Sulfonylureas are not associated with increased mortality in diabetics treated with thrombolysis for acute myocardial infarction

Emerging opportunities to target inflammation: myocardial infarction and type 2 diabetes

After myocardial infarction (MI), patients with type 2 diabetes have an increased rate of adverse outcomes, compared to patients without. Diabetes confers a 1.5-2-fold increase in early mortality and, importantly, this discrepancy has been consistent over recent decades, despite advances in treatment and overall survival. Certain assumptions have emerged to explain this increased risk, such as differences in infarct size or coronary artery disease severity. Here, we re-evaluate that evidence and show how contemporary analyses using state-of-the-art characterization tools suggest that the received wisdom tells an incomplete story. Simultaneously, epidemiological and mechanistic biological data suggest additional factors relating to processes of diabetes-related inflammation might play a prominent role. Inflammatory processes after MI mediate injury and repair and are thus a potential therapeutic target. Recent studies have shown how diabetes affects immune cell numbers and drives changes in the bone marrow, leading to pro-inflammatory gene expression and functional suppression of healing and repair. Here, we review and re-evaluate the evidence around adverse prognosis in patients with diabetes after MI, with emphasis on how targeting processes of inflammation presents unexplored, yet valuable opportunities to improve cardiovascular outcomes in this vulnerable patient group.

Sulfonylureas and the Risk of Ventricular Arrhythmias Among People with Type 2 Diabetes: A Systematic Review of Observational Studies

Previous studies have suggested an association between sulfonylureas and an increased risk of cardiovascular death among patients with type 2 diabetes. A potential mechanism involves sulfonylurea-induced ventricular arrhythmias (VAs). We conducted a systematic review of observational studies to determine whether the use of sulfonylureas, compared with the use of other antihyperglycemic drugs, is associated with the risk of VA (ventricular tachycardia, ventricular fibrillation, and premature ventricular complexes), cardiac arrest, and sudden cardiac death among patients with type 2 diabetes. Two independent reviewers searched MEDLINE, EMBASE, CINAHL Plus, CENTRAL, and ClinicalTrials.gov from inception to July 2021 for observational studies comparing sulfonylureas vs. other antihyperglycemic therapies or intraclass comparisons of sulfonylureas. Our systematic review included 17 studies (1,607,612 patients). Per Risk Of Bias In Non-randomized Studies of Interventions (ROBINS)-I, there were few high-quality studies (2 studies at moderate risk of bias; 4 at serious risk; and 11 at critical risk). All studies at a moderate or serious risk of bias reporting comparisons with other therapies were consistent with an increased risk of VA. Sulfonylureas were associated with a higher risk of arrhythmia vs. dipeptidyl peptidase-4 inhibitors (adjusted hazard ratio (aHR): 1.52, 95% confidence interval (CI): 1.27-1.80) and of VA vs. metformin (aHR: 1.52, 95% CI: 1.10-2.13). One moderate quality study reported inconsistent results for a composite of cardiac arrest/VA in analyses of US Medicaid claims and Optum claims data. Our systematic review suggests that, among higher-quality observational studies, sulfonylureas are associated with an increased risk of VA. However, we identified few methodologically rigorous studies, underscoring the need for additional real-world studies.

Clinical Observation of SGLT2 Inhibitor Therapy for Cardiac Arrhythmia and Related Cardiovascular Disease in Diabetic Patients with Controlled Hypertension

Sodium-glucose transporter 2 (SGLT2) inhibitors are new glucose-lowering agents that have been proven to be beneficial for patients with cardiovascular diseases, heart failure, and sudden cardiac death. However, the possible protective effects of cardiac arrhythmia have not yet been clarified in clinical practice. In this study, we attempted to demonstrate the effects of SGLT2 inhibitors on cardiac arrhythmia by medical records from a single center. This retrospective study included patients diagnosed with type 2 diabetes mellitus (DM) and controlled hypertension who prescribed the indicated glucose-lowering agents based on medical records from 2016 to 2019 from Kaohsiung Medical University Hospital. These patients were divided into two groups. Group one patients were defined as patients with SGLT2 inhibitor therapy, and group two patients were defined as patients without SGLT2 inhibitor therapy. Baseline characteristics were collected from medical records. Univariate, multivariate, and match-paired statistical analyses were performed for the study endpoints. The primary study outcome was the incidence of cardiac arrhythmias, including atrial and ventricular arrhythmias, after SGLT2 inhibitor therapy. The secondary study outcomes were the incidence of stroke, heart failure, and myocardial infarction after SGLT2 inhibitor therapy. From the initial 62,704 medical records, a total of 9609 people who met our experimental design criteria were included. The mean follow-up period was 51.50 ± 4.23 months. Group one included 3203 patients who received SGLT2 inhibitors for treatment, and group two included 6406 patients who received non-SGLT2 inhibitors for treatment. Multivariate analysis showed that group one patients had significantly lower incidences of total cardiac arrhythmia (hazard ratio (HR): 0.58, 95% confidence interval (CI): 0.38–0.89, p = 0.013) and atrial fibrillation (HR: 0.56, 95% CI: 0.35–0.88, p = 0.013) than those of group two patients. The secondary outcome analysis showed that group one patients also had a significantly lower risk of stroke (HR: 0.48, 95% CI: 0.33–0.7; p < 0.001), heart failure (HR: 0.54, 95% CI: 0.41–0.7, p < 0.001), and myocardial infarction (HR: 0.47, 95% CI: 0.31–0.72, p < 0.001). A time-to-event analysis showed that treatment of type 2 DM patients with SGLT2 inhibitors could reduce the probability of total cardiac arrhythmia and related cardiovascular disease, such as atrial fibrillation, stroke, heart failure, or myocardial infarction, by 0.5%~0.8%. This databank analysis showed that SGLT2 inhibitor therapy reduced the incidence of total cardiac arrhythmia and atrial fibrillation in type 2 DM patients and decreased the incidence of related cardiovascular diseases, such as stroke, heart failure, and myocardial infarction. However, additional investigations are needed to confirm this hypothesis.

Characteristics of Ventricular Electrophysiological Substrates in Metabolic Mice Treated with Empagliflozin

Empagliflozin (EMPA) is a sodium–glucose transporter 2 (SGLT2) inhibitor that functions as a new-generation glucose-lowering agent and has been proven to be beneficial for patients with cardiovascular diseases. However, the possible benefits and mechanisms of its antiarrhythmic effects in cardiac tissue have not yet been reported. In this study, we elucidated the possible antiarrhythmic effects and mechanisms of EMPA treatment in cardiac tissues of metabolic syndrome (MS) mice. A total of 20 C57BL/6J mice (age: 8 weeks) were divided into four groups: (1) control group, mice fed a standard chow for 16 weeks; (2) MS group, mice fed a high-fat diet for 16 weeks; (3) EMPA group, mice fed a high-fat diet for 12 weeks and administered EMPA at 10 mg/kg daily for the following 4 weeks; and (4) glibenclamide (GLI) group, mice fed a high-fat diet for 12 weeks and administered GLI at 0.6 mg/kg daily for the following 4 weeks. All mice were sacrificed after 16 weeks of feeding. The parameters of electrocardiography (ECG), echocardiography, and the effective refractory period (ERP) of the left ventricle were recorded. The histological characteristics of cardiac tissue, including connexin (Cx) expression and fibrotic areas, were also evaluated. Compared with the MS group, the ECG QT interval in the EMPA group was significantly shorter (57.06 ± 3.43 ms vs. 50.00 ± 2.62 ms, p = 0.011). The ERP of the left ventricle was also significantly shorter in the EMPA group than that in the GLI group (20.00 ± 10.00 ms vs. 60.00 ± 10.00 ms, p = 0.001). The expression of Cx40 and Cx43 in ventricular tissue was significantly lower in the MS group than in the control group. However, the downregulation of Cx40 and Cx43 was significantly attenuated in the EMPA group compared with the MS and GLI groups. The fibrotic areas of ventricular tissue were also fewer in the EMPA group than that in the MS group. In this study, the ECG QT interval in the EMPA group was shorter than that in the MS group. Compared with the MS group, the EMPA group exhibited significant attenuation of downregulated connexin expression and significantly fewer fibrotic areas in ventricles. These results may provide evidence of possible antiarrhythmic effects of EMPA.

Pro- and Antiarrhythmic Actions of Sulfonylureas: Mechanistic and Clinical Evidence

Sulfonylureas are the most commonly used second-line drug class for treating type 2 diabetes mellitus (T2DM). While the cardiovascular safety of sulfonylureas has been examined in several trials and nonrandomized studies, little is known of their specific effects on sudden cardiac arrest (SCA) and related serious arrhythmic outcomes. This knowledge gap is striking, because persons with DM are at increased risk of SCA. In this review, we explore the influence of sulfonylureas on the risk of serious arrhythmias, with specific foci on ischemic preconditioning, cardiac excitability, and serious hypoglycemia as putative mechanisms. Elucidating the relationship between individual sulfonylureas and serious arrhythmias is critical, especially as the diabetes epidemic intensifies and SCA incidence increases in persons with diabetes.

Review: Sulphonylureas and cardiovascular risk: facts and controversies

Cardiovascular complications are the principal cause of death in type 2 diabetes. The importance of glycaemic control in preventing cardiovascular complications has been demonstrated. However, some oral antidiabetic agents and especially some sulphonylureas (SU) have been accused of having a deleterious effect on cardiovascular risk. A retrospective analysis of the administrative database of Saskatchewan Health for 5,795 subjects, identified by their first-ever dispensation for an oral antidiabetic agent, suggests that a higher exposure to SUs was associated with increased mortality. Nevertheless, the effects of SUs on cardiac ATP-sensitive potassium channels in experimental studies vary between agents and studies, so that the clinical relevance of this phenomenon is unclear. Moreover, 11 years of follow-up of patients randomised to glibenclamide or chlorpropamide in the United Kingdom Prospective Diabetes Study demonstrated no adverse effects on a range of cardiovascular end points. Despite SU structural differences and differences in binding to cardiac SU receptors, the clinical evidence base does not support the selection of one sulphonylurea over another on the basis of ischaemic preconditioning, possibly because ischaemic preconditioning may be blunted or absent in diabetes. The main objective remains the prevention or delay of diabetic complications through improvement of glycaemic control together with other cardiovascular risk factors.

Sulfonylurea use is associated with larger infarct size in patients with diabetes and ST-elevation myocardial infarction

BACKGROUND

Animal models have demonstrated that sulfonylureas increase the size of myocardial infarction; however, data in humans is scarce. This study evaluated the association between sulfonylurea use and infarct size in diabetes patients with ST-elevation myocardial infarction (STEMI).

METHODS

Consecutive STEMI patients admitted in Edmonton, Canada between 2006 and 2011 were enrolled in a regional prospective registry program. Patients with type 2 diabetes were identified from this group and the maximum recorded troponin I (max cTnI) within the first 48 h of chest pain onset was used as the primary outcome to quantify infarct size. The relationship between preadmission sulfonylurea use and max cTnI was assessed using multivariable linear regression to adjust for patient demographics, cardiovascular risk factors, clinical data on admission, ischemia time, reperfusion therapy and preadmission drugs.

RESULTS

There were 560 STEMI patients with type 2 diabetes; mean (standard deviation; SD) age was 63.3 (12.8) years, 395 (70.5%) were male, 216 (38.6%) received primary percutaneous intervention, and 211 (37.7%) received thrombolysis. The max cTnI was higher in 146 sulfonylurea users compared to 414 non-sulfonylurea users (mean (SD): 49.8 (74.3) ng/mL versus 39.9 (50.4) ng/mL, respectively; adjusted between-group difference: 12.9 ng/mL; 95% CI 0.3-25.5; p=0.044).

CONCLUSION

This study adds further evidence to the proposed causal relationship between sulfonylureas and adverse cardiovascular events by observing a significant difference in infarct size among type 2 diabetes patients presenting with STEMI. Clinicians should consider this association when prescribing sulfonylureas to manage patients with type 2 diabetes.

Cardiovascular safety of sulphonylureas: over 40 years of continuous controversy without an answer

More than 40 years after publication of the University Group Diabetes Program trial, the cardiovascular safety of sulphonylureas is still contentious. Although several hypotheses linking sulphonylureas to adverse cardiovascular effects exist, none provide conclusive evidence. Adding to the controversy, current clinical trials and observational studies provide inconsistent, and sometimes conflicting, evidence for the cardiovascular effects of sulphonylureas. Overall, observational evidence suggests that an increased risk of adverse cardiovascular outcomes is associated with sulphonylureas; however, these data may be subject to residual confounding and bias. Although evidence from randomized controlled trials has suggested a neutral effect, the majority of these studies were not specifically designed to assess the effect of sulphonylureas on adverse cardiovascular event risk. Current ongoing large clinical trials may provide some clarity on the cardiovascular safety of sulphonylureas, but the results are not expected for several years. With the continued uncertainties concerning the cardiovascular safety of all antidiabetic drugs, a clear answer with regard to sulphonylureas is warranted. The objectives of the present article were to provide an overview of the controversy surrounding sulphonylurea-related cardiovascular effects, to discuss the limitations of the current literature, and to provide recommendations for future studies aiming to elucidate the true relationship between sulphonylureas and adverse cardiovascular effects in people with type 2 diabetes.

Mortality risk with sulphonylureas compared to metformin

Current clinical guidelines in the USA and the UK recommend first-line glucose-lowering treatment with metformin monotherapy for glucose control in type 2 diabetes, where not contraindicated. Consequently, the proportion of people treated with sulphonylureas is decreasing. The purpose of this commentary is to discuss the risks and benefits associated with sulphonylurea monotherapy versus metformin monotherapy and the evidence that, in comparison with metformin, sulphonylureas cause increased harm to people with type 2 diabetes.

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.

Risk of acute coronary events associated with glyburide compared with gliclazide use in patients with type 2 diabetes: a nested case-control study

AIM

Sulfonylureas might increase the risk of adverse cardiovascular events; however, emerging evidence suggests there may be important differences amongst these drugs. Some, like glyburide, inhibit KATP channels in the heart and pancreas, while others, like gliclazide, are more likely to selectively inhibit KATP channels in the pancreas. We hypothesized that the risk of acute coronary syndrome (ACS) events would be higher in patients using glyburide compared with gliclazide.

METHODS

This nested case-control study used administrative health data from Alberta, Canada. New users of glyburide or gliclazide aged ≥66 years between 1998 and 2010 were included. Cases were individuals with an ACS-related hospitalization or death. Up to four controls were matched based on birth year, sex, cohort-entry year and follow-up time. Multivariable conditional logistic regression was used to estimate adjusted odds ratios (OR), controlling for baseline drug use and co-morbidities.

RESULTS

Our cohort included 7441 gliclazide and 13 884 glyburide users; 51.4% men, mean (s.d.) age 75.5 (6.6) years and mean (s.d.) duration of follow-up 5.5 (4.0) years. A total of 4239 patients had an ACS-related hospitalization or death and were matched to 16 723 controls. Compared with gliclazide use, glyburide use was associated with a higher risk (adjusted OR 1.14; 95% CI 1.06-1.23) of ACS-related hospitalization or death over 5.5 years (number needed to harm: 50).

CONCLUSION

In this observational study, glyburide use was associated with a 14% higher risk of ACS events compared with gliclazide use. Although the difference is small and probably to have implications at the population level rather than the individual patient or clinician, any causal inferences regarding sulfonylurea use and adverse cardiovascular risk should be tested in a large-scale randomized controlled trial.

Variations in tissue selectivity amongst insulin secretagogues: a systematic review

AIM

Insulin secretagogues promote insulin release by binding to sulfonylurea receptors on pancreatic β-cells (SUR1). However, these drugs also bind to receptor isoforms on cardiac myocytes (SUR2A) and vascular smooth muscle (SUR2B). Binding to SUR2A/SUR2B may inhibit ischaemic preconditioning, an endogenous protective mechanism enabling cardiac tissue to survive periods of ischaemia. This study was designed to identify insulin secretagogues that selectively bind to SUR1 when given at therapeutic doses.

METHODS

Using accepted systematic review methods, three electronic databases were searched from inception to 13 June 2011. Original studies measuring the half-maximal inhibitory concentration (IC(50)) for an insulin secretagogue on K(ATP) channels using standard electrophysiological techniques were included. Steady-state concentrations (C(SS)) were estimated from the usual oral dose and clearance values for each drug.

RESULTS

Data were extracted from 27 studies meeting all inclusion criteria. IC(50) values for SUR1 were below those for SUR2A/SUR2B for all insulin secretagogues and addition of C(SS) values identified three distinct patterns. The C(SS) for gliclazide, glipizide, mitiglinide and nateglinide lie between IC(50) values for SUR1 and SUR2A/SUR2B, suggesting that these drugs bind selectively to pancreatic receptors. The C(SS) for glimepiride and glyburide (glibenclamide) was above IC(50) values for all three isoforms, suggesting these drugs are non-selective. Tolbutamide and repaglinide may have partial pancreatic receptor selectivity because IC(50) values for SUR1 and SUR2A/SUR2B overlapped somewhat, with the C(SS) in the midst of these values.

CONCLUSIONS

Insulin secretagogues display different tissue selectivity characteristics at therapeutic doses. This may translate into different levels of cardiovascular risk.

Macrovascular effects and safety issues of therapies for type 2 diabetes

Type 2 diabetes has long been recognized as an independent risk factor for cardiovascular disease (CVD), including coronary artery disease (CAD), stroke, peripheral arterial disease, cardiomyopathy, and congestive heart failure. Cardiovascular (CV) complications are the leading cause of comorbidity and death in the patient with diabetes. Vascular complications of diabetes also extend to microvascular disease, manifest as diabetic nephropathy, neuropathy, and retinopathy. The impact of glycemic control in reducing microvascular complications is well established. Although more controversial, there is also evidence that glycemic control can limit macrovascular disease, including CAD, peripheral arterial disease, and stroke. Glycemic control in the context of type 2 diabetes, as well as prediabetes, is also intertwined with CV risk factors such as obesity, hypertriglyceridemia, and blood pressure control. Similarly, major issues and concerns have arisen around the CV safety of antidiabetic therapy. Together, these issues have focused attention on the need to understand the CV effects of current treatments for type 2 diabetes and the optimal strategies for care of patients with this disease.

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

BACKGROUND

The impact of antidiabetic medications on clinical outcomes in patients developing acute myocardial infarction (MI) is controversial. We sought to determine whether in-hospital outcomes in patients who were on sulfonylureas (SUs) when they developed their MIs differed from that of diabetic patients not receiving SUs and whether clinical outcomes were related to the pancreatic cells specificity of SUs.

METHODS AND RESULTS

We analyzed the outcomes of the 1310 diabetic patients included in the nationwide French Registry of Acute ST-Elevation and Non-ST-Elevation Myocardial Infarction in 2005. Medications used before the acute episode were recorded. In-hospital complications were analyzed according to prior antidiabetic treatment. Mortality was lower in patients previously treated with SUs (3.9%) vs. those on other oral medications (6.4%), insulin (9.4%), or no medication (8.4%) (P = 0.014). Among SU-treated patients, in-hospital mortality was lower in patients receiving pancreatic cells-specific SUs (gliclazide or glimepiride) (2.7%), compared with glibenclamide (7.5%) (P = 0.019). Arrhythmias and ischemic complications were also less frequent in patients receiving gliclazide/glimepiride. The lower risk in patients receiving gliclazide/glimepiride vs. glibenclamide persisted after multivariate adjustment (odds ratio 0.15; 95% confidence interval 0.04-0.56) and in propensity score-matched cohorts.

CONCLUSION

In this nationwide registry of patients hospitalized for acute MI, no hazard was associated with the use of SUs before the acute episode. In addition, patients previously receiving gliclazide/glimepiride had improved in-hospital outcomes, compared with those on glibenclamide.

Sulfonylureas and prognosis after myocardial infarction in patients with diabetes: a population-based follow-up study

BACKGROUND

The cardiovascular safety, including risk of myocardial infarction (MI), of individual sulfonylureas (SUs) may differ. It remains uncertain whether treatment with individual SUs influences prognosis following MI.

METHODS

We conducted a nationwide population-based follow-up study among all Danish patients hospitalized with first-time MI from 1996 to 2004. From the national health databases, we identified 3930 MI patients who used SUs at the time of admission. We computed mortality rates and rates of MI and heart failure readmission according to type of SU and used Cox's proportional hazards regression analysis to compute hazard ratios (HRs) as estimates of relative risk controlling for differences in prognostic covariates.

RESULTS

The 30-day and 1-year mortality after MI among SU users was 22.0% and 35.3%, respectively. We found no substantial differences in 30-day and 1-year mortality among users of different SUs. Use of gliclazide in monotherapy showed a trend towards lower mortality; adjusted HR of 1-year mortality 0.70 (95% CI: 0.48-1.00). Users of the different SUs appeared to have similar risks of new MI and heart failure following MI.

CONCLUSIONS

The prognosis after MI was not substantially influenced by the choice of SU.

Type of preadmission glucose-lowering treatment and prognosis among patients hospitalised with myocardial infarction: a nationwide follow-up study

AIMS/HYPOTHESIS

We examined whether the type of preadmission glucose-lowering treatments explained differences in mortality rate and risk of readmission with myocardial infarction (MI) and heart failure following first-time hospitalisation for MI in patients with type 2 diabetes mellitus.

METHODS

We conducted a nationwide population-based follow-up study among all Danish patients hospitalised with first-time MI from 1996 to 2004. Data on use of glucose-lowering drugs and other medications, comorbidities, socioeconomic status, laboratory findings, readmission with MI and heart failure, and death were obtained from medical databases. We computed mortality rates and rates of MI and heart failure readmission, according to type of glucose-lowering treatment and used Cox's proportional hazards regression analysis to compute hazard ratios (HRs) as estimates of relative risks.

RESULTS

We identified 8,494 MI patients with type 2 diabetes mellitus. The overall cumulative 30 day and 1 year mortality rates were 22.2 and 36.6%, respectively. Patients not receiving any glucose-lowering drugs (adjusted 30 day HR: 0.79, 95% CI: 0.57-1.10) and users of any combination (adjusted 30 day HR: 1.43, 95% CI: 0.98-2.09) had the lowest and highest mortality rates, respectively, when compared with users of sulfonylureas. We found that glycaemic control had no impact on the risk estimates in a subanalysis including biochemical laboratory data. We found no differences in the risk of new MI and heart failure between the different glucose-lowering agents.

CONCLUSIONS/INTERPRETATION

Type of preadmission glucose-lowering treatment in monotherapy is not associated with substantial differences in prognosis following hospitalisation with MI. However, patients treated with any combination had increased mortality rates.

Progress in the treatment of type 2 diabetes: new pharmacologic approaches to improve glycemic control

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a leading cause of morbidity and mortality that places a substantial economic and health burden on the public. Successful management of T2DM requires strict control of glycemia as well as other risk factors to prevent disease progression. Despite the availability of multiple classes of oral antidiabetic drugs and insulin, the majority of patients fail to attain or maintain tight glycemic control over time, raising their risk of serious microvascular and macrovascular complications.

SCOPE

This review briefly outlines current standards of diabetes treatment and explores several new and investigational approaches. It is based on MEDLINE literature searches (1966-August 2006) and on abstracts from the American Diabetes Association Scientific Sessions (2002-2006) and the European Association for the Study of Diabetes Annual Meetings (1998-2006). Articles concerning basic science, preclinical, and clinical trial results were selected for this review based on their originality and relevance.

FINDINGS

Medical professional societies and other specialist groups have proposed a series of practical steps to enable more patients with T2DM to reach treatment goals. Among their most important recommendations is a call for new drugs to stabilize or reverse the progressive pancreatic islet-cell dysfunction that characterizes the disease. New modalities, such as incretin mimetics and DPP-4 inhibitors, are now emerging from clinical development and will provide patients with more treatment options.

CONCLUSIONS

It appears likely that early and aggressive treatment with multiple drug combinations will become more common in the management of T2DM. The new treatment modalities discussed here offer hope for improved outcomes and for meeting the considerable public health challenges posed by this complex condition. However, long-term studies are needed to determine durability of treatment effects, as well as the ultimate role of these new agents in the management of patients with T2DM.

Dysrhythmia and electrocardiographic changes in diabetes mellitus: pathophysiology and impact on the incidence of sudden cardiac death

BACKGROUND

The incidence of sudden cardiac death (SCD) is increasing in diabetes mellitus. Susceptibility to dysrhythmias and the reliability of an electrocardiogram in diabetic hearts are debatable issues.

OBJECTIVES

To highlight the underlying mechanism of dysrhythmia and electrocardiographic changes in diabetic patients and the impact on the incidence of SCD.

METHODS

Most the pertinent articles (English and non-English) published in Medline, Scopus and EBSCO Host research databases have been reviewed.

RESULTS AND CONCLUSION

In the absence of systematic reviews, susceptibility to dysrhythmias and electrical instability in diabetic patients are underestimated. This susceptibility has been found to be enhanced, unchanged or reduced in different studies. To find a link between SCD and diabetes, the published studies provide controversial results; however, the majority of studies with a long-term follow-up support this link. The role of hyperglycemia, autonomic neuropathy and anti-diabetic agents as predisposing factors deserve more attention to fortify the clinical judgment and decrease the incidence of SCD.

Sulfonylureas and the risk of myocardial infarction

Patients with diabetes mellitus have an increased risk of coronary artery diseases such as myocardial infarction. Sulfonylureas are used in the treatment of diabetes mellitus and have been linked with adverse cardiovascular effects due to an apparent effect on myocardial ischemic preconditioning. Individual sulfonylureas differ pharmacologically and may have different effects. Although the hypotheses were stimulated by animal studies and experimental studies using intermediate end points, data on the possible clinical implications in humans remain sparse. However, recent data seem reassuring.

Role of previous treatment with sulfonylureas in diabetic patients with acute myocardial infarction: results from a nationwide French registry

BACKGROUND

The cardiovascular effects of sulfonylureas (SU) in diabetic patients are controversial and it has been suggested that diabetic patients with acute myocardial infarction while on SU were at increased risk.

OBJECTIVES

To assess the in-hospital outcome of patients with acute myocardial infarction according to the use of SU at the time of the acute episode.

METHODS

Of 443 intensive care units in France, 369 (83%) prospectively collected all cases of infarction admitted within 48 h of symptom onset in November 2000.

RESULTS

Among the 2320 patients included in the registry, 487 (21%) had diabetes, of whom 215 (44%) were on SU. Patients on SU were older and had a more frequent history of hyperlipidemia than those not receiving SU. Type and location of infarction were similar in the two groups, and there was no difference in Killip class on admission. In-hospital mortality was lower in patients on SU (10.2%) than in those without SU (16.9%) (p = 0.035). There was a trend toward less frequent ventricular fibrillation (2.3% vs 5.9%, p = 0.052). In two models of multivariate analyses, SU therapy was associated with decreased in-hospital mortality (model 1: relative risk: 0.44, p = 0.012; model 2: relative risk: 0.37, p = 0.020).

CONCLUSIONS

In this nationwide registry reflecting real-world practice, the use of sulfonylureas in diabetic patients was not associated with increased in-hospital mortality.

Is impairment of ischaemic preconditioning by sulfonylurea drugs clinically important?

In the UGDP study, published in the 1970s, a high incidence of cardiovascular mortality was found in patients treated with the sulfonylurea agent tolbutamide. Impaired ischaemic preconditioning is presumed to be the most important mechanism for the excess cardiovascular mortality observed. However, as tolbutamide has only a low affinity for cardiac sulfonylurea receptors, interference with ischaemic preconditioning seems unlikely to account for this excess mortality. Several smaller studies also failed to establish a definite link between sulfonylurea treatment before acute myocardial infarction and in-hospital mortality. However, when the myocardium becomes exposed to repeated or prolonged periods of ischaemia, ischaemic preconditioning may become clinically important. Myocardial ischaemia can also develop during emergency or elective angioplasty and during coronary bypass surgery. Therefore discontinuation of sulfonylurea treatment should be considered in these circumstances.

Sulfonylureas and cardiovascular effects: from experimental data to clinical use. Available data in humans and clinical applications

OBJECTIVES

33 years after the UGDP study, the question of deleterious effects of the sulfoylurea (SU) is still raised. We have made a systematic review of the literature from experimental studies to clinical and epidemiological studies.

RESULTS

The main molecule studied is glibenclamide (GB). In vitro and in animal studies, GB is both deleterious for ischemic preconditionning (IPC) and protective for arrhythmia during acute ischemia. Glimepiride (GM) and gliclazide (GCZ) do not seem to have effect on IPC. These effects have been few studied in diabetic animals. In human, according to the investigations used, the GB seems nil or suppressing for IPC, it seems elsewhere decreases ventricular arrhythmias during periods of acute ischemia. It is possible that these two actions account for the non-appearance of concordant deleterious effects between short and long-term studies. With regards to other drugs, only the GM has been specifically studied in human and appears to be nil on IPC. The only prospective clinical study available, although not having for objective to answer to this question, is the UKPDS study. This trial demonstrates the absence of deleterious cardiac effects of GB compared to chlorpropamide and particularly compared to insulin.

CONCLUSION

In conclusion, in experimental studies the cardiac effects of SU differ: both deleterious and protective for GB, nil for GM and GCZ on IPC. In all cases the clinical consequences seems to be nil.