Rurality is associated with lower likelihood of dipeptidyl peptidase 4 inhibitor use for treatment intensification

Background

Antihyperglycemic drug utilization studies are conducted frequently and describe the uptake of new drug therapies across may jurisdictions. An increasingly important, yet often absent, aspect of these studies is the impact of rurality on drug utilization.

Objectives

The objective of this study was to explore the association between place of residence (rural, urban, metropolitan) and the use of dipeptidyl peptidase 4 inhibitors (DPP-4i) for first treatment intensification of type 2 diabetes.

Methods

A retrospective cohort study was conducted from April 1, 2008 to March 31, 2019 of new metformin users. A multivariable logistic regression analysis was performed to determine the association between place of residence (using postal codes) and likelihood of DPP-4i dispensing.

Results

After adjusting for confounders, analysis revealed that rural-dwellers are less likely to have a DPP-4i dispensed, compared with metropolitan-dwellers (aOR:0.64; 95%CI:0.61-0.67) and over-time, the uptake in rural areas was slower.

Conclusions

This study demonstrates that rurality can have an impact on drug therapy decisions at first treatment intensification, with respect to the utilization of new therapies.

Thalidomide and a Dipeptidyl Peptidase 4 Inhibitor in a Rat Model of Experimental Autoimmune Myocarditis

BACKGROUND AND OBJECTIVES

Myocarditis is a potentially fatal disease, but curative treatments have not yet been established. Myocardial inflammation is an important pathogenesis of this disease, and immunosuppressants such as methylprednisolone and immunoglobulin have been used for treatment; however, the effectiveness needs to be improved. Thalidomide and dipeptidyl peptidase (DPP) 4 inhibitors were recently investigated regarding their immunomodulatory properties. This study aimed to test whether thalidomide or a DPP4 inhibitor (evogliptin) can improve the effectiveness of myocarditis treatment using a rat model of experimental autoimmune myocarditis (EAM).

METHODS

Rats with or without myocarditis were administered thalidomide at 100 mg/kg/day and DPP4 inhibitor at 10 mg/kg/day orally. Measurement of echocardiography, serum inflammatory cytokines, myocardial histopathological examination, and immunohistochemical staining for leukocytes, macrophages, CD4+ T cells, and cytoskeleton were performed after 3 weeks, and the fibrosis area was measured after 3 and 6 weeks.

RESULTS

Thalidomide and DPP4 inhibitor did not reduce the severity of myocarditis compared with the EAM without treatment rats by comparing the echocardiographic data, myocardial CD4+, macrophages, neutrophil infiltrations, and the heart weight/body weight ratio in 3 weeks. The levels of inflammatory cytokines were not lower in the thalidomide and DPP4 inhibitor-treated group than in the untreated group in 3 weeks. In 6 weeks, thalidomide and DPP4 inhibitors did not reduce the fibrosis area compared to untreated groups.

CONCLUSIONS

Although thalidomide and the DPP4 inhibitor had an immunomodulatory effect and are used against inflammatory diseases, they did not ameliorate myocardial inflammation and fibrosis in this rat model of EAM.

Preconception SGLT2 or DPP4 inhibitor use and adverse pregnancy outcomes

AIMS

To compare preconception use of sodium-glucose cotransporter-2 (SGLT2i) and dipeptidyl peptidase-4 (DPP4i) inhibitors to sulfonylurea agents, and associated peri-conceptional A1c concentration, and risk of pregnancy loss and congenital anomalies.

METHODS

This population-based cohort study used administrative datasets for all of Ontario, Canada, and included women eligible for free medication coverage and who achieved a recognized pregnancy from April 2007-November 2021. Exposure was a SGLT2i, DPP4i or sulfonylurea (referent) dispensed at least 90 days preconception. Study outcomes included differences in periconceptional A1c; miscarriage, induced abortion, or stillbirth; and any congenital anomaly - the latter two outcomes assessed using propensity score overlap weighting.

RESULTS

The mean (SD) periconceptional A1c was 8.1 % (2.0) among those prescribed any sulfonylurea, compared with 8.3 % (2.0) with a DPP4i and 7.8 % (1.6) with any SGLT2i. The risk of pregnancy loss was lowest among those exclusively prescribed a SGLT2i (relative risk [RR] 0.51, 95 % CI 0.22 to 0.91). Risk of a congenital anomaly at birth did not differ significantly comparing DPP4i or SGLT2i to sulfonylurea agents.

CONCLUSIONS

Neither SGLT2i nor DPP4i use before pregnancy was associated with a difference in A1c, or a higher risk of selective adverse outcomes, compared to sulfonylureas. Future larger studies are required, including assessment of medication use after conception, during the critical period of embryogenesis.

Cost-Effectiveness of Newer Antidiabetic Drugs as Second-Line Treatment for Type 2 Diabetes: A Systematic Review

INTRODUCTION

Evidence from cardiovascular outcome trials (CVOTs) for newer antidiabetic drugs is increasingly influencing revised recommendations for second-line therapy in type 2 diabetes (T2D). This systematic review aimed to compare the cost-effectiveness of newer antidiabetic drugs specified as sodium-glucose cotransporter 2 inhibitor (SGLT2i), glucagon-like peptide 1 receptor agonist (GLP-1RA), and dipeptidyl peptidase 4 inhibitor (DPP-4i) for T2D in a second-line setting.

METHODS

A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines, and all relevant published studies were searched comprehensively in electronic databases, including PubMed, Embase, Web of Science, and International Health Technology Assessment database published from April 2023. The quality of the included studies was evaluated using Consolidated Health Economic Evaluation Reporting Standards (CHEERS) 2022 reporting checklists.

RESULTS

We included 28 studies that met the inclusion criteria. Overall reporting of the identified studies largely met CHEERS 2022 recommendations. The CORE and Cardiff models were the most frequently utilized for pharmacoeconomic evaluation in T2D. Four studies consistently discovered that SGLT2i was more cost-effective than GLP-1RA in T2D who were not adequately controlled by metformin monotherapy. Four studies compared GLP-1RA with DPP-4i, sufonylurea (SU), or insulin. Except for one that demonstrated SU was cost-effective, all were GLP-1RA. Five studies revealed that SGLT2i was more cost-effective than DPP-4i or SU. Eleven studies indicated that DPP-4i was more cost-effective than traditional antidiabetic drugs. Four additional studies explored the cost-effectiveness of various antidiabetic drugs as second-line options, indicating that SU, SGLT2i, or meglitinides were more economically advantageous. The most common driven factors were the cost of new antidiabetic drugs.

CONCLUSION

Newer antidiabetic drugs as second line are the cost-effective option for T2D from the cost-effectiveness perspective, especially SGLT2i.

Effect of dipeptidyl peptidase-4 inhibitors on glycated hemoglobin levels relies on dietary sodium intake

AIMS

Sodium load increases endogenous glucagon-like peptide-1 (GLP-1) levels in humans. Therefore, patients with an increased amount of dietary sodium intake are supposed to have higher endogenous GLP-1 levels compared to those with less dietary sodium intake. Therefore, it can be hypothesized that patients with type 2 diabetes mellitus (T2DM) with more dietary sodium intake show better dipeptidyl peptidase-4 inhibitor (DPP-4i) effect on glycemic control because of the expected higher GLP-1 level. Thus, we performed a single-center cohort study to explore this idea.

METHODS

Medical records of patients with T2DM prescribed DPP-4i in the last 11 years were investigated. Dietary sodium intake was measured before the DPP-4i prescription with Tanaka's formula using casual spot urine samples. The effect of DPP-4i on glycemic control was estimated by the subtraction of glycated hemoglobin (HbA1c) before DPP-4i initiation from HbA1c 1 year after DPP-4i administration. We analyzed 50 patients.

RESULTS

DPP-4i improved HbA1c by -0.41% ± 0.66%. The effect of DPP-4i on glycemic control was significantly negatively correlated with the dietary sodium intake (r = -0.400). Thus, the more dietary sodium intake, the better the glycemic control by DPP-4i.

CONCLUSIONS

Thus, patients can expect better plasma glucose control by DPP-4is if patients are taking increased dietary sodium intake.

Hyperamylasemia is not Associated with Dipeptidyl Peptidase 4 Inhibitors in South Indian Adults with Type 2 Diabetes Mellitus

Introduction

Although not definitive, there is small increased risk of acute pancreatitis with the use of dipeptidyl peptidase 4 inhibitors (DPP4i). Hence, there is an interest in the elevation of pancreatic enzymes among type 2 diabetes mellitus (T2DM) patients using DPP4i. However, the studies regarding their association are limited and provide conflicting results. Moreover, there are no such studies among South Indian T2DM patients. Hence, we evaluated the prevalence of hyperamylasemia among South Indian T2DM patients and its association with DPP4i use.

Methods

This cross-sectional study was conducted at a tertiary health care center from South India. Adult T2DM patients on stable doses of antidiabetic medications for at least previous 3 months were included in the study. Patients with other types of diabetes mellitus, gall stones, diabetic ketoacidosis, acute illness, chronic kidney disease and untreated hypothyroidism were excluded from the study. All participants were evaluated with glycemic parameters, serum creatinine and serum amylase. Hyperamylasemia was defined as serum amylase ≥220 U/L.

Results

A total of 200 participants were included in the study among whom 93 patients were not on DPP4i whereas 107 were on DPP4i including 41 (38.32%) each on teneligliptin and sitagliptin. Baseline characteristics including glycemic measures were comparable between DPP4i users and nonusers. A total of 14 patients (7%) had hyperamylasemia but the prevalence of hyperamylasemia did not differ between DPP4i users and nonuser (6/107 vs. 8/93, P = 0.42).

Conclusions

Asymptomatic hyperamylasemia is not uncommon in South Indian T2DM patients but is not associated with the use of DPP4i.

Combined saline and vildagliptin induced M2 macrophage polarization in hepatic injury induced by acute kidney injury

Acute kidney injury (AKI) is a prevalent medical condition accompanied by mutual affection of other organs, including the liver resulting in complicated multiorgan malfunction. Macrophages play a vital role during tissue injury and healing; they are categorized into "classically activated macrophages" (M1) and "alternatively activated macrophages" (M2). The present study investigated and compared the conventional fluid therapy vs Dipeptidyl peptidase 4 inhibitor (DPP-4i) vildagliptin on the liver injury induced by AKI and evaluated the possible molecular mechanisms. Thirty rats comprised five groups (n = 6 rats/group): control, AKI, AKI+saline (received 1.5 mL of normal saline subcutaneous injection), AKI+vildagliptin (treated with oral vildagliptin 10 mg/kg), AKI+saline+vildagliptin. AKI was induced by intramuscular (i.m) injection of 50% glycerol (5 ml/kg). At the end of the work, we collected serum and liver samples for measurements of serum creatinine, blood urea nitrogen (BUN), alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrotic factor-α (TNF-α), and interleukin-10 (IL-10). Liver samples were processed for assessment of inducible nitric oxide synthase (iNOS) as a marker for M1, arginase 1 (Arg-1) as an M2 marker, c-fos, c-Jun, mitogen-activated protein kinase (MAPK), activator protein 1 (AP-1), and high-mobility-group-box1 (HMGB1) protein. The difference was insignificant regarding the relative expression of AP-1, c-Jun, c-fos, MAPK, and HMGB between the AKI+saline group and the AKI+Vildagliptin group. The difference between the same two groups concerning the hepatic content of the M1 marker (iNOS) and the M2 marker Arg-1 was insignificant. However, combined therapy produced more pronounced changes in these markers, as the difference in their relative expression between the AKI+saline+Vildagliptin group and both the AKI+saline group and the AKI+Vildagliptin group was significant. Accordingly, we suggest that the combined saline and vildagliptin hepatoprotective effect involves the downregulation of the MAPK/AP-1 signaling pathway.

Dipeptidyl peptidase 4 inhibitor improves insulin resistance in Japanese patients with type 2 diabetes: a single-arm study, a brief report

BACKGROUND

Dipeptidyl peptidase 4 inhibitor (DPP4i) is an effective medicine for type 2 diabetes mellitus (T2DM). Some articles reported DPP4i improves insulin secretion and insulin resistance. However, these effects are not well established by glucose clamp test and test meal in Japanese. We investigated the effect of DPP4i on insulin resistance and insulin secretion by using the glucose clamp test and meal tolerance test (MTT).

METHODS

We performed a MTT, and the hyperinsulinemic-euglycemic clamp in 8 Japanese patients with T2DM. This study was a single-arm study. We measured fasting and postprandial glucose, insulin, incretins, and glucagon levels. We also measured serum adiponectin levels.

RESULTS

HbA1c was significantly decreased after 3 months. The fasting and postprandial glucose levels were significantly decreased. Fasting and postprandial insulin levels were not changed. The insulin resistance derived from the glucose clamp test was significantly improved. HOMA-IR was not significantly changed. GLP-1 and GIP were significantly increased but glucagon did not change. Adiponectin was not significantly changed.

CONCLUSIONS

Although the number of patients was very small, these results suggested that DPP4i treatment might improve insulin resistance without changing insulin secretion.

Effects of omarigliptin on glucose variability and oxidative stress in type 2 diabetes patients: A prospective study

AIMS

To date, no clinical studies have compared once-weekly dipeptidyl peptidase 4 (DPP-4) inhibitors with once-daily DPP-4 inhibitors in terms of glucose variability (GV) and oxidative stress (OS).

METHODS

Thirty-six patients with type 2 diabetes mellitus (T2DM) treated with once-daily DPP-4 inhibitors for at least 12 weeks were randomized to either continue once-daily DPP-4 inhibitors or receive omarigliptin, a once-weekly DPP-4 inhibitor, for 24 weeks. The primary end points were changes in the diacron-reactive oxygen metabolite (d-ROMs) test, a marker of OS, and GV using flash glucose monitoring. The secondary end point was changes in the diabetes treatment satisfaction questionnaire (DTSQ) scores.

RESULTS

There were no significant group differences in d-ROMs and DTSQ scores after 24 weeks of treatments. However, omarigliptin was superior to once-daily DPP-4 inhibitors in controlling fasting plasma glucose (FPG) and time in range (TIR). Although FPG and TIR were unchanged at 24 weeks after switching to omarigliptin, these parameters increased in the group receiving maintenance therapy with once-daily DPP-4 inhibitors. No statistically significant changes in hemoglobin A1c were observed between the two groups.

CONCLUSIONS

Our findings suggest that switching from once-daily DPP-4 inhibitors to omarigliptin may be efficacious for maintaining FPG and TIR in T2DM patients.

Association between dipeptidyl peptidase-4 inhibitors and risk of bullous pemphigoid in patients with type 2 diabetes: A population-based cohort study

AIMS

Higher bullous pemphigoid (BP) risk has been reported to be associated with dipeptidyl peptidase 4 inhibitor (DPP4i). The aim of this study is to examine the association between BP risk and DPP4i treatment.

METHODS

We conducted a nationwide cohort study based on the Taiwan National Health Insurance Database between 2000 and 2015. 124,619 diabetic patients who were receiving DPP4i therapy were matched 1: 1 with diabetic patients who had never received DPP4i by age, sex, duration of diabetes, insulin usage, and propensity score-matching of comorbidities.

RESULTS

The 6-year cumulative incidence of BP in the DPP4i-treated cohort was significantly higher than that in the non-DPP4i group (0.74 per 1000 vs 0.38 per 1000, P = 0.001). Modified Cox regression analysis revealed that DPP4i treatment (HR: 2.15, 95% CI: 1.18-3.91, P = 0.01), age (HR: 1.06, P < 0.001), renal disease (HR: 2.32, P < 0.001), and metformin user (HR: 1.93, P = 0.006) were associated with increased BP risk.

CONCLUSIONS

DPP4i users had a 2.2-fold increase in the risk of BP, and the risk was the highest in those with concomitant use of DPP4i and insulin.

What Next After Metformin in Type 2 Diabetes? Selecting the Right Drug for the Right Patient

INTRODUCTION

Metformin is the recommended initial treatment in type 2 diabetes mellitus (T2DM), but when this does not give adequate glucose control the choice of which second-line drug to use is uncertain as none have been found to have a better overall glycaemic response. In this real-world study dipeptidyl peptidase 4 inhibitors (DPP4i), sulphonylureas (SU), thiazolidinediones (TZD) and sodium glucose co-transporter 2 inhibitors (SGLT2i) were compared for their effectiveness in lowering glycated haemoglobin (HbA1c) levels for a particular individual based on their clinical characteristics.

METHODS

A retrospective analysis was undertaken of electronic health records of people with T2DM prescribed metformin alongside a DPP4i, SU, TZD or SGLT2i at second-line. Regression modelling was used to model the changes in HbA1c from baseline at month 6 and month 12 for the individual therapies, adjusting for demographic and clinical characteristics.

RESULTS

There were 7170 people included in the study. Treatment at second-line with SUs, DPP4i, TZDs and SGLT2i resulted in similar percentages of people achieving the recommended HbA1c target of < 7.5% (58 mmol/mol) at both 6 and 12 months. For those receiving SGLT2i and SUs, the greatest improvement in HbA1c was observed in relatively younger and older people, respectively. Trends were detected between other baseline characteristics and HbA1c improvement by drug class, but they were not statistically significant. Non-adherence rates were low for all drug classes. People with a higher medication possession ratio (≥ 80%) also had greater improvements in HbA1c at 12 months.

CONCLUSION

This study identified patients' phenotypic characteristics that may have the potential to influence individual treatment response. Accounting for these characteristics in clinical treatment decisions may facilitate individualised prescribing by being able to select the right drug for the right patient.

Sitagliptin attenuates the progression of coronary atherosclerosis in patients with coronary disease and type 2 diabetes

BACKGROUND AND AIMS

Type 2 diabetes mellitus (T2DM) is a well-recognized independent risk factor for ASCVD, the aim of this study was to investigate the effects of a dipeptidyl peptidase-4 inhibitor, sitagliptin, on prevention of progression of coronary atherosclerosis assessed by three-dimensional quantitative coronary angiography (3D-QCA) in T2DM patients with coronary artery disease (CAD).

METHODS

This was a prospective, randomized, double-center, open-label, blinded end point, controlled 18-month study in patients with CAD and T2DM. A total of 149 patients, who had at least 1 atherosclerotic plaque with 20%-80% luminal narrowing in a coronary artery, and had not undergone intervention during a clinically indicated coronary angiography or percutaneous coronary intervention, were randomized to sitagliptin group (n = 74) or control group (n = 75). Atherosclerosis progression was measured by repeat 3D-QCA examination in 88 patients at study completion. The primary outcome was changes in percent atheroma volume (PAV) from baseline to study completion measured by 3D-QCA. Secondary outcomes included change in 3D-QCA-derived total atheroma volume (TAV) and late lumen loss (LLL).

RESULTS

The primary outcome of PAV increased of 1.69% (95%CL, -0.8%-4.2%) with sitagliptin and 5.12% (95%CL, 3.49%-6.74%) with the conventional treatment (p = 0.023). The secondary outcome of change in TAV in patients treated with sitagliptin increased of 6.45 mm³ (95%CL,-2.46 to 6.36 mm³) and 9.45 mm³ (95%CL,-4.52 to 10.14 mm³) with conventional treatment (p = 0.023), however, no significant difference between groups was observed (p = 0.175). Patients treated with sitagliptin had similar LLL as compared with conventional antidiabetics (-0.06, 95%CL, -0.22 to 0.03 vs. -0.08, -0.23 to -0.03 mm, p = 0.689).

CONCLUSIONS

In patients with type 2 diabetes and coronary artery disease, treatment with sitagliptin resulted in a significantly lower rate of progression of coronary atherosclerosis compared with conventional treatment.

Oral diabetes medication and risk of dementia in elderly patients with type 2 diabetes

AIM

To examine the effect of oral diabetes medication on the risk of dementia in an elderly cohort with type 2 diabetes.

METHODS

This was a population-based cohort study using the Korean National Health Insurance claims data from 2002 to 2013. Elderly subjects (60 years of age or older) with and without type 2 diabetes were included; patients with new-onset type 2 diabetes were further divided into the oral diabetes medication group and no-medication group.

RESULTS

Among 278,290 patients with type 2 diabetes, 56,587 developed dementia (20.3%) over 11 years of follow-up. Type 2 diabetes was associated with a 1.69-fold increased risk of dementia (95% CI 1.66-1.72). Among patients with newly diagnosed type 2 diabetes, the risk of dementia was lower in the oral diabetes medication group than in the no-medication group (adjusted hazard ratio [aHR], 0.79; 95% CI 0.77-0.81). Lower risk of dementia was particularly noticeable in all of the combination therapy groups and especially lower in the combination therapy group treated with dipeptidyl peptidase 4 inhibitor (aHR 0.48, 95% CI 0.45-0.51).

CONCLUSION

Overall, the use of oral diabetes medication in type 2 diabetes patients significantly decreased the risk of dementia.

[Research progress of dipeptidyl peptidase 4 inhibitors on healing of chronic diabetic foot ulcers]

Objective

To review the effect of dipeptidyl peptidase 4 (DPP-4) inhibitors on the wound healing and its mechanisms in chronic diabetic foot ulcers.

Methods

The latest literature concerning DPP-4 inhibitors for chronic diabetic foot ulcers was extensively reviewed, as well as the potential benefit and mechanism of DPP-4 inhibitors on wound healing of diabetic foot ulcers was analyzed thoroughly.

Results

DPP-4 inhibitors can accelerated the ulcer healing. The mechanisms probably include inhibiting the expression of the matrix metalloproteinase (MMP) and restoring the balance of the wound MMP and the tissue inhibitors of MMP; promoting recruitment of endothelial progenitor cells and augmenting angiogenesis; optimizing extracellular matrix construction and the immune response to persistent hypoxia in chronic diabetes wounds, and so on. At present, clinical researches show that DPP-4 inhibitors may be considered as an adjuvant treatment for chronic diabetic foot ulcers.

Conclusion

DPP-4 inhibitors show promise in the local wound healing of chronic diabetic foot ulcers. However, more strictly designed, adequately powered, long-term follow-up, and high-quality randomized control trials are needed to further verify their efficacy and safety for chronic diabetic foot ulcers.

Dipeptidyl peptidase 4 inhibitor anagliptin ameliorates hypercholesterolemia in hypercholesterolemic mice through inhibition of intestinal cholesterol transport

Aims/Introduction

Recent data showed that dipeptidyl peptidase 4 (DPP‐4) inhibitors exert a lipid‐lowering effect in diabetes patients. However, the mechanism of action is not yet clearly understood. We investigated the effect of anagliptin on cholesterol metabolism and transport in the small intestine using non‐diabetic hyperlipidemic animals, to clarify the mechanisms underlying the cholesterol‐lowering action.

Materials and Methods

Male apolipoprotein E (ApoE)‐deficient mice were orally administered anagliptin in the normal chow. Serum cholesterol levels and lipoprotein profiles were measured, and cholesterol transport was assessed by measuring the radioactivity in the tissues after oral loading of ¹⁴C‐labeled cholesterol (¹⁴C‐Chol). In additional experiments, effects of exendin‐4 in mice and of anagliptin in DPP‐4‐deficient rats were assessed. Effects on target gene expressions in the intestine were analyzed by quantitative polymerase chain reaction in normal mice.

Results

The serum total and non‐high‐density lipoprotein cholesterol concentrations decreased after anagliptin treatment in the ApoE‐deficient mice. The cholesterol‐lowering effect was predominantly observed in the chylomicron fraction. The plasma ¹⁴C‐Chol radioactivity was significantly decreased by 26% at 2 h after cholesterol loading, and the fecal ¹⁴C‐Chol excretion was significantly increased by 38% at 72 h. The aforementioned effects on cholesterol transport were abrogated in rats lacking DPP‐4 activity, and exendin‐4 had no effect on the ¹⁴C‐Chol transport in ApoE‐deficient mice. Furthermore, significant decreases of the intestinal cholesterol transport‐related microsomal triglyceride transfer protein, acyl‐coenzyme A:cholesterol acyltransferase 2, ApoA2 and ApoC2 messenger ribonucleic acid expressions were observed in the mice treated with repeated doses of anagliptin.

Conclusions

These findings suggest that anagliptin might exert a cholesterol‐lowering action through DPP‐4‐dependent and glucagon‐like peptide 1‐independent suppression of intestinal cholesterol transport.

Impact of dipeptidyl-peptidase 4 inhibitors on cardiovascular diseases

Dipeptidyl peptidase 4 (DPP-4) inhibitor is a novel group of medicine employed in type 2 diabetes mellitus (T2DM),which improves meal stimulated insulin secretion by protecting glucagon-like peptide-1 (GLP-1) and glucose dependent insulinotropic polypeptide (GIP) from enzymatic degradation. Cardiovascular diseases are serious complications and leading causes of mortality among individuals with diabetes mellitus. Glycemic control per se seems to fail in preventing the progression of diabetic cardiovascular complications. DPP-4 has the capability to inactivate not only incretins, but also a series of cytokines, chemokines, and neuropeptides involved in inflammation, immunity, and vascular function. Pre-clinical studies suggested that DPP-4 inhibitors may have potential cardiovascular protective effects in addition to their antidiabetic actions. In recent years, a number of clinical trials have been conducted to evaluate the effect of different DPP-4 inhibitors on the cardiovascular system. We herein review the available clinical studies in cardiovascular effects played by each DPP-4 inhibitor and discuss the prospective application of DPP-4 inhibitors on cardiovascular diseases.

Linagliptin prevents atrial electrical and structural remodeling in a canine model of atrial fibrillation

Dipeptidyl peptidase 4 (DPP-4) inhibitors have recently been reported to exhibit additional cardioprotective effects; however, their effect in atrial remodeling, such as in atrial fibrillation (AF), remains unclear. In this study, the effect of linagliptin on atrial electrical and structural remodeling was evaluated in a canine AF model. Sixteen beagle dogs with 3-week atrial rapid stimulation were divided into the linagliptin group (9 mg/kg/day, n = 8) and pacing control group (n = 8). Three additional dogs without rapid pacing were assigned into non-pacing group, which was used as sham in this study. In the dogs with rapid pacing, the atrial effective refractory period (AERP), conduction velocity (CV), and AF inducibility were evaluated and blood was sampled every week. After the entire protocol, atrial tissue was sampled for histological examinations using HE, Azan, and dihydroethidium (DHE) staining to evaluate any tissue damage or oxidative stress. The pacing control group exhibited a gradual AERP shortening and CV decrease along the time course as previously reported. In the linagliptin group, the AERP shortening was not affected, but the CV decrease was suppressed in comparison to the control group (p < 0.05). The AF inducibility was increased in the control group and suppressed in the linagliptin group (p < 0.05). The control group exhibited tissue fibrosis, the degree of which was suppressed in the linagliptin group. DHE staining exhibited suppression of the reactive oxygen species expression in the linagliptin group in comparison to the pacing control group. Linagliptin, a DPP-4-inhibitor, suppressed the AF inducibility, CV decrease, and overexpression of oxidative stress in the canine AF model. Such suppressive effects of linagliptin on AF in the canine model may possibly be related to the anti-oxidative effect.

Comparison of effects of anagliptin and alogliptin on serum lipid profile in type 2 diabetes mellitus patients

INTRODUCTION

Anagliptin (ANA) improves dyslipidemia in addition to blood glucose levels. However, there are no comparative studies on the effects of ANA and other dipeptidyl peptidase-4 inhibitors on serum lipid profile. We compared the effects of ANA on serum lipid profile with those of alogliptin (ALO) in type 2 diabetes mellitus outpatients.

MATERIALS AND METHODS

The study participants were 87 type 2 diabetes mellitus patients who had been treated with dipeptidyl peptidase-4 inhibitors for ≥8 weeks and had a low-density lipoprotein cholesterol (LDL-C) level of ≥120 mg/dL. Participants were switched to either 200 mg/day ANA or 25 mg/day ALO for 24 weeks.

RESULTS

There was no significant difference in percentage change in LDL-C level at 24 weeks between the ANA and ALO groups. Treatment with ANA for 12 weeks significantly decreased LDL-C levels, one of the secondary end-points. Treatment with ANA for 24 weeks significantly improved apolipoprotein B-100 levels, and the percentage change in LDL-C levels at 24 weeks correlated significantly with the percentage change in apolipoprotein B-100 levels in the ANA group.

CONCLUSIONS

The LDL-C-lowering effects of ANA and ALO at 24 weeks were almost similar in patients with type 2 diabetes mellitus. However, the results showed a tendency for a decrease in LDL-C level at 24 weeks in the ANA group, and that such improvement was mediated, at least in part, through the suppression of apolipoprotein B-100 synthesis.

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

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

Impact of glycemic control with sitagliptin on the 2-year progression of arterial stiffness: a sub-analysis of the PROLOGUE study

Background

No conclusive evidence has been obtained yet on the significance of the effects of dipeptidyl peptidase-4 (DPP-4 inhibitor) treatment on the arterial stiffness in clinical settings. In addition, the effects of good glycemic control on the arterial stiffness have also not been clarified yet. As a sub-analysis of the PROLOGUE study, we examined the effect of a DPP-4 inhibitor (sitagliptin) on the 2-year progression of the arterial stiffness and also to determine the effect of good glycemic control on the rate of progression of the arterial stiffness.

Methods

In the PROLOGUE study, the study participants were either allocated to add-on sitagliptin treatment or to continued treatment with conventional anti-diabetic agents. Among the 463 participants of the PROLOGUE study, we succeeded in measuring the brachial-ankle pulse wave velocity (baPWV) at least two times during the 2-year study period in 96 subjects.

Results

The changes in the baPWV during the study period were similar between the both groups (i.e., with/without staglipitin), overall. On the other hand, when the study subjects were divided into two groups according to the glycemic control status during the study period {good glycemic control group (GC) = hemoglobin (Hb)A1c <7.0 at both 12 and 24 months after the treatment randomization; poor glycemic control group (PC) = HbA1c ≥7.0 at either 12 months, 24 months, or both}, the 2-year increase of the baPWV was marginally significantly larger in the PC group (144 ± 235 cm/s) as compared to that the GC group (−10 ± 282 cm/s) (p = 0.036).

Conclusion

While the present study could not confirm the beneficial effect of sitagliptin per se on the arterial stiffness, the results suggested that good glycemic control appears to be beneficial for delaying the annual progression of the arterial stiffness.

Trial registration University Hospital Medical Information Network Clinical Trials Registry UMIN000004490

Long-term effect of sitagliptin on endothelial function in type 2 diabetes: a sub-analysis of the PROLOGUE study

Background

As a sub-analysis of the PROLOGUE study, we evaluated the long-term effect of sitagliptin, a dipeptidyl peptidase 4 inhibitor, on endothelial function in the conduit brachial artery in patients with type 2 diabetes.

Methods

In the PROLOGUE study, patients were randomly assigned to either add-on sitagliptin treatment (sitagliptin group) or continued conventional antihyperglycemic treatment (conventional group). Among the 463 participants in the PROLOGUE study, FMD was measured in 17 patients in the sitagliptin group and 18 patients in the conventional group at the beginning and after 12 and 24 months of treatment.

Results

HbA1c levels were significantly decreased after 12 and 24 months of treatment compared to baseline values in both groups (7.0 ± 0.4 vs. 6.6 ± 0.3 and 6.6 ± 0.4 % in the sitagliptin group; 7.0 ± 0.6 vs. 6.6 ± 0.7 and 6.6 ± 0.7 % in the conventional group; P < 0.05, respectively). There was no significant difference between FMD values at baseline and after 12 and 24 months in the sitagliptin group (4.3 ± 2.6 vs. 4.4 ± 2.1 and 4.4 ± 2.3 %, P = 1.0, respectively). Although FMD had a tendency to increase from 4.3 ± 2.4 % at baseline to 5.2 ± 1.9 % after 12 months and 5.1 ± 2.2 % after 24 months in the conventional group, there was no significant difference between FMD values at baseline and after 12 and 24 months (P = 0.36 and 0.33, respectively).

Conclusions

Add-on sitagliptin to conventional antihyperglycemic drugs in patients with type 2 diabetes did not alter endothelial function in the conduit brachial artery measured by FMD during a 2-year study period. Sitagliptin may be used without concern for an adverse effect on endothelial function in patients with type 2 diabetes.

Trial registration: University hospital Medical Information Network (UMIN) Center: ID UMIN000004490

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-016-0438-x) contains supplementary material, which is available to authorized users.

Comparison of Vildagliptin and Pioglitazone in Korean Patients with Type 2 Diabetes Inadequately Controlled with Metformin

BACKGROUND

We compared the efficacies of vildagliptin (50 mg twice daily) relative to pioglitazone (15 mg once daily) as an add-on treatment to metformin for reducing glycosylated hemoglobin (HbA1c) levels in Korean patients with type 2 diabetes.

METHODS

The present study was a multicenter, randomized, active-controlled investigation comparing the effects of vildagliptin and pioglitazone in Korean patients receiving a stable dose of metformin but exhibiting inadequate glycemic control. Each patient underwent a 16-week treatment period with either vildagliptin or pioglitazone as an add-on treatment to metformin.

RESULTS

The mean changes in HbA1c levels from baseline were -0.94% in the vildagliptin group and -0.6% in the pioglitazone group and the difference between the treatments was below the non-inferiority margin of 0.3%. The mean changes in postprandial plasma glucose (PPG) levels were -60.2 mg/dL in the vildagliptin group and -38.2 mg/dL in the pioglitazone group and these values significantly differed (P=0.040). There were significant decreases in the levels of total, low density lipoprotein, high density lipoprotein (HDL), and non-HDL cholesterol in the vildagliptin group but increases in the pioglitazone group. The mean change in body weight was -0.07 kg in the vildagliptin group and 0.69 kg in the pioglitazone group, which were also significantly different (P=0.002).

CONCLUSION

As an add-on to metformin, the efficacy of vildagliptin for the improvement of glycemic control is not inferior to that of pioglitazone in Korean patients with type 2 diabetes. In addition, add-on treatment with vildagliptin had beneficial effects on PPG levels, lipid profiles, and body weight compared to pioglitazone.

Noncardiac Pulmonary Edema induced by Sitagliptin Treatment

A 74-year-old male patient with type 2 diabetes mellitus admitted to the emergency department with the complaints of progressive breathlessness, dry cough, and swollen lower extremities. Our patient had type 2 diabetes mellitus and hypertension for 3 years. His HbA1c was not within the target range so sitagliptin was added to on-going therapy. After 1 week of starting sitagliptin therapy, even though the patient had not heart failure he applied to the emergency department with a complaint of dyspnea. The cardiovascular safety and efficacy of many anti-hyperglycemic agents such as sitagliptin, saxagliptin are unclear. Our case has shown that dipeptidyl peptidase 4 inhibitors may cause pulmonary edema. Hence, it should be used with cautious, especially in patients with heart failure.

Noncardiac Pulmonary Edema induced by Sitagliptin Treatment

A 74-year-old male patient with type 2 diabetes mellitus admitted to the emergency department with the complaints of progressive breathlessness, dry cough, and swollen lower extremities. Our patient had type 2 diabetes mellitus and hypertension for 3 years. His HbA1c was not within the target range so sitagliptin was added to on-going therapy. After 1 week of starting sitagliptin therapy, even though the patient had not heart failure he applied to the emergency department with a complaint of dyspnea. The cardiovascular safety and efficacy of many anti-hyperglycemic agents such as sitagliptin, saxagliptin are unclear. Our case has shown that dipeptidyl peptidase 4 inhibitors may cause pulmonary edema. Hence, it should be used with cautious, especially in patients with heart failure.

Predictive clinical parameters and glycemic efficacy of vildagliptin treatment in korean subjects with type 2 diabetes

BACKGROUND

The aims of this study are to investigate the glycemic efficacy and predictive parameters of vildagliptin therapy in Korean subjects with type 2 diabetes.

METHODS

In this retrospective study, we retrieved data for subjects who were on twice-daily 50 mg vildagliptin for at least 6 months, and classified the subjects into five treatment groups. In three of the groups, we added vildagliptin to their existing medication regimen; in the other two groups, we replaced one of their existing medications with vildagliptin. We then analyzed the changes in glucose parameters and clinical characteristics.

RESULTS

Ultimately, 327 subjects were analyzed in this study. Vildagliptin significantly improved hemoglobin A1c (HbA1c) levels over 6 months. The changes in HbA1c levels (ΔHbA1c) at month 6 were -2.24% (P=0.000), -0.77% (P=0.000), -0.80% (P=0.001), -0.61% (P=0.000), and -0.34% (P=0.025) for groups 1, 2, 3, 4, and 5, respectively, with significance. We also found significant decrements in fasting plasma glucose levels in groups 1, 2, 3, and 4 (P<0.05). Of the variables, initial HbA1c levels (P=0.032) and history of sulfonylurea use (P=0.026) were independently associated with responsiveness to vildagliptin treatment.

CONCLUSION

Vildagliptin was effective when it was used in subjects with poor glycemic control. It controlled fasting plasma glucose levels as well as sulfonylurea treatment in Korean type 2 diabetic subjects.