Sitagliptin on carotid intima-media thickness in type 2 diabetes patients receiving primary or secondary prevention of cardiovascular disease: A subgroup analysis of the PROLOGUE study

Dipeptidyl peptidase-4 inhibitors reduce the incidence of first cardiovascular events in Japanese diabetic patients

BACKGROUND

Dipeptidyl Peptidase-4 (DPP-4) inhibitors do not suppress cardiovascular events in diabetic patients with a history of cardiovascular disease. However, the effect of DPP-4 inhibitors on cardiovascular events in Japanese diabetic patients is unclear. Therefore, we investigated whether DPP-4 inhibitors alter the incidence of cardiovascular events in Japanese diabetic patients without a history of cardiovascular events.

METHODS

The Japanese Primary Prevention of Atherosclerosis with Aspirin for Diabetes (JPAD) trial was a multicenter, prospective, randomized, open label, blinded, end-point study conducted from 2002 to 2008. After completion of the JPAD trial, we followed up the patients until 2019. Patients who had had a cardiovascular event by the 2013 follow-up were excluded from the study. JPAD patients were divided into a DPP-4 group and a non-DPP-4 group based on whether they were taking DPP-4 inhibitors at the 2013 follow-up because few patients took DPP-4 inhibitors before 2013. We investigated the incidence of cardiovascular events consisting of coronary events, cerebrovascular events, heart failure requiring hospitalization, and aortic and peripheral vascular disease in 1099 JPAD patients until 2019.

RESULTS

During the observation period from 2013 to 2019, 37 (7%) first cardiovascular events occurred in the DPP-4 group (n = 518) and 66 (11%) in the non-DPP-4 group (n = 581). The incidence of cardiovascular events was significantly lower in the DPP-4 group than in the non-DPP-4 group (Log-Rank P = 0.0065). Cox proportional hazards model analysis revealed that the use of DPP-4 inhibitors (hazard ratio 0.65; 95% confidence interval 0.43-0.98; P = 0.038) was an independent factor after adjustment for age ≥ 65 years, hypertension, statin usage, and insulin usage.

CONCLUSIONS

Our findings have demonstrated that the use of DPP-4 inhibitors may be associated with a reduced incidence of first cardiovascular events in Japanese diabetic patients. The results require confirmation in randomized controlled trials.

Effect of ipragliflozin on carotid intima-media thickness in patients with type 2 diabetes: a multicenter, randomized, controlled trial

AIMS

To examine the effects of a 24-month treatment with ipragliflozin on carotid intima-media thickness (IMT) in type 2 diabetes patients.

METHODS AND RESULTS

In this multicenter, prospective, randomized, open-label, and blinded-endpoint investigator-initiated clinical trial, adults with type 2 diabetes and haemoglobin A1C (HbA1c) of 6.0-10.0% (42-86 mmol/mol) were randomized equally to ipragliflozin (50 mg daily) and non-sodium-glucose cotransporter-2 (SGLT2) inhibitor use of standard-care (control group) for type 2 diabetes and were followed-up to 24 months. The primary endpoint was the change in mean common carotid artery IMT (CCA-IMT) from baseline to 24 months. A total of 482 patients were equally allocated to the ipragliflozin (N = 241) and control (N = 241) groups, and 464 patients (median age 68 years, female 31.7%, median type 2 diabetes duration 8 years, median HbA1c 7.3%) were included in the analyses. For the primary endpoint, the changes in the mean CCA-IMT from baseline to 24 months were 0.0013 [95% confidence interval (CI), -0.0155-0.0182] mm and 0.0015 (95% CI, -0.0155-0.0184) mm in the ipragliflozin and control groups, respectively, with an estimated group difference (ipragliflozin-control) of -0.0001 mm (95% CI, -0.0191-0.0189; P = 0.989). A group difference in HbA1c change at 24 months was also non-significant between the treatment groups [-0.1% (95% CI, -0.2-0.1); P = 0.359].

CONCLUSION

Twenty-four months of ipragliflozin treatment did not affect carotid IMT status in patients with type 2 diabetes recruited in the PROTECT study, relative to the non-SGLT2 inhibitor-use standard care for type 2 diabetes.

Retracted: Effect of dipeptidyl peptidase-4 inhibitors on the progression of atherosclerosis in patients with type 2 diabetes mellitus: A meta-analysis of randomised controlled trials

Yang, T, Li, W, Kan, Z, Liu, Y, Peng, M, Shi, H, Effect of dipeptidyl peptidase-4 inhibitors on the progression of atherosclerosis in patients with type 2 diabetes mellitus: A meta-analysis of randomised controlled trials. Int J Clin Pract. 2021; 00:e14213. https://onlinelibrary.wiley.com/doi/10.1111/ijcp.14213. The above article from the International Journal of Clinical Practice, published online on 5 April 2021 in Wiley Online Library (wileyonlinelibrary.com), has been retracted at the request of the authors, and by agreement of the journal Editor in Chief, Charles Young, and John Wiley and Sons Ltd. The retraction has been agreed following an author review of the research which led to the removal of some studies which did not meet the inclusion criteria. Following the removal of these studies the overall sample size was too small and the studies still included too heterogenuous for the results and conclusions to be reliable.

Hypertension in diabetes care: emerging roles of recent hypoglycemic agents

Patients with type 2 diabetes (T2D) frequently have multiple cardiovascular, metabolic, and renal comorbidities, such as hypertension, dyslipidemia, hyperuricemia, chronic kidney disease, and heart failure. Accordingly, this patient population often requires polypharmacy, which is associated with an increased risk of drug-drug interactions, poor adherence, and even adverse outcomes. Accumulating evidence on newer hypoglycemic agents, such as glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter 2 inhibitors, has highlighted the marked improvements in cardiovascular and renal outcomes associated with the off-target benefits for relevant comorbidities, including hypertension. These classes of hypoglycemic agents are unique, as they achieve consistently modest but significant reductions in systolic and diastolic blood pressure (BP), an effect that has not been targeted and observed with conventional hypoglycemic agents. In addition to this BP-lowering effect, these agents also have multifaceted beneficial impacts on other cardiometabolic and renal parameters, which appear to be helpful for providing an important comprehensive therapeutic approach to improve the prognosis in patients with T2D. The clinical advantages of these agents may reduce the dose and number of concomitant medications used to treat T2D and related comorbidities. These positive spillover effects may also enhance the clinical use of agents to achieve better diabetes care. As a consequence, the clinical significance of these hypoglycemic agents now extends beyond their hypoglycemic effects, thereby providing a new-normal strategy to use in an evidence-based, patient-centric approach to diabetes care.

DPP4 Activity, Hyperinsulinemia, and Atherosclerosis

CONTEXT

Obesity and type 2 diabetes are associated with chronic hyperinsulinemia, elevated plasma levels of dipeptidyl peptidase-4 (DPP4), and a pro-atherosclerotic milieu.

EVIDENCE ACQUISITION

PubMed search of the term "insulin and atherosclerosis," "hyperinsulinemia," "atherosclerosis," or "cardiovascular outcomes" cross-referenced with "DPP4." Relevant research and review articles were reviewed.

EVIDENCE SYNTHESIS

Hyperinsulinemia in the setting of insulin resistance promotes vascular inflammation, vascular smooth muscle cell growth, pathological cholesterol profile, hypertension, and recruitment of immune cells to the endothelium, all contributing to atherosclerosis. DPP4 has pleiotropic functions and its activity is elevated in obese humans. DPP4 mirrors hyperinsulinemia's atherogenic actions in the insulin resistant state, and genetic deletion of DPP4 protects rodents from developing insulin resistance and improves cardiovascular outcomes. DPP4 inhibition in pro-atherosclerotic preclinical models results in reduced inflammation and oxidative stress, improved endothelial function, and decreased atherosclerosis. Increased incretin levels may have contributed to but do not completely account for these benefits. Small clinical studies with DPP4 inhibitors demonstrate reduced carotid intimal thickening, improved endothelial function, and reduced arterial stiffness. To date, this has not been translated to cardiovascular risk reduction for individuals with type 2 diabetes with prior or exaggerated risk of cardiovascular disease.

CONCLUSION

DPP4 may represent a key link between central obesity, insulin resistance, and atherosclerosis. The gaps in knowledge in DPP4 function and discrepancy in cardiovascular outcomes observed in preclinical and large-scale randomized controlled studies with DPP4 inhibitors warrant additional research.

Cardiovascular surrogate markers and cardiometabolic therapeutics: a viewpoint learned from clinical trials on dipeptidyl peptidase-4 inhibitors

Clinical trials are often performed to investigate the effects of various types of cardiometabolic therapies on cardiovascular surrogate markers, including vascular function and biomarkers. This study platform has the potential to provide information on the suspected actions of drugs and mechanistic insights into their prognostic impact. However, despite using the same class of drugs and similar study designs we are often faced with inconsistent and even conflicting results, possibly leading to some confusion in the clinical setting. When interpreting these results, it is important to investigate what caused the differences and carefully assess the information, taking into account the research situation and the patient population investigated. Using this approach, assessment of the impact on cardiovascular surrogate markers observed in clinical studies from multiple perspectives should help to better understand the potential cardiovascular effects. In this commentary we discuss how we should interpret the effects of cardiometabolic therapeutics on vascular surrogate markers, based on viewpoints learned from the results of clinical trials on dipeptidyl peptidase-4 inhibitors. This learning strategy could also be helpful for appropriate selection of drugs for evidence-based, patient-centric, tailored medication.

Roles and Mechanisms of Dipeptidyl Peptidase 4 Inhibitors in Vascular Aging

Vascular aging is characterized by alterations in the constitutive properties and biological functions of the blood vessel wall. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are indispensability elements in the inner layer and the medial layer of the blood vessel wall, respectively. Dipeptidyl peptidase-4 (DPP4) inhibitors, as a hypoglycemic agent, play a protective role in reversing vascular aging regardless of their effects in meliorating glycemic control in humans and animal models of type 2 diabetes mellitus (T2DM) through complex cellular mechanisms, including improving EC dysfunction, promoting EC proliferation and migration, alleviating EC senescence, obstructing EC apoptosis, suppressing the proliferation and migration of VSMCs, increasing circulating endothelial progenitor cell (EPC) levels, and preventing the infiltration of mononuclear macrophages. All of these showed that DPP4 inhibitors may exert a positive effect against vascular aging, thereby preventing vascular aging-related diseases. In the current review, we will summarize the cellular mechanism of DPP4 inhibitors regulating vascular aging; moreover, we also intend to compile the roles and the promising therapeutic application of DPP4 inhibitors in vascular aging-related diseases.

Sitagliptin on Carotid Intima-Media Thickness in Type 2 Diabetes Mellitus Patients and Anemia: A Subgroup Analysis of the PROLOGUE Study

Introduction

Randomized clinical trials have not shown an additional clinical benefit of sitagliptin treatment over conventional treatment alone. However, studies of sitagliptin treatment have not examined the relationship between anemia and treatment group outcomes.

Methods

The PROLOGUE study is a prospective clinical trial of 442 participants with type 2 diabetes mellitus (T2DM) randomized to sitagliptin treatment or conventional treatment which showed no treatment differences [Estimated mean (± standard error) common carotid intima-media thickness (CIMT) was 0.827 ± 0.007 mm and 0.837 ± 0.007 mm, respectively, with a mean difference of -0.009 mm (97.2% CI −0.028 to 0.011, p = 0.309) at 24 mo of follow-up]. This is a post hoc subanalysis using data obtained from the PROLOGUE study; the study population was divided into anemic groups (n = 94) and nonanemic group (n = 343) based on hemoglobin level. And we analyzed for the changes in each CIMT parameter from baseline to 24 months in subgroups.

Results

The treatment group difference in baseline-adjusted mean common carotid artery- (CCA-) IMT at 24 months was −0.003 mm (95% CI −0.022 to 0.015, p = 0.718) in the nonanemic subgroup and −0.007 mm (95% CI −0.043 to 0.030, p = 0.724) in the anemic subgroup. Although there were no significant differences in the other CIMT parameters between the treatment groups in the anemic subgroup, the changes in mean and max ICA-IMT at 24 months in the nonanemic subgroup were significantly lower in the sitagliptin group than the conventional group [−0.104 mm (95% CI −0.182 to −0.026), p = 0.009 and −0.142 mm (−0.252 to −0.033), p = 0.011, respectively].

Conclusion

These data suggest that nonanemia may indicate a potentially large subgroup of those with T2DM patients that sitagliptin therapy has a better antiatherosclerotic effect than conventional therapy. Further research is needed to confirm these preliminary observations.

Clinical utility of carotid ultrasonography: Application for the management of patients with diabetes

Carotid ultrasonography is a non-invasive, simple and inexpensive modality to assess the severity of atherosclerosis. This article reviews related articles, summarizes the rationale for the application of carotid ultrasonography in clinical practice, and addresses the features and the limitations of carotid ultrasonography in cardiovascular risk prediction. Numerous large studies have confirmed that various carotid ultrasound measures, such as carotid intima-media thickness, the presence or absence of carotid plaque, plaque number and plaque area, can be independent predictors of cardiovascular diseases in individuals with and without diabetes mellitus. Furthermore, many studies showed that the use of carotid intima-media thickness (especially maximum intima-media thickness, including plaque thickness) and/or carotid plaque in addition to traditional risk factors significantly improved the prediction of the occurrence of cardiovascular diseases, while controversy remains. Several studies showed that the progression of carotid intima-media thickness also can be a surrogate end-point of cardiovascular events. However, the accumulated evidence has not been sufficient. Further study with sufficient power should be carried out. As plaque disruption, which plays a crucial role in the pathogenesis of cardiovascular events, is dependent on the content of lipid in the atheroma and the thickness of the fibrous cap, tissue characterization of a plaque might be useful for determining its fragility. Interestingly, recent studies have shown that ultrasonic tissue characterization of carotid lesions could improve the prediction ability of future cardiovascular diseases. Thus, carotid ultrasonography is a useful modality for better clinical practice of atherosclerosis in patients with diabetes.

Differential effect of concomitant antidiabetic agents on carotid atherosclerosis: a subgroup analysis of the PROLOGUE study

Accumulated evidence shows that some antidiabetic agents attenuate the progression of carotid atherosclerosis assessed as intima-media thickness (IMT). Although some studies have demonstrated an inhibitory effect of dipeptidyl peptidase-4 inhibitors on carotid IMT progression, in the PROLOGUE study sitagliptin failed to slow progression relative to conventional therapy for 24 months. We hypothesized that differences in the concomitant antidiabetic agents between the groups have influenced the progression of carotid IMT. We performed a post hoc analysis of the PROLOGUE study using subgroups stratified by concomitant antidiabetic agents. Although no subgroup with any combination of agents in the overall patients showed a significant difference between sitagliptin group and conventional therapy group in the changes from baseline in mean common carotid artery (CCA)-IMT at 24 months, a significant attenuation of mean CCA-IMT progression was observed in the sitagliptin group relative to conventional therapy group only in three combination subgroups aged < 70 years, namely no thiazolidinedione; no thiazolidinedione or biguanide; and no thiazolidinedione, biguanide or α-glucosidase inhibitor, even after adjustment for multiple confounding factors. In the three subgroups, no significant difference between sitagliptin group and conventional therapy group in the changes from baseline in HbA1c at 24 months was detected. Our data suggest that some concomitant agents, whose prescription frequencies were increased in the conventional therapy group, may have masked the inhibitory effect of sitagliptin on carotid IMT progression in the PROLOGUE study.