GLP-1 agonist therapy for advanced heart failure with reduced ejection fraction: design and rationale for the functional impact of GLP-1 for heart failure treatment study

Hierarchical End Points in Prior Heart Failure Trials and the HEART-FID Trial

BACKGROUND

Clinical trials in heart failure (HF) traditionally use time-to-event analyses focusing on death and hospitalization for HF. These time-to-first event analyses may have more limited abilities to assess the probability of benefiting from a therapy, especially if that benefit manifests as improved functional status rather than reduced risk of death or HF hospitalization. Hierarchical end points including clinical outcomes and patient status measures allow for ranked evaluation of outcomes in 1 metric assessing whether patients randomized to intervention or control are more likely to derive an overall benefit while also allowing more patients to contribute to the primary outcome.

METHODS

We review the rationale for using hierarchical end points in HF trials, provide examples of HF trials that used this type of end point, and discuss its use in the HEART-FID trial (Randomized Placebo-Controlled Trial of Ferric Carboxymaltose as Treatment for Heart Failure With Iron Deficiency), the largest HF trial to date implementing a hierarchical end point analysis for the primary outcome.

RESULTS

Using a hierarchical end point as the primary outcome allows for the inclusion of different types of outcomes in 1 ranked end point, making it possible to more holistically assess the potential utility of a new therapy on patient well-being and outcomes.

CONCLUSIONS

Hierarchical end points assess the potential utility of a new therapy on patient well-being and outcome more holistically than time-to-first event analysis. Trials that would not have been feasible due to decreasing rates of death and hospitalization in the HF population can use hierarchical end points to successfully power studies to identify promising HF therapies. The HEART-FID trial used hierarchical end points to better determine the role of intravenous ferric carboxymaltose in patients with HF.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03037931.

Role of Liraglutide Use in Patients With Heart Failure

Heart failure is a clinical condition in which the heart is unable to maintain adequate cardiac output. Liraglutide is a glucagon-like peptide 1 (GLP-1) analogue that is used for the treatment of type 2 diabetes mellitus, but recent evidence suggests that it might have a beneficial role in treating heart failure. We conducted a review of existing literature and found five relevant studies. Data from these studies were extracted and then extrapolated into results following analysis. Four of the five studies found an increase in heart rate in heart failure patients. All five studies reported an increased rate of hospitalization. The five studies also showed an increased risk of adverse effects such as arrhythmia, ventricular tachycardia, atrial fibrillation, and worsening of heart failure. Given the scarcity of evidence in the available literature on liraglutide in heart failure, more research on this population is required.

[Advantages of glucagon-like peptide-1 receptor agonists in the treatment of patients with type 2 diabetes mellitus: A review]

Glucagon-like peptide-1 receptor agonists (arGLP1) are an effective treatment for patients with type 2 diabetes mellitus (T2DM), mainly due to increasing insulin secretion and suppressing glucagon release by stimulating the respective receptors. Taking into account their positive effect on major cardiovascular events, drugs in this group with proven cardioprotective effects are recommended for patients with T2DM and clinical cardiovascular diseases or multiple cardiovascular risk factors. In this paper, we present an overview of current clinical studies on the clinical efficacy and safety of arGLP1 and discuss current prospects for arGLP1 as a therapy for patients with T2DM.

The Early Effects of Bariatric Surgery on Cardiac Structure and Function: a Systematic Review and Meta-Analysis

BACKGROUND

This meta-analysis was performed to investigate how cardiac structures and functions change in the very early stage after bariatric surgery.

MATERIALS AND METHODS

We thoroughly searched the PubMed, Embase, Cochrane Library, and Web of Science databases for articles including patients who underwent bariatric surgery and examined the changes of their cardiac indices. Results were pooled by using Review Manager 5.1 and Stata 12.0. Weighted mean differences (WMDs) with 95% confidence intervals (CIs) were obtained. The I-squared (I²) test was used to determine the heterogeneity between studies. To identify publication bias, funnel plots and Egger's test were utilized. The leave-one-out method was used to conduct sensitivity analysis.

RESULTS

In this meta-analysis, 24 research including 942 patients were considered. According to our findings, most cardiac indices changed 3-6 months following bariatric surgery. An improvement in cardiac geometry was reflected by a reduction in left ventricular mass (LVM) (WMD =  - 22.06, 95% CI = (- 27.97, - 16.16)). The left ventricular diastolic function improved, as reflected by the decrease in the E/e' ratio (WMD =  - 0.90, 95% CI = (- 1.83, - 0.16)). Left ventricular ejection fraction (LVEF) did not show an obvious change (WMD = 0.94, 95% CI = (- 0.19, 2.07)), while a more sensitive indicator of left ventricular systolic function, left ventricular longitudinal strain (LV LS), increased (WMD =  - 2.43, 95% CI = (- 3.96, - 0.89)).

CONCLUSION

This meta-analysis includes the newest and most comprehensive cardiac indices to prove that cardiac structures and functions are improved early after bariatric surgery, which has not been reported by any other studies.

Risk of adverse events with liraglutide in heart failure with reduced ejection fraction: A post hoc analysis of the FIGHT trial

AIM

To perform a post hoc analysis of the FIGHT trial, evaluating the effect of liraglutide (vs. placebo) on the totality of events in patients with heart failure with reduced ejection fraction (HFrEF).

MATERIALS AND METHODS

FIGHT was a double-blind randomized controlled trial (RCT) that studied liraglutide versus placebo in 300 recently hospitalized patients with HFrEF followed for 180 days. The main outcome of the present analysis was total events of hospitalizations for heart failure (HF) or all-cause death. Secondary outcomes included total arrhythmic events and prespecified total events of interest (arrhythmias, sudden cardiac death, acute coronary syndrome, worsening HF, cerebrovascular event, venous thromboembolism, lightheadedness, presyncope/syncope or worsening renal function). Treatment effect was evaluated with negative binomial regression.

RESULTS

Compared to placebo, there was a trend towards increased risk with liraglutide of total HF hospitalizations or all-cause deaths (96 vs. 143 events, incidence rate ratio [IRR] 1.41, 95% confidence interval [CI] 0.98-2.04; P = 0.064) and total arrhythmias (21 vs. 39, IRR 1.76, 95% CI 0.92-3.37; P = 0.088). Total prespecified events of interest were increased with liraglutide compared to placebo (196 vs. 295, IRR 1.43, 95% CI 1.06-1.92; P = 0.018). The risk of HF hospitalizations or all-cause deaths with liraglutide was higher among patients in New York Heart Association (NYHA) Class III to IV (IRR 1.86, 95% CI 1.21-2.85) than in those in NYHA Class I to II (IRR 0.62, 95% CI 0.31-1.23; interaction P = 0.008), and among patients with diabetes (interaction P = 0.051). The risk of arrhythmic events was higher among those without an implanted cardiac device (interaction P = 0.047).

CONCLUSIONS

In patients with HFrEF, liraglutide might increase the risk of cardiovascular adverse effects, an effect possibly driven by excess risk of arrhythmias and worsening HF events. As this was a post hoc analysis, these results should be interpreted as exploratory and hypothesis-generating. Further RCTs must be conducted before drawing definitive conclusions.

Renin–Angiotensin System in Liver Metabolism: Gender Differences and Role of Incretins

The impaired hepatic lipids and carbohydrates metabolism result in various metabolic disorders, including obesity, diabetes, insulin resistance, hyperlipidemia and metabolic syndrome. The renin–angiotensin system (RAS) has been identified in the liver and it is now recognized as an important modulator of body metabolic processes. This review is intended to provide an update of the impact of the renin–angiotensin system on lipid and carbohydrate metabolism, regarding gender difference and prenatal undernutrition, specifically focused on the role of the liver. The discovery of angiotensin-converting enzyme 2 (ACE2) has renewed interest in the potential therapeutic role of RAS modulation. RAS is over activated in non-alcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma. Glucagon-like peptide-1 (GLP-1) has been shown to modulate RAS. The GLP-I analogue liraglutide antagonizes hepatocellular steatosis and exhibits liver protection. Liraglutide has a negative effect on the ACE/AngII/AT1R axis and a positive impact on the ACE2/Ang(1-7)/Mas axis. Activation of the ACE2/Ang(1-7)/Mas counter-regulatory axis is able to prevent liver injuries. Angiotensin(1-7) and ACE2 shows more favorable effects on lipid homeostasis in males but there is a need to do more investigation in female models. Prenatal undernutrition exerts long-term effects in the liver of offspring and is associated with a number of metabolic and endocrine alterations. These findings provide a novel therapeutic regimen to prevent and treat many chronic diseases by accelerating the effect of the ACE2/Ang1-7/Mas axis and inhibiting the ACE/AngII/AT1R axis.

Primary Prevention of Cardiovascular and Heart Failure Events With SGLT2 Inhibitors, GLP-1 Receptor Agonists, and Their Combination in Type 2 Diabetes

OBJECTIVE

To assess associations between current use of sodium-glucose cotransporter 2 inhibitors (SGLT2is), glucagon-like peptide 1 receptor agonists (GLP-1RAs), and their combination and risk for major adverse cardiac and cerebrovascular events (MACCE) and heart failure (HF) in people with type 2 diabetes.

RESEARCH DESIGN AND METHODS

In three nested case-control studies involving patients with type 2 diabetes in England and Wales (primary care data from the Clinical Practice Research Datalink and Secure Anonymised Information Linkage Databank with linkage to hospital and mortality records), we matched each patient experiencing an event with up to 20 control subjects. Adjusted odds ratios (ORs) for MACCE and HF among patients receiving SGLT2i or GLP-1RA regimens versus other combinations were estimated using conditional logistic regression and pooled using random-effects meta-analysis.

RESULTS

Among 336,334 people with type 2 diabetes and without cardiovascular disease, 18,531 (5.5%) experienced a MACCE. In a cohort of 411,206 with type 2 diabetes and without HF, 17,451 (4.2%) experienced an HF event. Compared with other combination regimens, the adjusted pooled OR and 95% CI for MACCE associated with SGLT2i regimens was 0.82 (0.73, 0.92), with GLP-1RA regimens 0.93 (0.81, 1.06), and with the SGLT2i/GLP-1RA combination 0.70 (0.50, 0.98). Corresponding data for HF were SGLT2i 0.49 (0.42, 0.58), GLP-1RA 0.82 (0.71, 0.95), and SGLT2i/GLP-1RA combination 0.43 (0.28, 0.64).

CONCLUSIONS

SGLT2i and SGLT2i/GLP-1RA combination regimens may be beneficial in primary prevention of MACCE and HF and GLP-1RA for HF. These data call for primary prevention trials using these agents and their combination.

Management of patients with chronic heart failure and type 2 diabetes mellitus: the SCODIAC-II study

SCODIAC was a pilot study which revealed an increasing use of SGLT2i in 123 outpatients affected with Heart Failure (HF) and Type 2 Diabetes Mellitus. SCODIAC-II study, the second phase of the program, has been carried out to determine diagnostic and therapeutic pathways in a larger group of patients and to verify whether the use of innovative antidiabetic therapies could modify echocardiographic parameters and cardiovascular therapies. 406 HF-diabetic patients, referred to Cardiologists and Diabetologists of pertaining healthcare districts in Campania, were enrolled in this retrospective study and divided in Group A, composed of 136 patients with preserved Ejection Fraction (HF-pEF)(> 45%) and Group B, formed of 270 patients with reduced EF (HF-rEF)(≤ 45%). All patients had performed periodic clinical and echocardiographic evaluations. The antidiabetic therapies resulted modified after 1 year with a greater use of GLP1-AR, gliptins and SGLT2i. Cardiovascular therapies resulted also modified with a greater use of sacubitril/valsartan and a reduction of ACEi and ARBs in HF-rEF patients. Echocardiography E velocity, A velocity and E/e' ratio resulted markedly reduced in 25 HF-pEF and in 60 HF-rEF patients treated with SGLT2i, in respect to both the whole sample of subjects at beginning and the other diabetic patients. LAVi resulted reduced only in HF-pEF patients and EF increased only in HF-rEF patients. The approach to the patients with HF and diabetes must necessarily take place in the healthcare districts, be multidisciplinary and integrated. SGLT2i could improve left ventricular function in HF-rEF patients and modify cardiovascular therapies, almost in this setting of patients.Trial registration The protocol was approved by the University of Naples Federico II Ethics Committee and registered at ClinicalTrial.gov (CT04375943). The principles outlined in the Declaration of Helsinki were followed.

Cardiorenal Protection in Diabetic Kidney Disease

Over the last 5 years there have been many new developments in the management of diabetic kidney disease. Glucagon-like peptide-1 receptor agonists (GLP-1 RA) and sodium-glucose cotransporter-2 (SGLT2) inhibitors were initially used for glycemic control, but more recent studies have now shown that their benefits extend to cardiovascular and kidney outcomes. The recent addition of data on the novel mineralocorticoid receptor antagonist (MRA) gives us another approach to further decrease the residual risk of diabetic kidney disease progression. In this review we describe the mechanism of action, key studies, and possible adverse effects related to these three classes of medications. The management of type 2 diabetes now includes an increasing number of medications for the management of comorbidities in a patient population at significant risk of cardiovascular disease and progression of chronic kidney disease. It is from this perspective that we seek to outline the rationale for the sequential and/or combined use of SGLT2 inhibitors, GLP-1 RA and MRAs in patients with type 2 diabetes for heart and kidney protection.

Systematic Review of Glucagon-Like Peptide One Receptor Agonist Liraglutide of Subjects with Heart Failure with Reduced Left Ventricular Ejection Fraction

BACKGROUND

The major cardiovascular outcome trials on glucagon-like peptide one-receptor agonists have examined its effect on hospitalization of subjects with heart failure; however, very limited trials have been conducted on subjects with reduced left ventricular ejection fraction (r- LVEF) as a primary outcome.

OBJECTIVE

We have conducted a systematic review of two major (FIGHT and LIVE) placebo-controlled trials of liraglutide and its clinical effect on the ejection fraction of subjects with heart failure.

METHODS

Medline data was retrieved for trials involving liraglutide from 2012 to 2020. The inclusion criteria for trials were: subjects with or without type 2 diabetes mellitus (T2DM), subjects with heart failure with rLVEF, major trials (phase II or III) on liraglutide, trials included liraglutide with defined efficacy primary outcome of patients with heart failure with rLVEF. The search was limited to the English language, whereby two trials [FIGHT and LIVE] had been included and two trials were excluded due to different primary outcomes. Participants (541) had been randomized for either liraglutide or placebo for 24 weeks.

RESULTS

In the FIGHT trial the primary intention-to-treat, sensitivity, and diabetes subgroup analyses have shown no significant between-group difference in the global rank scores (mean rank of 146 in the liraglutide group versus 156 in the placebo group; Wilcoxon rank-sum P=.31), number of deaths, re-hospitalizations for heart failure, or the composite of death or change in NT-pro BNP level (P= .94). In the LIVE trial, the change in the left ventricular ejection fraction (LVEF) from baseline to week 24 was not significantly different between treatment groups. The overall discontinuation rate of liraglutide was high in the FIGHT trial (29%, 86) as compared to that in the LIVE trial (11.6%, 28).

CONCLUSION

FIGHT and LIVE trials have demonstrated that liraglutide use in subjects with heart failure and rLVEF was implicated with an increased adverse risk of heart failure-related outcomes.

Cellular Protein Quality Control in Diabetic Cardiomyopathy: From Bench to Bedside

Heart failure is a serious comorbidity and the most common cause of mortality in diabetes patients. Diabetic cardiomyopathy (DCM) features impaired cellular structure and function, culminating in heart failure; however, there is a dearth of specific clinical therapy for treating DCM. Protein homeostasis is pivotal for the maintenance of cellular viability under physiological and pathological conditions, particularly in the irreplaceable cardiomyocytes; therefore, it is tightly regulated by a protein quality control (PQC) system. Three evolutionarily conserved molecular processes, the unfolded protein response (UPR), the ubiquitin-proteasome system (UPS), and autophagy, enhance protein turnover and preserve protein homeostasis by suppressing protein translation, degrading misfolded or unfolded proteins in cytosol or organelles, disposing of damaged and toxic proteins, recycling essential amino acids, and eliminating insoluble protein aggregates. In response to increased cellular protein demand under pathological insults, including the diabetic condition, a coordinated PQC system retains cardiac protein homeostasis and heart performance, on the contrary, inappropriate PQC function exaggerates cardiac proteotoxicity with subsequent heart dysfunction. Further investigation of the PQC mechanisms in diabetes propels a more comprehensive understanding of the molecular pathogenesis of DCM and opens new prospective treatment strategies for heart disease and heart failure in diabetes patients. In this review, the function and regulation of cardiac PQC machinery in diabetes mellitus, and the therapeutic potential for the diabetic heart are discussed.

Cardiovascular outcomes trials with incretin-based medications: a critical review of data available on GLP-1 receptor agonists and DPP-4 inhibitors

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitors are so called "incretin-based therapies" (IBTs) that represent innovative therapeutic approaches and are commonly used in clinical practice for the treatment of type 2 diabetes mellitus (T2DM). The cardiovascular outcome trials (CVOTs) have provided useful information that has helped to shape changes in clinical practice guidelines for the management of T2DM. At the same time, the mechanisms that may explain the nonglycemic and cardiovascular (CV) benefits of these medications are still being explored. A summary of the main findings from CVOTs performed to-date with particular emphasis on various outcomes and inconsistencies observed in the trials is provided. Overall, available data is favourable to the early deployment of GLP-1RAs in clinical practice, fully in line with recommendations from international scientific guidelines, and based on their effects on glucose metabolism parameters, body weight reduction and CV outcomes. Evidence further suggest that the CV benefits of GLP-1RAs may not be a class effect, with GLP-1 analogues having a greater benefit rather than exendin-based agents.

The promise and pitfalls of composite endpoints in sepsis and COVID-19 clinical trials

Composite endpoints reveal the tendency for statistical convention to arise locally within subfields. Composites are familiar in cardiovascular trials, yet almost unknown in sepsis. However, the VITAMINS trial in patients with septic shock adopted a composite of mortality and vasopressor-free days, and an ordinal scale describing patient status rapidly became standard in COVID studies. Aware that recent use could incite interest in such endpoints, we are motivated to flag their potential value and pitfalls for sepsis research and COVID studies.

Exercise Training Promotes Cardiac Hydrogen Sulfide Biosynthesis and Mitigates Pyroptosis to Prevent High-Fat Diet-Induced Diabetic Cardiomyopathy

Obesity increases the risk of developing diabetes and subsequently, diabetic cardiomyopathy (DMCM). Reduced cardioprotective antioxidant hydrogen sulfide (H₂S) and increased inflammatory cell death via pyroptosis contribute to adverse cardiac remodeling and DMCM. Although exercise training (EX) has cardioprotective effects, it is unclear whether EX mitigates obesity-induced DMCM by increasing H₂S biosynthesis and mitigating pyroptosis in the heart. C57BL6 mice were fed a high-fat diet (HFD) while undergoing treadmill EX for 20 weeks. HFD mice developed obesity, hyperglycemia, and insulin resistance, which were reduced by EX. Left ventricle pressure-volume measurement revealed that obese mice developed reduced diastolic function with preserved ejection fraction, which was improved by EX. Cardiac dysfunction was accompanied by increased cardiac pyroptosis signaling, structural remodeling, and metabolic remodeling, indicated by accumulation of lipid droplets in the heart. Notably, EX increased cardiac H₂S concentration and expression of H₂S biosynthesis enzymes. HFD-induced obesity led to features of type 2 diabetes (T2DM), and subsequently DMCM. EX during the HFD regimen prevented the development of DMCM, possibly by promoting H₂S-mediated cardioprotection and alleviating pyroptosis. This is the first report of EX modulating H₂S and pyroptotic signaling in the heart.

Heart failure in the patient with diabetes: Epidemiology, aetiology, prognosis, therapy and the effect of glucose-lowering medications

In people with type 2 diabetes the frequency of heart failure (HF) is increased and mortality from HF is higher than with non-diabetic HF. The increased frequency of HF is attributable to the cardiotoxic tetrad of ischaemic heart disease, left ventricular hypertrophy, diabetic cardiomyopathy and an extracellular volume expansion resistant to atrial natriuretic peptides. Activation of the renin-angiotensin-aldosterone system and sympathetic nervous systems results in cardiac remodelling, which worsens cardiac function. Reversal of remodelling can be achieved, and cardiac function improved in people with HF with reduced ejection fraction (HFrEF) by treatment with angiotensin-converting enzyme inhibitors and β-blockers. However, with HF with preserved ejection fraction (HFpEF), only therapy for the underlying risk factors helps. Blockers of mineralocorticoid receptors may be beneficial in both HFrEF and HFpEF. Glucose-lowering drugs can have a negative effect (insulin, sulphonylureas, dipeptidyl peptidase-4 inhibitors and thiazolidinediones), a neutral effect (α-glucosidase inhibitors and glucagon-like peptide-1 receptor agonists) or a positive effect (sodium-glucose co-transporter-2 inhibitors and metformin).

Liraglutide and weight loss among patients with advanced heart failure and a reduced ejection fraction: insights from the FIGHT trial

AIMS

Obesity is present in up to 45% of patients with heart failure (HF). Liraglutide, a glucagon-like peptide-1 (GLP-1) receptor antagonist, facilitates weight loss in obese patients. The efficacy of liraglutide as a weight loss agent among patients with HF and reduced ejection fraction (HFrEF) and a recent acute HF hospitalization remains unknown.

METHODS AND RESULTS

The Functional Impact of GLP-1 for Heart Failure Treatment study randomized 300 patients with HFrEF (ejection fraction ≤ 40%), both with and without diabetes and a recent HF hospitalization to liraglutide or placebo. The primary outcome for this post hoc analysis was the change in weight from baseline to last study visit. We conducted an 'on-treatment' analysis of patients with at least one follow-up visit on study drug (123 on liraglutide and 124 on placebo). The median age was 61 years, 21% were female, and 69% of patients had New York Heart Association functional Class III or IV symptoms. The median ejection fraction was 25% (25th, 75th percentile 19-32%). Liraglutide use was associated with a significant weight reduction [liraglutide -1.00 lbs vs. placebo 2.00 lbs; treatment difference -4.10 lbs; 95% confidence interval (CI) -7.94, -0.25; P = 0.0367; percentage treatment difference -2.07%, 95% CI -3.86, -0.28; P = 0.0237]. Similar results were seen after multivariable adjustments. Liraglutide also significantly reduced triglyceride levels (liraglutide 7.5 mg/dL vs. placebo 12.0 mg/dL; treatment difference -33.1 mg/dL; 95% CI -60.7, -5.6; P = 0.019).

CONCLUSIONS

Liraglutide is an efficacious weight loss agent in patients with HFrEF. These findings will require further exploration in a well-powered cardiovascular outcomes trial.

Effects of Newer Antidiabetic Drugs on Endothelial Function and Arterial Stiffness: A Systematic Review and Meta-Analysis

BACKGROUND

Newer antidiabetic drugs, i.e., dipeptidyl peptidase-4 (DPP-4) inhibitors, sodium-glucose cotransporter-2 (SGLT-2) inhibitors, and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) may exert distinct cardiovascular effects. We sought to explore their impact on vascular function.

METHODS

Published literature was systematically searched up to January 2018 for clinical studies assessing the effects of DPP-4 inhibitors, GLP-1 RAs, and SGLT-2 inhibitors on endothelial function and arterial stiffness, assessed by flow-mediated dilation (FMD) of the brachial artery and pulse wave velocity (PWV), respectively. For each eligible study, we used the mean difference (MD) with 95% confidence intervals (CIs) for FMD and PWV. The pooled MD for FMD and PWV were calculated by using a random-effect model. The presence of heterogeneity among studies was evaluated by the I ² statistic.

RESULTS

A total of 26 eligible studies (n = 668 patients) were included in the present meta-analysis. Among newer antidiabetic drugs, only SGLT-2 inhibitors significantly improved FMD (pooled MD 1.14%, 95% CI: 0.18 to 1.73, p = 0.016), but not DPP-4 inhibitors (pooled MD = 0.86%, 95% CI: -0.15 to 1.86, p = 0.095) or GLP-1 RA (pooled MD = 2.37%, 95% CI: -0.51 to 5.25, p = 0.107). Both GLP-1 RA (pooled MD = -1.97, 95% CI: -2.65 to -1.30, p < 0.001) and, to a lesser extent, DPP-4 inhibitors (pooled MD = -0.18, 95% CI: -0.30 to -0.07, p = 0.002) significantly decreased PWV.

CONCLUSIONS

Newer antidiabetic drugs differentially affect endothelial function and arterial stiffness, as assessed by FMD and PWV, respectively. These findings could explain the distinct effects of these drugs on cardiovascular risk of patients with type 2 diabetes.

Treating Diabetes in Patients with Heart Failure: Moving from Risk to Benefit

Over the past two decades, therapeutics for diabetes have evolved from drugs with known heart failure risk to classes with potential benefit for patients with heart failure. As many as 25 to 35 % of patients with heart failure carry a diagnosis of type 2 diabetes mellitus. Therefore, newer drug classes including dipeptidyl peptidase 4 (DPP-4) inhibitors, glucagon-like peptide 1 (GIP-1) agonists, and sodium-glucose cotransporter 2 (SGLT-2) inhibitors are being examined for cardiovascular safety as well as their effects on left ventricular function, quality of life, and other measures of disease progression. The purpose of this review is to summarize the existing evidence on these classes of anti-diabetic agents in patients with heart failure.

Dioxygen and Metabolism; Dangerous Liaisons in Cardiac Function and Disease

The heart must consume a significant amount of energy to sustain its contractile activity. Although the fuel demands are huge, the stock remains very low. Thus, in order to supply its daily needs, the heart must have amazing adaptive abilities, which are dependent on dioxygen availability. However, in myriad cardiovascular diseases, “fuel” depletion and hypoxia are common features, leading cardiomyocytes to favor low-dioxygen-consuming glycolysis rather than oxidation of fatty acids. This metabolic switch makes it challenging to distinguish causes from consequences in cardiac pathologies. Finally, despite the progress achieved in the past few decades, medical treatments have not improved substantially, either. In such a situation, it seems clear that much remains to be learned about cardiac diseases. Therefore, in this review, we will discuss how reconciling dioxygen availability and cardiac metabolic adaptations may contribute to develop full and innovative strategies from bench to bedside.

Turning Failure into Success: Trials of the Heart Failure Clinical Research Network

The Heart Failure Clinical Research Network (HFN) was established in 2008 on behalf of the NIH National Heart, Lung and Blood Institute, with the primary goal of improving outcomes in heart failure (HF) by designing and conducting high-quality concurrent clinical trials testing interventions across the spectrum of HF. Completed HFN trials have answered several important and relevant clinical questions concerning the safety and efficacy of different decongestive and adjunctive vasodilator therapies in hospitalized acute HF, phosphodiesterase-5 inhibition and nitrate therapies in HF with preserved ejection fraction, and the role of xanthine oxidase inhibition in hyperuricemic HF. These successes, independent of the "positive" or "negative" result of each individual trial, have helped to shape the current clinical care of HF patients and serve as a platform to inform future research directions and trial designs.

Cardiovascular Actions and Clinical Outcomes With Glucagon-Like Peptide-1 Receptor Agonists and Dipeptidyl Peptidase-4 Inhibitors

Potentiation of glucagon-like peptide-1 (GLP-1) action through selective GLP-1 receptor (GLP-1R) agonism or by prevention of enzymatic degradation by inhibition of dipeptidyl peptidase-4 (DPP-4) promotes glycemic reduction for the treatment of type 2 diabetes mellitus by glucose-dependent control of insulin and glucagon secretion. GLP-1R agonists also decelerate gastric emptying, reduce body weight by reduction of food intake and lower circulating lipoproteins, inflammation, and systolic blood pressure. Preclinical studies demonstrate that both GLP-1R agonists and DPP-4 inhibitors exhibit cardioprotective actions in animal models of myocardial ischemia and ventricular dysfunction through incompletely characterized mechanisms. The results of cardiovascular outcome trials in human subjects with type 2 diabetes mellitus and increased cardiovascular risk have demonstrated a cardiovascular benefit (significant reduction in time to first major adverse cardiovascular event) with the GLP-1R agonists liraglutide (LEADER trial [Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Ourcome Results], -13%) and semaglutide (SUSTAIN-6 trial [Trial to Evaluate Cardiovascular and Other Long-term Outcomes with Semaglutide], -24%). In contrast, cardiovascular outcome trials examining the safety of the shorter-acting GLP-1R agonist lixisenatide (ELIXA trial [Evaluation of Lixisenatide in Acute Coronary Syndrom]) and the DPP-4 inhibitors saxagliptin (SAVOR-TIMI 53 trial [Saxagliptin Assessment of Vascular Outcomes Recorded in Patients With Diabetes Mellitus-Thrombolysis in Myocardial Infarction 53]), alogliptin (EXAMINE trial [Examination of Cardiovascular Outcomes With Alogliptin Versus Standard of Care in Patients With Type 2 Diabetes Mellitus and Acute Coronary Syndrome]), and sitagliptin (TECOS [Trial Evaluating Cardiovascular Outcomes With Sitagliptin]) found that these agents neither increased nor decreased cardiovascular events. Here we review the cardiovascular actions of GLP-1R agonists and DPP-4 inhibitors, with a focus on the translation of mechanisms derived from preclinical studies to complementary findings in clinical studies. We highlight areas of uncertainty requiring more careful scrutiny in ongoing basic science and clinical studies. As newer more potent GLP-1R agonists and coagonists are being developed for the treatment of type 2 diabetes mellitus, obesity, and nonalcoholic steatohepatitis, the delineation of the potential mechanisms that underlie the cardiovascular benefit and safety of these agents have immediate relevance for the prevention and treatment of cardiovascular disease.

Multiphasic Regulation of Systemic and Peripheral Organ Metabolic Responses to Cardiac Hypertrophy

BACKGROUND

Reduced fat oxidation in hypertrophied hearts coincides with a shift of carnitine palmitoyl transferase I from muscle to increased liver isoforms. Acutely increased carnitine palmitoyl transferase I in normal rodent hearts has been shown to recapitulate the reduced fat oxidation and elevated atrial natriuretic peptide message of cardiac hypertrophy.

METHODS AND RESULTS

Because of the potential for reduced fat oxidation to affect cardiac atrial natriuretic peptide, and thus, induce adipose lipolysis, we studied peripheral and systemic metabolism in male C57BL/6 mice model of transverse aortic constriction in which left ventricular hypertrophy occurred by 2 weeks without functional decline until 16 weeks (ejection fraction, -45.6%; fractional shortening, -22.6%). We report the first evidence for initially improved glucose tolerance and insulin sensitivity in response to 2 weeks transverse aortic constriction versus sham, linked to enhanced insulin signaling in liver and visceral adipose tissue (epididymal white adipose tissue [WAT]), reduced WAT inflammation, elevated adiponectin, mulitilocular subcutaneous adipose tissue (inguinal WAT) with upregulated oxidative/thermogenic gene expression, and downregulated lipolysis and lipogenesis genes in epididymal WAT. By 6 weeks transverse aortic constriction, the metabolic profile reversed with impaired insulin sensitivity and glucose tolerance, reduced insulin signaling in liver, epididymal WAT and heart, and downregulation of oxidative enzymes in brown adipose tissue and oxidative and lipogenic genes in inguinal WAT.

CONCLUSIONS

Changes in insulin signaling, circulating natriuretic peptides and adipokines, and varied expression of adipose genes associated with altered insulin response/glucose handling and thermogenesis occurred prior to any functional decline in transverse aortic constriction hearts. The findings demonstrate multiphasic responses in extracardiac metabolism to pathogenic cardiac stress, with early iWAT browning providing potential metabolic benefits.

Differential effects of glucagon-like peptide-1 receptor agonists on heart rate

While glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are known to increase heart rate (HR), it is insufficiently recognized that the extent varies greatly between the various agonists and is affected by the assessment methods employed. Here we review published data from 24-h time-averaged HR monitoring in healthy individuals and subjects with type 2 diabetes mellitus (T2DM) treated with either short-acting GLP-1 RAs, lixisenatide or exenatide, or long-acting GLP-1 RAs, exenatide LAR, liraglutide, albiglutide, or dulaglutide (N = 1112; active-treatment arms). HR effects observed in two independent head-to-head trials of lixisenatide and liraglutide (N = 202; active-treatment arms) are also reviewed. Short-acting GLP-1 RAs, exenatide and lixisenatide, are associated with a transient (1-12 h) mean placebo- and baseline-adjusted 24-h HR increase of 1-3 beats per minute (bpm). Conversely, long-acting GLP-1 RAs are associated with more pronounced increases in mean 24-h HR; the highest seen with liraglutide and albiglutide at 6-10 bpm compared with dulaglutide and exenatide LAR at 3-4 bpm. For both liraglutide and dulaglutide, HR increases were recorded during both the day and at night. In two head-to-head comparisons, a small, transient mean increase in HR from baseline was observed with lixisenatide; liraglutide induced a substantially greater increase that remained significantly elevated over 24 h. The underlying mechanism for increased HR remains to be elucidated; however, it could be related to a direct effect at the sinus node and/or stimulation of the sympathetic nervous system, with this effect related to the duration of action of the respective GLP-1 RAs. In conclusion, this review indicates that the effects on HR differ within the class of GLP-1 RAs: short-acting GLP-1 RAs are associated with a modest and transient HR increase before returning to baseline levels, while some long-acting GLP-1 RAs are associated with a more pronounced and sustained increase during the day and night. Findings from recently completed trials indicate that a GLP-1 RA-induced increase in HR, regardless of magnitude, does not present an increased cardiovascular risk for subjects with T2DM, although a pronounced increase in HR may be associated with adverse clinical outcomes in those with advanced heart failure.

Mitochondrial dysfunction and its impact on diabetic heart

Mitochondrial dysfunction and associated oxidative stress are strongly linked to cardiovascular, neurodegenerative, and age associated disorders. More specifically cardiovascular diseases are common in patients with diabetes and significant contributor to the high mortality rates associated with diabetes. Studies have shown that the heart failure risk is increased in diabetic patients even after adjusting for coronary artery disease and hypertension. Although the actual basis of the increased heart failure risk is multifactorial, increasing evidences suggest that imbalances in mitochondrial function and associated oxidative stress play an important role in this process. This review summarizes these abnormalities in mitochondrial function and discusses potential underlying mechanisms. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.

Glucagon-Like Peptide-1 (GLP-1) Receptor Agonists in Cardiac Disorders

OBJECTIVE

To evaluate the literature about the use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in the treatment of cardiac disorders, specifically myocardial infarction (MI) and heart failure (HF).

DATA SOURCES

Searches were conducted in MEDLINE (1946-May 2016) and Excerpta Medica (1980-May 2016) using EMBASE with the search terms glucagon-like peptide 1, exenatide, albiglutide, liraglutide, dulaglutide, myocardial infarction, heart failure, and cardiovascular The references of relevant articles were reviewed to identify additional citations.

STUDY SELECTION AND DATA EXTRACTION

Clinical trials were limited to the English language and human trials. In all, 18 trials explored the use of GLP-1 RAs in the treatment of cardiac disorders in patients with and without diabetes mellitus.

DATA SYNTHESIS

Of the 18 trials reviewed, 11 trials studied the impact of GLP-1 RAs in MI. All showed a significant beneficial effect on various cardiac parameters. Favorable outcome improvements included myocardial blood flow, left ventricular (LV) function, and MI size. Seven trials reviewed the use of GLP-1 RAs in the treatment of HF. Three trials showed significant improvements in LV ejection fraction, cardiac index, and peak oxygen consumption.

CONCLUSIONS

Limited data suggest that GLP-1 RAs may be effective for the treatment of cardiac disorders in patients with and without diabetes mellitus. These studies suggest that GLP-1 RAs may have potential pleiotropic beneficial effects in patients with cardiovascular disease beyond their role in managing diabetes. These medications may be cardioprotective after a MI but are less promising in HF.

Effects of Liraglutide on Clinical Stability Among Patients With Advanced Heart Failure and Reduced Ejection Fraction: A Randomized Clinical Trial

IMPORTANCE

Abnormal cardiac metabolism contributes to the pathophysiology of advanced heart failure with reduced left ventricular ejection fraction (LVEF). Glucagon-like peptide 1 (GLP-1) agonists have shown cardioprotective effects in early clinical studies of patients with advanced heart failure, irrespective of type 2 diabetes status.

OBJECTIVE

To test whether therapy with a GLP-1 agonist improves clinical stability following hospitalization for acute heart failure.

DESIGN, SETTING, AND PARTICIPANTS

Phase 2, double-blind, placebo-controlled randomized clinical trial of patients with established heart failure and reduced LVEF who were recently hospitalized. Patients were enrolled between August 2013 and March 2015 at 24 US sites.

INTERVENTIONS

The GLP-1 agonist liraglutide (n = 154) or placebo (n = 146) via a daily subcutaneous injection; study drug was advanced to a dosage of 1.8 mg/d during the first 30 days as tolerated and continued for 180 days.

MAIN OUTCOMES AND MEASURES

The primary end point was a global rank score in which all patients, regardless of treatment assignment, were ranked across 3 hierarchical tiers: time to death, time to rehospitalization for heart failure, and time-averaged proportional change in N-terminal pro-B-type natriuretic peptide level from baseline to 180 days. Higher values indicate better health (stability). Exploratory secondary outcomes included primary end point components, cardiac structure and function, 6-minute walk distance, quality of life, and combined events.

RESULTS

Among the 300 patients who were randomized (median age, 61 years [interquartile range {IQR}, 52-68 years]; 64 [21%] women; 178 [59%] with type 2 diabetes; median LVEF of 25% [IQR, 19%-33%]; median N-terminal pro-B-type natriuretic peptide level of 2049 pg/mL [IQR, 1054-4235 pg/mL]), 271 completed the study. Compared with placebo, liraglutide had no significant effect on the primary end point (mean rank of 146 for the liraglutide group vs 156 for the placebo group, P = .31). There were no significant between-group differences in the number of deaths (19 [12%] in the liraglutide group vs 16 [11%] in the placebo group; hazard ratio, 1.10 [95% CI, 0.57-2.14]; P = .78) or rehospitalizations for heart failure (63 [41%] vs 50 [34%], respectively; hazard ratio, 1.30 [95% CI, 0.89-1.88]; P = .17) or for the exploratory secondary end points. Prespecified subgroup analyses in patients with diabetes did not reveal any significant between-group differences. The number of investigator-reported hyperglycemic events was 16 (10%) in the liraglutide group vs 27 (18%) in the placebo group and hypoglycemic events were infrequent (2 [1%] vs 4 [3%], respectively).

CONCLUSIONS AND RELEVANCE

Among patients recently hospitalized with heart failure and reduced LVEF, the use of liraglutide did not lead to greater posthospitalization clinical stability. These findings do not support the use of liraglutide in this clinical situation.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01800968.

The Cardiovascular Biology of Glucagon-like Peptide-1

Glucagon-like peptide-1, produced predominantly in enteroendocrine cells, controls glucose metabolism and energy homeostasis through regulation of islet hormone secretion, gastrointestinal motility, and food intake, enabling development of GLP-1 receptor (GLP-1R) agonists for the treatment of diabetes and obesity. GLP-1 also acts on the immune system to suppress inflammation, and GLP-1R signaling in multiple tissues impacts cardiovascular function in health and disease. Here we review how GLP-1 and clinically approved GLP-1R agonists engage mechanisms that influence the risk of developing cardiovascular disease. We discuss how GLP-1R agonists modify inflammation, cardiovascular physiology, and pathophysiology in normal and diabetic animals through direct and indirect mechanisms and review human studies illustrating mechanisms linking GLP-1R signaling to modification of the cardiovascular complications of diabetes. The risks and benefits of GLP-1R agonists are updated in light of recent data suggesting that GLP-1R agonists favorably modify outcomes in diabetic subjects at high risk for cardiovascular events.

New Management Strategies in Heart Failure

Despite >100 clinical trials, only 2 new drugs had been approved by the US Food and Drug Administration for the treatment of chronic heart failure in more than a decade: the aldosterone antagonist eplerenone in 2003 and a fixed dose combination of hydralazine-isosorbide dinitrate in 2005. In contrast, 2015 has witnessed the Food and Drug Administration approval of 2 new drugs, both for the treatment of chronic heart failure with reduced ejection fraction: ivabradine and another combination drug, sacubitril/valsartan or LCZ696. Seemingly overnight, a range of therapeutic possibilities, evoking new physiological mechanisms, promise great hope for a disease that often carries a prognosis worse than many forms of cancer. Importantly, the newly available therapies represent a culmination of basic and translational research that actually spans many decades. This review will summarize newer drugs currently being used in the treatment of heart failure, as well as newer strategies increasingly explored for their utility during the stages of the heart failure syndrome.

Composite End Points in Acute Heart Failure Research: Data Simulations Illustrate the Limitations

Composite end points are frequently used in clinical trials of investigational treatments for acute heart failure, eg, to boost statistical power and reduce the overall sample size. By incorporating multiple and varying types of clinical outcomes they provide a test for the overall efficacy of the treatment. Our objective is to compare the performance of popular composite end points in terms of statistical power and describe the uncertainty in these power estimates and issues concerning implementation. We consider several composites that incorporate outcomes of varying types (eg, time to event, categorical, and continuous). Data are simulated for 5 outcomes, and the composites are derived and compared. Power is evaluated graphically while varying the size of the treatment effects, thus describing the sensitivity of power to varying circumstances and eventualities such as opposing effects. The average z score offered the most power, although caution should be exercised when opposing effects are anticipated. Results emphasize the importance of an a priori assessment of power and scientific basis for construction, including the weighting of individual outcomes deduced from data simulations. The interpretation of a composite should be made alongside results from the individual components. The average z score offers the most power, but this should be considered in the research context and is not without its limitations.

Hospitalisation for heart failure and mortality associated with dipeptidyl peptidase 4 (DPP-4) inhibitor use in an unselected population of subjects with type 2 diabetes: a nested case-control study

OBJECTIVE

The SAVOR TIMI-53 study reported a significant increase in the risk of hospitalisation for heart failure (HF) in patients treated with a DPP-4 inhibitor (DPP-4i) in comparison with placebo. A recent case-control study in part confirmed this risk signal. Our aim was to compare the occurrence of HF in relation to DPP-4i use versus any antidiabetic treatment.

DESIGN

Population-based matched case-control study conducted using administrative data.

SETTING

The Italian Region of Piedmont (4.4 million inhabitants).

PARTICIPANTS

From a database of 282,000 patients treated with antidiabetic drugs, we identified 14,613 hospitalisations for HF, 7212 incident cases, and 1727 hospital re-admissions between 2008 and 2012; each case was matched for gender, age and antidiabetic therapy with 10 controls; cases and controls were compared for exposure to DPP-4i.

OUTCOME MEASURES

ORs and 95% CIs were calculated by fitting a conditional logistic model. All analyses were adjusted for available risk factors for HF.

RESULTS

We found no increased risk of hospitalisation for HF associated with the use of DPP-4i (OR for admission for HF 1.00 (0.94 to 1.07), incident HF1.01 (0.92 to 1.11), recurrent HF 1.02 (0.84 to 1.22)). All-cause mortality was 6% lower in DPP-4i users (p<0.001), whereas insulin users showed an excess of risk for any type of hospital admission (19%) and death (20%) (p<0.001).

CONCLUSIONS

Our findings suggest that, in an unselected population of diabetic patients, the use of DPP-4i is not associated with an increased risk of HF. The favourable impact on all-cause mortality should be viewed with caution and also other explanations investigated.