 diabetes mellitus

AIMS

This study aimed to assess the risk of non-fatal cardiovascular events among patients with type 2 diabetes mellitus (T2DM) who are taking metformin, glimepiride or glyburide.

MATERIALS AND METHODS

Using the National Health Insurance Research database in Taiwan, this retrospective cohort study identified 1159 patients with newly diagnosed T2DM from 1998 to 2007, 30 years and older and without a history of cardiovascular disease at baseline. Patients with cancer, liver cirrhosis or chronic kidney disease were excluded. On the basis of prescription, patients were grouped into three medication subcohorts: metformin (N = 595), glimepiride (N = 234) or glyburide (N = 330) monotherapy for 100% of the follow-up period without any oral anti-diabetic agents added or changed, by the end of 2009. Incidence and hazard ratios of non-fatal cardiovascular events including coronary artery disease, peripheral artery disease, stroke and heart failure among these three subcohorts were compared.

RESULTS

The overall incidence of non-fatal cardiovascular events was the highest for patients taking glyburide (169.1 per 1000 person-years), followed by for those taking glimepiride and metformin (95.2 and 49.1 per 1000 person-years, respectively). Compared with the adjusted hazard ratio for patients taking glyburide, the adjusted hazard ratio for those taking glimepiride was 0.52 (95% CI 0.40-0.69) and for those taking metformin was 0.31 (95% CI 0.24-0.40).

CONCLUSIONS

T2DM patients taking metformin and glimepiride are at lower risk of non-fatal cardiovascular events than those taking glyburide.

Are users of sulphonylureas at the time of an acute coronary syndrome at risk of poorer outcomes?

AIMS

Adenosine triphosphate sensitive potassium (K(ATP)) channel activity is cardioprotective during ischaemia. One of the purported mechanisms for sulphonylurea adverse effects is through inhibition of these channels. The purpose of this study is to examine whether patients using K(ATP) channel inhibitors at the time of an acute coronary syndrome are at greater risk of death or heart failure (HF) than those not exposed.

METHODS

Using linked administrative databases we identified all adults who had an acute coronary syndrome between April 2002 and October 2006 (n = 21 023).

RESULTS

Within 30 days of acute coronary syndrome, 5.3% of our cohort died and 15.6% were diagnosed with HF. Individuals with diabetes exhibited significantly higher risk of death (adjusted OR: 1.20, 95% CI: 1.03-1.40) and death or HF (aOR: 1.73, 95% CI: 1.59-1.89) than individuals without diabetes. However, there was no significantly increased risk of death (aOR: 1.00, 95% CI: 0.76-1.33) or death/HF (aOR: 1.06, 95% CI: 0.89-1.26) in patients exposed to K(ATP) channel inhibitors versus patients not exposed to K(ATP) channel inhibitors prior to their acute coronary syndrome.

CONCLUSIONS

Diabetes is associated with an increased risk of death or HF within 30 days of an acute coronary syndrome. However, we did not find any excess risk of death or HF associated with use of K(ATP) channel inhibitors at the time of an acute coronary syndrome, raising doubts about the hypothesis that sulphonylureas inhibit the cardioprotective effects of myocardial K(ATP) channels.

Cardiovascular outcome trials in type 2 diabetes and the sulphonylurea controversy: rationale for the active-comparator CAROLINA trial

Sulphonylureas (SUs) are widely used glucose-lowering agents in type 2 diabetes mellitus (T2DM) with apparent declining efficacy over time. Concerns have been raised from observational retrospective studies on the cardiovascular (CV) safety of SUs but there are few long-term data on CV outcomes from randomized controlled trials (RCTs) involving the use of this class of agents. Most of the observational studies and registry data are conflicting and vary with study population and methodology used for analyses. To address the SU controversy, we reviewed the recently published literature (until end of the year 2011) to evaluate the impact of SUs on CV outcomes in modern, longer-term (≥72 weeks) RCTs where they were compared in a head-to-head fashion versus an active comparator or were used as part of a treatment strategy. We identified 15 trials and found no report of an increase in the incidence of CV events with the use of SUs. However, the available data are limited, and, most importantly, there was no adequately powered formal head-to-head CV outcome trial designed to address CV safety. Since SUs are still being advocated as second-line therapy added-on to metformin, as one of several classes, and in certain circumstances first-line therapy in T2DM management, definitive data from a dedicated RCT addressing the CV safety question with SUs would be informative. Cardiovascular Outcome Study of Linagliptin versus Glimepiride in Patients with Type 2 Diabetes (CAROLINA) is such a trial, ongoing since November 2010, and is currently the largest head-to-head CV outcome trial that involves a comparison of a SU (glimepiride) with a dipeptidyl peptidase-4 (DPP-4) inhibitor (linagliptin) and will provide a unique perspective with respect to CV outcomes with these two commonly used agents.

Estimating the effect of sulfonylurea on HbA1c in diabetes: a systematic review and meta-analysis

AIMS/HYPOTHESIS

Sulfonylureas are widely prescribed glucose-lowering medications for diabetes, but the extent to which they improve glycaemia is poorly documented. This systematic review evaluates how sulfonylurea treatment affects glycaemic control.

METHODS

Medline, EMBASE, the Cochrane Library and clinical trials registries were searched to identify double-blinded randomised controlled trials of fixed-dose sulfonylurea monotherapy or sulfonylurea added on to other glucose-lowering treatments. The primary outcome assessed was change in HbA1c, and secondary outcomes were adverse events, insulin dose and change in body weight.

RESULTS

Thirty-one trials with a median duration of 16 weeks were included in the meta-analysis. Sulfonylurea monotherapy (nine trials) lowered HbA1c by 1.51% (17 mmol/mol) more than placebo (95% CI, 1.25, 1.78). Sulfonylureas added to oral diabetes treatment (four trials) lowered HbA1c by 1.62% (18 mmol/mol; 95% CI 1.0, 2.24) compared with the other treatment, and sulfonylurea added to insulin (17 trials) lowered HbA1c by 0.46% (6 mmol/mol; 95% CI 0.24, 0.69) and lowered insulin dose. Higher sulfonylurea doses did not reduce HbA1c more than lower doses. Sulfonylurea treatment resulted in more hypoglycaemic events (RR 2.41, 95% CI 1.41, 4.10) but did not significantly affect the number of other adverse events. Trial length, sulfonylurea type and duration of diabetes contributed to heterogeneity.

CONCLUSIONS/INTERPRETATION

Sulfonylurea monotherapy lowered HbA1c level more than previously reported, and we found no evidence that increasing sulfonylurea doses resulted in lower HbA1c. HbA1c is a surrogate endpoint, and we were unable to examine long-term endpoints in these predominately short-term trials, but sulfonylureas appear to be associated with an increased risk of hypoglycaemic events.

Diabetes therapy--focus on Asia: second-line therapy debate: insulin/secretagogues

The following review is based on the second part of a debate entitled 'Diabetes therapy--focus on Asia: 2nd line therapy: GLP1/DPP4 inhibitors versus Secretagogue/insulin therapy', which was held during the '1st Asia Pacific Congress on Controversies to Consensus in Diabetes, Obesity and Hypertension (CODHy)', in Shanghai, China, 2011. As such we reviewed only insulin and secretagogue therapy despite the existence of other therapeutic options. The article aims to shed light on the circumstances most adequate for use of these as second-line agents, despite possible drawbacks. It is important to emphasize that regardless of it being a review of published evidence, it primarily represents the professional opinion of the writers.

Adverse cardiovascular events during treatment with glyburide (glibenclamide) or gliclazide in a high-risk population

AIMS

Sulphonylureas promote insulin release by inhibiting pancreatic potassium channels. Older sulphonylureas such as glyburide (glibenclamide), but not newer ones such as gliclazide, antagonize similar channels in myocardium, interfering with the protective effects of ischaemic preconditioning. Whether this imparts a higher risk of adverse cardiac events is unknown.

METHODS

We conducted a population-based cohort study of patients aged 66 years and older who were hospitalized for acute myocardial infarction or who underwent percutaneous coronary intervention between 1 April 2007 and 31 March 2010 while receiving either glyburide or gliclazide. We used a high-dimensional propensity score matching process to ensure similarity of glyburide- and gliclazide-treated patients. The primary outcome was a composite of death or hospitalization for myocardial infarction or heart failure.

RESULTS

During the 2-year study period, we matched 1690 patients treated with glyburide to 984 patients treated with gliclazide at the time of hospitalization for acute myocardial infarction or percutaneous coronary intervention. We found no difference in the risk of the composite outcome among patients receiving glyburide (adjusted hazard ratio 1.01; 95% CI 0.86-1.18). We found similar results in secondary analyses of each outcome individually, and in two supplementary analyses (haemorrhage and pneumonia) in which we anticipated no difference between the two patient groups.

CONCLUSIONS

Among older patients hospitalized for acute myocardial infarction or percutaneous coronary intervention, treatment with glyburide is not associated with an increased risk of future adverse cardiovascular events relative to gliclazide, suggesting that the effect of glyburide on ischaemic preconditioning is of little clinical relevance.

Addition of either pioglitazone or a sulfonylurea in type 2 diabetic patients inadequately controlled with metformin alone: impact on cardiovascular events. A randomized controlled trial

BACKGROUND AND AIMS

Metformin is the first-line therapy in type 2 diabetes. In patients inadequately controlled with metformin, the addition of a sulfonylurea or pioglitazone are equally plausible options to improve glycemic control. However, these drugs have profound differences in their mechanism of action, side effects, and impact on cardiovascular risk factors. A formal comparison of these two therapies in terms of cardiovascular morbidity and mortality is lacking. The TOSCA.IT study was designed to explore the effects of adding pioglitazone or a sulfonylurea on cardiovascular events in type 2 diabetic patients inadequately controlled with metformin.

METHODS

Multicentre, randomized, open label, parallel group trial of 48 month duration. Type 2 diabetic subjects, 50-75 years, BMI 20-45 Kg/m(2), on secondary failure to metformin monotherapy will be randomized to add-on a sulfonylurea or pioglitazone. The primary efficacy outcome is a composite endpoint of all-cause mortality, nonfatal myocardial infarction, nonfatal stroke, and unplanned coronary revascularization. Principal secondary outcome is a composite ischemic endpoint of sudden death, fatal and non-fatal myocardial infarction and stroke, endovascular or surgical intervention on the coronary, leg or carotid arteries, major amputations. Side effects, quality of life and economic costs will also be evaluated. Efficacy, safety, tolerability, and study conduct will be monitored by an independent Data Safety Monitoring Board. End points will be adjudicated by an independent external committee.

CONCLUSIONS

TOSCA.IT is the first on-going study investigating the head-to-head comparison of adding a sulfonylurea or pioglitazone to existing metformin treatment in terms of hard cardiovascular outcomes.

REGISTRATION

Clinicaltrials.gov ID NCT00700856.

Blockers of sulfonylureas receptor 1 subunits may lead to cardiac protection against isoprenaline-induced injury in obese rats

Recent studies have found that blockers of sulfonylureas receptor 1(SUR1) might have cardiac ischemic protective effects. We evaluated the effects of a selective SUR1 blocker gliclazide on cardiac function and arrhythmia after isoprenaline-induced myocardial injury in obese rats. Diet-induced obese rats received isoprenaline or saline shots subcutaneously. Gliclazide or saline was given q12 h for 48 h to rats received isoprenaline. We measured ECG and hemodynamic parameters and collected blood samples for CK-MB, glucose and lipid profile determination, and then harvested hearts for water content, histological and immunohistochemical analysis and infarct size measurements. The obese rats' hearts receiving isoprenaline-induced myocardial injury showed up-regulated SUR-1 expression in the peri-microvascular area. Obese rats receiving gliclazide lavage had less severe arrhythmia (ASI: 4.00 ± 0.61 vs. 2.14 ± 0.39, P<0.05) and myocardial edema (water percentage: 85.16 ± 0.46% vs. 81.56 ± 0.57%, P<0.05). Less infarct size (47.6 ± 12.8% vs. 32.7 ± 9.1%, P<0.05) and improved diastolic function (LVEDP: 6.86 ± 0.85% vs. 2.51 ± 1.09%, P<0.05;-(dp/dt)(max): -1663.6 ± 387.91 mmHg/s vs. -2834.8 ± 290.76 mmHg/s, P<0.05) were also observed in rats receiving gliclazide lavage. Blocking of the SUR1 thus exerts a protective effect on the isoprenaline-induced myocardial injury in obese rats. That SUR1 blocker leads to ischemic protection suggesting a critical biological role of SUR1 in regulating the function of the cardiovascular system than previously recognized under pathophysiological conditions.

Increase in overall mortality risk in patients with type 2 diabetes receiving glipizide, glyburide or glimepiride monotherapy versus metformin: a retrospective analysis

AIMS

It remains uncertain if differences in mortality risk exist among the sulfonylureas, especially in patients with documented coronary artery disease (CAD). The purpose of this study was to assess the overall mortality risk of the individual sulfonylureas versus metformin in a large cohort of patients with type 2 diabetes.

METHODS

A retrospective cohort study was conducted using an academic health centre enterprise-wide electronic health record (EHR) system to identify 23 915 patients with type 2 diabetes who initiated monotherapy with metformin (N = 12774), glipizide (N = 4325), glyburide (N = 4279) or glimepiride (N = 2537), ≥ 18 years of age, with and without a history of CAD, and not on insulin or a non-insulin injectable at baseline. The patients were followed for mortality by documentation in the EHR and Social Security Death Index. Multivariable Cox models with propensity analysis were used to compare cohorts.

RESULTS

An increase in overall mortality risk was observed in the entire cohort with glipizide (HR 1.64; 95% CI 1.39-1.94), glyburide (HR 1.59; 95% CI 1.35-1.88), and glimepiride (HR 1.68; 95% CI 1.37-2.06) versus metformin; however, in those patients with documented CAD, a statistically significant increase in overall mortality risk was only found with glipizide (HR 1.41; 95% CI 1.07-1.87) and glyburide (HR 1.38; 95% CI 1.04-1.83) versus metformin.

CONCLUSIONS

Glipizide, glyburide and glimepiride are associated with an increased risk of overall mortality versus metformin. Our results suggest that if a sulfonylurea is required to obtain glycaemic control, glimepiride may be the preferred sulfonylurea in those with underlying CAD.

The risk of overall mortality in patients with Type 2 diabetes receiving different combinations of sulfonylureas and metformin: a retrospective analysis

AIMS

Sulfonylureas have been shown to increase mortality when used in combination with metformin. This may not be a class effect of sulfonylureas, but rather secondary to differences in properties inherent to the individual sulfonylureas (hypoglycaemic risk, sulfonylurea receptor selectivity and effects on myocardial ischemic preconditioning). The purpose of this study was to assess the risk of overall mortality in patients with Type 2 diabetes treated with different combinations of sulfonylureas and metformin.

METHODS

A retrospective cohort study was conducted using an academic health center enterprise-wide electronic health record system to identify 7320 patients with Type 2 diabetes (3768 initiators of glyburide (glibenclamide) and metformin, 2277 initiators of glipizide and metformin and 1275 initiators of glimepiride and metformin), ≥ 18 years of age and not on insulin or a non-insulin injectable at baseline. The patients were followed for mortality by documentation in the electronic health record and Social Security Death Index. Multivariable Cox models with propensity analysis were used to compare cohorts.

RESULTS

No statistically significant difference in overall mortality risk was observed among the different combinations of sulfonylureas and metformin: glimepiride and metformin vs. glipizide and metformin (HR 1.03; 95% CI 0.89-1.20), glimepiride and metformin vs. glyburide (glibenclamide) and metformin (HR 1.08; 95% CI 0.90-1.30), or with glipizide and metformin vs. glyburide (glibenclamide) and metformin (HR 1.05; 95% CI 0.95-1.15).

CONCLUSIONS

Our results did not identify an increased mortality risk among the different combinations of sulfonylureas and metformin, suggesting that overall mortality is not substantially influenced by the choice of sulfonylurea.

Treating diabetes today with gliclazide MR: a matter of numbers

Type 2 diabetes mellitus (T2DM) is a progressive disease characterized by worsening hyperglycaemia. Lowering haemoglobin A1c to below or around 7% has been shown to reduce microvascular and neuropathic complications of diabetes. The ongoing uncertainty regarding whether intensive glycaemic control can reduce the increased risk of cardiovascular disease (CVD) in people with T2DM stirred the launch of the recent long-term megatrials. These trials compared the effects of intensive vs. standard control on vascular complications in relatively high CV risk participants with T2DM. While in Veterans Affairs Diabetes Trial, and Action to Control Cardiovascular Risk in Diabetes, the effect of glucose optimization resulted either in no protection or in an excessive CVD death, the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation trial showed that intensive glycaemic control reduced the risk of combined major macrovascular and microvascular events. In this trial, the glucose control strategy was based on gliclazide MR at randomization in all patients and then further sequential addition of other glucose-lowering drugs. Several studies showed that gliclazide has antioxidant properties, reduces markers of endothelial inflammation, and prevents glucose-induced apoptosis of endothelial cells. These positive antioxidant effects are not confined to the vascular wall but they are effective also in the β cells. These properties are important because (i) in patients with atherosclerotic process, microvascular abnormalities may hasten disease progression and (ii) slowing the microvascular complications may have a potentially remarkable effect on the natural history of macrovascular disease.

The future of incretin-based therapy: novel avenues--novel targets

Incretin-based therapy for type 2 diabetes is based on the antidiabetic effects of glucagon-like peptide-1 (GLP-1) and instituted by GLP-1 receptor agonists and dipeptidyl peptidase-4 inhibitors targeting the key islet defects of the disease. The treatment is clinically efficient and safe, and associated with a low risk of adverse events. It can be used both in early and late stages of the disease and both as monotherapy and add-on to other therapies. Current research on the future of incretin-based therapy focuses on optimizing its place in diabetes treatment and examines its potential in type 1 diabetes, in subjects with obesity without type 2 diabetes and in cardiovascular and neurodegenerative disorders. Other studies aim at prolonging the duration of action of the GLP-1 receptor agonists to allow weekly administration, and to develop orally GLP-1 receptor agonists. Furthermore, other investigators focus on stimulation of GLP-1 secretion by activating GLP-1-producing L-cells or using gene therapy. Finally, also other gastro-entero-pancreatic bioactive peptides are potential targets for drug development as are synthetic peptides engineered as co-agonists stimulating more than one receptor. We can therefore expect a dynamic development within this field in the coming years.

The potential effects of anti-diabetic medications on myocardial ischemia-reperfusion injury

Heart disease and stroke account for 65% of the deaths in people with diabetes mellitus (DM). DM and hyperglycemia cause systemic inflammation, endothelial dysfunction, a hypercoagulable state with impaired fibrinolysis and increased platelet degranulation, and reduced coronary collateral blood flow. DM also interferes with myocardial protection afforded by preconditioning and postconditioning. Newer anti-diabetic agents should not only reduce serum glucose and HbA1c levels, but also improve cardiovascular outcomes. The older sulfonylurea agent, glyburide, abolishes the benefits of ischemic and pharmacologic preconditioning, but newer sulfonylurea agents, such as glimepiride, may not interfere with preconditioning. GLP-1 analogs and sitagliptin, an oral dipeptidyl peptidase IV inhibitor, limit myocardial infarct size in animal models by increasing intracellular cAMP levels and activating protein kinase A, whereas metformin protects the heart by activating AMP-activated protein kinase. Both thiazolidinediones (rosiglitazone and pioglitazone) limit infarct size in animal models. The protective effect of pioglitazone is dependent on downstream activation of cytosolic phospholipase A(2) and cyclooxygenase-2 with subsequent increased production of 15-epi-lipoxin A(4), prostacyclin and 15-d-PGJ(2). We conclude that agents used to treat DM have additional actions that have been shown to affect the ability of the heart to protect itself against ischemia-reperfusion injury in preclinical models. However, the effects of these agents in doses used in the clinical setting to minimize ischemia-reperfusion injury and to affect clinical outcomes in patients with DM have yet to be shown. The clinical implications as well as the mechanisms of protection should be further studied.

Sulfonylureas: do we need to introspect safety again?

INTRODUCTION

Sulfonylureas (SUs) are the most commonly prescribed medications for type 2 diabetes mellitus worldwide. Differences among SUs for kinetic and adenosine triphosphate sensitive potassium (KATP) channels selectivity and consequential extrapancreatic effects, although recognized in literature, are not considered by treatment guidelines.

AREAS COVERED

The roles of SUs in various system-related adverse effects have not been well understood. Inconsistencies in the literature and lack of clinical trials assessing the long-term effects of monotherapy or combination therapy with SUs add to the concern. This review provides insights in issues concerning safety of SUs based on literature published between 1980 and 2011. A comprehensive search was carried out on PubMed, Embase and Cochrane databases using the search terms: sulfonylureas, sulfonylureas and KATP channels, sulfonylureas and cardiovascular (CV) effects and sulfonylureas side effects.

EXPERT OPINION

SUs have been linked to CV events, growth hormone (GH) disorder, malignancy, weight gain, erectile dysfunction and central nervous system (CNS) adverse effects. These adverse effects generally get masked as they are thought to be related to diabetes per se. The current article will allow the fraternity to ponder and undertake further research on the ill effects of largely prescribed antidiabetic medication.