Does hypoglycaemia increase the risk of cardiovascular events? A report from the ORIGIN trial

Recognizing and minimizing hypoglycemia: The need for individualized care

Hypoglycemia is a condition known to disrupt many everyday activities and is associated with increased risks of hospitalization, falls, motor vehicle accidents and mortality. Many patients with diabetes have an increased risk of hypoglycemia due to interventions targeting glycemic control. In these patients, hypoglycemia and fear of hypoglycemia may further reduce adherence to glucose-lowering regimens, contributing to the further aggravation of diabetes-related complications. Avoiding hypoglycemia should be one of the principal goals of any treatment strategies employing agents that can induce hypoglycemia in order to prevent the occurrence of associated symptoms and consequences. The education of patients and their families is an important feature of individualized management strategies in order to prevent, mitigate and treat hypoglycemic episodes. Patients with diabetes need to be made aware of how to recognize the signs of hypoglycemia and of the simple, highly effective steps that they can take to self-manage hypoglycemic episodes. Clinicians should be familiar with the risk factors for hypoglycemia, especially the profiles of the different classes of glucose-lowering medications such as the sulfonylureas and insulin. This article aims to review the risk factors for hypoglycemia and its implications for patients and healthcare systems, and provide practical advice for minimizing the risk of hypoglycemia and its consequences.

Use of insulin in type 2 diabetes: what we learned from recent clinical trials on the benefits of early insulin initiation

The majority of people with type 2 diabetes mellitus (T2DM) require insulin therapy to maintain HbA(1c) levels < 7% during the first decade of diagnosis. Large prospective trials investigating the cardiovascular (CV) benefits of intensive glycaemic control have produced inconsistent results; however, meta-analyses have suggested that intensive glycaemic control provides both micro- and macrovascular benefits. The ORIGIN study investigated the impact of basal insulin glargine therapy targeting ≤ 5.3 mmol/L for fasting plasma glucose compared with standard care on CV outcomes in people with pre- or early diabetes, and demonstrated a neutral effect on CV outcomes with long-term use of insulin glargine early in the course of diabetes, with a low rate of severe hypoglycaemia and modest weight gain. The EARLY, GLORY and EASIE studies also demonstrated that insulin use earlier in the treatment pathway led to improved glycaemic control, reduced weight gain and fewer hypoglycaemic episodes than when insulin was added later in the course of disease. The beneficial effect of early transient intensive insulin therapy (TIIT) at diagnosis has been demonstrated in a number of trials; it rapidly limits the damage caused by gluco- and lipotoxicity, improving residual β-cell function and potentially slowing disease progression. The evidence suggests that people newly diagnosed with T2DM and HbA(1c) > 9% should be given early TIIT to achieve normoglycaemia within weeks, after which standard care should then be adopted. Insulin use earlier in the treatment pathway should be considered, as it reduces the risk of hypoglycaemia as well as allows β-cell rest, which can help preserve β-cell function.

Economic resources consumption structure in severe hypoglycemia episodes: a systematic review and meta-analysis

Diabetes mellitus (DM) is associated with severe hypoglycemia events (SHEs) that vary in severity and resource consumption. Here we perform a systematic review in Medline of studies evaluating SHE-related health resource use. Eligible studies investigated patients with DM and included ≥10 SHEs. We also assessed studies identified in another systematic review, and through references from the included studies. We identified 14 relevant studies and used data from 11 (encompassing 6075 patients). Study results were interpreted to fit our definitions, which sometimes required assumptions. SHE type structure was synthesized using Bayesian modeling. Estimating Type 1 & 2 DM separately revealed only small differences; therefore, we used joint results. Of the analyzed SHEs, 9.97% were hospital-treated, 22.3% medical professional-treated, and 67.73% family-treated. These meta-analysis results help in understanding the structure of resource consumption following SHE and can be used in economic studies.

Inverse association between fasting plasma glucose and risk of ventricular arrhythmias

AIMS/HYPOTHESIS

In nondiabetic individuals, low values of fasting plasma glucose (FPG) have been associated with an increased risk of cardiovascular events. Identification of the potential mechanisms behind this association could help to elucidate the relationship between glycaemia and cardiovascular disease. We aimed to determine the association between FPG and ventricular arrhythmias.

METHODS

FPG and other cardiometabolic risk factors were measured in a population-based cohort of 2,482 men without a known history of type 2 diabetes mellitus at baseline. Associations between FPG levels and incident cases of ventricular arrhythmias (ventricular tachycardia or fibrillation events ascertained using the National Hospital Discharge Register) were estimated using Cox regression analysis adjusted for potential confounders.

RESULTS

During a median follow-up of 23.3 (interquartile range 18.5-25.3) years, 74 (2.9%) incident events were recorded. In a multivariable analysis adjusted for age, systolic BP, smoking status, LDL- and HDL-cholesterol, and C-reactive protein, the HR for ventricular arrhythmia per 1 mmol/l higher baseline FPG was 0.58 (95% CI 0.34, 0.98); this estimate did not materially change after further adjustment for BMI, alcohol consumption, triacylglycerols and history of ischaemic heart disease (0.50 [95% CI 0.28, 0.89]).

CONCLUSIONS/INTERPRETATION

In this nondiabetic male population, FPG was inversely associated with incident risk of ventricular arrhythmias. While our results could help clarify the relationship between low glucose levels and cardiovascular risk, further studies are required to confirm these findings in other populations.

Minimizing Hypoglycemia in Diabetes

Hypoglycemia caused by treatment with a sulfonylurea, a glinide, or insulin coupled with compromised defenses against the resulting falling plasma glucose concentrations is a problem for many people with diabetes. It is often recurrent, causes significant morbidity and occasional mortality, limits maintenance of euglycemia, and impairs physiological and behavioral defenses against subsequent hypoglycemia. Minimizing hypoglycemia includes acknowledging the problem; considering each risk factor; and applying the principles of intensive glycemic therapy, including drug selection and selective application of diabetes treatment technologies. For diabetes health-care providers treating most people with diabetes who are at risk for or are suffering from iatrogenic hypoglycemia, these principles include selecting appropriate individualized glycemic goals and providing structured patient education to reduce the incidence of hypoglycemia. This is typically combined with short-term scrupulous avoidance of hypoglycemia, which often will reverse impaired awareness of hypoglycemia. Clearly, the risk of hypoglycemia is modifiable.

Insulin pump therapy, multiple daily injections, and cardiovascular mortality in 18,168 people with type 1 diabetes: observational study

OBJECTIVE

To investigate the long term effects of continuous subcutaneous insulin infusion (insulin pump therapy) on cardiovascular diseases and mortality in people with type 1 diabetes.

DESIGN

Observational study.

SETTING

Swedish National Diabetes Register, Sweden 2005-12.

PARTICIPANTS

18,168 people with type 1 diabetes, 2441 using insulin pump therapy and 15,727 using multiple daily insulin injections.

MAIN OUTCOME MEASURES

Cox regression analysis was used to estimate hazard ratios for the outcomes, with stratification of propensity scores including clinical characteristics, risk factors for cardiovascular disease, treatments, and previous diseases.

RESULTS

Follow-up was for a mean of 6.8 years until December 2012, with 114,135 person years. With multiple daily injections as reference, the adjusted hazard ratios for insulin pump treatment were significantly lower: 0.55 (95% confidence interval 0.36 to 0.83) for fatal coronary heart disease, 0.58 (0.40 to 0.85) for fatal cardiovascular disease (coronary heart disease or stroke), and 0.73 (0.58 to 0.92) for all cause mortality. Hazard ratios were lower, but not significantly so, for fatal or non-fatal coronary heart disease and fatal or non-fatal cardiovascular disease. Unadjusted absolute differences were 3.0 events of fatal coronary heart disease per 1000 person years; corresponding figures were 3.3 for fatal cardiovascular disease and 5.7 for all cause mortality. When lower body mass index and previous cardiovascular diseases were excluded, results of subgroup analyses were similar to the results from complete data. A sensitivity analysis of unmeasured confounders in all individuals showed that an unmeasured confounders with hazard ratio of 1.3 would have to be present in >80% of the individuals treated with multiple daily injections versus not presence in those treated with pump therapy to invalidate the significantly lower hazard ratios for fatal cardiovascular disease. Data on patient education and frequency of blood glucose monitoring were missing, which might have influenced the observed association.

CONCLUSION

Among people with type 1 diabetes use of insulin pump therapy is associated with lower cardiovascular mortality than treatment with multiple daily insulin injections.

Implantable cardioverter defibrillators in diabetics: efficacy and safety in patients at risk of sudden cardiac death

Diabetes mellitus is a major risk factor for arrhythmogenesis and is associated with a two-fold increase in all-cause mortality and a four-fold increase in cardiovascular mortality including sudden cardiac death when compared with nondiabetics. Implantable cardioverter defibrillators (ICD) have been shown to effectively reduce arrhythmic death and all-cause mortality in patients with severe myocardial dysfunction. With a high competing risk of nonarrhythmic cardiac and noncardiac death, survival benefit of ICD in patients with diabetes mellitus could be reduced, but the subanalysis of diabetic patients in randomized clinical trials provides reassurance regarding a similar beneficial survival effect of ICD and cardiac resynchronization therapy in diabetics, as observed in the overall population with advanced heart disease. In this article, the authors highlight some of the clinical issues related to diabetes, summarize the data on the efficacy of ICD in diabetics when compared with nondiabetics and discuss concerns related to ICD implantation in patients with diabetes.

Impact of glucose-lowering drugs on cardiovascular disease in type 2 diabetes

Type 2 diabetes mellitus (T2DM) is characterized by multiple pathophysiologic abnormalities. With time, multiple glucose-lowering medications are commonly required to reduce and maintain plasma glucose concentrations within the normal range. Type 2 diabetes mellitus individuals also are at a very high risk for microvascular complications and the incidence of heart attack and stroke is increased two- to three-fold compared with non-diabetic individuals. Therefore, when selecting medications to normalize glucose levels in T2DM patients, it is important that the agent not aggravate, and ideally even improve, cardiovascular risk factors (CVRFs) and reduce cardiovascular morbidity and mortality. In this review, we examine the effect of oral (metformin, sulfonylureas, meglitinides, thiazolidinediones, DPP4 inhibitors, SGLT2 inhibitors, and α-glucosidase inhibitors) and injectable (glucagon-like peptide-1 receptor agonists and insulin) glucose-lowering drugs on established CVRFs and long-term studies of cardiovascular outcomes. Firm evidence that in T2DM cardiovascular disease can be reversed or prevented by improving glycaemic control is still incomplete and must await large, long-term clinical trials in patients at low risk using modern treatment strategies, i.e., drug combinations designed to maximize HbA1c reduction while minimizing hypoglycaemia and excessive weight gain.

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.

Glucose-lowering with exogenous insulin monotherapy in type 2 diabetes: dose association with all-cause mortality, cardiovascular events and cancer

AIMS

To evaluate the association between insulin exposure and all-cause mortality, incident major adverse cardiovascular events (MACE) and incident cancer in people with type 2 diabetes treated with insulin monotherapy.

METHODS

For this retrospective study, people with type 2 diabetes who progressed to insulin monotherapy from the year 2000 were identified from the UK Clinical Practice Research Datalink. The risks of progression to serious adverse outcomes were compared using Cox proportional hazards models. In the main analysis, insulin exposure was introduced into the model as prescribed international units per kilogram per day, as a cumulative, continuous, annually updated, time-dependent covariable.

RESULTS

A total of 6484 subjects with type 2 diabetes who progressed to treatment with insulin monotherapy from the year 2000 onwards were followed for a mean of 3.3 years. The event numbers were as follows: deaths, n = 1110; incident MACE, n = 342; incident cancers, n = 382. Unadjusted event rates were 61.3 deaths per 1000 person-years, 26.4 incident MACE per 1000 person-years and 24.6 incident cancers per 1000 person-years. The adjusted hazard ratios in relation to 1-unit increases in insulin dose were 1.54 [95% confidence interval (CI) 1.32-1.78] for all-cause mortality, 1.37 (95% CI 1.05-1.81) for MACE and 1.35 (95% CI 1.04-1.75) for cancer.

CONCLUSIONS

There was an association between increasing exogenous insulin dose and increased risk of all-cause mortality, MACE and cancer in people with type 2 diabetes. The limitations of observational studies mean that this should be further investigated using an interventional study design.

"Mild dysglycemia" in type 2 diabetes: to be neglected or not?

"Mild dysglycemia" in type 2 diabetes can be defined by the range of HbA1c levels≥6.5% (48 mmol/mol) and<7% (53 mmol/mol), which corresponds to when the risk for vascular complications begins to increase. This "mild dysglycemia" is characterized by both a dawn phenomenon (a spontaneous blood glucose rise in the early morning) and an excess of post-prandial glucose excursions in the absence of abnormal elevation in basal glucose, especially during nocturnal periods. This represents an intermediary stage between pre-diabetes (HbA1c≥5.7%, 39 mmol/mol, and<6.5%, 48 mmol/mol) and those who begin to show a steadily progressive worsening in basal glucose (HbA1c≥7%, 53 mmol/mol). Should this relatively minor intermediate dysglycemic phase deserve more attention, that is the question. The now available incretin-based therapies, and more specifically the DPP-4 inhibitors provide the clinician with the possibility to reduce or eradicate both the dawn phenomenon and post-meal glucose excursions with minimal side effects. The availability of 24-h glycemic profiles in those with "mild dysglycemia" will help to describe their individual glycemic phenotype, based on which the early and appropriate life style changes and/or pharmacological interventions can be introduced.

SGLT-2 inhibitors and cardiovascular risk: proposed pathways and review of ongoing outcome trials

Given the multi-faceted pathogenesis of atherosclerosis in type 2 diabetes mellitus (T2DM), it is likely that interventions to mitigate this risk must address cardiovascular (CV) risk factors beyond glucose itself. Sodium glucose cotransporter-2 (SGLT-2) inhibitors are newer antihyperglycaemic agents with apparent multiple effects. Inherent in their mode of action to decrease glucose reabsorption by the kidneys by increasing urinary glucose excretion, these agents improve glycaemic control independent of insulin secretion with a low risk of hypoglycaemia. In this review, we outline those CV risk factors that this class appears to influence and provide the design features and trial characteristics of six ongoing outcome trials involving more than 41,000 individuals with T2DM. Those risk factors beyond glucose that can potentially be modulated positively with SGLT-2 inhibitors include blood pressure, weight, visceral adiposity, hyperinsulinaemia, arterial stiffness, albuminuria, circulating uric acid levels and oxidative stress. On the other hand, small increases in low-density lipoprotein (LDL)-cholesterol levels have also been observed for the class, which theoretically might offset some of these benefits. The potential translational impact of these effects is being tested with outcome trials, also reviewed in this article, powered to assess both macrovascular as well as certain microvascular outcomes in T2DM. These are expected to begin to report in late 2015.

Treatment-dependent and treatment-independent risk factors associated with the risk of diabetes-related events: a retrospective analysis based on 229,042 patients with type 2 diabetes mellitus

BACKGROUND

The aim of this study was to analyse which factors predict the real-world macro-/microvascular event, hospitalisation and death risk in patients with type 2 diabetes mellitus. Furthermore, we aimed to investigate whether there exists both an under- and over-treatment risk of these patients.

METHODS

We used a German claims/clinical data set covering the years 2010-12. Diabetes-related events were defined as (1) macro-, (2) microvascular events leading to inpatient hospitalisation, (3) other hospitalisations with type 2 diabetes mellitus as main diagnosis, (4) all-cause death and (5) a composite outcome including all event categories 1-4. Factors associated with event risk were analysed by a Kaplan-Meier curve analysis and by multivariable Cox regression models.

RESULTS

229,042 patients with type 2 diabetes mellitus (mean age 70.2 years; mean CCI 6.03) were included. Among factors that increased the event risk were patients' age, male gender, the adapted Charlson Comorbidity Index, the adapted Diabetes Complication Severity Index, previous events, and number of prescribed chronic medications. For systolic blood pressure/HbA1C, a double-J/U-curve pattern was detected: HbA1C of 6-6.5% (42-48 mmol/mol) and systolic blood pressure of 130-140 mmHg (17.3-18.7kPa) were associated with the lowest event risk, values below/above that range were associated with higher risk. However, this pattern was mainly driven by the death risk and was much less clearly observed for the macrovascular/microvascular/hospitalization risk and for young/less comorbid patients.

CONCLUSIONS

Both blood pressure and HbA1C seem to be very important treatment targets, especially in comorbid old patients. It is of particular clinical importance that both over- and under-treatment pose a threat to patients with type 2 diabetes mellitus.

Hypoglycemia and risk of cardiovascular disease and all-cause mortality in insulin-treated people with type 1 and type 2 diabetes: a cohort study

OBJECTIVE

Hypoglycemia has been associated with an increased risk of cardiovascular (CV) events and all-cause mortality. This study assessed whether, in a nationally representative population, there is an association between hypoglycemia, the risk of CV events, and all-cause mortality among insulin-treated people with type 1 diabetes or type 2 diabetes.

RESEARCH DESIGN AND METHODS

This retrospective cohort study used data from the Clinical Practice Research Datalink database and included all insulin-treated patients (≥30 years of age) with a diagnosis of diabetes.

RESULTS

In patients who experienced hypoglycemia, hazard ratios (HRs) for CV events in people with type 1 diabetes were 1.51 (95% CI 0.83, 2.75; P = ns) and 1.61 (1.17, 2.22), respectively, for those with and without a history of CV disease (CVD) before the index date. In people with type 2 diabetes, the HRs for patients with and without a history of CVD were 1.60 (1.21, 2.12) and 1.49 (1.23, 1.82), respectively. For all-cause mortality, HRs in people with type 1 diabetes were 1.98 (1.25, 3.17), and 2.03 (1.66, 2.47), respectively, for those with and without a history of CVD. Among people with type 2 diabetes, HRs were 1.74 (1.39, 2.18) and 2.48 (2.21, 2.79), respectively, for those with and without a history of CVD. The median time (interquartile range) from first hypoglycemia event to first CV event was 1.5 years (0.5, 3.5 years) and 1.5 years (0.5, 3.0 years), respectively, for people with type 1 and type 2 diabetes.

CONCLUSIONS

Hypoglycemia is associated with an increased risk of CV events and all-cause mortality in insulin-treated patients with diabetes. The relationship between hypoglycemia and CV outcomes and mortality exists over a long period.

[Hypoglycemia and cardiac arrhythmia in patients with diabetes mellitus type 2]

Hypoglycemia is a common and potentially life-threatening adverse effect of inappropriate diabetes treatment. Typical cardiac complications are ischemia with angina pectoris, myocardial infarction, stroke and arrhythmias, such as atrial fibrillation (AF), ventricular tachycardia and heart failure. Elderly multimorbid patients with type 2 diabetes and polypharmacy and/or cardiac autonomous neuropathy represent a very high risk group for cardiovascular complications associated with hypoglycemia. Targets for glycemic control have to be adapted to the risk of hypoglycemia with a priority of stable glucose homeostasis without rapid fluctuations. Elderly patients with diabetes have a >20% risk of AF. At blood glucose levels of <3 mmol/l with a duration of >30 min, prolongation of QTc time and ventricular tachycardia occur with an increased risk of ventricular fibrillation and sudden death. Ventricular arrhythmias and AF significantly increase mortality in patients with heart failure. Rapid fluctuations with a mean amplitude of glucose excursion (MAGE) >5 mmol/l promote vulnerability of electrical stability of the heart, particularly in frail patients with preexisting coronary heart disease and autonomic neuropathy. Antihyperglycemic agents, such as metformin, acarbose and sodium glucose cotransporter 2 (SGLT2) inhibitors have only a low risk of severe hypoglycemia. Dipeptidyl peptase 4 (DPP-IV) inhibitors and glucagon-like peptide 1 (GLP1) analogues as insulin secretagogues have a lower risk for hypoglycemia than sulfonylurea and insulin. Early basal insulin treatment in patients insufficiently controlled with metformin is efficient, safe and convenient. Targets for glucose control and HbA1c have to be individualized and the choice of drugs must be risk-adjusted. Risk of hypoglycemia should be used as guide in decision-making for safe treatment of diabetes.

Predictors of nonsevere and severe hypoglycemia during glucose-lowering treatment with insulin glargine or standard drugs in the ORIGIN trial

OBJECTIVE

Hypoglycemia is a leading risk of glucose-lowering therapy. Treatment with insulin glargine compared with standard care early in the course of dysglycemia in the Outcome Reduction with an Initial Glargine Intervention (ORIGIN) trial provides information on the frequency and predictors of hypoglycemia in this setting.

RESEARCH DESIGN AND METHODS

A total of 12,537 people with high cardiovascular risk and dysglycemia treated with one or no oral glucose-lowering agents were randomized to add glargine titrated to a fasting glucose level of ≤5.3 mmol/L (≤95 mg/dL) or to use standard therapies. Independent associations of both nonsevere hypoglycemia (symptomatic and confirmed with a glucose level of ≤3 mmol/L [≤54 mg/dL]) and severe hypoglycemia with characteristics at baseline, treatment allocation, and average HbA1c were assessed by Cox proportional hazards models.

RESULTS

During a median follow-up period of 6.2 years, 28% of participants reported nonsevere hypoglycemia, and 3.8% reported severe hypoglycemia. Prior use of a sulfonylurea and allocation to glargine independently predicted a higher risk for both categories of participants. Nonsevere events were independently associated with younger age, lower BMI, the presence of diabetes, and higher baseline HbA1c level. Severe events were associated with older age, hypertension, higher serum creatinine level, and lower cognitive function, but not baseline glycemic status. Progressively higher on-treatment HbA1c level was associated with a lower risk of nonsevere events in both treatment groups; a lower risk of severe events in the glargine group, and a higher risk of severe events with standard care.

CONCLUSIONS

Hypoglycemia was relatively uncommon in the ORIGIN trial, but was more frequent with sulfonylurea use at baseline and allocation to glargine. Nonsevere and severe events were associated with different clinical characteristics, awareness of which may guide individualized therapy.

Hypoglycaemia in diabetes mellitus: epidemiology and clinical implications

Hypoglycaemia is a frequent adverse effect of treatment of diabetes mellitus with insulin and sulphonylureas. Fear of hypoglycaemia alters self-management of diabetes mellitus and prevents optimal glycaemic control. Mild (self-treated) and severe (requiring help) hypoglycaemia episodes are more common in type 1 diabetes mellitus but people with insulin-treated type 2 diabetes mellitus are also exposed to frequent hypoglycaemic events, many of which occur during sleep. Hypoglycaemia can disrupt many everyday activities such as driving, work performance and leisure pursuits. In addition to accidents and physical injury, the morbidity of hypoglycaemia involves the cardiovascular and central nervous systems. Whereas coma and seizures are well-recognized neurological sequelae of hypoglycaemia, much interest is currently focused on the potential for hypoglycaemia to cause dangerous and life-threatening cardiac complications, such as arrhythmias and myocardial ischaemia, and whether recurrent severe hypoglycaemia can cause permanent cognitive impairment or promote cognitive decline and accelerate the onset of dementia in middle-aged and elderly people with diabetes mellitus. Prevention of hypoglycaemia is an important part of diabetes mellitus management and strategies include patient education, glucose monitoring, appropriate adjustment of diet and medications in relation to everyday circumstances including physical exercise, and the application of new technologies such as real-time continuous glucose monitoring, modified insulin pumps and the artificial pancreas.

Association between severe hypoglycemia, adverse macrovascular events, and inflammation in the Edinburgh Type 2 Diabetes Study

OBJECTIVE

To determine whether a history of severe hypoglycemia was associated with an increased risk of subsequent macrovascular events in people with type 2 diabetes and to explore possible mediation of this association by inflammation.

RESEARCH DESIGN AND METHODS

A cohort of 1,066 adults aged 60-75 years with type 2 diabetes was evaluated prospectively. Baseline history of severe hypoglycemia and plasma levels of the inflammatory markers C-reactive protein, fibrinogen, interleukin-6, and tumor necrosis factor-α were recorded. Their association with incident macrovascular events after 4 years was explored.

RESULTS

At baseline, 87 participants (8.2%) reported one or more episodes of severe hypoglycemia within the preceding year, and at follow-up 99 participants (9.3%) had suffered a new macrovascular event. Hypoglycemia was associated with increased odds of macrovascular events (odds ratio [OR] 2.11 [95% CI 1.06, 4.21], P = 0.035), including coronary heart events (OR 2.44 [95% CI 1.13, 5.26], P = 0.023), largely due to increased myocardial infarction (OR 4.02 [95% CI 1.54, 10.48], P = 0.004). Hypoglycemia was also associated with increased levels of inflammatory markers, including a general inflammation factor derived using principal-components analysis (P = 0.030, after adjustment for cardiometabolic risk factors). However, the significant association between hypoglycemia and macrovascular events persisted after adjustment for inflammatory markers.

CONCLUSIONS

The odds of suffering a macrovascular event were higher in patients with type 2 diabetes who had a history of severe hypoglycemia. There was no evidence that a proinflammatory state had a major role in mediating this association.

A review of cardiovascular outcomes in the treatment of people with type 2 diabetes

INTRODUCTION

Cardiovascular disease (CVD) is a common and serious complication of type 2 diabetes mellitus (T2DM) often linked to the increased morbidity and mortality associated with T2DM. Monitoring and treating risk factors for CVD are important elements of diabetes management. This review aims to examine CV risk in people with relatively early and mild diabetes who are at substantial risk of CVD; it considers the impact of insulin therapy on this risk by focusing on key studies in patients with diabetes.

METHODS

A literature search was carried out using PubMed to identify key publications, between 2008 and 2013, related to insulin and its possible effect on CVD. This review examines CV risk in diabetes and the impact of insulin therapy on this risk.

RESULTS

Studies have shown that treatment with insulin glargine is associated with marked improvement in the lipid profile of people with T2DM. Intensive insulin therapy has been shown to lower mortality rates in people with diabetes following acute myocardial infarction after 1 year. Retrospective data also indicate that insulin reduces the risk of CVD events, regardless of whether people had comorbidities known to increase CV risk. The prospective ORIGIN (Outcome Reduction with Initial Glargine Intervention) trial found that treatment with insulin glargine had a neutral effect with regard to CV outcomes in people with prediabetes or early diabetes, compared with standard care.

CONCLUSIONS

Other ongoing, large-scale studies of insulin therapy should provide further insights into whether or not insulin therapy can influence long-term CV outcomes.

Contemporary treatment strategies for Type 2 diabetes-related macrovascular disease

Type 2 diabetes mellitus poses a major challenge to healthcare providers in the coming years as its prevalence increases across the globe. The disease doubles the risk of cardiovascular morbidity and mortality, with 70% of sufferers dying from a cardiac cause. Large clinical trials of current glucose-lowering therapies for Type 2 diabetes have shown no benefit in reducing the risk of macrovascular events. Blood pressure control, angiotensin-converting enzyme inhibitor therapy and improvement of dyslipidemia with statins have proven benefit in reducing cardiovascular risk in Type 2 diabetes. A growing understanding of the importance of pathological processes including endothelial dysfunction, abnormal growth factor biology, oxidative stress, dysregulation of adipokines and deficient vascular repair and regeneration in insulin-resistant states promises new treatments to combat the problem.

Glycemic variability and oxidative stress: a link between diabetes and cardiovascular disease?

Diabetes is associated with a two to three-fold increase in risk of cardiovascular disease. However, intensive glucose-lowering therapy aiming at reducing HbA1c to a near-normal level failed to suppress cardiovascular events in recent randomized controlled trials. HbA1c reflects average glucose level rather than glycemic variability. In in vivo and in vitro studies, glycemic variability has been shown to be associated with greater reactive oxygen species production and vascular damage, compared to chronic hyperglycemia. These findings suggest that management of glycemic variability may reduce cardiovascular disease in patients with diabetes; however, clinical studies have shown conflicting results. This review summarizes the current knowledge on glycemic variability and oxidative stress, and discusses the clinical implications.

Basal insulin combined incretin mimetic therapy with glucagon-like protein 1 receptor agonists as an upcoming option in the treatment of type 2 diabetes: a practical guide to decision making

The combination of basal insulin and glucagon-like protein 1 receptor agonists (GLP-1 RAs) is a new intriguing therapeutic option for patients with type 2 diabetes. In our daily practice we abbreviate this therapeutic concept with the term BIT (basal insulin combined incretin mimetic therapy) in a certain analogy to BOT (basal insulin supported oral therapy). In most cases BIT is indeed an extension of BOT, if fasting, prandial or postprandial blood glucose values have not reached the target range. In our paper we discuss special features of combinations of short- or prandial-acting and long- or continuous-acting GLP-1 RAs like exenatide, lixisenatide and liraglutide with basal insulin in relation to different glycemic targets. Overall it seems appropriate to use a short-acting GLP-1 RA if, after the near normalization of fasting blood glucose with BOT, the prandial or postprandial values are elevated. A long-acting GLP-1 RA might well be given, if fasting blood glucose values are the problem. Based on pathophysiological findings, recent clinical studies and our experience with BIT and BOT as well as BOTplus we developed chart-supported algorithms for decision making, including features and conditions of patients. The development of these practical tools was guided by the need for a more individualized antidiabetic therapy and the availability of the new BIT principle.

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.

Identifying and meeting the challenges of insulin therapy in type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a chronic illness that requires clinical recognition and treatment of the dual pathophysiologic entities of altered glycemic control and insulin resistance to reduce the risk of long-term micro- and macrovascular complications. Although insulin is one of the most effective and widely used therapeutic options in the management of diabetes, it is used by less than one-half of patients for whom it is recommended. Clinician-, patient-, and health care system-related challenges present numerous obstacles to insulin use in T2DM. Clinicians must remain informed about new insulin products, emerging technologies, and treatment options that have the potential to improve adherence to insulin therapy while optimizing glycemic control and mitigating the risks of therapy. Patient-related challenges may be overcome by actively listening to the patient’s fears and concerns regarding insulin therapy and by educating patients about the importance, rationale, and evolving role of insulin in individualized self-treatment regimens. Enlisting the services of Certified Diabetes Educators and office personnel can help in addressing patient-related challenges. Self-management of diabetes requires improved patient awareness regarding the importance of lifestyle modifications, self-monitoring, and/or continuous glucose monitoring, improved methods of insulin delivery (eg, insulin pens), and the enhanced convenience and safety provided by insulin analogs. Health care system-related challenges may be improved through control of the rising cost of insulin therapy while making it available to patients. To increase the success rate of treatment of T2DM, the 2012 position statement from the American Diabetes Association and the European Association for the Study of Diabetes focused on individualized patient care and provided clinicians with general treatment goals, implementation strategies, and tools to evaluate the quality of care.

Glycemic goals in diabetes: trade-off between glycemic control and iatrogenic hypoglycemia

The selection of a glycemic goal in a person with diabetes is a compromise between the documented upside of glycemic control-the partial prevention or delay of microvascular complications-and the documented downside of glycemic control-the recurrent morbidity and potential mortality of iatrogenic hypoglycemia. The latter is not an issue if glycemic control is accomplished with drugs that do not cause hypoglycemia or with substantial weight loss. However, hypoglycemia becomes an issue if glycemic control is accomplished with a sulfonylurea, a glinide, or insulin, particularly in the setting of absolute endogenous insulin deficiency with loss of the normal decrease in circulating insulin and increase in glucagon secretion and attenuation of the sympathoadrenal response as plasma glucose concentrations fall. Then the selection of a glycemic goal should be linked to the risk of hypoglycemia. A reasonable individualized glycemic goal is the lowest A1C that does not cause severe hypoglycemia and preserves awareness of hypoglycemia, preferably with little or no symptomatic or even asymptomatic hypoglycemia, at a given stage in the evolution of the individual's diabetes.

Cardiovascular outcome trials of glucose-lowering drugs or strategies in type 2 diabetes

Few trials of glucose-lowering drugs or strategies in people with type 2 diabetes have investigated cardiovascular outcomes, even though most patients die from cardiovascular causes despite the beneficial effects of lipid-reducing and blood pressure-lowering treatments. The evidence-based reduction in risk of microvascular disease with glucose lowering has resulted in guidelines worldwide recommending optimisation of glycosylated haemoglobin, but no trial results have shown unequivocal cardiovascular risk reduction with glucose lowering. However, results of the post-trial follow-up of the UK Prospective Diabetes Study, and of a meta-analysis of the four glucose-lowering outcome trials completed to date, suggest about a 15% cardiovascular relative risk reduction per 1% decrement in HbA1c. The 2008 US Food and Drug Administration industry guidance for licensing of antidiabetic drugs greatly increased the number of cardiovascular outcome trials in diabetes, but most trials opted for non-inferiority designs aiming primarily to show absence of cardiovascular toxicity in the shortest possible time. This unintended consequence of the new regulations has meant that the potential long-term benefits, and the possible risks of new therapies, are not being assessed effectively. Also, essential head-to-head trials of therapies for this complex progressive disease, to answer issues such as how best to achieve and maintain optimum glycaemia without promoting weight gain or hypoglycaemia, are not being undertaken. In this Series paper, we summarise randomised controlled cardiovascular outcome trials in type 2 diabetes, provide an overview of ongoing trials and their limitations, and speculate on how future trials could be made more efficient and effective.

The proarrhythmic effect of hypoglycemia: evidence for increased risk from ischemia and bradycardia

Hypoglycemia increases the risk for both overall and sudden death. At a cellular level, hypoglycemia causes alterations in the physiology of myocardial tissue that are identical to proarrhythmic medications. Reduced serum glucose blocks the repolarizing K(+) channel HERG, which leads to action potential and QT prolongation and is uniformly associated with risk for torsades de pointes ventricular tachycardia. The sympathetic response induced by hypoglycemia also increases the risk of arrhythmias from Ca(2+) overload, which occur with sympathomimetic medications and excessive beta adrenergic stimulation. Thus, hypoglycemia can be considered a proarrhythmic event. This review focuses on emerging evidence for two other important changes induced by hypoglycemia that promote arrhythmias: ischemia and bradycardia. Studies of patients with "insulin shock" therapy from the early twentieth century and other more recent data strongly suggest that hypoglycemia can cause ischemia of myocardial tissue, both in association with coronary artery obstructions and by cellular mechanisms. Ischemia induces multiple proarrhythmic responses. Since ischemia itself reduces the possibility of using energy substrates other than glucose, hypoglycemia may generate positive feedback for electrophyisologic destabilization. Recent studies also show that hypoglycemia can cause bradycardia and heart block. Bradycardia is known to cause action potential prolongation and potentiate the development of torsades de pointes, particularly with low-serum K(+) which can be induced by hypoglycemic episodes. Thus, hypoglycemia-induced bradycardia may also create a dynamic, positive feedback for the development of arrhythmias and sudden death. These studies further support the hypothesis that hypoglycemia is a proarrhythmic event.