Dipeptidyl peptidase-4 inhibitors and risk of heart failure in type 2 diabetes: systematic review and meta-analysis of randomised and observational studies

Medical Management of Diabesity: Do We Have Realistic Targets?

PURPOSE OF REVIEW

The global prevalence of "diabesity"-diabetes related to obesity-is increasing steadily over the past few decades because of the obesity epidemic. Although bariatric surgery is an effective treatment option for patients with diabesity, its limited availability, invasiveness, relatively high costs and the potential for surgical and postsurgical complications restrict its widespread use. Therefore, medical management is the only option for a majority of patients with diabesity. Diabetes control with several anti-diabetic agents, including insulin, causes weight gain with probability of worsening diabesity. Rational use of anti-diabetic medications with weight loss potential in varying combinations may help to address this key issue for long-term management of diabesity. There is no consensus on such an approach from different professional bodies like American Diabetes Association, European Association for Study of Diabetes, or International Diabetes Federation. We attempt to discuss the key issues and realistic targets for diabesity management in this paper.

RECENT FINDINGS

Rational use of anti-diabetic combinations can mitigate worsening of diabesity to some extent while managing patients. Retrospective studies showed that combination therapy with glucagon-like peptide-1 (GLP-1) receptor agonists and sodium glucose co-transporter 2 (SGLT-2) inhibitors, when administered along with other anti-diabetic medications, offer the best therapeutic benefit in the medical management of diabesity. Different combinations of other anti-diabetic drugs with minimum weight gain potential were also found useful. Because of insufficient evidence based on prospective randomised controlled trials (RCTs), future research should focus on evolving the appropriate rational drug combinations for the medical management of diabesity.

Cardiovascular Outcomes of New Medications for Type 2 Diabetes

Cardiovascular (CV) disease remains the leading cause of death in people with diabetes, highlighting the importance of using treatment options that do not increase CV risk or possibly decrease CV outcomes. Since 2008, the Food and Drug Administration has required demonstration of CV safety for all new medications developed for the glycemic management of diabetes. Seven trials have been published that have established CV safety for three DPP-4 inhibitors (alogliptin, saxagliptin, and sitagliptin), three GLP-1 receptor agonists (liraglutide, lixisenatide, and semaglutide), and one sodium-glucose cotransporter-2 inhibitor (empagliflozin). Three of those studies also established superiority with liraglutide, empagliflozin, and semaglutide at reducing the composite primary endpoint of major CV events (CV death, nonfatal myocardial infarction, and nonfatal stroke). In addition, one trial found an increase in heart failure hospitalizations with saxagliptin. The findings of these trials must be compared and contrasted cautiously given the differences in patient populations and trial designs, but together they provide important information that can be used to shape our treatment guideline recommendations and patient-specific treatment decisions.

Bringing patient centricity to diabetes medication access in Canada

Canada must become proactive in addressing type 2 diabetes. With the second highest rate of diabetes prevalence in the developed world, the number of Canadians living with diabetes will soon reach epidemic levels. Against international comparisons, Canada also performs poorly with respect to diabetes-related hospitalizations, mortality rates, and access to medications. Diabetes and its comorbidities pose a significant burden on people with diabetes (PWD) and their families, through out-of-pocket expenses for medications, devices, supplies, and the support needed to manage their illness. Rising direct and indirect costs of diabetes will become a drain on Canada's economy and undermine the financial stability of our health care system. Canada's approach to diabetes medication assessment and funding has created a patchwork of medication access across provinces. Access to treatments for those who rely on public programs is highly restricted compared to Canadians with private drug plans, as well in contrast with public payers in other countries. Each person living with diabetes has different needs, so a "patient-centric" approach ensures treatment focused on individual circumstances. Such tailoring is difficult to achieve, with the linear approach required by public payers. We may be undermining optimal care for PWD because of access policies that are not aligned with individualized approaches - and increasing overall health care costs in the process. The scope of Canada's diabetes challenge demands holistic and proactive solutions. Canada needs to get out from "behind the eight ball" and get "ahead of the curve" when it comes to diabetes care. Improving access to medications is one of the tools for getting there. Canada's "call to action" for diabetes starts with effective implementation of existing best practices. A personalized approach to medication access, to meet individual needs and optimize outcomes, is also a key enabler. PWD and prescribers need reimbursement approaches that allow them to use existing tools (ie, medications and supplies) to manage diabetes in a timely manner and to avoid and/or delay major downstream complications.

Effect of liraglutide, a glucagon-like peptide-1 analogue, on left ventricular function in stable chronic heart failure patients with and without diabetes (LIVE)-a multicentre, double-blind, randomised, placebo-controlled trial

AIMS

To determine the effect of the glucagon-like peptide-1 analogue liraglutide on left ventricular function in chronic heart failure patients with and without type 2 diabetes.

METHODS AND RESULTS

LIVE was an investigator-initiated, randomised, double-blinded, placebo-controlled multicentre trial. Patients (n = 241) with reduced left ventricular ejection fraction (LVEF ≤45%) were recruited (February 2012 to August 2015). Patients were clinically stable and on optimal heart failure treatment. Intervention was liraglutide 1.8 mg once daily or matching placebo for 24 weeks. The LVEF was similar at baseline in the liraglutide and the placebo group (33.7 ± 7.6% vs. 35.4 ± 9.4%). Change in LVEF did not differ between the liraglutide and the placebo group; mean difference (95% confidence interval) was -0.8% (-2.1, 0.5; P = 0.24). Heart rate increased with liraglutide [mean difference: 7 b.p.m. (5, 9), P < 0.0001]. Serious cardiac events were seen in 12 (10%) patients treated with liraglutide compared with 3 (3%) patients in the placebo group (P = 0.04).

CONCLUSION

Liraglutide did not affect left ventricular systolic function compared with placebo in stable chronic heart failure patients with and without diabetes. Treatment with liraglutide was associated with an increase in heart rate and more serious cardiac adverse events, and this raises some concern with respect to the use of liraglutide in patients with chronic heart failure and reduced left ventricular function. More data on the safety of liraglutide in different subgroups of heart failure patients are needed.

Cardiovascular safety of therapies for type 2 diabetes

INTRODUCTION

Dipeptidyl peptidase-4 (DPP4) inhibitors, glucagon-like peptide-1 (GLP-1) analogs and sodium-glucose cotransporter 2 (SGLT2) inhibitors are relatively new therapies for the treatment of type 2 diabetes mellitus. Given the high prevalence of cardiovascular complications in patients with type 2 diabetes and recent concerns questioning CV safety of newer antidiabetic medications, cardiovascular safety of these medications requires evaluation. Areas covered: Cardiovascular effects of these drug classes from preclinical and clinical data as well as non-cardiovascular safety issues are delineated from literature searches covering the last decade and up to June 2016. Major clinical trials assessing the cardiovascular safety of GLP-1 agonists (ELIXA and LEADER), DPP-4 inhibitors (SAVOR-TIMI 53, EXAMINE, and TECOS) and SGLT2 inhibitors (EMPA-REG OUTCOME) are reviewed and interpreted. Expert opinion: Based on review of the present evidence, these 3 classes of antihyperglycemic therapies have acceptably safe CV safety profiles for patients with type 2 diabetes. The latest evidence from LEADER and EMPA-REG OUTCOME trials indicate that liraglutide and empagliflozin have cardiovascular benefits that may prove to be of clinical importance in the management of type 2 DM.

Efficacy and safety of DPP-4 inhibitors in patients with type 2 diabetes: Meta-analysis of placebo-controlled randomized clinical trials

BACKGROUND

Guidelines for type 2 diabetes (T2D) recommend reducing HbA_1c through lifestyle interventions and glucose-lowering drugs (metformin, then combination with dipeptidyl peptidase-4 inhibitors [DPP-4Is] among other glucose-lowering drugs). However, no double-blind randomized clinical trial (RCT) compared with placebo has so far demonstrated that DDP-4Is reduce micro- and macrovascular complications in T2D. Moreover, the safety of DPP-4Is (with increased heart failure and acute pancreatitis) remains controversial.

METHODS

A systematic review of the literature (PubMed, Cochrane Library Central Register of Controlled Trials [CENTRAL] and https://clinicaltrials.gov), including all RCTs vs placebo published up to May 2015 and the Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS), published June 2015, was performed. Primary endpoints were all-cause mortality and death from cardiovascular causes; secondary endpoints were macrovascular and microvascular events. Safety endpoints were acute pancreatitis, pancreatic cancer, serious adverse events and severe hypoglycaemia.

RESULTS

A total of 36 double-blind RCTs were included, allowing analyses of 54,664 patients. There were no significant differences in all-cause mortality (RR=1.03, 95% confidence interval [CI]=0.95-1.12), cardiovascular mortality (RR=1.02, 95% CI=0.92-1.12), myocardial infarction (RR=0.98, 95% CI=0.89-1.08), strokes (RR=1.02, 95% CI=0.88-1.17), renal failure (RR=1.06, 95% CI=0.88-1.27), severe hypoglycaemia (RR=1.14, 95% CI=0.95-1.36) and pancreatic cancer (RR=0.54, 95% CI=0.28-1.04) with the use of DPP-4Is. However, DDP-4Is were associated with an increased risk of heart failure (RR=1.13, 95% CI=1.01-1.26) and of acute pancreatitis (RR=1.57, 95% CI=1.03-2.39).

CONCLUSION

There is no significant evidence of short-term efficacy of DPP-4Is on either morbidity/mortality or macro-/microvascular complications in T2D. However, there are warning signs concerning heart failure and acute pancreatitis. This suggests a great need for additional relevant studies in future.

Glucose, cholesterol, and blood pressure: is lower always better for type 2 diabetes?

Diabetes mellitus is a major risk factor for cardiovascular disease. However, the excess risk of death may vary substantially in subgroups of patients with type 2 diabetes, being highest in those younger than 55 years of age. A HbA1c value of 7.0 % or less is recommended for most patients with type 2 diabetes to reduce the incidence of microvascular disease, although individualized approaches that balance the benefits of glycemic control against the harms of hypoglycemia are encouraged. The selection of antidiabetic medications is of paramount importance, as the drug should not aggravate, and ideally even improve cardiovascular risk factors, with the hope to reduce cardiovascular morbidity and mortality. Patients with diabetes mellitus between 40 and 75 years of age with LDL-C between 70 and 189 mg/dL should be treated with a moderate-intensity statin. Implicit in this recommendation is the aim to reduce further LDL-C level in diabetes, in order to improve the cardiovascular outlook. The new PCSK9 inhibitors (evolocumab and arilocumab) are very promising, but, at present, their cost-effectiveness ratios exceed commonly accepted thresholds. For many people with diabetes mellitus and hypertension blood pressure should be <140/90 mmHg, although lower systolic targets (e.g., <130 mmHg) may be appropriate for certain individuals. With the likely exception of LDL-C, it is difficult to define a universal HbA1c and blood pressure target for all patients with type 2 diabetes mellitus. Ultimately, in the face of uncertainty in medicine, the final decision regarding a specific patient is best left to the clinician.

Current perspectives on cardiovascular outcome trials in diabetes

Cardiovascular disease (CVD) is one of the most common diabetes-associated complications, as well as a leading cause for death in type 2 diabetes patients (T2D). Despite the well-known correlation between the two, up until the 2008 FDA industry guidance for licensing of new anti-hyperglycemic drugs, which required an investigation of cardiovascular outcomes (CVO) of glucose-lowering agents, only a few studies had looked into the relationship between glucose lowering drugs and cardiovascular (CV) risk. Thereafter, CVOT design has focused on non-inferiority short-term studies on high-risk patient populations aiming at capturing CV safety issues. Despite the wealth of information and useful data provided by CVOTs, this approach still suffers from certain limitations. The present review will condense the main results of the most recently completed CVOTs, reflect on the lessons learned, discuss on the issues presented by current CVOT design and offer some suggestions for improvement.

Dipeptidyl peptidase-4 inhibitors and cardiovascular risks in patients with pre-existing heart failure

BACKGROUND

Although recent clinical trials raised concerns about the risk for heart failure (HF) in dipeptidyl peptidase-4 (DPP-4) inhibitor use, data on the cardiovascular risks in the patients with pre-existing HF are still lacking.

METHODS

We used Taiwan's National Health Insurance Research Database to identify 196 986 patients diagnosed with type 2 diabetes mellitus (T2DM) who had previous history of HF between 2009 and 2013. This population included 30 204 DPP-4 inhibitor users and 166 782 propensity score-matched DPP-4 inhibitor non-users. The outcomes of interest were all-cause mortality, combination of myocardial infarction (MI) and ischaemic stroke, and hospitalisation for HF.

RESULTS

The incidence in DPP-4 users compared with non-users was 67.02 vs 102.85 per 1000 person-years for all-cause mortality, 37.89 vs 47.54 per 1000 person-years for the combination of MI and ischaemic stroke, 12.70 vs 16.18 per 1000 person-years for MI and 26.37 vs 32.46 per 1000 person-years for ischaemic stroke. The risk of all-cause mortality was lower in DPP-4 inhibitor users (HR 0.67, 95% CI 0.64 to 0.70), combination of MI and stroke (HR 0.81, 95% CI 0.76 to 0.87), MI (HR 0.80, 95% CI 0.71 to 0.89) and ischaemic stroke (HR 0.83, 95% CI 0.76 to 0.89) than in non-users. Notably, the risk of hospitalisation for HF did not differ significantly between groups. The results were similar after accounting for death as a competing risk.

CONCLUSIONS

In this nationwide T2DM cohort, the risks of mortality and the combination of MI and ischaemic stroke were lower for patients receiving DPP-4 inhibitors than for those who did not receive such treatment. DPP-4 inhibitor use was not associated with a higher risk of hospitalisation for HF even in patients with pre-existing HF.

Continued efforts to translate diabetes cardiovascular outcome trials into clinical practice

Diabetic patients suffer from a high rate of cardiovascular events and such risk increases with HbA1c. However, lowering HbA1c does not appear to yield the same benefit on macrovascular endpoints, as observed for microvascular endpoints. As the number of glucose-lowering medications increases, clinicians have to consider several open questions in the management of type 2 diabetes, one of which is the cardiovascular risk profile of each regimen. Recent placebo-controlled cardiovascular outcome trials (CVOTs) have responded to some of these questions, but careful interpretation is needed. After general disappointment around CVOTs assessing safety of DPP-4 inhibitors (SAVOR, TECOS, EXAMINE) and the GLP-1 receptor agonist lixisenatide (ELIXA), the EMPA-REG Outcome trial and the LEADER trial have shown superiority of the SGLT2-I empagliflozin and the GLP-1RA liraglutide, respectively, on the 3-point MACE outcome (cardiovascular death, non-fatal myocardial infarction or stroke) and cardiovascular, as well as all-cause mortality. While available mechanistic studies largely support a cardioprotective effect of GLP-1, the ability of SGLT2 inhibitor(s) to prevent cardiovascular death was unexpected and deserves future investigation. We herein review the results of completed CVOTs of glucose-lowering medications and suggest a possible treatment algorithm based on cardiac and renal co-morbidities to translate CVOT findings into clinical practice.

DPP-4 inhibitors in diabetic complications: role of DPP-4 beyond glucose control

Dipeptidyl peptidase-4 (DPP-4) inhibitors (gliptins) are an emerging class of antidiabetic drugs that constitutes approximately fifty percent of the market share of the oral hypoglycemic drugs. Its mechanism of action for lowering blood glucose is essentially via inhibition of the rapid degradation of incretin hormones, such as glucagon-like peptide (GLP)-1 and gastric inhibitory polypeptide (GIP), thus the plasma concentration of GLP-1 increases, which promotes insulin secretion from the pancreatic β cells and suppresses glucagon secretion from the α cells. In addition to the direct actions on the pancreas, GLP-1 exhibits diverse actions on different tissues through its action on GLP-1 receptor, which is expressed ubiquitously. Moreover, DPP-4 has multiple substrates besides GLP-1 and GIP, including cytokines, chemokines, neuropeptides, and growth factors, which are involved in many pathophysiological conditions. Recently, it was suggested that DPP-4 is a new adipokine secreted from the adipose tissue, which plays an important role in the regulation of the endocrine function in obesity-associated type 2 diabetes. Consequently, DPP-4 inhibitors have been reported to exhibit cytoprotective functions against various diabetic complications affecting the liver, heart, kidneys, retina, and neurons. This review outlines the current understanding of the effect of DPP-4 inhibitors on the complications associated with type 2 diabetes, such as liver steatosis and inflammation, dysfunction of the adipose tissue and pancreas, cardiovascular diseases, nephropathy, and neuropathy in preclinical and clinical studies.

Acute decompensated heart failure (ADHF): A comprehensive contemporary review on preventing early readmissions and postdischarge death

Heart failure (HF) is an increasingly prevalent syndrome and a leading cause of both first hospitalization and readmissions. Strikingly, up to 25% of the patients are readmitted within 30 to 60-days, accounting for HF as the primary cause for readmission in the adult population. Given its poor prognosis, one could describe it as a "malignant condition". Acute decompensation is intrinsically related to increased right heart tele-diastolic pressures and often related to congestive symptoms. In-hospital strategies to adequately compensate and timely discharge patients are limited. Conversely, the fragile early postdischarge phase is a vulnerable period when one could potentially intervene cost-effectively to improve survival and to reduce morbidity. Promising transitional hospital-to-home programs may have a broader role in the near future, namely for selected higher risk patients. However, identifying patients at risk for hospital readmission has been challenging. Novel approaches, such as ferric carboxymaltose and valsartan/sacubitril, and reemerging drugs, particularly digoxin, may reduce hospitalizations. Despite this, optimizing the use of "older" therapies is still warranted. Right heart pressures monitoring may provide novel insights into promptly outpatient management. Unfortunately, randomized trials in the specific ADHF population are scarce. A novel paradigmatic approach is needed in order to suitably improve the currently poor prognosis of ADHF. Both improving survival and reducing hospitalizations are, therefore, primordial therapy goals. Lastly, no single drug has consistently proved to improve survival in HF with preserved ejection fraction (HFpEF); yet, some approaches may efficiently reduce hospitalizations. Awareness on HFpEF management beyond the failing heart is imperative.

DPP-4 inhibitor plus SGLT-2 inhibitor as combination therapy for type 2 diabetes: from rationale to clinical aspects

INTRODUCTION

Type 2 diabetes (T2D) is a complex disease with multiple defects, which generally require a combination of several pharmacological approaches to control hyperglycemia. Combining a dipeptidyl peptidase-4 inhibitor (DPP-4i) and a sodium-glucose cotransporter type 2 inhibitor (SGT2i) appears to be an attractive approach. Area covered: An extensive literature search was performed to analyze the pharmacokinetics, pharmacodynamics and clinical experience of different gliptin-gliflozin combinations. Expert opinion: There is a strong rationale for combining a DPP-4i and a SGLT2i in patients with T2D because the two drugs exert different and complementary glucose-lowering effects. Dual therapy (initial combination or stepwise approach) is more potent than either monotherapy in patients treated with diet and exercise or already treated with metformin. Combining the two pharmacological options is safe and does not induce hypoglycemia. The additional glucose-lowering effect is more marked when a gliflozin is added to a gliptin than when a gliptin is added to a gliflozin. Two fixed-dose combinations (FDCs) are already available (saxagliptin-dapagliflozin and linagliptin-empagliflozin) and others are in current development. Bioequivalence of the two compounds given as FDC tablets was demonstrated when compared with coadministration of the individual tablets. FDCs could simplify the anti-hyperglycaemic therapy and improve drug compliance.

Dipeptidyl peptidase-4 inhibition with linagliptin prevents western diet-induced vascular abnormalities in female mice

BACKGROUND

Vascular stiffening, a risk factor for cardiovascular disease, is accelerated, particularly in women with obesity and type 2 diabetes. Preclinical evidence suggests that dipeptidylpeptidase-4 (DPP-4) inhibitors may have cardiovascular benefits independent of glycemic lowering effects. Recent studies show that consumption of a western diet (WD) high in fat and simple sugars induces aortic stiffening in female C57BL/6J mice in advance of increasing blood pressure. The aims of this study were to determine whether administration of the DPP-4 inhibitor, linagliptin (LGT), prevents the development of aortic and endothelial stiffness induced by a WD in female mice.

METHODS

C56Bl6/J female mice were fed a WD for 4 months. Aortic stiffness and ex vivo endothelial stiffness were evaluated by Doppler pulse wave velocity (PWV) and atomic force microscopy (AFM), respectively. In addition, we examined aortic vasomotor responses and remodeling markers via immunohistochemistry. Results were analyzed via 2-way ANOVA, p < 0.05 was considered as statistically significant.

RESULTS

Compared to mice fed a control diet (CD), WD-fed mice exhibited a 24 % increase in aortic PWV, a five-fold increase in aortic endothelial stiffness, and impaired endothelium-dependent vasodilation. In aorta, these findings were accompanied by medial wall thickening, adventitial fibrosis, increased fibroblast growth factor 23 (FGF-23), decreased Klotho, enhanced oxidative stress, and endothelial cell ultrastructural changes, all of which were prevented with administration of LGT.

CONCLUSIONS

The present findings support the notion that DPP-4 plays a role in development of WD-induced aortic stiffening, vascular oxidative stress, endothelial dysfunction, and vascular remodeling. Whether, DPP-4 inhibition could be a therapeutic tool used to prevent the development of aortic stiffening and the associated cardiovascular complications in obese and diabetic females remains to be elucidated.

The EMPA-REG outcome study: critical appraisal and potential clinical implications

Diabetes health care professionals have to face a study with results of incomparable success in secondary and tertiary cardiovascular disease prevention. In the past, no studies in patients with type 2 diabetes resulted to be successful in inducing an improvement of cardiovascular prognosis, no matter whether they were focused on a target, on life-style or on pharmacological intervention. On a clinical perspective, should the diabetologist's way to think about the anti-diabetic therapy of patients on secondary cardiovascular prevention change based on the results of Empa-Reg outcome? Due to the complexity of the clinical picture of patients with type 2 diabetes, a tailored therapy based on targets, complications, co-morbidity, familial and social environment, personal and cultural features must be conceived and applied in starting pharmacological therapy; however, the question whether should we consider empagliflozin as first choice therapy in individuals with type 2 diabetes exposed to high cardiovascular risk, the Empa-Reg outcome-like patient, awaits now for an answer. Waiting for data confirming the results of the Empa-Reg outcome study, this report goes through the good reasons in support of this way of thinking, but at the same time explores the many unanswered questions raising potential concerns about this clinical choice.