The incidence of congestive heart failure associated with antidiabetic therapies

Preventing new-onset heart failure: Intervening at stage A

Heart failure (HF) prevention is an urgent public health need with national and global implications. Stage A HF patients do not show HF symptoms or structural heart disease but are at risk of HF development. There are no unique recommendations on detecting Stage A patients. Patients in Stage A are heterogeneous; many patients have different combinations of risk factors and, therefore, have markedly different absolute risks for HF. Comprehensive strategies to prevent HF at Stage A include intensive blood pressure lowering, adequate glycemic and lipid management, and heart-healthy behaviors (adopting Life's Essential 8). First and foremost, it is imperative to improve public awareness of HF risk factors and implement healthy lifestyle choices very early. In addition, recognize the HF risk-enhancing factors, which are nontraditional cardiovascular (CV) risk factors that identify individuals at high risk for HF (genetic susceptibility for HF, atrial fibrillation, chronic kidney disease, chronic liver disease, chronic inflammatory disease, sleep-disordered breathing, adverse pregnancy outcomes, radiation therapy, a history of cardiotoxic chemotherapy exposure, and COVID-19). Early use of biomarkers, imaging markers, and echocardiography (noninvasive measures of subclinical systolic and diastolic dysfunction) may enhance risk prediction among individuals without established CV disease and prevent chemotherapy-induced cardiomyopathy. Efforts are needed to address social determinants of HF risk for primordial HF prevention.Central illustrationPolicies developed by organizations such as the American Heart Association, American College of Cardiology, and the American Diabetes Association to reduce CV disease events must go beyond secondary prevention and encompass primordial and primary prevention.

Chronic kidney disease begets heart failure and vice versa: temporal associations between heart failure events in relation to incident chronic kidney disease in type 2 diabetes

AIM

To investigate the interplay of incident chronic kidney disease (CKD) and/or heart failure (HF) and their associations with prognosis in a large, population-based cohort with type 2 diabetes (T2DM).

METHODS

Patients aged ≥18 years with new-onset T2DM, without renal disease or HF at baseline, were identified from the territory-wide Clinical Data Analysis Reporting System between 2000 and 2015. Patients were followed up until December 31, 2020 for incident CKD and/or HF and all-cause mortality.

RESULTS

Among 102 488 patients (median age 66 years, 45.7% women, median follow-up 7.5 years), new-onset CKD occurred in 14 798 patients (14.4%), in whom 21.7% had HF. In contrast, among 9258 patients (9.0%) with new-onset HF, 34.6% had CKD. The median time from baseline to incident CKD or HF (4.4 vs. 4.1 years) did not differ. However, the median (interquartile range) time until incident HF after CKD diagnosis was 1.7 (0.5-3.6) years and was 1.2 (0.2-3.4) years for incident CKD after HF diagnosis (P < 0.001). The crude incidence of CKD was higher than that of HF: 17.6 (95% confidence interval [CI] 17.3-17.9) vs. 10.6 (95% CI 10.4-10.9)/1000 person-years, respectively, but incident HF was associated with a higher adjusted-mortality than incident CKD. The presence of either condition (vs. CKD/HF-free status) was associated with a three-fold hazard of death, whereas concomitant HF and CKD conferred a six to seven-fold adjusted hazard of mortality.

CONCLUSION

Cardiorenal complications are common and are associated with high mortality risk among patients with new-onset T2DM. Close surveillance of these dual complications is crucial to reduce the burden of disease.

Dysregulated Epicardial Adipose Tissue as a Risk Factor and Potential Therapeutic Target of Heart Failure with Preserved Ejection Fraction in Diabetes

Cardiovascular (CV) disease and heart failure (HF) are the leading cause of mortality in type 2 diabetes (T2DM), a metabolic disease which represents a fast-growing health challenge worldwide. Specifically, T2DM induces a cluster of systemic metabolic and non-metabolic signaling which may promote myocardium derangements such as inflammation, fibrosis, and myocyte stiffness, which represent the hallmarks of heart failure with preserved ejection fraction (HFpEF). On the other hand, several observational studies have reported that patients with T2DM have an abnormally enlarged and biologically transformed epicardial adipose tissue (EAT) compared with non-diabetic controls. This expanded EAT not only causes a mechanical constriction of the diastolic filling but is also a source of pro-inflammatory mediators capable of causing inflammation, microcirculatory dysfunction and fibrosis of the underlying myocardium, thus impairing the relaxability of the left ventricle and increasing its filling pressure. In addition to representing a potential CV risk factor, emerging evidence shows that EAT may guide the therapeutic decision in diabetic patients as drugs such as metformin, glucagon-like peptide‑1 (GLP-1) receptor agonists and sodium-glucose cotransporter 2 inhibitors (SGLT2-Is), have been associated with attenuation of EAT enlargement.

Effects of Metformin in Heart Failure: From Pathophysiological Rationale to Clinical Evidence

Type 2 diabetes mellitus (T2DM) is a worldwide major health burden and heart failure (HF) is the most common cardiovascular (CV) complication in affected patients. Therefore, identifying the best pharmacological approach for glycemic control, which is also useful to prevent and ameliorate the prognosis of HF, represents a crucial issue. Currently, the choice is between the new drugs sodium/glucose co-transporter 2 inhibitors that have consistently shown in large CV outcome trials (CVOTs) to reduce the risk of HF-related outcomes in T2DM, and metformin, an old medicament that might end up relegated to the background while exerting interesting protective effects on multiple organs among which include heart failure. When compared with other antihyperglycemic medications, metformin has been demonstrated to be safe and to lower morbidity and mortality for HF, even if these results are difficult to interpret as they emerged mainly from observational studies. Meta-analyses of randomized controlled clinical trials have not produced positive results on the risk or clinical course of HF and sadly, large CV outcome trials are lacking. The point of force of metformin with respect to new diabetic drugs is the amount of data from experimental investigations that, for more than twenty years, still continues to provide mechanistic explanations of the several favorable actions in heart failure such as, the improvement of the myocardial energy metabolic status by modulation of glucose and lipid metabolism, the attenuation of oxidative stress and inflammation, and the inhibition of myocardial cell apoptosis, leading to reduced cardiac remodeling and preserved left ventricular function. In the hope that specific large-scale trials will be carried out to definitively establish the metformin benefit in terms of HF failure outcomes, we reviewed the literature in this field, summarizing the available evidence from experimental and clinical studies reporting on effects in heart metabolism, function, and structure, and the prominent pathophysiological mechanisms involved.

Cellular mechanisms and recommended drug-based therapeutic options in diabetic cardiomyopathy

Diabetes mellitus (DM) is associated with a specific cardiac phenotype characterized by structural and functional alterations. This so-called diabetic cardiomyopathy (DM CM) is clinically relevant as patients with DM show high incidence of heart failure. Mechanistically, several parameters interact on the cardiomyocyte level leading to increased inflammation, apoptosis, reactive oxygen species and altered calcium signaling. This in turn provokes functional myocardial changes that might inter alia play into the worsened clinical outcome in DM patients. Therefore, efficient therapeutic options are urgently needed. This review focuses on mechanistic effects of currently recommended antidiabetic treatment and heart failure therapy for DM CM.

Heart failure subtypes: Pathophysiology and definitions

The diagnosis of heart failure is classified in two main types depending on left ventricular ejection fraction usually by ejection fraction < or > 40%. The division has important implications for the treatment of heart failure. Type 2 diabetes is an important and common co-morbidity in chronic heart failure. It makes the prognosis of heart failure worse and chronic heart failure impacts the choice of treatment for type 2 diabetes.

Heart failure documentation in outpatients with diabetes and volume overload: an observational cohort study from the Diabetes Collaborative Registry

Background

Heart failure is a common and devastating complication of type 2 diabetes (T2D). Prompt recognition of heart failure may avert hospitalization, facilitate use of guideline-directed therapies, and impact choice of T2D medications. We sought to determine the rate and factors associated with heart failure documentation in T2D patients with evidence of volume overload requiring loop diuretics.

Methods

DCR is an on-going, prospective US registry of outpatient T2D patients from > 5000 cardiology, endocrinology, and primary care clinicians (current analysis used data from 2013–2019). Among T2D patients receiving loop diuretics, we examined the rate of chart documentation of heart failure. We used a 3-level hierarchical logistic regression model (patients nested within physician within practice) to examine factors associated with heart failure diagnosis.

Results

Among 1,322,640 adults with T2D, 225,125 (17.0%) were receiving a loop diuretic, of whom 91,969 (40.9%) had documentation of heart failure. Male sex, lower body mass index, atrial fibrillation, chronic kidney disease, and coronary artery disease were associated with greater odds of heart failure diagnosis. After accounting for patient factors, patients seen by cardiologists were the most likely to have HF documented followed by PCPs and then endocrinologists.

Conclusions

Among US outpatients with T2D, 17% of patients had evidence of volume overload—defined by loop diuretic prescription—of whom fewer than half had a clinical diagnosis of heart failure. While there may be non-heart failure indications for loop diuretics, our data suggest that a substantial proportion of T2D patients may have unrecognized heart failure and therefore could be missing opportunities for targeted therapies that could alter the clinical course of heart failure.

Where Does Metformin Stand in Modern Day Management of Type 2 Diabetes?

Metformin is the most commonly used glucose-lowering therapy (GLT) worldwide and remains the first-line therapy for newly diagnosed individuals with type 2 diabetes (T2D) in management algorithms and guidelines after the UK Prospective Diabetes Study (UKPDS) showed cardiovascular mortality benefits in the overweight population using metformin. However, the improved Major Adverse Cardiovascular Events (MACE) realised in some of the recent large cardiovascular outcomes trials (CVOTs) using sodium-glucose co-transporter 2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA) have challenged metformin's position as a first-line agent in the management of T2D. Many experts now advocate revising the existing treatment algorithms to target atherosclerotic cardiovascular disease (ASCVD) and improving glycaemic control as a secondary aim. In this review article, we will revisit the major cardiovascular outcome data for metformin and include a critique of the UKPDS data. We then review additional factors that might be pertinent to metformin's status as a first-line agent and finally answer key questions when considering metformin's role in the modern-day management of T2D.

Effects of metformin on atrial and ventricular arrhythmias: evidence from cell to patient

Metformin has been shown to have various cardiovascular benefits beyond its antihyperglycemic effects, including a reduction in stroke, heart failure, myocardial infarction, cardiovascular death, and all-cause mortality. However, the roles of metformin in cardiac arrhythmias are still unclear. It has been shown that metformin was associated with decreased incidence of atrial fibrillation in diabetic patients with and without myocardial infarction. This could be due to the effects of metformin on preventing the structural and electrical remodeling of left atrium via attenuating intracellular reactive oxygen species, activating 5′ adenosine monophosphate-activated protein kinase, improving calcium homeostasis, attenuating inflammation, increasing connexin-43 gap junction expression, and restoring small conductance calcium-activated potassium channels current. For ventricular arrhythmias, in vivo reports demonstrated that activation of 5′ adenosine monophosphate-activated protein kinase and phosphorylated connexin-43 by metformin played a key role in ischemic ventricular arrhythmias reduction. However, metformin failed to show anti-ventricular arrhythmia benefits in clinical trials. In this review, in vitro and in vivo reports regarding the effects of metformin on both atrial arrhythmias and ventricular arrhythmias are comprehensively summarized and presented. Consistent and controversial findings from clinical trials are also summarized and discussed. Due to limited numbers of reports, further studies are needed to elucidate the mechanisms and effects of metformin on cardiac arrhythmias. Furthermore, randomized controlled trials are needed to clarify effects of metformin on cardiac arrhythmias in human.

Metformin in Pulmonary Hypertension in Left Heart Disease

Metformin is ubiquitously used in the management of Type II Diabetes Mellitus (DMII). Over the years, our growing knowledge of its therapeutic potential has broadened its use to the treatment of infertility in polycystic ovarian syndrome, gestational diabetes, and even obesity. Recently, it has been suggested as a novel therapy in cardiovascular disease (CVD). Given that CVD is the leading cause of death in patients with DMII, with ~ 75% dying from a cardiovascular event, the intersection of DMII and CVD provides a unique therapeutic target. In particular, pulmonary hypertension (PH) related to CVD (Group II PH) may be an optimal target for metformin therapy. The objective of this review article is to provide an overview of the pathophysiology of PH related to left heart disease (PH-LHD), outline the proposed pathophysiologic mechanism of insulin resistance in heart failure and PH-LHD, and evaluate the role metformin may have in heart failure and PH-LHD.

Glucagon-Like Peptide 1 Receptor Agonists and Heart Failure

With worsening epidemiological trends for both the incidence and prevalence of type 2 diabetes mellitus (T2DM) and heart failure (HF) worldwide, it is critical to implement optimal prevention and treatment strategies for patients with these comorbidities, either alone or concomitantly. Several guidelines and consensus statements have recommended glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter type 2 inhibitors as add-ons to lifestyle interventions with or without metformin in those at high atherosclerotic cardiovascular disease risk. However, these recommendations are either silent about HF or fail to differentiate between the prevention of HF in those at risk versus the treatment of individuals with manifest HF. Furthermore, these documents do not differentiate among those with different HF phenotypes. This distinction, even though important, may not be critical for sodium-glucose cotransporter type 2 inhibitors in view of the consistent data for benefit for both atherosclerotic cardiovascular disease– and HF-related outcomes that have emerged from the regulatory-mandated cardiovascular outcome trials for all sodium-glucose cotransporter type 2 inhibitors and the recent DAPA-HF trial (Dapagliflozin in Patients with Heart Failure and Reduced Ejection Fraction)demonstrating the benefit of dapagliflozin on HF-related outcomes in patients with HF with reduced ejection fraction with or without T2DM. However, the distinction may be crucial for glucagon-like peptide-1 receptor agonists and other antihyperglycemic agents. Indeed, in several of the new statements, glucagon-like peptide-1 receptor agonists are suggested treatment not only for patients with T2DM and atherosclerotic cardiovascular disease, but also in those with manifest HF, despite a lack of evidence for the latter recommendation. Although glucagon-like peptide-1 receptor agonists may be appropriate to use in patients at risk for HF, mechanistic insights and observations from randomized trials suggest no clear benefit on HF-related outcomes and even uncertainty regarding the safety in those with HF with reduced ejection fraction. Conversely, theoretical rationales suggest that these agents may benefit patients with HF with preserved ejection fraction. Considering that millions of patients with T2DM have HF, these concerns have public health implications that necessitate the thoughtful use of these therapies. Achieving this aim will require dedicated trials with these drugs in both patients who have HF with reduced ejection fraction and HF with preserved ejection fraction with T2DM to assess their efficacy, safety, and risk-benefit profile.

[Diabetes and Heart failure]

Diabetes is a very important comorbidity in patients with heart failure. When both diseases are present, mortality is greatly increased. Therefore, it is important to sufficiently diagnose and treat patients with diabetes and heart failure to improve outcome. This article provides an overview on epidemiology, pathogeneses, diagnostic and therapeutic options.

Therapeutic approaches to diabetic cardiomyopathy: Targeting the antioxidant pathway

The global epidemic of cardiovascular disease continues unabated and remains the leading cause of death both in the US and worldwide. We hereby summarize the available therapies for diabetes and cardiovascular disease in diabetics. Clearly, the current approaches to diabetic heart disease often target the manifestations and certain mediators but not the specific pathways leading to myocardial injury, remodeling and dysfunction. Better understanding of the molecular events determining the evolution of diabetic cardiomyopathy will provide insight into the development of specific and targeted therapies. Recent studies largely increased our understanding of the role of enhanced inflammatory response, ROS production, as well as the contribution of Cyp-P450-epoxygenase-derived epoxyeicosatrienoic acid (EET), Peroxisome Proliferator-Activated Receptor Gamma Coactivator-1α (PGC-1α), Heme Oxygenase (HO)-1 and 20-HETE in pathophysiology and therapy of cardiovascular disease. PGC-1α increases production of the HO-1 which has a major role in protecting the heart against oxidative stress, microcirculation and mitochondrial dysfunction. This review describes the potential drugs and their downstream targets, PGC-1α and HO-1, as major loci for developing therapeutic approaches beside diet and lifestyle modification for the treatment and prevention of heart disease associated with obesity and diabetes.

Predictors of heart failure development in type 2 diabetes: a practical approach

Purpose of review

Although type 2 diabetes (T2D) is one of the most important risk factors that leads to the development of de novo heart failure, there are limited data, particularly from a practical/qualitative standpoint, about predictors of heart failure in this population.

Recent findings

Sodium-glucose cotransporter-2 (SGLT-2) inhibitors have been shown to prevent the development of heart failure and the composite of heart failure and cardiovascular death in patients with T2D without known heart failure who have either established atherosclerotic vascular disease or multiple risk factors. The concept of primary prevention of heart failure has led many clinicians to inquire if there are specific risk/enrichment factors that may predict an increased risk of heart failure.

Summary

In this review, we identify some general and diabetes-specific risk factors that are associated with an increased risk of developing heart failure in people with T2D.

Should metformin still be the first-line of treatment in type 2 diabetes mellitus? A comprehensive review and suggested algorithm

For more than a century, the high occurrences of coronary and peripheral artery diseases in diabetes mellitus patients has been well recognised; despite that, the ability to improve CV event rates by optimizing glycaemic control has remained elusive. Nevertheless, the last decade has seen several cardiovascular outcome clinical trials (CVOTs) of many antihyperglycemic agents that reported promising results for cardiovascular and renal outcomes. This leads to a hot debate on the ideal drug choice for first-line treatment in T2DM. The purpose of this paper is to review the evidence supporting the use of metformin, sodium-glucose cotransporter 2 (SGLT2) inhibitors and incretin-based therapies for the management of individuals with T2DM and, discuss the rationale for selection.

New advances in perioperative cardioprotection

With the increasing age of the general population, medical conditions necessitating a surgical intervention will increase. Concomitant with advanced age, the prevalence of type 2 diabetes mellitus will also increase. These patients have a two- to three-fold higher risk of occurrence of cardiovascular events and are at higher risk of perioperative myocardial ischemia. This review will discuss recent advances in the field of perioperative cardioprotection and focus specifically on strategies that have aimed to protect the diabetic and the aged myocardium. This review will not deal with potential putative cardioprotective effects of opioids and anesthetic agents, as this is a very broad area that would necessitate a dedicated overview.

Sodium glucose cotransporter (SGLT)-2 inhibitors: Do we need them for glucose-lowering, for cardiorenal protection or both?

Sodium glucose cotransporter (SGLT)-2 inhibitors are the newest addition to our treatment armamentarium for the management of hyperglycemia in type 2 diabetes. Glucose-lowering per se reduces the risk of microvascular complications, but not the risk of cardiovascular disease, including heart failure and cardiovascular mortality. Also, even when embedded in optimal cardiovascular prevention, a large residual risk remains with respect to progression of diabetic kidney disease. SGLT-2 inhibitors lower blood glucose levels by inducing glucosuria. Through various proposed mechanisms, among which diuretic and natriuretic effects, SGLT-2 inhibitors decrease heart failure hospitalization, reduce cardiovascular mortality, and mitigate progression of diabetic kidney disease. In this perspective, we will discuss the glucose-lowering and other protective effects of SGLT-2 inhibitors on the cardiorenal axis, both in primary and secondary prevention. By comparing the glycemic and pleiotropic effects of these agents to other glucose-lowering drugs, we will address questions around whether SGLT-2 inhibitors should be considered primarily as glucose-lowering agents, cardiorenal drugs or both.

Management of patients with diabetes and heart failure with reduced ejection fraction: An international comparison

AIMS

To compare the management of patients with diabetes and heart failure with reduced ejection fraction (HFrEF) in the United States and Asia to understand variations in treatment patterns across different healthcare systems.

MATERIALS AND METHODS

Our cohort included patients with diabetes and HFrEF (ejection fraction <40%) from a US-based registry of adults with diabetes (2013-2016, electronic health records) and a multi-national Asian registry of adults with heart failure (2010-2016, prospective registry). Asian countries were categorized as high income (HI) or low income (LI), according to the United Nations classification. Rates of use of guideline-directed medical therapies (determined through review of active medication lists) were compared across regions.

RESULTS

Patients with diabetes and HFrEF in the United States (n = 28 877) were older, had higher body mass indices, and were more likely to have coronary disease than those in Asia (n = 2235). Compared with US patients, the use of guideline-directed medical therapy for HFrEF was lower in patients in LI Asian countries (angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers: patients in the United States, 77% vs. patients in HI Asian countries, 76% vs patients in LI Asian countries, 69%; β-blockers: patients in the United States, 91% vs. patients in HI Asian countries, 87% vs. patients in LI Asian countries, 69%; P < 0.001 for both). Insulin was used more commonly in the United States (44% vs. 24% vs. 25%, respectively; P < 0.001), whereas sulphonylureas were more often prescribed in Asian countries (42% vs. 52% vs. 54%; respectively, P < 0.001). Thiazolidinediones were prescribed in 6% of US patients compared with <1% of patients in Asia. The use of newer diabetes medications was <5% in all.

CONCLUSION

In both the United States and Asia, opportunities for improvement in the use of evidence-based therapies exist for patients with both diabetes and HFrEF. Effective tools to guide medication choices for these complex, high-risk patients could have substantial impact on quality and outcomes.

Metformin improves diastolic function in an HFpEF-like mouse model by increasing titin compliance

Heart failure with preserved ejection fraction (HFpEF) is a syndrome characterized by increased diastolic stiffness, for which effective therapies are lacking. Slater et al. show that metformin lowers titin-based passive stiffness in an HFpEF mouse model and may therefore be of therapeutic benefit.

Heart failure with preserved ejection fraction (HFpEF) is a complex syndrome characterized by a preserved ejection fraction but increased diastolic stiffness and abnormalities of filling. Although the prevalence of HFpEF is high and continues to rise, no effective therapies exist; however, the diabetic drug metformin has been associated with improved diastolic function in diabetic patients. Here we determine the therapeutic potential of metformin for improving diastolic function in a mouse model with HFpEF-like symptoms. We combine transverse aortic constriction (TAC) surgery with deoxycorticosterone acetate (DOCA) supplementation to obtain a mouse model with increased diastolic stiffness and exercise intolerance. Echocardiography and pressure–volume analysis reveal that providing metformin to TAC/DOCA mice improves diastolic function in the left ventricular (LV) chamber. Muscle mechanics show that metformin lowers passive stiffness of the LV wall muscle. Concomitant with this improvement in diastolic function, metformin-treated TAC/DOCA mice also demonstrate preserved exercise capacity. No metformin effects are seen in sham operated mice. Extraction experiments on skinned ventricular muscle strips show that the metformin-induced reduction of passive stiffness in TAC/DOCA mice is due to an increase in titin compliance. Using phospho-site-specific antibodies, we assay the phosphorylation of titin’s PEVK and N2B spring elements. Metformin-treated mice have unaltered PEVK phosphorylation but increased phosphorylation of PKA sites in the N2B element, a change which has previously been shown to lower titin’s stiffness. Consistent with this result, experiments with a mouse model deficient in the N2B element reveal that the beneficial effect of metformin on LV chamber and muscle stiffness requires the presence of the N2B element. We conclude that metformin offers therapeutic benefit during HFpEF by lowering titin-based passive stiffness.

Patterns of glucose-lowering medication use in patients with type 2 diabetes and heart failure. Insights from the Diabetes Collaborative Registry (DCR)

BACKGROUND

Optimal glucose-lowering strategies in patients with both heart failure (HF) and type 2 diabetes mellitus (T2D) are not well defined, particularly as novel medication classes emerge.We sought to evaluate current patterns of glucose-lowering medication use in adults with T2D with and without HF.

METHODS

The DCR is a US-based outpatient registry of adults with diabetes; currently includes 3074 providers in 203 practices. We used hierarchical, modified Poisson regression models to examine the relationship between concomitant HF with use of each glucose-lowering medication class, adjusting for other factors that could impact selection of one medication class over another: age, chronic kidney disease (CKD), coronary artery disease (CAD), number of glucose-lowering medications, and insurance.

RESULTS

Among 456,106 adults with T2D, 125,161 (27%) had a diagnosis of HF (30% HFrEF, 15%HFmrEF, 55% HFpEF). Patients with T2D and HF were more likely to be older and male, and to have CAD, atrial fibrillation, and CKD. In the multivariable models, HF was associated with a greater use of insulin (RR 1.39, 95% CI 1.36-1.42) and lower use of thiazolidinediones (RR 0.79, 95% CI 0.74-0.83), SGLT2 inhibitors (RR 0.83, 95% CI 0.79-0.89), and metformin (RR 0.84, 95% CI 0.82-0.86). Among the subgroup of patients with HF, thiazolidinediones, GLP-1 receptor agonists, and SGLT2 inhibitors were used even less often in patients with lower ejection fraction, indicating that both the diagnosis of clinical HF and ejection fraction may influence the choice of glucose-lowering medications.

CONCLUSION

In a large US-based outpatient registry, we found that a quarter of adults with T2D had a diagnosis of HF, which was predominantly HFpEF. Although certain T2D medication use in patients with HF appeared consistent with evidence (less use of thiazolidinediones), others appeared contrary to evidence (less use of metformin and SGLT2 inhibitors).

Potentiation of Insulin Signaling Contributes to Heart Failure in Type 2 Diabetes: A Hypothesis Supported by Both Mechanistic Studies and Clinical Trials

The heightened risk of heart failure in type 2 diabetes cannot be explained by the occurrence of clinically overt myocardial ischemic events or hyperglycemia. Experimentally, insulin exerts detrimental effects on the heart, vasculature, kidneys, and adipose tissue that can lead to heart failure. In both randomized clinical trials and observational studies, antihyperglycemic drugs that act through insulin signaling (i.e., sulfonylureas, thiazolidinediones, and incretins) increase the risk or worsen the clinical course of heart failure, whereas drugs that ameliorate hyperinsulinemia and do not signal through insulin (i.e., metformin and sodium-glucose cotransporter 2 inhibitors) reduce the risk of heart failure.

Cardioprotection by Metformin: Beneficial Effects Beyond Glucose Reduction

Metformin is a biguanide that is widely used as an insulin-sparing agent to treat diabetes. When compared with the general population, diabetics are twice as likely to die from fatal myocardial infarction and congestive heart failure (CHF). There has been a significant concern regarding the use of metformin in patients with CHF because of their higher tendency to develop lactic acidosis. However, large epidemiological trials have reported better cardiovascular prognosis with metformin compared to other glucose-lowering agents among diabetics. Additionally, metformin has reduced the risk of reinfarction and all-cause mortality in patients with coronary artery disease and CHF, respectively. The protection against cardiovascular diseases appears to be independent of the anti-hyperglycemic effects of metformin. These effects are mediated through an increase in 5' adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and by increased phosphorylation of endothelial nitric oxide synthase (eNOS) in cardiomyocytes with an increased production of nitric oxide (NO). Metformin preconditions the heart against ischemia-reperfusion injury and may improve myocardial remodeling after an ischemic insult. The preponderance of evidence currently suggests that metformin is safe in patients with CHF, prompting the Food and Drug Administration to remove CHF as a contraindication from the package insert of all generic metformin preparations. In this narrative, along with a limited meta-analysis of available studies, we have reviewed the pleiotropic (non-glucose-lowering) effects of metformin that potentially contribute to its cardioprotective properties. Additionally, we have reviewed issues surrounding the safety of metformin in patients with cardiac diseases.

Epicardial Adipose Tissue May Mediate Deleterious Effects of Obesity and Inflammation on the Myocardium

Epicardial adipose tissue has unique properties that distinguish it from other depots of visceral fat. Rather than having distinct boundaries, the epicardium shares an unobstructed microcirculation with the underlying myocardium, and in healthy conditions, produces cytokines that nourish the heart. However, in chronic inflammatory disorders (especially those leading to heart failure with preserved ejection fraction), the epicardium becomes a site of deranged adipogenesis, leading to the secretion of proinflammatory adipokines that can cause atrial and ventricular fibrosis. Accordingly, in patients at risk of heart failure with preserved ejection fraction, drugs that promote the accumulation or inflammation of epicardial adipocytes may lead to heart failure, whereas treatments that ameliorate the proinflammatory characteristics of epicardial fat may reduce the risk of heart failure. These observations suggest that epicardial adipose tissue is a transducer of the adverse effects of systemic inflammation and metabolic disorders on the heart, and thus, represents an important target for therapeutic interventions.

Relaxin as a Therapeutic Target for the Cardiovascular Complications of Diabetes

Cardiovascular complications are the major cause of mortality in patients with diabetes. This is closely associated with both macrovascular and microvascular complications of diabetes, which lead to organ injuries in diabetic patients. Previous studies have consistently demonstrated the beneficial effects of relaxin treatment for protection of the vasculature, with evidence of antioxidant and anti-remodeling actions. Relaxin enhances nitric oxide, prostacyclin and endothelium-derived hyperpolarization (EDH)-type-mediated relaxation in various vascular beds. These effects of relaxin on the systemic vasculature, coupled with its cardiac actions, reduce pulmonary capillary wedge pressure and pulmonary artery pressure. This results in an overall decrease in systemic and pulmonary vascular resistance in heart failure patients. The anti-fibrotic actions of relaxin are well established, a desirable property in the context of diabetes. Further, relaxin ameliorates diabetic wound healing, with accelerated angiogenesis and vasculogenesis. Relaxin-mediated stimulation of vascular endothelial growth factor (VEGF) and stromal cell-derived factor 1-α, as well as regulation of metalloproteinase expression, ameliorates cardiovascular fibrosis in diabetic mice. In the heart, relaxin is a cardioprotective molecule in several experimental animal models, exerting anti-fibrotic, anti-hypertrophy and anti-apoptotic effects in diabetic pathologies. Collectively, these studies provide a foundation to propose the therapeutic potential for relaxin as an adjunctive agent in the prevention or treatment of diabetes-induced cardiovascular complications. This review provides a comprehensive overview of the beneficial effects of relaxin, and identifies its therapeutic possibilities for alleviating diabetes-related cardiovascular injury.

Sex-dependent effects of diabetes mellitus on the revascularization rate in mid-term follow up of young patients with coronary artery disease

AIMS

We investigated the association between Type-2 diabetes mellitus (DM) and the need for revascularization at a 5-year follow-up of young coronary artery disease patients and the role of sex in this regard.

METHODS

Among 1121 young (males≤45, and females≤55years) patients (female: 49.7%) from Tehran Heart Center's Premature Coronary Atherosclerosis Cohort, 371(33.1%) had diabetes prior to angiography. Revascularization was considered as either percutaneous coronary intervention or coronary artery bypass graft surgery.

RESULTS

The mean follow-up duration was 57.67±22.43months. In the univariable analysis, diabetics were at a significantly higher risk of revascularization than nondiabetics (Sub-distributional Hazard Ratio [SHR]=1.843, P value<0.001). There was no association between DM and revascularization among men (SHR=1.232, P value=0.508). In contrast, women with DM had threefold more revascularization risk than women without DM (SHR=3.519, P value<0.001). After adjustment for confounding factors, the risk of revascularization in diabetics compared to nondiabetics increased to 2.139 fold (95% CI=1.473, 3.108) among the whole subjects, remained nonsignificant among men, and increased significantly to 3.725 fold (95% CI=2.067, 6.725) in women.

CONCLUSIONS

Our data showed that in women with premature CAD, but not in men, DM may have a significant role in emerging revascularization during a mean follow-up of 5years.

Metformin reduces all-cause mortality and diseases of ageing independent of its effect on diabetes control: A systematic review and meta-analysis

This systematic review investigated whether the insulin sensitiser metformin has a geroprotective effect in humans. Pubmed and Embase were searched along with databases of unpublished studies. Eligible research investigated the effect of metformin on all-cause mortality or diseases of ageing relative to non-diabetic populations or diabetics receiving other therapies with adjustment for disease control achieved. Overall, 260 full-texts were reviewed and 53 met the inclusion criteria. Diabetics taking metformin had significantly lower all-cause mortality than non-diabetics (hazard ratio (HR)=0.93, 95%CI 0.88-0.99), as did diabetics taking metformin compared to diabetics receiving non-metformin therapies (HR=0.72, 95%CI 0.65-0.80), insulin (HR=0.68, 95%CI 0.63-0.75) or sulphonylurea (HR=0.80, 95%CI 0.66-0.97). Metformin users also had reduced cancer compared to non-diabetics (rate ratio=0.94, 95%CI 0.92-0.97) and cardiovascular disease (CVD) compared to diabetics receiving non-metformin therapies (HR=0.76, 95%CI 0.66-0.87) or insulin (HR=0.78, 95%CI 0.73-0.83). Differences in baseline characteristics were observed which had the potential to bias findings, although statistical adjustments were made. The apparent reductions in all-cause mortality and diseases of ageing associated with metformin use suggest that metformin could be extending life and healthspans by acting as a geroprotective agent.

Liraglutide improves cardiac function in patients with type 2 diabetes and chronic heart failure

PURPOSE

To compare the effect of liraglutide, sitagliptin and insulin glargine added to standard therapy on left ventricular function in post-ischemic type-2 diabetes mellitus patients.

METHODS

We evaluated 32 type-2 diabetes mellitus Caucasians with history of post-ischemic chronic heart failure NYHA class II/III and/or left ventricular ejection fraction ≤45 %. Participants underwent laboratory determinations, electrocardiogram, echocardiogram, Minnesota Living with Heart Failure questionnaire and 6 min walking test at baseline and following 52 weeks treatment. Patients were treated with standard therapy for chronic heart failure and were randomized to receive liraglutide, sitagliptin and glargine in addition to metformin and/or sulfonylurea.

RESULTS

Liraglutide treatment induced an improvement in left ventricular ejection fraction from 41.5 ± 2.2 to 46.3 ± 3 %; P = 0.001). On the contrary, treatment with sitagliptin and glargine induced no changes in left ventricular ejection fraction (41.8 ± 2.6 vs. 42.5 ± 2.5 % and 42 ± 1.5 vs. 42 ± 1.6 %, respectively; P = NS). Indexed end-systolic LV volume was reduced only in liraglutide-treated patients (51 ± 9 vs. 43 ± 8 ml/m²; P < 0.05). Liraglutide treatment induced also a significant increase in the anterograde stroke volume (39 ± 9 vs. 49 ± 11 ml; P < 0.05), whereas no differences were observed in the other two groups. Cardiac output and cardiac index showed a significant increase only in liraglutide-treated patients (4.4 ± 0.5 vs. 5.0 ± 0.6 L/min; P < 0.05 and 1.23 ± 0.26 vs. 1.62 ± 0.29 L/m²; P = 0.005, respectively). Liraglutide treatment was also associated with an improvement of functional capacity and an improvement of quality of life.

CONCLUSIONS

These data provide evidence that treatment with liraglutide is associated with improvement of cardiac function and functional capacity in failing post-ischemic type-2 diabetes mellitus patients.

Dose Modification of Antidiabetic Agents in Patients with Type 2 Diabetes Mellitus and Heart Failure

Heart failure is the most common comorbidity of diabetes. The incidence of heart failure in patients with diabetes is about 9%-22%, which is four times higher Than that in patients without diabetes. Heart failure and diabetes are collectively associated with increased morbidity and mortality compared to either condition alone. Several epidemiological studies have demonstrated an increased risk of heart failure in patients with diabetes; moreover, poor glycemic control accounts for the increased risk of heart failure. At present, several oral (metformin, sulfonylureas, thiazolidinediones, dipeptidyl peptidase-4 inhibitors, etc.) as well as injectable (insulins, glucagon-like peptide 1 receptor agonists) antidiabetic agents are available. However, optimal treatment strategy to achieve adequate glycemic control in patients with type 2 diabetes mellitus (T2DM) and heart failure has not been well studied. In the view of rising prevalence of heart failure in patients with diabetes mellitus, clinicians need to understand the potential implications of antidiabetic agents in patients with heart failure. A group of experts from across India were involved in a consensus meeting in Pondicherry during the National Insulin Summit in November 2015. They evaluated agents currently available for the treatment of diabetes looking at existing scientific evidence relevant to each class of therapy. In addition, the existing guidelines and prescribing literature available with all these agents were also reviewed. Findings from the expert evaluations were then factored into the national context incorporating personal experience and common clinical practices in India. The purpose of this consensus document is to assist the clinicians while treating patients with T2DM and heart failure.

METFORMIN: NONGLYCEMIC EFFECTS AND POTENTIAL NOVEL INDICATIONS

OBJECTIVE

Metformin is the most commonly prescribed drug for the treatment of type 2 diabetes because of its apparent robust effects in reducing cardiovascular risk. This review examines the current literature regarding the nonglycemic effects and potential novel indications for metformin.

METHODS

Review of the literature, with a focus on metformin use in Stage 3 chronic kidney disease (CKD-3) and heart failure (HF).

RESULTS

The United Kingdom Prospective Diabetes Study suggests that metformin reduces the risk of myocardial infarction, and more recent retrospective studies have shown an association between metformin use and a reduction in stroke, atrial fibrillation and all-cause mortality. The mechanism(s) explaining these putative benefits are not clear but may involve decreased energy intake (with attendant weight loss), improvement in lipids, and lowering of blood pressure; a literature review suggests that metformin lowers blood pressure when it is elevated, but not when it is normal. Metformin appears to be safe when given to patients with CKD-3. In addition, there is evidence that individuals with CKD-3, who are at increased cardiovascular risk, stand to benefit from metformin therapy. Lactic acidosis is an extremely remote and probably avoidable risk; measurement of plasma metformin levels and more frequent monitoring of renal function may be useful in selected patients with CKD-3 who are treated with metformin. Finally, there is evidence that metformin is safe in patients with HF; metformin therapy is associated with a reduction in newly incident HF and in HF mortality.

CONCLUSION

Metformin has a dominant position in the treatment of type 2 diabetes that is deserved due to its favorable and robust effects on cardiovascular risk.

ABBREVIATIONS

AMP = adenosine monophosphate BP = blood pressure CKD = chronic kidney disease CKD-3 = Stage 3 CKD eGFR = estimated glomerular filtration rate HDL = high-density lipoprotein HF = heart failure MAP = mean arterial pressure mVO2 = myocardial oxygen consumption T2DM = type 2 diabetes mellitus UKPDS = United Kingdom Prospective Diabetes Study.

Comparative Safety of Sulfonylurea and Metformin Monotherapy on the Risk of Heart Failure: A Cohort Study

BACKGROUND

Medications that impact insulin sensitivity or cause weight gain may increase heart failure risk. Our aim was to compare heart failure and cardiovascular death outcomes among patients initiating sulfonylureas for diabetes mellitus treatment versus metformin.

METHODS AND RESULTS

National Veterans Health Administration databases were linked to Medicare, Medicaid, and National Death Index data. Veterans aged ≥18 years who initiated metformin or sulfonylureas between 2001 and 2011 and whose creatinine was <1.4 (females) or 1.5 mg/dL (males) were included. Each metformin patient was propensity score-matched to a sulfonylurea initiator. The outcome was hospitalization for acute decompensated heart failure as the primary reason for admission or a cardiovascular death. There were 126 867 and 79 192 new users of metformin and sulfonylurea, respectively. Propensity score matching yielded 65 986 per group. Median age was 66 years, and 97% of patients were male; hemoglobin A1c 6.9% (6.3, 7.7); body mass index 30.7 kg/m2 (27.4, 34.6); and 6% had heart failure history. There were 1236 events (1184 heart failure hospitalizations and 52 cardiovascular deaths) among sulfonylurea initiators and 1078 events (1043 heart failure hospitalizations and 35 cardiovascular deaths) among metformin initiators. There were 12.4 versus 8.9 events per 1000 person-years of use (adjusted hazard ratio 1.32, 95%CI 1.21, 1.43). The rate difference was 4 heart failure hospitalizations or cardiovascular deaths per 1000 users of sulfonylureas versus metformin annually.

CONCLUSIONS

Predominantly male patients initiating treatment for diabetes mellitus with sulfonylurea had a higher risk of heart failure and cardiovascular death compared to similar patients initiating metformin.

Comorbidities in Heart Failure

Comorbidities frequently accompany chronic heart failure (HF), contributing to increased morbidity and mortality, and an impaired quality of life. We describe the prevalence of several high-impact comorbidities in chronic HF patients and their impact on morbidity and mortality. Furthermore, we try to explain the underlying pathophysiological processes and the complex interaction between chronic HF and specific comorbidities. Although common risk factors are likely to contribute, it is reasonable to believe that factors associated with HF might cause other comorbidities and vice versa. Potential factors are inflammation, neurohormonal activation, and hemodynamic changes.

Review: 50 years later: is metformin a vascular drug with antidiabetic properties?

Since the clinical demonstration of a protective effect of metformin against chronic diabetic angiopathy in the United Kingdom Prospective Diabetes Study, many data have accumulated which confirm such effects in acute or chronic situations as diverse as ischaemia, non-diabetic insulin resistant states and diabetes. Recent years have provided several mechanisms of action and further documented some unique properties of this compound such as improvements in microcirculatory flow, glycation and oxidative stress. In particular, the latter effect could be shown in mitochondria, i.e. the most important sources of reactive oxygen species in diabetes. Specific, non-toxic actions of metformin at the level of the mitochondrial respiratory chain also prevent apoptosis, another mechanism to explain the long-term protection afforded by metformin. Noteworthy, most of these effects of metformin are unrelated to drug dosage and largely independent of its antihyperglycaemic effect (intrinsic properties). These new data open potential avenues for larger therapeutic utilisations of this drug, 50 years after its launch for the treatment of type 2 diabetes.

Associations of dipeptidyl peptidase-4 inhibitors with mortality in hospitalized heart failure patients with diabetes mellitus

BACKGROUND

Heart failure (HF) and diabetes mellitus (DM) often co-exist. Treatment of DM in HF patients is challenging because some therapies for DM are contraindicated in HF. Although previous experimental studies have reported that dipeptidyl peptidase-4 (DPP-4) inhibitors improve cardiovascular function, whether DPP-4 inhibition improves mortality of HF patients with DM remains unclear. Therefore, we examined the impact of DPP-4 inhibition on mortality in hospitalized HF patients using propensity score analyses.

METHODS AND RESULTS

We performed observational study analysed by propensity score method with 962 hospitalized HF patients. Of these patients, 293 (30.5%) had DM, and 122 of these DM patients were treated with DPP-4 inhibitors. Propensity scores for treatment with DPP-4 inhibitors were estimated for each patient by logistic regression with clinically relevant baseline variables. The propensity-matched 1:1 cohorts were assessed based on propensity scores (DPP-4 inhibitors, n = 83, and non-DPP-4 inhibitors, n = 83). Kaplan-Meier analysis in the propensity score-matched cohort demonstrated that cardiac and all-cause mortality was significantly lower in the DPP-4 inhibitor group than in the non-DPP-4 inhibitor group (cardiac mortality: 4.8% vs. 18.1%, P = 0.015; all-cause mortality: 14.5% vs. 41.0%, P = 0.003, by a log-rank test). In the multivariable Cox proportional hazard analyses, after adjusting for other potential confounding factors, the use of DPP-4 inhibitors was an independent predictor of all-cause mortality (pre-matched cohort: hazard ratio 0.467, P = 0.010; post-matched cohort: hazard ratio 0.370, P = 0.003) in HF patients with DM.

CONCLUSIONS

Our data suggest that DPP-4 inhibitors may improve cardiac and all-cause mortality in hospitalized HF patients with DM.

The mitochondria in diabetic heart failure: from pathogenesis to therapeutic promise

SIGNIFICANCE

Diabetes is an important risk factor for the development of heart failure (HF). Given the increasing prevalence of diabetes in the population, strategies are needed to reduce the burden of HF in these patients.

RECENT ADVANCES

Diabetes is associated with several pathologic findings in the heart including dysregulated metabolism, lipid accumulation, oxidative stress, and inflammation. Emerging evidence suggests that mitochondrial dysfunction may be a central mediator of these pathologic responses. The development of therapeutic approaches targeting mitochondrial biology holds promise for the management of HF in diabetic patients.

CRITICAL ISSUES

Despite significant data implicating mitochondrial pathology in diabetic cardiomyopathy, the optimal pharmacologic approach to improve mitochondrial function remains undefined.

FUTURE DIRECTIONS

Detailed mechanistic studies coupled with more robust clinical phenotyping will be necessary to develop novel approaches to improve cardiac function in diabetes. Moreover, understanding the interplay between diabetes and other cardiac stressors (hypertension, ischemia, and valvular disease) will be of the utmost importance for clinical translation of scientific discoveries made in this field.

Heart failure in diabetes: effects of anti-hyperglycaemic drug therapy

Individuals with diabetes are not only at high risk of developing heart failure but are also at increased risk of dying from it. Fortunately, antiheart failure therapies such as angiotensin-converting-enzyme inhibitors, β blockers and mineralocorticoid-receptor antagonists work similarly well in individuals with diabetes as in individuals without the disease. Response to intensive glycaemic control and the various classes of antihyperglycaemic agent therapy is substantially less well understood. Insulin, for example, induces sodium retention and thiazolidinediones increase the risk of heart failure. The need for new glucose-lowering drugs to show cardiovascular safety has led to the unexpected finding of an increase in the risk of admission to hospital for heart failure in patients treated with the dipeptidylpeptidase-4 (DPP4) inhibitor, saxagliptin, compared with placebo. Here we review the relation between glycaemic control and heart failure risk, focusing on the state of knowledge for the various types of antihyperglycaemic drugs that are used at present.

Prediction of heart failure in patients with type 2 diabetes mellitus- a systematic review and meta-analysis

BACKGROUND

Heart failure (HF) is a major cause of mortality and disability in type 2 diabetes mellitus (T2DM). This study sought to improve the assessment of HF risk in patients with T2DM-a step that would be critical for effective HF screening.

METHODS

A systematic literature search was performed on electronic databases including MEDLINE and EMBASE, using MeSH terms 'heart failure', 'risk factor', 'T2DM', 'cardiac dysfunction', 'stage B heart failure', 'incident heart failure', 'risk assessment', 'risk impact', 'risk score', 'predictor', 'prediction' and related free text terms. The search was limited to human studies in full-length publications in English language journal from 1946 to 2014. Univariable and multivariable relative risk (RR) and hazard ratio (HR) were obtained from each study.

RESULTS

Twenty-one studies (n=1111,569, including 507,637 subjects with T2DM) were included in this analysis with a follow-up ranging from 1 to 12 years. Associations between incident HF and risk variables described in ≥3 studies were reported. This association was greatest for insulin use (HR 2.48; 1.24-4.99), HbA1c 7.0-8.0% (2.41; 1.62-3.59), 5 years increase in age (1.47; 1.25-1.73), fasting glucose (1.28; 1.10-1.51 per standard deviation) and HbA1c (1.18; 1.14-1.23 each 1% increase). After adjustment for confounders, there were strong associations with coronary artery disease (1.77; 1.31, 2.39), HbA1c ≥ 10% (1.66; 1.45-1.89), insulin use (1.43; 1.14-1.79), HbA1c 9.0-10.0% (1.31; 1.14-1.50), fasting glucose (1.27; 1.10-1.47 per standard deviation) and 5 years increase in age (1.26; 1.13-1.40).

CONCLUSION

Among patients with T2DM, five common clinical variables are associated with significantly increased risk of incident HF.

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.

Observational studies of the association between glucose-lowering medications and cardiovascular outcomes: addressing methodological limitations

BACKGROUND

Recent years have witnessed a growing body of observational literature on the association between glucose-lowering treatments and cardiovascular disease. However, many of the studies are based on designs or analyses that inadequately address the methodological challenges involved.

METHODS

We reviewed recent observational literature on the association between glucose-lowering medications and cardiovascular outcomes and assessed the design and analysis methods used, with a focus on their ability to address specific methodological challenges. We describe and illustrate these methodological issues and their impact on observed associations, providing examples from the reviewed literature. We suggest approaches that may be employed to manage these methodological challenges.

RESULTS

From the evaluation of 81 publications of observational investigations assessing the association between glucose-lowering treatments and cardiovascular outcomes, we identified the following methodological challenges: 1) handling of temporality in administrative databases; 2) handling of risks that vary with time and treatment duration; 3) definitions of the exposure risk window; 4) handling of exposures that change over time; and 5) handling of confounding by indication. Most of these methodological challenges may be suitably addressed through application of appropriate methods.

CONCLUSIONS/INTERPRETATION

Observational research plays an increasingly important role in the evaluation of the clinical effects of diabetes treatment. Implementation of appropriate research methods holds the promise of reducing the potential for spurious findings and the risk that the spurious findings will mislead the medical community about risks and benefits of diabetes medications.

Heart failure, saxagliptin, and diabetes mellitus: observations from the SAVOR-TIMI 53 randomized trial

BACKGROUND

Diabetes mellitus and heart failure frequently coexist. However, few diabetes mellitus trials have prospectively evaluated and adjudicated heart failure as an end point.

METHODS AND RESULTS

A total of 16 492 patients with type 2 diabetes mellitus and a history of, or at risk of, cardiovascular events were randomized to saxagliptin or placebo (mean follow-up, 2.1 years). The primary end point was the composite of cardiovascular death, myocardial infarction, or ischemic stroke. Hospitalization for heart failure was a predefined component of the secondary end point. Baseline N-terminal pro B-type natriuretic peptide was measured in 12 301 patients. More patients treated with saxagliptin (289, 3.5%) were hospitalized for heart failure compared with placebo (228, 2.8%; hazard ratio, 1.27; 95% confidence intercal, 1.07-1.51; P=0.007). Corresponding rates at 12 months were 1.9% versus 1.3% (hazard ratio, 1.46; 95% confidence interval, 1.15-1.88; P=0.002), with no significant difference thereafter (time-varying interaction, P=0.017). Subjects at greatest risk of hospitalization for heart failure had previous heart failure, an estimated glomerular filtration rate ≤60 mL/min, or elevated baseline levels of N-terminal pro B-type natriuretic peptide. There was no evidence of heterogeneity between N-terminal pro B-type natriuretic peptide and saxagliptin (P for interaction=0.46), although the absolute risk excess for heart failure with saxagliptin was greatest in the highest N-terminal pro B-type natriuretic peptide quartile (2.1%). Even in patients at high risk of hospitalization for heart failure, the risk of the primary and secondary end points were similar between treatment groups.

CONCLUSIONS

In the context of balanced primary and secondary end points, saxagliptin treatment was associated with an increased risk or hospitalization for heart failure. This increase in risk was highest among patients with elevated levels of natriuretic peptides, previous heart failure, or chronic kidney disease.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01107886.

Use of metformin in diseases of aging

Metformin is the most commonly prescribed medication for type 2 diabetes (T2DM) in the world. It has primacy in the treatment of this disease because of its safety record and also because of evidence for reduction in the risk of cardiovascular events. Evidence has accumulated indicating that metformin is safe in people with stage 3 chronic kidney disease (CKD-3). It is estimated that roughly one-quarter of people with CKD-3 and T2DM in the United States (well over 1 million) are ineligible for metformin treatment because of elevated serum creatinine levels. This could be overcome if a scheme, perhaps based on pharmacokinetic studies, could be developed to prescribe reduced doses of metformin in these individuals. There is also substantial evidence from epidemiologic studies to indicate that metformin may not only be safe, but may actually benefit people with heart failure (HF). Prospective, randomized trials of the use of metformin in HF are needed to investigate this possibility.