Increased Risk of Hospitalization for Heart Failure with Newly Prescribed Dipeptidyl Peptidase-4 Inhibitors and Pioglitazone Using the Korean Health Insurance Claims Database

Cardioprotective effects of dipeptidyl peptidase-4 inhibitors versus sulfonylureas in addition to metformin: A nationwide cohort study of patients with type 2 diabetes

AIMS

Cardiovascular effects of dipeptidyl peptidase-4 inhibitors (DPP4i) versus sulfonylureas (SU) remain controversial in observational studies. This study aimed to evaluate the influence of DPP4i on major adverse cardiovascular events (MACEs), including acute myocardial infarction, cerebrovascular disease, heart failure, cardiogenic shock, malignant dysrhythmia, and revascularisation.

MATERIALS AND METHODS

We conducted a nationwide cohort study using claims data from the National Health Insurance in Taiwan from 2007 to 2013. We enrolled type 2 diabetes patients who received DPP4i or SU in addition to metformin. DPP4i users were matched to SU users using propensity scores at a ratio of 1:1. The study outcomes were hospitalisation for MACE, heart failure, acute myocardial infarction, cerebrovascular disease, coronary revascularisation, and hypoglycaemia.

RESULTS

There were 37,317 matched pairs of DPP4i and SU users with a mean follow-up of 2.1 years. Compared with SU users, DPP4i users showed a significantly lower risk of hospitalisation for MACE (HR 0.79 [95% CI 0.75-0.82]), heart failure (0.86 [0.79-0.93]), acute myocardial infarction (0.76 [0.68-0.92]), and cerebrovascular disease (0.72 [0.67-0.77]). Both sitagliptin (0.89 [0.85-0.94]) and vildagliptin ([0.77 [0.60-0.99]) showed a significantly lower risk of hospitalisation for MACE, but saxagliptin showed a borderline significantly higher risk of hospitalisation for heart failure (1.59 [1.00-2.55]).

CONCLUSIONS

DPP4i showed better cardioprotective effects than SU, especially among patients receiving sitagliptin or vildagliptin.

Cardiovascular Safety and Benefits of Noninsulin Antihyperglycemic Drugs for the Treatment of Type 2 Diabetes Mellitus: Part 2

Ideal drugs to improve outcomes in type 2 diabetes mellitus (T2DM) are those with antiglycemic efficacy, as well as cardiovascular safety that has to be determined in appropriately designed cardiovascular outcome trials as mandated by regulatory agencies. The more recent antihyperglycemic medications have shown promise with regards to cardiovascular disease (CVD) risk reduction in T2DM patients at a high cardiovascular risk. Sodium glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor agonists are associated with better cardiovascular outcomes and mortality in T2DM patients than are dipeptidylpeptidase-4 inhibitors, leading to the Food and Drug Administration's approval of empagliflozin to reduce mortality, and of liraglutide to reduce CVD risk in high-risk T2DM patients. For heart failure outcomes, sodium glucose cotransporter-2 inhibitors are beneficial, while glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors are neutral. Ongoing and planned randomized controlled trials of these newer drugs should clarify the possibility of class effects and of CVD risk reduction benefits in low-moderate cardiovascular risk patients. While we eagerly await the results on ongoing studies, these medications should be appropriately prescribed in T2DM patients with baseline CVD or those at a high CVD risk after carefully evaluating the elevated risk for adverse events like gastrointestinal disturbances, bladder cancer, genital infections, and amputations. Studies to understand the pleotropic and novel pathophysiological mechanisms demonstrated by the sodium glucose cotransporter-2 inhibitors will shed light on the effects of the modulation of microvascular, inflammatory, and thrombotic milieu for improving the CVD risk in T2DM patients. This is part 2 of the series on noninsulin antihyperglycemic drugs for the treatment of T2DM.

Changing Fields-Diabetes Medications Invading the Cardiovascular Space

Cardiovascular disease (CVD) remains the leading cause of mortality in patients with type 2 diabetes, and treatment strategies that impact cardiovascular (CV) outcomes in this population is an area of growing interest. Pharmacologic agents that reduce CVD risk have been developed, and data supporting their use have grown extensively. Glucagon-like peptide 1 agonists and sodium-glucose cotransporter 2 inhibitors when added to metformin therapy provide the most CV benefit and should be considered in most patients. Data available suggest that sulfonylureas should be avoided in patients at risk for CVD and if a thiazolidinedione is utilized, pioglitazone may be preferred. When selecting an agent, the potential benefit, risk, and cost of each agent should be considered prior to initiation. The purpose of this review is to summarize the literature surrounding the CV effects of antidiabetic agents and to provide practical guidance on their use in patients with type 2 diabetes and CVD.

Effects of antidiabetic drugs on left ventricular function/dysfunction: a systematic review and network meta-analysis

BACKGROUND

Although a variety of antidiabetic drugs have significant protective action on the cardiovascular system, it is still unclear which antidiabetic drugs can improve ventricular remodeling and fundamentally delay the process of heart failure. The purpose of this network meta-analysis is to compare the efficacy of sodium glucose cotransporter type 2 (SGLT-2) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) agonists, metformin (MET), sulfonylurea (SU) and thiazolidinediones (TZDs) in improving left ventricular (LV) remodeling in patients with type 2 diabetes (T2DM) and/or cardiovascular disease (CVD).

METHODS

We searched articles published before October 18, 2019, regardless of language or data, in 4 electronic databases: PubMed, EMBASE, Cochrane Library and Web of Science. We included randomized controlled trials in this network meta-analysis, as well as a small number of cohort studies. The differences in the mean changes in left ventricular echocardiographic parameters between the treatment group and control group were evaluated.

RESULTS

The difference in the mean change in LV ejection fraction (LVEF) between GLP-1 agonists and placebo in treatment effect was greater than zero (MD = 2.04% [0.64%, 3.43%]); similar results were observed for the difference in the mean change in LV end-diastolic diameter (LVEDD) between SGLT-2 inhibitors and placebo (MD = - 3.3 mm [5.31, - 5.29]), the difference in the mean change in LV end-systolic volume (LVESV) between GLP-1 agonists and placebo (MD = - 4.39 ml [- 8.09, - 0.7]); the difference in the mean change in E/e' between GLP-1 agonists and placebo (MD = - 1.05[- 1.78, - 0.32]); and the difference in the mean change in E/e' between SGLT-2 inhibitors and placebo (MD = - 1.91[- 3.39, - 0.43]).

CONCLUSIONS

GLP-1 agonists are more significantly associated with improved LVEF, LVESV and E/e', SGLT-2 inhibitors are more significantly associated with improved LVEDD and E/e', and DPP-4 inhibitors are more strongly associated with a negative impact on LV end-diastolic volume (LVEDV) than are placebos. SGLT-2 inhibitors are superior to other drugs in pairwise comparisons.

Dipeptidyl peptidase-4 inhibitor compared with sulfonylurea in combination with metformin: cardiovascular and renal outcomes in a propensity-matched cohort study

Background

To determine the impact of dipeptidyl peptidase-4 inhibitor (DPP4i) on the risk of major cardiocerebrovascular and renal outcomes compared with sulfonylurea (SU) combined with metformin in patients with type 2 diabetes from a population-based cohort.

Methods

From a nationwide cohort in Korea (2008–2013), 23,674 patients with type 2 diabetes treated with DPP4i plus metformin or SU plus metformin were selected and matched by propensity score. Composite cardiocerebrovascular events including incident ischemic heart disease (IHD), ischemic stroke (IS), hospitalization for heart failure (HHF), and cardiocerebrovascular death, as well as renal events including incident end-stage renal disease or initiation of renal-replacement therapy were assessed by Cox proportional-hazards models.

Results

During a median follow-up of 19.6 months (interquartile range 7.2–36.4), 762 composite cardiocerebrovascular events and 17 end-stage renal events occurred. There was no significant difference in the risk of IHD (hazard ratio [HR], 1.00; 95% CI 0.81–1.23), IS (HR, 0.95; 95% CI 0.74–1.23), or cardiocerebrovascular death (HR, 0.74; 95% CI 0.46–1.18) in the DPP4i group compared to that in the SU group. Likewise, DPP4i therapy was not associated with the risk of end-stage renal outcomes (HR, 1.23; 95% CI 0.41–3.62). However, the risk of HHF was significantly higher in the DPP4i group than in the SU group (HR, 1.47; 95% CI 1.07–2.04).

Conclusions

This real-world database analysis showed that DPP4i therapy did not increase the overall risk of major cardiovascular and renal outcomes compared to SU therapy. However, the DPP4i-associated risk of HHF remained significant.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0835-z) contains supplementary material, which is available to authorized users.

Pioglitazone Induces Cardiomyocyte Apoptosis and Inhibits Cardiomyocyte Hypertrophy Via VEGFR-2 Signaling Pathway

Background

Pioglitazone has been widely used as an insulin-sensitizing agent for improving glycemic control in patients with type 2 diabetes mellitus. However, cardiovascular risk and protective effects of pioglitazone remain controversial.

Objectives

In this study, we investigated whether pioglitazone affects cardiomyocyte apoptosis and hypertrophy by regulating the VEGFR-2 signaling pathway.

Methods

Cardiomyocytes were enzymatically isolated from 1- to 3-day-old Sprague-Dawley rat ventricles. Effects of pioglitazone and the VEGFR-2-selective inhibitor apatinib on cardiomyocyte apoptotic rate was determined using flow cytometry, and hypertrophy was evaluated using [³H]-leucine incorporation. The protein expressions of unphosphorylated and phosphorylated VEGFR-2, Akt, P53, and mTOR were determined by Western-Blotting. Analysis of variance (ANOVA) was used to assess the differences between groups.

Results

Pioglitazone and VEGFR-2-selective inhibitor apatinib reduced rat cardiomyocyte viability and cardiomyocyte hypertrophy induced by angiotensin II in vitro. Furthermore, in the same in vitro model, pioglitazone and apatinib significantly increased the expression of Bax and phosphorylated P53 and decreased the expression of phosphorylated VEGFR-2, Akt, and mTOR, which promote cardiomyocyte hypertrophy.

Conclusions

These findings indicate that pioglitazone induces cardiomyocyte apoptosis and inhibits cardiomyocyte hypertrophy by modulating the VEGFR-2 signaling pathway.

Worsening Heart Failure During the Use of DPP-4 Inhibitors: Pathophysiological Mechanisms, Clinical Risks, and Potential Influence of Concomitant Antidiabetic Medications

Although dipeptidyl peptidase (DPP)-4 inhibitors have been reported to have a neutral effect on thromboembolic vaso-occlusive events in large-scale trials, they act to potentiate several endogenous peptides that can exert deleterious cardiovascular effects. Experimentally, DPP-4 inhibitors may augment the ability of glucagon-like peptide-1 to stimulate cyclic adenosine monophosphate in cardiomyocytes, and potentiation of the effects of stromal cell-derived factor-1 by DPP-4 inhibitors may aggravate cardiac fibrosis. These potentially deleterious actions of DPP-4 inhibitors might not become clinically apparent if these drugs were to promote sodium excretion. However, the natriuretic effect of DPP-4 inhibitors is modest, because they act on the distal (rather than proximal) renal tubules. Accordingly, both clinical trials and observational studies have reported an increase in the risk of heart failure in patients with type 2 diabetes who were receiving DPP-4 inhibitors. This risk may be muted in trials with a high prevalence of metformin use or with low and declining background use of insulin and thiazolidinediones. Still, the most vulnerable patients (i.e., those with established heart failure) were not well represented in these studies. The only trial that specifically evaluated patients with pre-existing left ventricular dysfunction observed important drug-related adverse structural and clinical effects. In conclusion, an increased risk of worsening heart failure appears to be a class effect of DPP-4 inhibitors, even in patients without a history of heart failure. Additional clinical trials are urgently needed to elucidate the benefits and risks of DPP-4 inhibitors in patients with established left ventricular dysfunction.

Comparative Cardiovascular Risks of Dipeptidyl Peptidase-4 Inhibitors: Analyses of Real-world Data in Korea

Background and Objectives

To compare cardiovascular disease (CVD) risk associated with 5 different dipeptidyl peptidase-4 inhibitors (DPP-4is) in people with type 2 diabetes.

Methods

We identified 534,327 people who were newly prescribed sitagliptin (n=167,157), vildagliptin (n=67,412), saxagliptin (n=29,479), linagliptin (n=220,672), or gemigliptin (n=49,607) between January 2013 and June 2015 using the claims database of the Korean National Health Insurance System. A Cox proportional hazards model was used to estimate hazard ratios (HRs) for major CVD events (myocardial infarction, stroke, or death) among users of different DPP-4is. The model was adjusted for sex, age, duration of DPP-4i use, use of other glucose-lowering drugs, use of antiplatelet agents, hypertension, dyslipidemia, atrial fibrillation, chronic kidney disease, microvascular complications of diabetes, Charlson comorbidity index, and the calendar index year as potential confounders.

Results

Compared to sitagliptin users, the fully adjusted HRs for CVD events were 0.97 (95% confidence interval [CI], 0.94–1.01; p=0.163) for vildagliptin, 0.76 (95% CI, 0.71–0.81; p<0.001) for saxagliptin, 0.95 (95% CI, 0.92–0.98; p<0.001) for linagliptin, and 0.84 (95% CI, 0.80–0.88; p<0.001) for gemigliptin.

Conclusions

Compared to sitagliptin therapy, saxagliptin, linagliptin, and gemigliptin therapies were all associated with a lower risk of cardiovascular events.

Do DPP-4 Inhibitors Cause Heart Failure Events by Promoting Adrenergically Mediated Cardiotoxicity? Clues From Laboratory Models and Clinical Trials

RATIONALE

DPP-4 (dipeptidyl peptidase-4) inhibitors have increased the risk of heart failure events in both randomized clinical trials and observational studies, but the mechanisms that underlie their deleterious effect remain to be elucidated. Previous work has implicated a role of these drugs to promote cardiac fibrosis.

OBJECTIVE

This article postulates that DPP-4 inhibitors increase the risk of heart failure events by activating the sympathetic nervous system to stimulate cardiomyocyte cell death, and it crystallizes the findings from both experimental studies and clinical trials that support the hypothesis.

METHODS AND RESULTS

Inhibition of DPP-4 not only potentiates the actions of GLP-1 (glucagon-like peptide-1; which can increase myocardial cAMP) but also potentiates the actions of SDF-1 (stromal cell-derived factor 1), NPY (neuropeptide Y), and substance P to activate the sympathetic nervous system and stimulate β-adrenergic receptors to cause cardiomyocyte apoptosis, presumably through a CaMKII (Ca++/calmodulin-dependent protein kinase II) pathway. An action of SDF-1 to interfere with cAMP and protein kinase A signaling may account for the absence of a clinically overt positive chronotropic effect. This conceptual framework is supported by the apparent ability of β-blocking drugs to attenuate the increased risk of DPP-4 inhibitors in a large-scale clinical trial.

CONCLUSIONS

Sympathetic activation may explain the increased risk of heart failure produced by DPP-4 inhibitors. The proposed mechanism has major implications for clinical care because in the treatment of patients with type 2 diabetes mellitus, DPP-4 inhibitors are widely prescribed, but β-blockers are underutilized because of fears that they might mask hypoglycemia.

Resistance exercise improves cardiac function and mitochondrial efficiency in diabetic rat hearts

Metabolic disturbance and mitochondrial dysfunction are a hallmark of diabetic cardiomyopathy (DC). Resistance exercise (RE) not only enhances the condition of healthy individuals but could also improve the status of those with disease. However, the beneficial effects of RE in the prevention of DC and mitochondrial dysfunction are uncertain. Therefore, this study investigated whether RE attenuates DC by improving mitochondrial function using an in vivo rat model of diabetes. Fourteen Otsuka Long-Evans Tokushima Fatty rats were assigned to sedentary control (SC, n = 7) and RE (n = 7) groups at 28 weeks of age. Long-Evans Tokushima Otsuka rats were used as the non-diabetic control. The RE rats were trained by 20 repetitions of climbing a ladder 5 days per week. RE rats exhibited higher glucose uptake and lower lipid profiles, indicating changes in energy metabolism. RE rats significantly increased the ejection fraction and fractional shortening compared with the SC rats. Isolated mitochondria in RE rats showed increase in mitochondrial numbers, which were accompanied by higher expression of mitochondrial biogenesis proteins such as proliferator-activated receptor-γ coactivator-1α and TFAM. Moreover, RE rats reduced proton leakage and reactive oxygen species production, with higher membrane potential. These results were accompanied by higher superoxide dismutase 2 and lower uncoupling protein 2 (UCP2) and UCP3 levels in RE rats. These data suggest that RE is effective at ameliorating DC by improving mitochondrial function, which may contribute to the maintenance of diabetic cardiac contractility.

Comparative safety for cardiovascular outcomes of DPP-4 inhibitors versus glimepiride in patients with type 2 diabetes: A retrospective cohort study

Concerns about the cardiovascular safety of dipeptidyl peptidase-4 (DPP-4) inhibitors persist. This study sought to determine whether there is a differential risk of hospitalization for cardiovascular diseases (CVDs) between DPP-4 inhibitors and glimepiride.We conducted this retrospective cohort study by using the Korean National Health Insurance Service database from December 1, 2008, to December 31, 2013. The study subjects were new users of DPP-4 inhibitors or glimepiride for type 2 diabetes. Outcome was defined as hospitalization for CVDs, including angina pectoris, myocardial infarction, transient cerebral ischemic attack, heart failure, or cerebrovascular disease or any procedure involving coronary artery bypass grafting or percutaneous coronary intervention. We used a Cox proportional hazard model to estimate the adjusted hazard ratios (aHRs) and their 95% confidence intervals (CIs), to assess the risk of CVDs associated with the use of DPP-4 inhibitors compared with glimepiride.The cohort consisted of 1,045,975 patients, with 6504 in the DPP-4 inhibitors group and 13,447 in the glimepiride group. No significant increased risk of total CVDs was found (aHR, 0.87; 95% CI, 0.75-1.01) in the DPP-4 inhibitors versus glimepiride group. A decreased risk of hospitalization for CVDs was found among patients with a history of visit for CVDs (aHR, 0.73; 95% CI, 0.56-0.97) or with >2.5 years' duration of type 2 diabetes (aHR, 0.77; 95% CI, 0.66-0.91) in the DPP-4 inhibitors versus glimepiride group.DPP-4 inhibitors did not increase cardiovascular risk compared with glimepiride regardless of CVD history and diabetes duration.

Alternative Interventions to Prevent Oxidative Damage following Ischemia/Reperfusion

Ischemia/reperfusion (I/R) lesions are a phenomenon that occurs in multiple pathological states and results in a series of events that end in irreparable damage that severely affects the recovery and health of patients. The principal therapeutic approaches include preconditioning, postconditioning, and remote ischemic preconditioning, which when used separately do not have a great impact on patient mortality or prognosis. Oxidative stress is known to contribute to the damage caused by I/R; however, there are no pharmacological approaches to limit or prevent this. Here, we explain the relationship between I/R and the oxidative stress process and describe some pharmacological options that may target oxidative stress-states.

Lessons learned from cardiovascular outcome clinical trials with dipeptidyl peptidase 4 (DPP-4) inhibitors

Previous trials of glucose-lowering strategies in subjects with type 2 diabetes have demonstrated a beneficial effect of intensive glycemic control on microvascular complications but failed to show a clear benefit on cardiovascular complications. The findings of meta-analyses of rosiglitazone trials suggesting that rosiglitazone might increase the risk of myocardial infarction have cast doubt on the cardiovascular safety of glucose-lowering drugs. In 2008, the US Food and Drug Administration has implemented rigorous criteria to approve new glucose-lowering drugs, requiring proof of cardiovascular safety. These regulatory requirements have led to a considerable increase in the number of cardiovascular outcome trials in type 2 diabetes to ensure that newer glucose-lowering drugs are not associated with increased cardiovascular risk. Incretin-based therapies including dipeptidyl peptidase 4 (DPP-4) inhibitors, and injectable glucagon-like peptide 1 (GLP-1) receptor agonists are novel treatment options for patients with inadequate glucose control. Although DPP-4 inhibitors have shown neutral effects on risk factors for cardiovascular diseases, it remains unclear whether treatment with these new glucose-lowering agents might be associated with a reduction in cardiovascular events. The results of the three cardiovascular outcome trials comparing DPP-4 inhibitors treatment to placebo in addition to other glucose-lowering drugs have been published. All the three DPP-4 inhibitor cardiovascular outcome trials have shown non-inferiority with regard to cardiovascular safety, compared with placebo, when added to usual care. In this review, we summarize cardiovascular outcome trials of DPP-4 inhibitors, and provide an overview of these trials and their limitations.

Effects of dipeptidyl peptidase-4 inhibitor in insulin-resistant rats with myocardial infarction

Adverse cardiac remodeling after myocardial infarction (MI) leads to progressive heart failure. Obese-insulin resistance increases risks of MI and heart failure. Although dipeptidyl peptidase-4 (DPP4) inhibitor is known to exert cardioprotection, its effects on adverse remodeling after MI in obese-insulin-resistant rats are unclear. We hypothesized that DPP4 inhibitor reduces adverse left ventricular (LV) remodeling and LV dysfunction in obese-insulin-resistant rats with MI. Rats were fed either normal diet (ND) or high-fat diet (HFD) for 12 weeks to induce obese-insulin resistance, followed by left anterior descending coronary artery ligation to induce MI. Then, rats in each dietary group were divided into five subgroups to receive vehicle, enalapril (10mg/kg/day), metformin (30mg/kg/day), DPP4 inhibitor vildagliptin (3mg/kg/day), or combined metformin and vildagliptin for 8 weeks. Heart rate variability (HRV), LV function, pathological and biochemical studies for LV remodeling, and cardiomyocyte apoptosis were determined. Obese-insulin-resistant rats had severe insulin resistance and LV dysfunction. HFD rats had a higher mortality rate than ND rats, and all treatments reduced the mortality rate in obese-insulin-resistant rats. Although all drugs improved insulin resistance, HRV, LV function as well as reduced cardiac hypertrophy and fibrosis, vildagliptin effectively reduced cardiomyocyte cross-sectional areas more than enalapril and was related to markedly decreased ERK1/2 phosphorylation. In ND rats with MI, metformin neither improved LV ejection fraction nor reduced cardiac fibrosis. The infarct size and transforming growth factor-β expression were not different among groups. In obese-insulin-resistant rats with chronic MI, DPP4 inhibitor vildagliptin exerts better cardioprotection than enalapril in attenuating adverse LV remodeling.

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

OBJECTIVES

To examine the association between dipeptidyl peptidase-4 (DPP-4) inhibitors and the risk of heart failure or hospital admission for heart failure in patients with type 2 diabetes.

DESIGN

Systematic review and meta-analysis of randomised and observational studies.

DATA SOURCES

Medline, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov searched up to 25 June 2015, and communication with experts.

ELIGIBILITY CRITERIA

Randomised controlled trials, non-randomised controlled trials, cohort studies, and case-control studies that compared DPP-4 inhibitors against placebo, lifestyle modification, or active antidiabetic drugs in adults with type 2 diabetes, and explicitly reported the outcome of heart failure or hospital admission for heart failure.

DATA COLLECTION AND ANALYSIS

Teams of paired reviewers independently screened for eligible studies, assessed risk of bias, and extracted data using standardised, pilot tested forms. Data from trials and observational studies were pooled separately; quality of evidence was assessed by the GRADE approach.

RESULTS

Eligible studies included 43 trials (n=68,775) and 12 observational studies (nine cohort studies, three nested case-control studies; n=1,777,358). Pooling of 38 trials reporting heart failure provided low quality evidence for a possible similar risk of heart failure between DPP-4 inhibitor use versus control (42/15,701 v 33/12,591; odds ratio 0.97 (95% confidence interval 0.61 to 1.56); risk difference 2 fewer (19 fewer to 28 more) events per 1000 patients with type 2 diabetes over five years). The observational studies provided effect estimates generally consistent with trial findings, but with very low quality evidence. Pooling of the five trials reporting admission for heart failure provided moderate quality evidence for an increased risk in patients treated with DPP-4 inhibitors versus control (622/18,554 v 552/18,474; 1.13 (1.00 to 1.26); 8 more (0 more to 16 more)). The pooling of adjusted estimates from observational studies similarly suggested (with very low quality evidence) a possible increased risk of admission for heart failure (adjusted odds ratio 1.41, 95% confidence interval 0.95 to 2.09) in patients treated with DPP-4 inhibitors (exclusively sitagliptin) versus no use.

CONCLUSIONS

The relative effect of DPP-4 inhibitors on the risk of heart failure in patients with type 2 diabetes is uncertain, given the relatively short follow-up and low quality of evidence. Both randomised controlled trials and observational studies, however, suggest that these drugs may increase the risk of hospital admission for heart failure in those patients with existing cardiovascular diseases or multiple risk factors for vascular diseases, compared with no use.

Cardiovascular, renal and gastrointestinal effects of incretin-based therapies: an acute and 12-week randomised, double-blind, placebo-controlled, mechanistic intervention trial in type 2 diabetes

INTRODUCTION

Incretin-based therapies, that is, glucagon-like peptide (GLP)-1 receptor agonists and dipeptidyl peptidase (DPP)-4 inhibitors, are relatively novel antihyperglycaemic drugs that are frequently used in type 2 diabetes management. Apart from glucose-lowering, these agents exhibit pleiotropic actions that may have favourable and unfavourable clinical consequences. Incretin-based therapies have been associated with heart rate acceleration, heart failure, acute renal failure and acute pancreatitis. Conversely, these agents may reduce blood pressure, glomerular hyperfiltration, albuminuria and hepatic steatosis. While large-sized cardiovascular safety trials can potentially identify the clinical significance of some of these pleiotropic actions, small-sized mechanistic studies are important to understand the (patho)physiological rationale of these findings. The current protocol describes a mechanistic study to assess cardiovascular, renal and gastrointestinal effects, and mechanisms of incretin-based therapies in type 2 diabetes.

METHODS AND ANALYSES

60 patients with type 2 diabetes will undergo acute and prolonged randomised, double-blind, intervention studies. The acute intervention will consist of intravenous administration of the GLP-1 receptor agonist exenatide or placebo. For the prolonged intervention, patients will be randomised to 12-week treatment with the GLP-1 receptor agonist liraglutide, the DPP-4 inhibitor sitagliptin or matching placebos. For each examined organ system, a primary end point is defined. Primary cardiovascular end point is change in resting heart rate variability assessed by beat-to-beat heart rate monitor and spectral analyses software. Primary renal end point is change in glomerular filtration rate assessed by the classic inulin clearance methodology. Primary gastrointestinal end points are change in pancreatic exocrine function assessed by MRI-techniques (acute intervention) and faecal elastase-1 levels (12-week intervention). Secondary end points include systemic haemodynamics, microvascular function, effective renal plasma flow, renal tubular function, pancreatic volume and gallbladder emptying-rate.

MEDICAL ETHICS AND DISSEMINATION

The study is approved by the local Ethics Review Board (VU University Medical Center, Amsterdam) and conducted in accordance with the Declaration of Helsinki and Good Clinical Practice.

TRIAL REGISTRATION NUMBER

NCT01744236.