Prevalent and Incident Heart Failure in Cardiovascular Outcome Trials of Patients With Type 2 Diabetes

Ferroptosis in diabetic cardiomyopathy: Advances in cardiac fibroblast-cardiomyocyte interactions

Diabetic cardiomyopathy (DCM) is a common complication of diabetes, and its pathogenesis remains elusive. Ferroptosis, a process dependent on iron-mediated cell death, plays a crucial role in DCM via disrupted iron metabolism, lipid peroxidation, and weakened antioxidant defenses. Hyperglycemia, oxidative stress, and inflammation may exacerbate ferroptosis in diabetes. This review emphasizes the interaction between cardiac fibroblasts and cardiomyocytes in DCM, influencing ferroptosis occurrence. By exploring ferroptosis modulation for potential therapeutic targets, this article offers a fresh perspective on DCM treatment. The study systematically covers the interplay, mechanisms, and targeted drugs linked to ferroptosis in DCM development.

Diabetes and Heart Failure: A Literature Review, Reflection and Outlook

Heart failure (HF) is a complex clinical syndrome caused by structural or functional dysfunction of the ventricular filling or blood supply. Diabetes mellitus (DM) is an independent predictor of mortality for HF. The increase in prevalence, co-morbidity and hospitalization rates of both DM and HF has further fueled the possibility of overlapping disease pathology between the two. For decades, antidiabetic drugs that are known to definitively increase the risk of HF are the thiazolidinediones (TZDs) and saxagliptin in the dipeptidyl peptidase-4 (DPP-4) inhibitor, and insulin, which causes sodium and water retention, and whether metformin is effective or safe for HF is not clear. Notably, sodium-glucose transporter 2 (SGLT2) inhibitors and partial glucagon-like peptide-1 receptor agonists (GLP-1 RA) all achieved positive results for HF endpoints, with SGLT2 inhibitors in particular significantly reducing the composite endpoint of cardiovascular mortality and hospitalization for heart failure (HHF). Further understanding of the mutual pathophysiological mechanisms between HF and DM may facilitate the detection of novel therapeutic targets to improve the clinical outcome. This review focuses on the association between HF and DM, emphasizing the efficacy and safety of antidiabetic drugs and HF treatment. In addition, recent therapeutic advances in HF and the important mechanisms by which SGLT2 inhibitors/mineralocorticoid receptor antagonist (MRA)/vericiguat contribute to the benefits of HF are summarized.

Sodium-glucose cotransporter-2 inhibitors (SGLT2) in frail or older people with type 2 diabetes and heart failure: a systematic review and meta-analysis

OBJECTIVE

Sodium-glucose cotransporter-2 inhibitors (SGLT2Is) reduce cardio-metabolic and renal outcomes in patients with type 2 diabetes (T2D) but their efficacy and safety in older or frail individuals remains unclear.

METHODS

We searched PubMed, Scopus, Web of Science, Cochrane CENTRA and Google Scholar and selected randomised controlled trials and observational studies comparing SGLT2Is versus placebo/other glucose-lowering agent for people with frailty or older individuals (>65 years) with T2D and heart failure (HF). Extracted data on the change in HbA1c % and safety outcomes were pooled in a random-effects meta-analysis model.

RESULTS

We included data from 20 studies (22 reports; N = 77,083 patients). SGLT2Is did not significantly reduce HbA1c level (mean difference -0.13, 95%CI: -0.41 to 0.14). SGLT2Is were associated with a significant reduction in the risk of all-cause mortality (risk ratio (RR) 0.81, 95%CI: -0.69 to 0.95), cardiac death (RR 0.80, 95%CI: -0.94 to 0.69) and hospitalisation for heart failure (HHF) (RR 0.69, 95%CI: 0.59-0.81). However, SGLT2Is did not demonstrate significant effect in reducing in the risk of macrovascular events (acute coronary syndrome or cerebral vascular occlusion), renal progression/composite renal endpoint, acute kidney injury, worsening HF, atrial fibrillation or diabetic ketoacidosis.

CONCLUSIONS

In older or frail patients with T2D and HF, SGLT2Is are consistently linked with a decrease in total mortality and the overall burden of cardiovascular (CV) events, including HHF events and cardiac death, but not protective for macrovascular death or renal events. Adverse events were more difficult to quantify but the risk of diabetic ketoacidosis or acute kidney injury was not significantly increase.

The neuropeptide substance P/neurokinin-1 receptor system and diabetes: From mechanism to therapy

Diabetes is a significant public health issue known as the world's fastest-growing disease condition. It is characterized by persistent hyperglycemia and subsequent chronic complications leading to organ dysfunction and, ultimately, the failure of target organs. Substance P (SP) is an undecapeptide that belongs to the family of tachykinin (TK) peptides. The SP-mediated activation of the neurokinin 1 receptor (NK1R) regulates many pathophysiological processes in the body. There is also a relation between the SP/NK1R system and diabetic processes. Importantly, deregulated expression of SP has been reported in diabetes and diabetes-associated chronic complications. SP can induce both diabetogenic and antidiabetogenic effects and thus affect the pathology of diabetes destructively or protectively. Here, we review the current knowledge of the functional relevance of the SP/NK1R system in diabetes pathogenesis and its exploitation for diabetes therapy. A comprehensive understanding of the role of the SP/NK1R system in diabetes is expected to shed further light on developing new therapeutic possibilities for diabetes and its associated chronic conditions.

Diabetes leading to heart failure and heart failure leading to diabetes: epidemiological and clinical evidence

Type 2 diabetes mellitus (T2DM) is a risk factor that plays a major role in the onset of heart failure (HF) both directly, by impairing cardiac function, and indirectly, through associated diseases such as hypertension, coronary disease, renal dysfunction, obesity, and other metabolic disorders. In a population of HF patients, the presence of T2DM ranged from 20 to 40%, according to the population studied, risk factor characteristics, geographic area, and age, and it is associated with a worse prognosis. Finally, patients with HF, when compared with those without HF, show an increased risk for the onset of T2DM due to several mechanisms that predispose the HF patient to insulin resistance. Despite the epidemiological data confirmed the relationship between T2DM and HF, the exact prevalence of HF in T2DM comes from interventional trials rather than from observational registries aimed to prospectively evaluate the risk of HF occurrence in T2DM population. This review is focused on the vicious cycle linking HF and T2DM, from epidemiological data to prognostic implications.

Mechanisms of action of SGLT2 inhibitors and their beneficial effects on the cardiorenal axis

Large clinical studies conducted with sodium-glucose co-transporter 2 inhibitors (SGLT2i) in patients with type 2 diabetes and heart failure with reduced ejection fraction have demonstrated their ability to achieve both cardiac and kidney benefits. Although there is huge evidence on SGLT2i-mediated clinical benefits both in diabetic and non-diabetic patients, the pathophysiological mechanisms underlying their efficacy are still poorly understood. Some favorable mechanisms are likely due to the prompt glycosuric action which is associated with natriuretic effects leading to hemodynamic benefits as well as a reduction in glomerular hyperfiltration and renin-angiotensin-aldosterone system activation. In addition to the renal mechanisms, SGLT2i may play a relevant role in cardiorenal axis protection by improving the cardiomyocyte metabolism, by exerting anti-fibrotic and anti-inflammatory actions, and by increasing cardioprotective adipokine expression. New studies will be needed to better understand the specific molecular mechanisms that mediate the SGLT2i favorable effects in patients suffering diabetes. Our aim is to first discuss about the molecular mechanisms underlying the cardiovascular benefits of SGLT2i in each of the main organs involved in the cardiorenal axis. Furthermore, we update on the most recent clinical trials evaluating the beneficial effects of SGLT2i in treatment of both diabetic and non-diabetic patients suffering heart failure.

Clinical Outcomes With Metformin and Sulfonylurea Therapies Among Patients With Heart Failure and Diabetes

OBJECTIVES

The authors sought to characterize associations between initiation of metformin and sulfonylurea therapy and clinical outcomes among patients with comorbid heart failure (HF) and diabetes (overall and by ejection fraction [EF] phenotype).

BACKGROUND

Metformin and sulfonylureas are frequently prescribed to patients with diabetes for glycemic control. The impact of these therapies on clinical outcomes among patients with comorbid HF and diabetes is unclear.

METHODS

The authors evaluated Medicare beneficiaries hospitalized for HF in the Get With The Guidelines-Heart Failure Registry between 2006 and 2014 with diabetes and not prescribed metformin or sulfonylurea before admission. In parallel separate analyses for metformin and sulfonylurea, patients with newly prescribed therapy within 90 days of discharge were compared with patients not prescribed therapy. Multivariable models landmarked at 90 days evaluated associations between prescription of therapy, and mortality and hospitalization for HF (HHF) at 12 months. Negative control (falsification) endpoints included hospitalization for urinary tract infection, hospitalization for gastrointestinal bleed, and influenza vaccination. Prespecified subgroup analyses were stratified by EF ≤40% versus >40%.

RESULTS

Of 5,852 patients, 454 (7.8%) were newly prescribed metformin and 504 (8.6%) were newly prescribed sulfonylurea. After adjustment, metformin prescription was independently associated with reduced risk of composite mortality/HHF (HR: 0.81; 95% CI: 0.67-0.98; P = 0.03), but individual components were not statistically significant. Findings among patients with EF >40% accounted for associations with mortality/HHF (HR: 0.68; 95% CI: 0.52-0.90) and HHF (HR: 0.58; 95% CI: 0.40-0.85) endpoints (all P for interaction ≤0.04). After adjustment, sulfonylurea initiation was associated with increased risk of mortality (HR: 1.24; 95% CI: 1.00-1.52; P = 0.045) and HHF (HR: 1.22; 95% CI: 1.00-1.48; P = 0.050) with nominal statistical significance. Associations between sulfonylurea initiation and endpoints were consistent regardless of EF (all P for interaction >0.11). Neither metformin initiation nor sulfonylurea initiation were associated with negative control endpoints.

CONCLUSIONS

In this population of older U.S. adults hospitalized for HF with comorbid diabetes, metformin initiation was independently associated with substantial improvements in 12-month clinical outcomes, driven by findings among patients with EF >40%. By contrast, sulfonylurea initiation was associated with excess risk of death and HF hospitalization, regardless of EF.

Replacement of Lost Substance P Reduces Fibrosis in the Diabetic Heart by Preventing Adverse Fibroblast and Macrophage Phenotype Changes

Reduced levels of the sensory nerve neuropeptide substance P (SP) have been reported in the diabetic rat heart, the consequence being a loss of cardioprotection in response to ischemic post-conditioning. We considered whether this loss of SP also predisposes the heart to non-ischemic diabetic cardiomyopathy in the form of fibrosis and hypertrophy. We report that diabetic Leprdb/db mice have reduced serum SP and that administration of exogenous replacement SP ameliorated cardiac fibrosis. Cardiac hypertrophy did not occur in Leprdb/db mice. Cardiac fibroblasts exposed to high glucose converted to a myofibroblast phenotype and produced excess extracellular matrix proteins; this was prevented by the presence of SP in the culture media. Cardiac fibroblasts exposed to high glucose produced increased amounts of the receptor for advanced glycation end products, reactive oxygen species and inflammatory cytokines, all of which were prevented by SP. Cultured macrophages assumed an M1 pro-inflammatory phenotype in response to high glucose as indicated by increased TNF-α, CCL2, and IL-6. SP promoted a shift to the reparative M2 macrophage phenotype characterized by arginase-1 and IL-10. Leprdb/db mice showed increased left ventricular M1 phenotype macrophages and an increase in the M1/M2 ratio. Replacement SP in Leprdb/db mice restored a favorable M1 to M2 balance. Together these findings indicate that a loss of SP predisposes the diabetic heart to developing fibrosis. The anti-fibrotic actions of replacement SP involve direct effects on cardiac fibroblasts and macrophages to oppose adverse phenotype changes. This study identifies the potential of replacement SP to treat diabetic cardiomyopathy.

Minireview: are SGLT2 inhibitors heart savers in diabetes?

Sodium-glucose cotransporter 2 (SGLT2) inhibitors, a class of drugs that promote urinary glucose excretion in the treatment of diabetes, have provoked large interest of scientific and professional community due to their positive and, somehow, unexpected results in the three major cardiovascular outcome trials (EMPA-REG OUTCOME trial with empagliflozin, CANVAS Program with canagliflozin, and DECLARE-TIMI 58 with dapagliflozin). In fact, along with the reduction of major adverse cardiovascular events, SGLT2 inhibitors reduced significantly hospitalization for heart failure regardless of existing atherosclerotic cardiovascular disease or a history of heart failure. The latter have reminded us of the frequent but neglected entity of diabetic cardiomyopathy which is currently poorly understood despite its great clinical importance. Physiological mechanisms responsible for the benefits of SGLT2 inhibitors are complex and multifactorial and still not well defined. Interestingly, the time frame of their effect excludes a glucose- and antiatherosclerotic-mediated effect. It would be of great importance to better understand SGLT2 inhibitor mechanisms of action since they could have a potential to be used in early stages of diabetes as cardioprotective agents. There are widely available biomarkers as well as echocardiography that are used in everyday clinical practice and could elucidate physiological mechanisms in the heart protection with SGLT2 inhibitors treatment but studies are still lacking. The purpose of this minireview is to summarize the latest concepts about SGLT2 inhibitors and its benefits regarding diabetic cardiomyopathy especially on its early stage development and to discuss controversies and potential future developments in the field.

Long-term variability of blood pressure and incidence of heart failure among individuals with Type 2 diabetes

AIMS

Data on the association of long-term variability of blood pressure (BP) with incident heart failure (HF) in individuals with Type 2 diabetes are scarce. We evaluated this association in a large community-based sample of adults with Type 2 diabetes.

METHODS AND RESULTS

A total of 4200 participants with Type 2 diabetes who had available BP measurements at four visits (baseline and 12, 24, and 36 months) in the Look AHEAD (Action for Health in Diabetes) study were included. Variability of systolic BP (SBP) and diastolic BP (DBP) across the four visits was assessed using four metrics. Participants free of HF during the first 36 months were followed for HF events. Cox regression was used to generate hazard ratios (HRs) and 95% confidence intervals (CIs) for HF. Of the 4200 participants, the average age was 59 years [standard deviation (SD): 6.8]; 58.5% were women. Over a median follow-up of 6.7 years, 129 developed HF events. After adjusting for relevant confounders, the HR of incident HF for the highest vs. lowest quartile of SD of SBP was 1.77 (95% CI 1.01-3.09); the HR for the highest (vs. lowest) quartile of variability independent of the mean of SBP was 1.29 (95% CI 0.78-2.14). The adjusted HR for participants in the highest (compared with the lowest) quartile of SD of DBP was 1.61 (95% CI 1.01-2.59), and the adjusted HR for variability independent of the mean of DBP was 1.65 (95% CI 1.03-2.65).

CONCLUSIONS

A greater variability in SBP and DBP is independently associated with greater risk of incident HF in individuals with Type 2 diabetes.

Transposition of cardiovascular outcome trial effects to the real-world population of patients with type 2 diabetes

Background

Transferring results obtained in cardiovascular outcome trials (CVOTs) to the real-world setting is challenging. We herein transposed CVOT results to the population of patients with type 2 diabetes (T2D) seen in routine clinical practice and who may receive the medications tested in CVOTs.

Methods

We implemented the post-stratification approach based on aggregate data of CVOTs and individual data of a target population of diabetic outpatients. We used stratum-specific estimates available from CVOTs to calculate expected effect size for the target population by weighting the average of the stratum-specific treatment effects according to proportions of a given characteristic in the target population. Data are presented as hazard ratio (HR) and 95% confidence intervals.

Results

Compared to the target population (n = 139,708), the CVOT population (n = 95,816) was younger and had a two to threefold greater prevalence of cardiovascular disease. EMPA-REG was the CVOT with the largest variety of details on stratum-specific effects, followed by TECOS, whereas DECLARE and PIONEER-6 had more limited stratum-specific information. The post-stratification HR estimate for 3 point major adverse cardiovascular event (MACE) based on EMPA-REG was 0.88 (0.74–1.03) in the target population, compared to 0.86 (0.74–0.99) in the trial. The HR estimate based on LEADER was 0.88 (0.77–0.99) in the target population compared to 0.87 (0.78–0.97) in the trial. Consistent results were obtained for SUSTAIN-6, EXSCEL, PIONEER-6 and DECLARE. The effect of DPP-4 inhibitors observed in CVOTs remained neutral in the target population.

Conclusions

Based on CVOT stratum-specific effects, cardiovascular protective actions of glucose lowering medications tested in CVOTs are transferrable to a much different real-world population of patients with T2D.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01300-y.

Metabolism and Chronic Inflammation: The Links Between Chronic Heart Failure and Comorbidities

Heart failure (HF) patients often suffer from multiple comorbidities, such as diabetes, atrial fibrillation, depression, chronic obstructive pulmonary disease, and chronic kidney disease. The coexistance of comorbidities usually leads to multi morbidity and poor prognosis. Treatments for HF patients with multi morbidity are still an unmet clinical need, and finding an effective therapy strategy is of great value. HF can lead to comorbidity, and in return, comorbidity may promote the progression of HF, creating a vicious cycle. This reciprocal correlation indicates there may be some common causes and biological mechanisms. Metabolism remodeling and chronic inflammation play a vital role in the pathophysiological processes of HF and comorbidities, indicating metabolism and inflammation may be the links between HF and comorbidities. In this review, we comprehensively discuss the major underlying mechanisms and therapeutic implications for comorbidities of HF. We first summarize the potential role of metabolism and inflammation in HF. Then, we give an overview of the linkage between common comorbidities and HF, from the perspective of epidemiological evidence to the underlying metabolism and inflammation mechanisms. Moreover, with the help of bioinformatics, we summarize the shared risk factors, signal pathways, and therapeutic targets between HF and comorbidities. Metabolic syndrome, aging, deleterious lifestyles (sedentary behavior, poor dietary patterns, smoking, etc.), and other risk factors common to HF and comorbidities are all associated with common mechanisms. Impaired mitochondrial biogenesis, autophagy, insulin resistance, and oxidative stress, are among the major mechanisms of both HF and comorbidities. Gene enrichment analysis showed the PI3K/AKT pathway may probably play a central role in multi morbidity. Additionally, drug targets common to HF and several common comorbidities were found by network analysis. Such analysis has already been instrumental in drug repurposing to treat HF and comorbidity. And the result suggests sodium-glucose transporter-2 (SGLT-2) inhibitors, IL-1β inhibitors, and metformin may be promising drugs for repurposing to treat multi morbidity. We propose that targeting the metabolic and inflammatory pathways that are common to HF and comorbidities may provide a promising therapeutic strategy.

Update on the Impact of Comorbidities on the Efficacy and Safety of Heart Failure Medications

PURPOSE OF REVIEW

Multiple newer medications benefit patients with heart failure with reduced ejection fraction (HFrEF). While these therapies benefit the broad population with HFrEF, the efficacy and safety of these therapies have been less well characterized in patients with significant comorbidities.

RECENT FINDINGS

Common comorbidities of high interest in heart failure (HF) include diabetes mellitus, chronic kidney disease (CKD), atrial fibrillation, and obesity, and each has potential implications for clinical management. As the burden of comorbidities increases in HF populations, risk-benefit assessments of HF therapies in the context of different comorbidities are increasingly relevant for clinical practice. This review summarizes data regarding the core HFrEF therapies in the context of comorbidities, with specific attention to sodium-glucose cotransporter 2 inhibitors, sacubitril/valsartan, mineralocorticoid receptor antagonists (MRAs), and beta-blockers. In general, studies support consistent treatment effects with regard to clinical outcome benefits in the presence of comorbidities. Likewise, safety profiles are relatively consistent irrespective of comorbidities, with the exception of heightened risk of hyperkalemia with MRA therapy in patients with severe CKD. In conclusion, while HF management is complex in the context of multiple comorbidities, the totality of evidence strongly supports guideline-directed medical therapies as foundational for improving outcomes in these high-risk patients.

The role of sodium glucose co-transporter inhibitors in heart failure prevention

The worldwide prevalences of diabetes mellitus (DM) and of heart failure (HF) have collectively been on the rise. HF accounts for a large portion of the cardiovascular mortality and morbidity associated with DM. DM increases the risk of developing heart failure by promoting atherosclerosis and exerting direct deleterious effects on the myocardium. Sodium-glucose co-transporter-2 (SGLT-2) inhibitors are agents approved for the treatment of DM; they exert their anti-hyperglycemic effects by blocking renal reabsorption of glucose and inducing glycosuria. SGLT-2 inhibitors have consistently decreased the hospitalization rate of HF and cardiovascular mortality in several clinical trials. SGLT-2 inhibitors also possess anti-inflammatory, anti-fibrotic, and antihypertensive in addition to beneficial effects on the myocardial metabolism, which may account for their heart failure benefits. However, further research still needs to be done to evaluate the use of SGLT-2 inhibitors in non-diabetic patients and their efficacy in preventing or treating different heart failure phenotypes.

Cardioprotective mechanism of SGLT2 inhibitor against myocardial infarction is through reduction of autosis

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce cardiovascular mortality in patients with diabetes mellitus but the protective mechanism remains elusive. Here we demonstrated that the SGLT2 inhibitor, Empagliflozin (EMPA), suppresses cardiomyocytes autosis (autophagic cell death) to confer cardioprotective effects. Using myocardial infarction (MI) mouse models with and without diabetes mellitus, EMPA treatment significantly reduced infarct size, and myocardial fibrosis, thereby leading to improved cardiac function and survival. In the context of ischemia and nutritional glucose deprivation where autosis is already highly stimulated, EMPA directly inhibits the activity of the Na⁺/H⁺ exchanger 1 (NHE1) in the cardiomyocytes to regulate excessive autophagy. Knockdown of NHE1 significantly rescued glucose deprivation-induced autosis. In contrast, overexpression of NHE1 aggravated the cardiomyocytes death in response to starvation, which was effectively rescued by EMPA treatment. Furthermore, in vitro and in vivo analysis of NHE1 and Beclin 1 knockout mice validated that EMPA’s cardioprotective effects are at least in part through downregulation of autophagic flux. These findings provide new insights for drug development, specifically targeting NHE1 and autosis for ventricular remodeling and heart failure after MI in both diabetic and non-diabetic patients.

How Diabetes and Heart Failure Modulate Each Other and Condition Management

Heart failure (HF) and diabetes mellitus (DM) confer considerable burden on the health care system. Although these often occur together, DM can increase risk of HF, whereas HF can accelerate complications of DM. HF is a clinical syndrome resulting from systolic or diastolic impairment caused by ischemic, nonischemic (eg, DM), or other etiologies. HF exists along a spectrum from stage A (ie, persons at risk of DM) to stage D (ie, refractory HF from end-stage DM cardiomyopathy [DMCM]). HF is further categorized by reduced, midrange, and preserved ejection fraction (EF). In type 2 DM, the most prevalent form of DM, several pathophysiological mechanisms (eg, insulin resistance and hyperglycemia) can contribute to myocardial damage, leading to DMCM. Management of HF and DM and patient outcomes are guided by EF and drug efficacy. In this review, we focus on the interplay between HF and DM on disease pathophysiology, management, and patient outcomes. Specifically, we highlight the role of novel antihyperglycemic (eg, sodium glucose cotransporter 2 inhibitors) and HF therapies (eg, renin-angiotensin-aldosterone system inhibitors) on HF outcomes in patients with DM and HF.

Incidence of Hospitalization for Heart Failure Relative to Major Atherosclerotic Events in Type 2 Diabetes: A Meta-analysis of Cardiovascular Outcomes Trials

BACKGROUND

Emerging evidence points to heart failure as being a common first presentation of cardiovascular (CV) disease in type 2 diabetes.

PURPOSE

The purpose of this study was to determine whether hospitalization for heart failure (HHF) occurs more or less frequently than major adverse CV events (MACE) in people with type 2 diabetes.

DATA SOURCES

Placebo arms of CV outcomes trials in type 2 diabetes were included.

STUDY SELECTION

Sixteen CV outcomes trials were selected, including five dipeptidyl peptidase 4 inhibitor trials, seven glucagon-like peptide 1 receptor agonist trials, and four sodium-glucose cotransporter 2 inhibitor trials.

DATA EXTRACTION

We extracted incidence rates of HHF, myocardial infarction (MI), stroke, and the composite outcomes of CV death or HHF and MACE (CV death, nonfatal MI, or nonfatal stroke).

DATA SYNTHESIS

In two trials enriched with people with chronic kidney disease, HHF was more common than both MI and stroke. Among the remaining 14 trials, HHF was less frequent than MI in 13 (93%), with this difference being significant in 8 (57%); however, HHF surpassed stroke in all but 1 study (93%; significant in 7 studies [50%]). Heterogeneity among trials was moderate/high (I ² >50%) and partly explained by HHF/MI correlating with age and previous MI history (P < 0.05). In seven trials that reported events stratified by presence/absence of preexisting CV disease, ratios of HHF/MI and HHF/stroke were similar between groups.

LIMITATIONS

Enrichment of trial populations with those at high risk of CV events limits generalizability.

CONCLUSIONS

Although less frequent than MI, HHF is a common event in type 2 diabetes, both in those with and those without prior CV disease.

Use of Glucagon-Like Peptide-1 Receptor Agonists in Patients With Type 2 Diabetes and Cardiovascular Disease: A Review

Importance

Recent randomized clinical trials have demonstrated that glucagon-like peptide-1 receptor agonists (GLP-1RAs) reduce cardiovascular events in at-risk individuals with type 2 diabetes. Despite these findings, GLP-1RAs are underused in eligible patients, particularly by cardiologists.

Observations

To date, randomized clinical trials of albiglutide, dulaglutide, liraglutide, and injectable semaglutide have reported favorable cardiovascular outcomes. Most recently approved for clinical use, oral semaglutide has a favorable safety profile and is currently undergoing regulatory evaluation and further study for cardiovascular outcomes. Professional society guidelines now recommend GLP-1RA therapy for cardiovascular risk mitigation in patients with type 2 diabetes and established atherosclerotic cardiovascular disease (ASCVD) or multiple ASCVD risk factors, independent of glucose control or background antihyperglycemic therapy (other diabetes medications being used). Additional conditions suitable for GLP-1RA therapy include obesity and advanced chronic kidney disease (estimated glomerular filtration rate <30 mL/min/1.73 m2), for which cardiovascular risk-reducing options are limited. Out-of-pocket costs and secondary advantages (eg, weight loss) may inform shared decision-making discussions regarding potential therapies. GLP-1RA therapy has a favorable safety profile. Its most common adverse effect is gastrointestinal upset, which typically wanes during the early weeks of therapy and may be mitigated by starting at the lowest dose and escalating as tolerated. Depending on baseline glycemic control, sulfonylureas and insulin may need to be decreased before GLP-1RA initiation; without concurrent use of insulin or sulfonylureas, GLP-1RAs are not associated with hypoglycemia. Multidisciplinary follow-up and collaborative care with primary care physicians and/or endocrinologists are important.

Conclusions and Relevance

Findings from this review suggest that GLP-1RAs are safe, are well tolerated, and improve cardiovascular outcomes, largely independent of their antihyperglycemic properties, but they remain underused by cardiologists. This review provides a practical resource for cardiologists for initiating GLP-1RAs and managing the therapy in patients with type 2 diabetes and established ASCVD or high risk for ASCVD.

Cardiovascular Effects of Dipeptidyl Peptidase-4 Inhibitors and Glucagon-Like Peptide-1 Receptor Agonists: a Review for the General Cardiologist

PURPOSE OF REVIEW

Results from cardiovascular (CV) outcome trials have revealed important insights into the CV safety and efficacy of glucose-lowering agents, including dipeptidyl peptidase-4 inhibitors (DPP-4i) and glucagon-like peptide-1 receptor agonists (GLP-1RA).

RECENT FINDINGS

Among patients with T2DM, DPP-4i have no significant effect on risk of major adverse CV events (MACE: CV death, myocardial infarction, or stroke) with mixed results regarding risk for heart failure (HF). While sitagliptin and linagliptin have neutral effects on HF risk, saxagliptin significantly increases the risk of HF. The CV safety of the GLP-1RA class of medications has been clearly demonstrated, and select agents, such as liraglutide, semaglutide, albiglutide, and dulaglutide, reduce the risk of MACE in patients with T2DM and established CV disease. CV outcome trials have demonstrated CV safety but not incremental efficacy for DPP-4i in most cases. Select GLP-1RA have proven efficacy for MACE and should be considered by cardiologists for CV risk mitigation in the care of patients with T2DM and established CV disease.

Effects of canagliflozin in patients with type 2 diabetes and chronic heart failure: a randomized trial (CANDLE)

AIMS

Little is known about the impact of sodium glucose co-transporter 2 (SGLT2) inhibitors on cardiac biomarkers, such as natriuretic peptides, in type 2 diabetes (T2D) patients with concomitant chronic heart failure (CHF). We compared the effect of canagliflozin with glimepiride, based on changes in N-terminal pro-brain natriuretic peptide (NT-proBNP), in that patient population.

METHODS AND RESULTS

Patients with T2D and stable CHF, randomized to receive canagliflozin 100 mg or glimepiride (starting-dose: 0.5 mg), were examined using the primary endpoint of non-inferiority of canagliflozin vs. glimepiride, defined as a margin of 1.1 in the upper limit of the two-sided 95% confidence interval (CI) for the group ratio of percentage change in NT-proBNP at 24 weeks. Data analysis of 233 patients showed mean left ventricular ejection fraction (LVEF) at randomization was 57.6 ± 14.6%, with 71% of patients having a preserved LVEF (≥50%). Ratio of NT-proBNP percentage change was 0.48 (95% CI, -0.13 to 1.59, P = 0.226) and therefore did not meet the prespecified non-inferiority margin. However, NT-proBNP levels did show a non-significant trend lower in the canagliflozin group [adjusted group difference; -74.7 pg/mL (95% CI, -159.3 to 10.9), P = 0.087] and also in the subgroup with preserved LVEF [-58.3 (95% CI, -127.6 to 11.0, P = 0.098]).

CONCLUSIONS

This study did not meet the predefined primary endpoint of changes in NT-proBNP levels, with 24 weeks of treatment with canagliflozin vs. glimepiride. Further research is warranted to determine whether patients with heart failure with preserved ejection fraction, regardless of diabetes status, could potentially benefit from treatment with SGLT2 inhibitors.

Association between glycated haemoglobin levels and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease: a secondary analysis of the TECOS randomized clinical trial

AIMS

Whether glycaemic control is associated with cardiovascular outcomes in patients with type 2 diabetes (T2D) is unclear. Consequently, we assessed the relationship between glycated haemoglobin (HbA_1c ) and cardiovascular outcomes in a placebo-controlled randomized trial which demonstrated no cardiovascular effect of sitagliptin in patients with T2D and atherosclerotic vascular disease.

METHODS AND RESULTS

Secondary analysis of 14 656 TECOS participants with time to event analyses using multivariable Cox proportional hazard models. During a median 3.0 (interquartile range 2.3-3.8) year follow-up, 456 (3.1% of 14 656) patients had first hospitalization for heart failure (HF), 1084 (11.5%) died, 1406 (9.6%) died or were hospitalized for HF, and 1689 (11.5%) had a non-HF cardiovascular event (cardiovascular death, non-fatal stroke, non-fatal myocardial infarction, or hospitalization for unstable angina). Associations between baseline or time-varying HbA_1c and cardiovascular outcomes were U-shaped, with the lowest risk when HbA_1c was around 7%. Each one-unit increase in the time-varying HbA_1c above 7% was associated with an adjusted hazard ratio (HR) of 1.21 [95% confidence interval (CI) 1.11-1.33] for first HF hospitalization, 1.11 (1.03-1.21) for all-cause death, 1.18 (1.09-1.26) for death or HF hospitalization, and 1.10 (1.02-1.17) for non-HF cardiovascular events. Each one-unit decrease in the time-varying HbA_1c below 7% was associated with an adjusted HR of 1.35 (95% CI 1.12-1.64) for first HF hospitalization, 1.37 (1.16-1.61) for death, 1.42 (1.23-1.64) for death or HF hospitalization, and 1.22 (1.06-1.41) for non-HF cardiovascular events.

CONCLUSION

Glycated haemogobin exhibits a U-shaped association with cardiovascular outcomes in patients with T2D and atherosclerotic vascular disease, with nadir around 7%.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00790205.

Focused Updates: SGLT2 Inhibitors in Patients With Heart Failure and/or Chronic Kidney Disease

Sodium-glucose cotransporter (SGLT2) inhibitors have demonstrated cardiovascular (CV) benefits in large-scale clinical trials of people who have type 2 diabetes and either established CV disease or multiple CV risk factors. These studies also indicated early signals in benefiting heart failure (HF) patients and those with chronic kidney diseases. This article reviews recent and future clinical studies that focus on evaluation of the use of SGLT2 inhibitors in HF management and renal protection.

Contemporary Treatment Patterns and Clinical Outcomes of Comorbid Diabetes Mellitus and HFrEF: The CHAMP-HF Registry

OBJECTIVES

The purpose of this study was to characterize the clinical profile, treatment patterns, and clinical outcomes of patients with comorbid diabetes mellitus (DM) and heart failure with reduced ejection fraction (HFrEF) in a contemporary, real-world U.S. outpatient registry in the context of evolving treatment strategies.

BACKGROUND

Specific antihyperglycemic classes have differential risks and benefits with respect to HF. Limited data are available evaluating contemporary treatment patterns and outcomes of patients with comorbid DM and HFrEF.

METHODS

Among 4,970 patients with chronic HFrEF (≤40%) across 152 U.S. sites in the CHAMP-HF prospective, observational registry (2015 to 2017), we examined therapies and clinical outcomes by DM status.

RESULTS

Median age was 68 (58 to 75) years of age; 29% were women; 73.5% were white; and 64% had coronary artery disease. Overall, 42% (n = 2,085) had comorbid DM with a median hemoglobin A1c (HbA1c) level of 7.2% (interquartile range [IQR]: 6.4% to 8.3%). One-fourth of DM patients (24%) were not treated with an antihyperglycemic therapy. Most patients with DM were taking 1 (46%) or 2 (23%) antihyperglycemic therapies: metformin (40%); insulin (33%); sulfonylureas (24%); dipeptidyl peptidase-4 inhibitors (10%); glucagon-like peptide (GLP)-1 receptor agonists (4%); sodium-glucose cotransporter (SGLT)-2 inhibitors (2%); and thiazolidinediones (2%). Among patients with DM, 62%, 16%, 80%, and 33.5% were receiving any angiotensin-converting enzyme (ACE) inhibitor/angiotensin receptor blockers (ARBs), angiotensin receptor-neprilysin inhibitor (ARNI), β-blockers, or mineralocorticoid receptor antagonists (MRAs) at baseline, respectively. Among patients without DM, corresponding baseline rates were 65%, 15%, 80%, and 37%, respectively. Patients with or without DM were infrequently treated with guideline-directed HFrEF therapies at target doses (≤27% across classes). During median 15-month follow-up, patients with DM experienced higher rates of all-cause mortality or HF hospitalization (30% vs. 23%, respectively), independent of 11 pre-specified covariates (adjusted hazard ratio: 1.35 (95% confidence interval: 1.21 to 1.52); p < 0.001).

CONCLUSIONS

Despite higher risk-adjusted clinical event rates in patients with comorbid HFrEF and DM, guideline-directed medical therapies for both disease states are incomplete and represent an important target for quality improvement through multidisciplinary care pathways.

Distinct cardiac energy metabolism and oxidative stress adaptations between obese and non-obese type 2 diabetes mellitus

Background: Little is known about the pathophysiological diversity of myocardial injury in type 2 diabetes mellitus (T2DM), but analyzing these differences is important for the accurate diagnosis and precise treatment of diabetic cardiomyopathy. This study aimed to elucidate the key cardiac pathophysiological differences in myocardial injury between obese and non-obese T2DM from mice to humans.

Methods: Obese and non-obese T2DM mouse models were successfully constructed and observed until systolic dysfunction occurred. Changes in cardiac structure, function, energy metabolism and oxidative stress were assessed by biochemical and pathological tests, echocardiography, free fatty acids (FFAs) uptake fluorescence imaging, transmission electron microscopy, etc. Key molecule changes were screened and verified by RNA sequencing, quantitative real-time polymerase chain reaction and western blotting. Further, 28 human heart samples of healthy population and T2DM patients were collected to observe the cardiac remodeling, energy metabolism and oxidative stress adaptations as measured by pathological and immunohistochemistry tests.

Results: Obese T2DM mice exhibited more severe cardiac structure remodeling and earlier systolic dysfunction than non-obese mice. Moreover, obese T2DM mice exhibited severe and persistent myocardial lipotoxicity, mainly manifested by increased FFAs uptake, accumulation of lipid droplets and glycogen, accompanied by continuous activation of the peroxisome proliferator activated receptor alpha (PPARα) pathway and phosphorylated glycogen synthase kinase 3 beta (p-GSK-3β), and sustained inhibition of glucose transport protein 4 (GLUT4) and adipose triglyceride lipase (ATGL), whereas non-obese mice showed no myocardial lipotoxicity characteristics at systolic dysfunction stage, accompanied by the restored PPARα pathway and GLUT4, sustained inhibition of p-GSK-3β and activation of ATGL. Additionally, both obese and non-obese T2DM mice showed significant accumulation of reactive oxygen species (ROS) when systolic dysfunction occurred, but the NF-E2-related factor 2 (Nrf2) pathway was significantly activated in obese mice, while was significantly inhibited in non-obese mice. Furthermore, the key differences found in animals were reliably verified in human samples.

Conclusion: Myocardial injury in obese and non-obese T2DM may represent two different types of complications. Obese T2DM individuals, compared to non-obese individuals, are more prone to develop cardiac systolic dysfunction due to severe and persistent myocardial lipotoxicity. Additionally, anti-oxidative dysfunction may be a key factor leading to myocardial injury in non-obese T2DM.

The Diabetic Cardiac Fibroblast: Mechanisms Underlying Phenotype and Function

Diabetic cardiomyopathy involves remodeling of the heart in response to diabetes that includes microvascular damage, cardiomyocyte hypertrophy, and cardiac fibrosis. Cardiac fibrosis is a major contributor to diastolic dysfunction that can ultimately result in heart failure with preserved ejection fraction. Cardiac fibroblasts are the final effector cell in the process of cardiac fibrosis. This review article aims to describe the cardiac fibroblast phenotype in response to high-glucose conditions that mimic the diabetic state, as well as to explain the pathways underlying this phenotype. As such, this review focuses on studies conducted on isolated cardiac fibroblasts. We also describe molecules that appear to oppose the pro-fibrotic actions of high glucose on cardiac fibroblasts. This represents a major gap in knowledge in the field that needs to be addressed.

Clinical and Biomarker Predictors of Expanded Heart Failure Outcomes in Patients With Type 2 Diabetes Mellitus After a Recent Acute Coronary Syndrome: Insights From the EXAMINE Trial

Background Improved heart failure (HF) risk stratification after a recent acute coronary syndrome may identify those who can benefit from therapies that reduce HF risk. We aimed to identify clinical and biomarker predictors for expanded HF outcomes in patients with type 2 diabetes mellitus after recent acute coronary syndrome. Methods and Results The EXAMINE (Examination of Cardiovascular Outcomes with Alogliptin versus Standard of Care) trial was a multicenter, non-inferiority, double-masked, placebo-controlled study which randomized 5380 patients with type 2 diabetes mellitus after recent acute coronary syndrome to alogliptin or placebo. Baseline biomarkers were measured in 5154 patients: NT-proBNP (N-terminal pro-B-type natriuretic peptide), high-sensitivity troponin I, adiponectin, growth-differentiation-factor-15, and galectin-3. Our primary outcome was cardiovascular) death, HF hospitalization, elevated NT-proBNP during follow-up, or loop diuretics initiation. The association between clinical variables, biomarkers, and outcomes were assessed using Cox regression models. In the study population, the median age was 61.0 years, 67.7% were men, and 28.0% had baseline HF (median follow-up was 18 months). In multivariable analyses, NT-proBNP had the strongest association with the primary outcome (per log2, hazard ratio 1.24; Wald χ2 67.4; P<0.0001) followed by a prior HF history (hazard ratio 1.42; Wald χ2 20.8; P<0.0001). A model with clinical variables and biomarkers allowed for risk prediction for expanded HF outcomes (C-statistic=0.72). Discrimination results were similar for cardiovascular death or HF hospitalization. Conclusions Among patients with type 2 diabetes mellitus after recent acute coronary syndrome, the use biomarkers such as N-terminal pro-B-type natriuretic peptide and clinical variables enables risk stratification for expanded HF outcomes. Clinical Trial Registration URL: https://www.clinicaltrials.gov/. Unique identifier: NCT00968708.

Heart Failure End Points in Cardiovascular Outcome Trials of Sodium Glucose Cotransporter 2 Inhibitors in Patients With Type 2 Diabetes Mellitus: A Critical Evaluation of Clinical and Regulatory Issues

Following regulatory guidance set forth in 2008 by the US Food and Drug Administration for new drugs for type 2 diabetes mellitus, many large randomized, controlled trials have been conducted with the primary goal of assessing the safety of antihyperglycemic medications on the primary end point of major adverse cardiovascular events, defined as cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke. Heart failure (HF) was not specifically mentioned in the US Food and Drug Administration guidance and therefore it was not a focus of these studies when planned. Several trials subsequently showed the impact of antihyperglycemic drugs on HF outcomes, which were not originally specified as the primary end point of the trials. The most impressive finding has been the substantial and consistent risk reduction in HF hospitalization seen across 4 trials of sodium glucose cotransporter 2 inhibitors. However, to date, these results have not led to regulatory approval of any of these drugs for a HF indication or a recommendation for use by US HF guidelines. It is therefore important to explore to what extent persuasive treatment effects on nonprimary end points can be used to support regulatory claims and guideline recommendations. This topic was discussed by researchers, clinicians, industry sponsors, regulators, and representatives from professional societies, who convened on the US Food and Drug Administration campus on March 6, 2019. This report summarizes these discussions and the key takeaway messages from this meeting.

Preventing and Treating Heart Failure with Sodium-Glucose Co-Transporter 2 Inhibitors

Heart failure is a common complication among patients with type 2 diabetes mellitus and is associated with significantly increased risks of subsequent morbidity and mortality. Until recently, therapies and strategies were lacking to attenuate this excess risk of heart failure in this population. Sodium-glucose co-transporter 2 (SGLT2) inhibitors represent a unique class of glucose-lowering therapies that have multisystem health benefits. Three large cardiovascular outcomes trials have demonstrated consistent reductions in heart failure events among patients with type 2 diabetes mellitus with, or at risk for, atherosclerotic cardiovascular disease. Another trial recently showed that an SGLT2 inhibitor, canagliflozin, also significantly reduced heart failure events among patients with type 2 diabetes mellitus and albuminuric chronic kidney disease. The SGLT2 inhibitor class represents an important new therapeutic approach for the prevention of heart failure in at-risk patients with type 2 diabetes mellitus, and is actively being studied for use in treating patients with heart failure (with or without type 2 diabetes mellitus). (Supplementary video "Preventing and Treating Heart Failure with Sodium-Glucose Co-Transporter 2 Inhibitors" is available online.).

Machine Learning to Predict the Risk of Incident Heart Failure Hospitalization Among Patients With Diabetes: The WATCH-DM Risk Score

OBJECTIVE

To develop and validate a novel, machine learning-derived model to predict the risk of heart failure (HF) among patients with type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

Using data from 8,756 patients free at baseline of HF, with <10% missing data, and enrolled in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, we used random survival forest (RSF) methods, a nonparametric decision tree machine learning approach, to identify predictors of incident HF. The RSF model was externally validated in a cohort of individuals with T2DM using the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).

RESULTS

Over a median follow-up of 4.9 years, 319 patients (3.6%) developed incident HF. The RSF models demonstrated better discrimination than the best performing Cox-based method (C-index 0.77 [95% CI 0.75-0.80] vs. 0.73 [0.70-0.76] respectively) and had acceptable calibration (Hosmer-Lemeshow statistic χ² = 9.63, P = 0.29) in the internal validation data set. From the identified predictors, an integer-based risk score for 5-year HF incidence was created: the WATCH-DM (Weight [BMI], Age, hyperTension, Creatinine, HDL-C, Diabetes control [fasting plasma glucose], QRS Duration, MI, and CABG) risk score. Each 1-unit increment in the risk score was associated with a 24% higher relative risk of HF within 5 years. The cumulative 5-year incidence of HF increased in a graded fashion from 1.1% in quintile 1 (WATCH-DM score ≤7) to 17.4% in quintile 5 (WATCH-DM score ≥14). In the external validation cohort, the RSF-based risk prediction model and the WATCH-DM risk score performed well with good discrimination (C-index = 0.74 and 0.70, respectively), acceptable calibration (P ≥0.20 for both), and broad risk stratification (5-year HF risk range from 2.5 to 18.7% across quintiles 1-5).

CONCLUSIONS

We developed and validated a novel, machine learning-derived risk score that integrates readily available clinical, laboratory, and electrocardiographic variables to predict the risk of HF among outpatients with T2DM.

Sodium-Glucose Cotransporter-2 Inhibitors and Heart Failure Prevention in Type 2 Diabetes

Diabetes and heart failure (HF) are closely linked, with one causing a worse prognosis in the other. The majority of anti-hyperglycaemic agents primarily reduce risk of ischaemic microvascular events without targeting the mechanisms involved for diabetes cardiomyopathy and HF. Sodium-glucose cotransporter-2 (SGLT2) inhibitors have emerged as a novel class of glucose-lowering agents that have consistently reduced HF hospitalisations, unlike other agents. The authors discuss the current evidence and highlight possible future directions for the role of SGLT2 inhibitors in HF prevention.

Mechanisms of Protective Effects of SGLT2 Inhibitors in Cardiovascular Disease and Renal Dysfunction

Type 2 diabetes mellitus is one of the most common forms of the disease worldwide. Hyperglycemia and insulin resistance play key roles in type 2 diabetes mellitus. Renal glucose reabsorption is an essential feature in glycaemic control. Kidneys filter 160 g of glucose daily in healthy subjects under euglycaemic conditions. The expanding epidemic of diabetes leads to a prevalence of diabetes-related cardiovascular disorders, in particular, heart failure and renal dysfunction. Cellular glucose uptake is a fundamental process for homeostasis, growth, and metabolism. In humans, three families of glucose transporters have been identified, including the glucose facilitators GLUTs, the sodium-glucose cotransporter SGLTs, and the recently identified SWEETs. Structures of the major isoforms of all three families were studied. Sodium-glucose cotransporter (SGLT2) provides most of the capacity for renal glucose reabsorption in the early proximal tubule. A number of cardiovascular outcome trials in patients with type 2 diabetes have been studied with SGLT2 inhibitors reducing cardiovascular morbidity and mortality. The current review article summarises these aspects and discusses possible mechanisms with SGLT2 inhibitors in protecting heart failure and renal dysfunction in diabetic patients. Through glucosuria, SGLT2 inhibitors reduce body weight and body fat, and shift substrate utilisation from carbohydrates to lipids and, possibly, ketone bodies. These pleiotropic effects of SGLT2 inhibitors are likely to have contributed to the results of the EMPA-REG OUTCOME trial in which the SGLT2 inhibitor, empagliflozin, slowed down the progression of chronic kidney disease and reduced major adverse cardiovascular events in high-risk individuals with type 2 diabetes. This review discusses the role of SGLT2 in the physiology and pathophysiology of renal glucose reabsorption and outlines the unexpected logic of inhibiting SGLT2 in the diabetic kidney.

Mechanisms and Evidence for Heart Failure Benefits from SGLT2 Inhibitors

PURPOSE OF REVIEW

To review the clinical trial data and underlying mechanistic principles in support of the robust cardiovascular (CV) benefits, in particular, heart failure (HF) outcomes association with sodium-glucose co-transporter-2 (SGLT2) inhibitors.

RECENT FINDINGS

Several large CV outcome trials in patients with type 2 diabetes mellitus (T2DM) and with either established atherosclerotic CV disease (ASCVD) or at high risk for ASCVD reveal that SGLT2 inhibitors cause reductions in CV and HF endpoints. The reduction in ASCVD appears to be confined to those with established ASCVD on the order of ≈ 14%, as does the mortality benefit-all-cause and CV-related. However, hospitalization for HF are reduced by ≈ 33% and occur regardless of baseline patient characteristics. The unprecedented HF outcomes are theorized to occur via several possible mechanisms and include optimization of conventional ASCVD risk factors, improvement in hemodynamics, prevention of cardiac and renal remodeling, inhibition of hormone dysregulation, use of more efficient metabolic substrates, ion channel inhibition, anti-inflammatory effects, and anti-oxidant effects. Recent evidence has unveiled the irrefutable data that SGLT2 inhibitors reduce CV events in patients with T2DM, with a profound effect on reductions in hospitalization for HF. Though several mechanisms conveying this benefit are suggested, most are based in limited data requiring further validation. Nonetheless, the arrival of SGLT2 inhibitors has ushered in a new era of CV risk reductions therapies.

Assessment of Heart Failure in Diabetes Cardiovascular Outcomes Trials: Is What We Are Currently Capturing Adequate?

PURPOSE OF REVIEW

Since the 2008 FDA guidance restructuring the design of trials for the approval of novel glucose-lowering agents, 13 medications have now been evaluated by dedicated cardiovascular outcome trials. All of the completed trials have included data (though with varying definitions) on rates of hospitalization for heart failure. This review is aimed at summarizing current heart failure outcome data available from cardiovascular safety trials for novel glucose-lowering agents in patients with type 2 diabetes mellitus.

RECENT FINDINGS

There appears to be growing evidence for the benefit of sodium-glucose cotransporter-2 inhibitors, and there are still not enough data to fully support the safety of glucagon-like peptide 1 receptor agonists in heart failure. Increased rates of hospitalization for heart failure were seen with both saxagliptin and alogliptin, and this has led to a class warning for all dipeptidyl peptidase-4 inhibitors. Future studies should have a standardized definition of "hospitalization for heart failure," should consider including hospitalization for heart failure as a component of the primary composite endpoint, and should provide a more detailed description of the baseline characteristics of enrolled study participants with heart failure.

Heart failure and type 2 diabetes: From cardiovascular outcome trials, with hope

An excess risk of heart failure (HF) persists in patients with type 2 diabetes (T2D) despite optimal control of an array of conventional risk factors, including hyperglycaemia. Twelve cardiovascular outcome trials (CVOTs) have been published to date, although none, with the exception of the DECLARE trial with dapagliflozin, has included HF as a primary endpoint. The four trials with dipeptidyl-peptidase inhibitors (DPP-4i) (SAVOR-TIMI 53 with saxagliptin, EXAMINE with alogliptin, TECOS with sitagliptin and CARMELINA with linagliptin) failed to show any significant effect on HF risk in patients with T2D, with the notable exception of saxagliptin which was associated with a 27% increased risk. Five completed CVOTs with the GLP-1 RAs lixisenatide (ELIXA), liraglutide (LEADER), semaglutide (SUSTAIN-6), exenatide once weekly (EXSCEL) and albiglutide (HARMONY) also failed to reveal any significant effect on HF risk. The three trials with sodium glucose co-transporter-2 inhibitors (SGLT-2i) (EMPA-REG OUTCOME with empagliflozin, CANVAS with canagliflozin and DECLARE with dapagliflozin) all revealed a robust and significant reduction in the hazard ratios of hospitalization for HF, from 27% to 35%, which remained consistent, significant and of similar magnitude regardless of the presence of a history of HF or established atherosclerotic cardiovascular disease. There is no association between reductions in HF risk and haemoglobin A1c (A1C) levels, while there is a significant association between reductions in HR for MACE and A1C levels (Spearman's correlation, r = 0.695; P = 0.013). All of the 12 CVOTs completed to date have provided reassurance of the overall cardiovascular safety of the newer anti-hyperglycaemic drugs. At present, the robust, consistent and reproducible reduction of approximately 30% in the risk of HF with SGLT-2i may be considered a class effect. The beneficial effect on MACE outcome observed with the use of some GLP-1RAs and SGLT-2i must be interpreted within the frame of the single trial.

Heart failure and diabetes: The confrontation of two major epidemics of the 21st century

There is a bidirectional association between heart failure (HF) and type 2 diabetes mellitus (DM2), which has resulted in an exponential increase in the combination of the 2 diseases in a single patient. This combination is one of many common causes that lead to the pathophysiological pathways resulting in the deleterious effect of DM2 on HF. The inevitable clinical consequence is that, when faced with this situation, patients present worse symptoms and a poorer prognosis than patients with HF but without DM2. We should therefore consider how to treat DM2 in patients with HF and how to treat HF in patients with DM2. In this review, we highlight the latest published data on this issue.

Type-2 diabetes mellitus and cardiovascular disease

The global prevalence of diabetes has risen in adults from 4.7% in 1980 to 8.5% in 2014. 90–95% of adults with diabetes have Type 2 diabetes (T2D). This paper focuses on the diagnosis and treatment of T2D patients who have or are at risk for cardiovascular disease. Hyperglycemia, insulin resistance and excess fatty acids increase oxidative stress, disrupt protein kinase C signaling and increase advanced glycation end-products that result in vascular inflammation, vasoconstriction, thrombosis and atherogenesis. Intensive T2D treatment produces a ≥10% risk reduction in major macrovascular and microvascular events. Glucose-lowering therapies must be individualized. Metformin is an optimal drug for monotherapy. If hemoglobin A1c is not at goal, a sodium-glucose cotransporter-2 inhibitor or a dipeptidyl peptidase-4 inhibitor should be considered for therapy with metformin. Coronary angioplasty/stenting is recommended for diabetic patients with acute myocardial infarctions. Coronary artery bypass grafting is recommended for symptomatic diabetic patients with multivessel disease.

SGLT2 inhibitors and mechanisms of cardiovascular benefit: a state-of-the-art review

Sodium-glucose cotransporter (SGLT)2 inhibitors have been demonstrated to reduce cardiovascular events, particularly heart failure, in cardiovascular outcome trials. Here, we review the proposed mechanistic underpinnings of this benefit. Specifically, we focus on the role of SGLT2 inhibitors in optimising ventricular loading conditions through their effect on diuresis and natriuresis, in addition to reducing afterload and improving vascular structure and function. Further insights into the role of SGLT2 inhibition in myocardial metabolism and substrate utilisation are outlined. Finally, we discuss two emerging themes: how SGLT2 inhibitors may regulate Na⁺/H⁺ exchange at the level of the heart and kidney and how they may modulate adipokine production. The mechanistic discussion is placed in the context of completed and ongoing trials of SGLT2 inhibitors in the prevention and treatment of heart failure in individuals with and without diabetes.

Do we need biomarkers for diabetics progressing to heart failure?

Cardiovascular changes produce unfavorable outcomes including arterial hypertension and diabetes, which are related to the increased risk of heart failure (HF). The latter is highly prevalent in the setting of glucose metabolism dysregulation and high hemodynamic load, and identifying predictors of the incidence of HF with preserved ejection fraction (HFpEF) requires a research and is a clinical need. Toward this end, the variability in glucose regulation represents a novel dynamic way to comprehend and study the impact of glycemia. The results of the published study highlight the independent association of glycated hemoglobin A1c variability with the development of HFpEF in hypertensive diabetic patients. Based on the above, the effect of diverse antidiabetic therapies on glycemic control variability and overall management of these patients to reduce the risk of HFpEF remain essential for the modern cardiologist.