Alogliptin versus glipizide monotherapy in elderly type 2 diabetes mellitus patients with mild hyperglycaemia: a prospective, double-blind, randomized, 1-year study

Evaluation of glucose-lowering medications in older people: a comprehensive systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Type 2 diabetes mellitus (T2DM) is increasingly being diagnosed in older adults. Our objective is to assess the advantages and potential drawbacks of different glucose-lowering medications in this specific population.

METHODS

A network meta-analysis was conducted to identify randomized controlled trials that examined patient-centered outcomes in adults aged ≥65 years with T2DM. We searched PubMed, Cochrane CENTRAL, and Embase up to September 23, 2023. Quality of eligible studies were assessed using the Cochrane RoB 2.0 tool.

RESULTS

A total of 22 trials that involved 41 654 participants were included, incorporating sodium-glucose cotransporter-2 (SGLT2) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs), dipeptidyl peptidase-4 (DPP-4) inhibitors, metformin, sulfonylureas (SU) and acarbose. Our findings reveal that GLP-1RAs reduce the risk of major adverse cardiovascular events (risk ratio [RR], 0.83; 95% confidence interval [CI], 0.71 to 0.97) and body weight (mean difference [MD], -3.87 kg; 95% CI, -5.54 to -2.21). SGLT2 inhibitors prevent hospitalization for heart failure (RR, 0.66; 95% CI, 0.57 to 0.77), renal composite outcome (RR, 0.69; 95% CI, 0.53 to 0.89), and reduce body weights (MD, -1.85 kg; 95% CI, -2.42 to -1.27). SU treatment increases the risk of any hypoglycaemia (RR, 4.19; 95% CI, 3.52 to 4.99) and severe hypoglycaemia (RR, 7.06; 95% CI, 3.03 to 16.43). GLP-1RAs, SGLT2 inhibitors, metformin, SU and DPP-4 inhibitors are effective in reducing glycaemic parameters. Notably, the number of treatments needed decreases in most cases as age increases.

CONCLUSIONS

Novel glucose-lowering medications with benefits that outweigh risks should be prioritized for older patients with diabetes.

Encyclopaedic Review of Glipizide Pre-clinical and Clinical Status

Glipizide is an oral glucose-lowering medication that is beneficial for the treatment of type 2 diabetes. This study compiles exhaustively all accessible information on glipizide, from preclinical to clinical studies. Glipizide may be used in concert with TRAIL to treat cancer cells; in vitro studies have shown that it suppresses angiogenesis and vasculogenesis while shielding cells from glycation-induced damage. Anticonvulsant effects and modifications in the pharmacokinetics of other medications, such as Divalproex Sodium, were seen in glipizide in vivo experiments. Propranolol amplifies glipizide's hypoglycemic effect briefly in normal animals but consistently enhances it in diabetic ones. In the treatment of cancer and neurodegenerative poly(Q) illnesses, glipizide has demonstrated to offer potential therapeutic advantages. It is ineffective in preventing DENA-induced liver cancer and may cause DNA damage over time. The way glipizide interacts with genetic variants may increase the risk of hypoglycemia. Combining Syzygium cumini and ARBE to glipizide may enhance glycemic and lipid control in type 2 diabetes. Individuals with coronary artery disease who take glipizide or glyburide have an increased risk of death. The risk of muscular responses and acute pancreatitis is minimal when glipizide and dulaglutide are combined. In conclusion, glipizide has shown promising therapeutic efficacy across a variety of disorders.

Systematic review and meta-analysis of head-to-head trials comparing sulfonylureas and low hypoglycaemic risk antidiabetic drugs

BACKGROUND

Safety of sulfonylurea drugs in the treatment of Type 2 Diabetes is still under debate. The aim of this study was to compare the all-cause mortality and cardiovascular adverse events of sulfonylureas and drugs with a low risk for hypoglycaemia in adults with type 2 diabetes.

METHODS

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

MEDLINE (PubMed, OVID), Embase, Cochrane Central Register of Controlled Trials, CINAHL, WOS and Lilacs.

STUDY SELECTION

Randomised controlled head-to-head trials that compared sulfonylureas with active control with low hypoglycaemic potential in adults (≥ 18 years old) with type 2 diabetes published up to August 2015. The drug classes involved in the analysis were metformin, dipeptidyl peptidase-4 (DPP-4) inhibitors, sodium-glucose co-transporter-2 (SGLT-2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists.

OUTCOMES

The primary endpoint was all-cause mortality. The secondary endpoints were MACE, cardiovascular events and severe hypoglycaemia.

SYNTHESIS OF RESULTS

Two reviewers checked study eligibility, independently extracted data and assessed quality with disagreements resolved through discussion. We assessed the risk of bias of the included studies using the Cochrane risk of bias tool for randomized trials v2. Pooled odds ratios (ORs) were estimated by using fixed effects model. The study is registered on PROSPERO (26/05/2016 CRD42016038780).

RESULTS

Our final analysis comprised 31 studies (26,204 patients, 11,711 patients given sulfonylureas and 14,493 given comparator drugs). In comparison to drugs with low hypoglycaemic potential, sulfonylureas had higher odds for all-cause mortality (OR 1.32, 95% CI 1.00-1.75), MACE (OR 1.32, 95% CI 1.07-1.61), myocardial infarction (fatal and non-fatal) (OR 1.67, 95% CI 1.17-2.38) and hypoglycaemia (OR 5.24, 95% CI 4.20-6.55). Subsequent sensitivity analysis revealed differences in the effect of sulfonylureas, with an increased risk of all-cause mortality with glipizide but not the other molecules.

CONCLUSION

Our meta-analysis raises concern about the safety of SUs compared to alternative drugs involved in current analysis. Important differences may exist within the drug class, and glimepiride seems to have best safety profile.

Comparison of Efficacy of Glimepiride, Alogliptin, and Alogliptin-Pioglitazone as the Initial Periods of Therapy in Patients with Poorly Controlled Type 2 Diabetes Mellitus: An Open-Label, Multicenter, Randomized, Controlled Study

BACKGROUND

The choice of an optimal oral hypoglycemic agent in the initial treatment periods for type 2 diabetes mellitus (T2DM) patients remains difficult and deliberate. We compared the efficacy and safety of glimepiride (GLIM), alogliptin (ALO), and alogliptin-pioglitazone (ALO-PIO) in poorly controlled T2DM patients with drug-naïve or metformin failure.

METHODS

In this three-arm, multicenter, open-label, randomized, controlled trial, poorly controlled T2DM patients were randomized to receive GLIM (n=35), ALO (n=31), or ALO-PIO (n=33) therapy for 24 weeks. The primary endpoint was change in the mean glycosylated hemoglobin (HbA1c) levels at week 24 from baseline. Secondary endpoints were changes in HbA1c level at week 12 from baseline, fasting plasma glucose (FPG) levels, lipid profiles at weeks 12 and 24, and parameters of glycemic variability, assessed by continuous glucose monitoring for 24 weeks.

RESULTS

At weeks 12 and 24, the ALO-PIO group showed significant reduction in HbA1c levels compared to the ALO group (-0.96%±0.17% vs. -0.37%±0.17% at week 12; -1.13%±0.19% vs. -0.18%±0.2% at week 24). The ALO-PIO therapy caused greater reduction in FPG levels and significant increase in high-density lipoprotein cholesterol levels at weeks 12 and 24 than the ALO therapy. Compared to low-dose GLIM therapy, ALO-PIO therapy showed greater improvement in glycemic variability. The adverse events were similar among the three arms.

CONCLUSION

ALO-PIO combination therapy during the early period exerts better glycemic control than ALO monotherapy and excellency in glycemic variability than low-dose sulfonylurea therapy in uncontrolled, drug-naïve or metformin failed T2DM patients.

Dipeptidyl peptidase-4 inhibitors and gallbladder or biliary disease in type 2 diabetes: systematic review and pairwise and network meta-analysis of randomised controlled trials

OBJECTIVE

To examine the association between dipeptidyl peptidase-4 inhibitors and gallbladder or biliary diseases.

DESIGN

Systematic review and pairwise and network meta-analysis.

DATA SOURCES

PubMed, EMBASE, Web of Science, and CENTRAL from inception until 31 July 2021.

ELIGIBILITY CRITERIA

Randomised controlled trials of adult patients with type 2 diabetes who received dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists, and sodium-glucose cotransporter-2 inhibitors compared with placebo or other antidiabetes drugs.

MAIN OUTCOME MEASURES

Composite of gallbladder or biliary diseases, cholecystitis, cholelithiasis, and biliary diseases.

DATA EXTRACTION AND DATA SYNTHESIS

Two reviewers independently extracted the data and assessed the quality of the studies. The quality of the evidence for each outcome was assessed using the Grading of Recommendations, Assessment, Development and Evaluations framework (GRADE) approach. The meta-analysis used pooled odds ratios and 95% confidence intervals.

RESULTS

A total of 82 randomised controlled trials with 104 833 participants were included in the pairwise meta-analysis. Compared with placebo or non-incretin drugs, dipeptidyl peptidase-4 inhibitors were significantly associated with an increased risk of the composite of gallbladder or biliary diseases (odds ratio 1.22 (95%confidence interval 1.04 to 1.43); risk difference 11 (2 to 21) more events per 10 000 person years) and cholecystitis (odds ratio 1.43 (1.14 to 1.79); risk difference 15 (5 to 27) more events per 10 000 person years) but not with the risk of cholelithiasis and biliary diseases. The associations tended to be observed in patients with a longer duration of dipeptidyl peptidase-4 inhibitor treatment. In the network meta-analysis of 184 trials, dipeptidyl peptidase-4 inhibitors increased the risk of the composite of gallbladder or biliary diseases and cholecystitis compared with sodium-glucose cotransporter-2 inhibitors but not compared with glucagon-like peptide-1 receptor agonists.

CONCLUSIONS

Dipeptidyl peptidase-4 inhibitors increased the risk of cholecystitis in randomised controlled trials, especially with a longer treatment duration, which requires more attention from physicians in clinical practice.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021271647.

Short-Term Treatment of Metformin and Glipizide on Oxidative Stress, Lipid Profile and Renal Function in a Rat Model with Diabetes Mellitus

Background: Oxidative stress, lipid profile and renal functions are well-known conventional risk factors for diabetes mellitus (DM). Metformin and gliclazide are popularly used monotherapy drugs for the treatment of DM. Aims: This study aims to assess the short-term treatment of single and dual therapy of glipizide/metformin on oxidative stress, glycemic control, serum lipid profiles and renal function in diabetic rats. Methods: DM was induced in rats with streptozotocin (STZ), then five different treatments were applied, including group I (untreated healthy control), group II (diabetic and untreated), group III (diabetic and treated with metformin), group IVI (diabetic and treated with glipizide) and group V (diabetic and treated with a combination of metformin and glipizide. Lipid peroxidation (LPO), nitric oxide (NO), total antioxidant capacity (TAC), fasting blood glucose (FBG), glycated hemoglobin (HbA1c), total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), creatinine and urea were measured. Results: Compared to the untreated DM group, FBG and HbA1c were significantly reduced in the DM groups (p < 0.01) treated with metformin (159.7 mg/dL & 6.7%), glipizide (184.3 mg/dL & 7.3%) and dual therapy (118 mg/dL & 5.2%), respectively. Treatment with dual therapy and metformin significantly decreased LPO and NO levels but increased TAC in diabetic rats more than glipizide compared to untreated diabetic rats. Furthermore, metformin (19.8 mg/dL, p < 0.001), glipizide (22.7 mg/dL, p < 0.001), and dual therapy (25.7 mg/dL, p < 0.001) significantly decreased urea levels in the treated rats compared to untreated DM rats (32.2 mg/dL). Both drugs and their combination exhibited a substantial effect on total cholesterol, HDL, LDL and atherogenic index. Conclusions: These results suggest that the therapeutic benefits of metformin and glipizide are complementary. Metformin exhibited superior performance in improving glycemic control and decreasing oxidative stress, while glipizide was more effective against dyslipidemia. These findings could be helpful for the treatment of future vascular patients, antilipidemic medicines and antioxidant therapy to improve the quality of life.

Safety of dipeptidyl peptidase-4 inhibitors in older adults with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

Registration:

PROSPERO: CRD42020210645

Introduction:

We aimed to assess the safety of dipeptidyl peptidase-4 (DPP-4) inhibitors in older patients with type 2 diabetes with inadequate glycaemic control.

Methods:

We included randomized controlled trials (RCTs) in older (⩾65 years) patients with type 2 diabetes. The intervention group was randomized to treatment with any DPP-4 inhibitors. A systematic search in MEDLINE and Embase was performed in December 2020. For assessing the risk of bias, RoB 2 tool was applied. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. We pooled outcomes using random effects meta-analyses.

Results:

We identified 16 RCTs that included 19,317 patients with a mean age of greater than 70 years. The mean HbA1c level ranged between 7.1 and 10.0 g/dl. Adding DPP-4 inhibitors to standard care alone may increase mortality slightly [risk ratio (RR) 1.04; 95% confidence interval (CI) 0.89–1.21]. Adding DPP-4 inhibitors to standard care increases the risk for hypoglycaemia (RR 1.08; 95% CI 1.01–1.16), but difference in overall adverse events is negligible. DPP-4 inhibitors added to standard care may reduce mortality compared with sulfonylureas (RR 0.88; 95% CI 0.75–1.04). DPP-4 inhibitors probably reduce the risk for hypoglycaemia compared with sulfonylureas (magnitude of effect not quantifiable because of heterogeneity) but difference in overall adverse events is negligible. There is insufficient evidence on hospitalizations, falls, fractures, renal impairment and pancreatitis.

Conclusion:

There is no evidence that DPP-4 inhibitors in addition to standard care decrease mortality but DPP-4 inhibitors increase hypoglycaemia risk. Second-line therapy in older patients should be considered cautiously even in drugs with a good safety profile such as DPP-4 inhibitors. In case second-line treatment is necessary, DPP-4 inhibitors appear to be preferable to sulfonylureas.

Plain language summary

Safety of dipeptidyl peptidase-4 inhibitors in older adults with type 2 diabetes Introduction: We performed the review to assess the safety of dipeptidyl peptidase-4 (DPP-4) inhibitors in older type 2 diabetes patients with blood sugar outside the normal level. Methods: To answer the question, we searched various electronic databases. We included studies in older (⩾65 years) patients with type 2 diabetes that assessed the safety of DPP-4 inhibitors. The data from the different studies were quantitatively summarized using statistical methods. We assessed the quality of the data to judge the certainty of the findings. Results: We identified 16 studies that included 19,317 patients with a mean age greater than 70 years. The average blood sugar level of patients in the included studies was slightly or moderately increased. Adding DPP-4 inhibitors to standard care alone may increase mortality slightly. Adding DPP-4 inhibitors to standard care increases the risk for hypoglycaemia, but difference in overall adverse events is negligible. DPP-4 inhibitors added to standard care may reduce mortality compared with sulfonylureas. DPP-4s probably reduce the risk of hypoglycaemia compared with sulfonylureas (magnitude of effect not quantifiable because of heterogeneity) but difference in overall adverse events is negligible. There is insufficient evidence on hospitalizations, falls, fractures, renal impairment and pancreatitis. Conclusion: There is no evidence that DPP-4 inhibitors in addition to standard care decrease mortality but DPP-4 inhibitors increase the risk that blood sugar falls below normal. Adding DPP-4 inhibitorss to standard care in older patients should be considered cautiously even in drugs with a good safety profile such as DPP-4 inhibitors. In case additional treatment is necessary, DPP-4 inhibitors appear to be preferable to sulfonylureas.

Efficacy / safety balance of DPP-4 inhibitors versus SGLT2 inhibitors in elderly patients with type 2 diabetes

Dipeptidyl peptidase-4 inhibitors (DPP-4is) and sodium-glucose cotransporter type 2 inhibitors (SGLT2is) offer new options for the oral management of type 2 diabetes mellitus (T2DM), with the advantage in the elderly population to be devoid of a high risk of hypoglycaemia. SGLT2is have also shown benefits regarding cardiovascular (heart failure) and renal protection, including in patients with T2DM aged ≥ 65 years while DPP-4is have only proved cardiovascular and renal safety without superiority compared with placebo. The glucose-lowering efficacy of the two pharmacological classes is almost similar including in older patients with T2DM. However, the tolerance and safety profile may be highly different and overall more favourable with DPP-4is than with SGLT2is. Some adverse events have been reported with SGLT2is which may be more prevalent or severe in older patients than in younger patients. The present comprehensive review focuses on the benefit/risk balance in the elderly population with T2DM by comparing the profile of DPP-4is and SGLT2is regarding the following potential issues: metabolic disorders (hypoglycaemia and diabetic ketoacidosis); cardiac and vascular issues (atheromatous cardiovascular disease, heart failure, volume reduction hypotension, and lower limb amputations); renal endpoints including acute renal injury; risk of infections; digestive disorders; bone and skin adverse events; and cancer risk. Both DPP-4is and SGLT2is have their own advantages and disadvantages. Personalised treatment is recommended based upon the efficacy/safety profile of each drug class and individual patient characteristics that may be markedly different among the heterogeneous population of older individuals with T2DM.

Careful use to minimize adverse events of oral antidiabetic medications in the elderly

INTRODUCTION

An increasing number of older patients has type 2 diabetes treated with different oral antidiabetic agents whose safety may raise concern considering some particularities of a heterogeneous elderly population.

AREAS COVERED

This article discusses some characteristics of older patients that could increase the risk of adverse events, with a focus on hypoglycemia. It describes the most frequent and/or severe complications reported in the elderly in both randomized controlled trials and observational studies with metformin, sulfonylureas, meglitinides, alpha-glucosidase inhibitors, thiazolidinediones, dipeptidyl peptidase-4 inhibitors (gliptins) and sodium-glucose cotransporter type 2 inhibitors (gliflozins).

EXPERT OPINION

Old patients may present comorbidities (renal impairment, vascular disease, heart failure, risk of dehydration, osteoporosis, cognitive dysfunction) that could increase the risk of severe adverse events. Sulfonylureas (and meglitinides) induce hypoglycemia, which may be associated with falls/fractures and cardiovascular events. Medications lacking hypoglycemia should be preferred. Gliptins appear to have the best tolerance/safety profile whereas gliflozins exert a cardiorenal protection. However, data are lacking in very old or frailty old patients so that caution and appropriate supervision of such patients are required. Taking advantage of a large choice of pharmacotherapies, personalized treatment is recommended based upon both drug safety profiles and old patient individual characteristics.

Cardiovascular Outcomes Comparison of Dipeptidyl Peptidase-4 Inhibitors versus Sulfonylurea as Add-on Therapy for Type 2 Diabetes Mellitus: a Meta-Analysis

Objective

Recent studies have raised concern about the cardiovascular safety of dipeptidyl peptidase-4 (DPP4) inhibitors. We performed a systematic review through meta-analysis to compare cardiovascular outcomes of sulfonylurea (SU) versus DPP4 inhibitors when used in combination with metformin.

Methods

After searching for trials using combination therapy of metformin with DPP4 inhibitor or SU in PubMed, Cochrane Library, and Embase, one prospective observation study and 15 randomized controlled studies were selected.

Results

Regarding the primary analysis endpoint, there were no significant differences in the risk of all-cause mortality between SU and DPP4 inhibitors as an add-on therapy to metformin (random-effect relative risk [RR], 1.14; 95% confidence interval [CI], 0.98–1.33; p=0.811; I²=0%). Cardiovascular death was also similar between the two drug classes in the five studies which reported outcomes (random-effect RR, 1.03; 95% CI, 0.83–1.27; p=0.517; I²=0%). Furthermore, there were no significant differences in major adverse cardiac events (MACE), coronary heart disease, myocardial infarction, ischemic stroke and heart failure. However, there were less hypoglycemic events and weight gain in the DPP4 inhibitor group as compared with the SU group (random-effect RR, 3.79; 95% CI, 1.53–9.39; p<0.001; I²=98.2 and weighted mean difference, 1.68; 95% CI, 1.07–2.29; p<0.001; I²=94.7, respectively).

Conclusion

As add-on therapy to metformin, there were no significant differences in all-cause mortality and cardiovascular mortality between DPP4 inhibitors and SUs.

Type 2 diabetes management in people aged over seventy-five years: targets and treatment strategies

Older people (those aged 65 years or more) with diabetes comprise a heterogenous group of patients with special needs and features; this is particularly true for those aged 75 years or more. It is important that individualized glycemic targets be adopted in this population, after considering life expectancy, presence of diabetic complications and other comorbidities. In general, less rigorous targets and avoidance of overtreatment seems to be a reasonable strategy in daily clinical settings. There is a paucity of data regarding the efficacy and safety of various hypoglycemic agents, especially for those aged over 75. The evidence suggests that sulfonylureas and insulin regimens should be used with caution due to a high risk of hypoglycemia. Dipeptidyl peptidase-4 inhibitors are a good choice for the management of diabetes in older age groups, although a warning against the use of specific agents in people with heart failure is valid. There are insufficient data to decide whether the cardiorenal protective properties of sodium-glucose co-transporter 2 inhibitors outweigh the risks associated with these drugs. The use of glucagon-like peptide-1 receptor agonists by older patients is supported not only by their good safety and efficacy profiles, but also by their potential to improve glucose-independent outcomes, through their pleiotropic actions. The aim of this narrative review is to summarize the evidence on glycemic targets and optimal therapeutic approaches for older patients with type 2 diabetes and discuss the risk-benefit balance of various therapeutic approaches in this group.

Dipeptidyl Peptidase-4 inhibitors use in type II diabetic patients in a tertiary hospital

Background

In Malaysia, for more than a decade, dipeptidyl peptidase-4 inhibitors (DPP-4i) are among the oral antidiabetic medications used as monotherapy or in combination to manage type II diabetes mellitus (T2DM). These medications are known for the efficacy in glycated haemoglobin (HbA1c) reduction and weight neutral effect with minimal hypoglycaemia occurrence. This study aimed to identify the outcomes of DPP-4i use in one of the largest tertiary public hospital in Southeast Asia.

Methods

This is a retrospective cross sectional study conducted in 2016, where stratified sampling method was used. Patients with T2DM treated with available DPP-4i; namely Linagliptin, Saxagliptin, Sitagliptin and Vildagliptin, for at least 3 months were identified from the pharmacy record. Medical records from Physician Clinic in Hospital Kuala Lumpur (HKL) were reviewed. Data on demographic, anthropometric, antidiabetic treatment modalities, laboratory and documented outcomes were collected. Outcomes endpoints which include changes in HbA1c, fasting blood glucose (FBG), and body weight were recorded and analysed. Adverse drug reactions (ADR) documented were also reported.

Results and discussion

A total of one hundred and five patients were recruited. The patients were 49.5% men (n = 52), with a mean age of 57 years, mean HbA1c of 8.5% (69 mmol/mol) and mean BMI of 29.5 kg/m². At least 50% of the patients had T2DM for more than 10 years and more than two third of these patients had both T2DM and hypertension. Thirty nine patients were on Vildagliptin, 32 on Sitagliptin, 26 on Saxagliptin and the remaining on Linagliptin. The most commonly prescribed DPP-4i were Vildagliptin and Sitagliptin. Majority of the patients (90.4%) were prescribed with Metformin, with 62.8% of patients on fixed-dose combination, and the remaining on add-on Metformin therapy. Use of DPP-4i as an adjunct was associated with a mean reduction of 0.9% (9 mmol/mol) in HbA1c (p < 0.0001) and 1.15 mmol/L (19.82 mg/dL) in FBG (p = 0.001) without significant weight changes (p = 0.745). Sitagliptin had the highest reduction in HbA1c (1.66%,19 mmol/mol; p-value< 0.0001). Twelve ADRs were reported with the highest report on gastrointestinal intolerance (n = 7). None of the ADR reported caused any significant harm to the patients.

Conclusion

Overall, use of these DPP-4i as an adjunct antidiabetic was associated with reduction in HbA1c.

Benefit-Risk Assessment of Alogliptin for the Treatment of Type 2 Diabetes Mellitus

The dipeptidyl peptidase-4 inhibitor (DPP-4i) alogliptin is an oral, antidiabetic treatment that is approved in many countries to treat patients with type 2 diabetes mellitus (T2DM), including the USA, Europe, and Japan. Alogliptin is efficacious both as monotherapy and as add-on/combination therapy with other commonly prescribed T2DM treatments, such as metformin and pioglitazone. Overall, alogliptin is well-tolerated in patients with T2DM, including older patients, those with renal and/or hepatic impairment, and those at high risk of cardiovascular events. There is a low risk of hypoglycemia, weight gain, acute pancreatitis, and gastrointestinal adverse events with alogliptin treatment, as demonstrated in long-term trials (lasting up to 4.5 years) and in a real-world setting. Additionally, alogliptin has a generally favorable or similar safety profile in comparison to other antidiabetic agents (metformin, thiazolidinediones, sulfonylureas, glucagon-like peptide-1 receptor agonists, sodium-glucose cotransporter 2 inhibitors, α-glucosidase inhibitors, and insulin). However, further evaluation would be required to determine the mechanism and effect of alogliptin on heart failure, bullous pemphigoid, and inflammatory bowel disease. Of note, due to the ethnic diversity in the epidemiology of T2DM, alogliptin has been shown to be more efficacious in Asian patients than in non-Asian patients with T2DM, but with a similar tolerability profile. These data indicate that DPP-4is, including alogliptin, are important treatment options, especially for Asian patients with T2DM, for whom they have potential as a first-line therapy. This benefit-risk assessment aims to place alogliptin within the current armamentarium of T2DM and aid physicians when choosing optimal diabetes treatment for their patients.

Efficacy and safety of linagliptin to improve glucose control in older people with type 2 diabetes on stable insulin therapy: A randomized trial

AIM

To assess the addition of linagliptin as an alternative to insulin uptitration in older people with type 2 diabetes on stable insulin therapy.

MATERIALS AND METHODS

This phase 4, randomized, multicentre, double-blinded, placebo-controlled, 24-week study recruited individuals on stable insulin, with baseline HbA1c 7.0%-10.0%, aged ≥60 years and body mass index ≤45 kg/m² . HbA1c and fasting plasma glucose were measured at study visits, and participants assessed glycaemic control with a self-monitoring blood glucose device. Adverse events (AEs) were reported during the study.

RESULTS

Three hundred and two participants were randomized 1:1 to linagliptin 5 mg qd and placebo, with one third of patients from Japan. Study population age and HbA1c (baseline mean ± SD) were 72.4 ± 5.4 years and 8.2 ± 0.8%, respectively; ~80% of participants were aged ≥70 years; 80% had macrovascular complications, one third had a baseline estimated glomerular filtration rate <60 mL/min/1.73 m² ; and half had been diagnosed with diabetes for >15 years. Linagliptin significantly improved glucose control at 24 weeks (HbA1c-adjusted mean change vs. placebo: -0.63%; P <0.0001) and the probability of achieving predefined HbA1c targets without hypoglycaemia (HbA1c <8.0%: OR 2.02; P <0.05 and HbA1c <7.0%: OR 2.44; P <0.01). Linagliptin versus placebo was well tolerated, with similar incidences of AEs, including clinically important hypoglycaemia (blood glucose <54 mg/dL) or severe hypoglycaemia.

CONCLUSIONS

Addition of linagliptin improves glucose control without an excess of hypoglycaemia in older patients with type 2 diabetes on stable insulin therapy.

An up-to-date evaluation of alogliptin benzoate for the treatment of type 2 diabetes

Introduction: A growth in the market for anti-diabetic drugs, along with an ever-increasing population suffering from type 2 diabetes mellitus (T2DM), requires a critical re-evaluation of anti-diabetic drugs used for a long time, in order to provide up-to-date practical prescribing information for clinicians. Alogliptin benzoate was firstly approved in 2010 in Japan for T2DM, both as a monotherapy or in combination with other anti-diabetic drugs. Areas covered: This article provides a comprehensive review of the latest data on alogliptin benzoate, including hypoglycemic activity and safety. Expert opinion: The cumulative evidence for alogliptin benzoate is robust with regards to glycemic efficacy and safety. Low hypoglycemia risks and weight changes support its consideration as a first-line medication for T2DM, either as a monotherapy or in combination therapy with other anti-diabetic drugs such as metformin. Ongoing trials will look to better analyze and address its safety and efficacy in pediatric patients and expand our clinical knowledge of this medication.

Ten years of experience with DPP-4 inhibitors for the treatment of type 2 diabetes mellitus

Achieving and maintaining recommended glycemic targets without causing adverse e ffects, including hypoglycemia, is challenging, especially in older patients with type 2 diabetes mellitus (T2DM). The introduction of dipeptidyl peptidase-4 (DPP-4) inhibitors, more than 10 years ago, has provided an alternative to conventional medications for the intensification of glucose-lowering treatment after failure of metformin monotherapy, and therefore, marked an important advance in the management of T2DM. By prolonging the activity of incretin hormones, DPP-4 inhibitors induce insulin release and decrease glucagon secretion in a glucose-dependent manner. This results in a more physiologic glycemic control as compared to that ensured by insulin secretagogues (sulfonylureas and glinides). Overall, DPP-4 inhibitors have a favorable safety profile and can be used without dose adjustments in older adults and in patients with mild renal impairment; they have a neutral effect on body weight and do not cause hypoglycemia by themselves. Safety issues, reported mainly in post-marketing surveillance programs and including cardiovascular outcomes and the risk of acute pancreatitis, are being extensively investigated. The aim of this review is to discuss the impact of DPP-4 inhibitors on the treatment of T2DM, after 10 years of experience, with an emphasis on diabetes care in Italy. We will first describe T2DM treatment in Italy and then provide an overview of the main findings from randomized controlled trials, real-world studies and post-marketing surveillance programs with DPP-4 inhibitors.

DPP-4 Inhibition and the Path to Clinical Proof

In the 1990s it was discovered that the enzyme dipeptidyl peptidase-4 (DPP-4) inactivates the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). DPP-4 inhibition results in raised levels of the two incretin hormones which in turn result in lowering of circulating glucose through stimulation of insulin secretion and inhibition of glucagon secretion. Since then, several small orally available molecules have been developed with DPP-4 inhibitory action. Early studies in the 1990s showed that the DPP-4 inhibitors improve glycemia in animals. Subsequent clinical studies during the 2000s showed a glucose-lowering action of DPP-4 inhibitors also in human subjects with type 2 diabetes. This action was seen when DPP-4 inhibitors were used both as monotherapy and as add-on to other therapies, i.e., metformin, sulfonylureas, tiazolidinediones or exogenous insulin. The DPP-4 inhibitors were also found to have a low risk of adverse events, including hypoglycemia. Five of the DPP-4 inhibitors (sitagliptin, vildagliptin, alogliptin, saxagliptin and linagliptin) were approved by regulatory authorities and entered the market between 2006 and 2013. DPP-4 inhibitors have thereafter undergone long-term cardiovascular outcome trials, showing non-inferiority for risk of major acute cardiovascular endpoints. Also the risk of other potential adverse events is low in these long-term studies. DPP-4 inhibitors are at present included in guidelines as a glucose-lowering concept both as monotherapy and in combination therapies. This article summarizes the development of the DPP-4 inhibition concept from its early stages in the 1990s. The article underscores that the development has its basis in scientific studies on pathophysiology of type 2 diabetes and the importance of targeting the islet dysfunction, that the development has been made possible through academic science in collaboration with the research-oriented pharmaceutical industry, and that the development of a novel concept takes time and requires focused efforts, persistence and long-term perserverance.

Risk of hypoglycaemia in people aged ≥65 years receiving linagliptin: pooled data from 1489 individuals with type 2 diabetes mellitus

AIMS

To investigate the risk of hypoglycaemia in people aged ≥65 years with type 2 diabetes mellitus (T2DM) treated with linagliptin, in the largest pooled analysis performed to date.

MATERIALS AND METHODS

One thousand four hundred and eighty-nine patients aged ≥65 years with T2DM were pooled from 11 randomised, double-blind, parallel group, placebo-controlled trials evaluating linagliptin 5 mg alone, or in addition to various background therapies. The primary safety endpoint was the incidence of investigator-defined hypoglycaemia.

RESULTS

There was no significant difference in the risk of hypoglycaemia between linagliptin and placebo in the all-patient population at 24 weeks (hazard ratio [HR] 1.07; 95% confidence interval [CI]: 0.84, 1.36; P = 0.5943)-despite significant (P < 0.0001) improvements in glycaemic control-and 1 year (HR 1.02; 95% CI: 0.81, 1.27; P = 0.8803). Similar findings were observed for linagliptin vs placebo in subgroup analyses by background medication (eg, sulphonylureas (SUs) and/or insulin vs no such drugs), age, baseline glycated haemoglobin (HbA1c), ethnicity, and baseline estimated glomerular filtration rate. Patients with a baseline HbA1c ≥7.5% had significantly higher odds of achieving HbA1c <7.5% without hypoglycaemia in the linagliptin group compared with placebo at 24 weeks (34.1% vs 13.7%; 95% CI: 2.04, 4.12; P < 0.0001).

CONCLUSIONS

This pooled analysis indicates that linagliptin was effective in treating older people with T2DM towards their HbA1c targets with a favourable safety and tolerability profile and low risk of hypoglycaemia. The safety profile was maintained even on background therapies with known risk of hypoglycaemia, such as insulin and SU.

Medications that cause weight gain and alternatives in Canada: a narrative review

BACKGROUND

The cause of the obesity epidemic is multifactorial, but may, in part, be related to medication-induced weight gain. While clinicians may strive to do their best to select pharmacotherapy(ies) that has the least negative impact on weight, the literature regarding the weight effects of medication is often limited and devoid of alternative therapies.

RESULTS

Antipsychotics, antidepressants, antihyperglycemics, antihypertensives and corticosteroids all contain medications that were associated with significant weight gain. However, there are several medication alternatives within the majority of these classes associated with weight neutral or even weight loss effects. Further, while not all of the classes of medication examined in this review have weight-favorable alternatives, there exist many other tools to mitigate weight gain associated with medication use, such as changes in dosing, medication delivery or the use of adjunctive therapies.

CONCLUSION

Medication-induced weight gain can be frustrating for both the patient and the clinician. As the use of pharmaceuticals continues to increase, it is pertinent for clinicians to consider the weight effects of medications prior to prescribing or in the course of treatment. In the case where it is not feasible to make changes to medication, adjunctive therapies should be considered.

[Treatment of type 2 diabetes mellitus in elderly patients]

The prevalence of type 2 diabetes mellitus (DM2) increases markedly with age. Antidiabetic treatment and the objectives of glycaemic control in elderly patients with DM2 should be individualised according to their biopsychosocial characteristics. In elderly patients for whom the benefits of intensive antidiabetic treatment are limited, the basic objectives should be to improve the quality of life, preserve functionality and avoid adverse effects, especially hypoglycaemia. Treatment of DM2 in the elderly was the subject of a consensus document published in 2012 and endorsed by several Spanish scientific societies. Since then, new therapeutic groups and evidence have emerged that warrant an update to this consensus document. The present document focuses on the therapeutic aspects of DM2 in elderly patients, understood as being older than 75 years or frail.

Canagliflozin, dapagliflozin and empagliflozin monotherapy for treating type 2 diabetes: systematic review and economic evaluation

BACKGROUND

Most people with type 2 diabetes are overweight, so initial treatment is aimed at reducing weight and increasing physical activity. Even modest weight loss can improve control of blood glucose. If drug treatment is necessary, the drug of first choice is metformin. However, some people cannot tolerate metformin, which causes diarrhoea in about 10%, and it cannot be used in people with renal impairment. This review appraises three of the newest class of drugs for monotherapy when metformin cannot be used, the sodium-glucose co-transporter 2 (SGLT2) inhibitors.

OBJECTIVE

To review the clinical effectiveness and cost-effectiveness of dapagliflozin (Farxiga, Bristol-Myers Squibb, Luton, UK), canagliflozin (Invokana, Janssen, High Wycombe, UK) and empagliflozin (Jardiance, Merck & Co., Darmstadt, Germany), in monotherapy in people who cannot take metformin.

SOURCES

MEDLINE (1946 to February 2015) and EMBASE (1974 to February 2015) for randomised controlled trials lasting 24 weeks or more. For adverse events, a wider range of studies was used. Three manufacturers provided submissions.

METHODS

Systematic review and economic evaluation. A network meta-analysis was carried out involving the three SGLT2 inhibitors and key comparators. Critical appraisal of submissions from three manufacturers.

RESULTS

We included three trials of dapagliflozin and two each for canagliflozin and empagliflozin. The trials were of good quality. The canagliflozin and dapagliflozin trials compared them with placebo, but the two empagliflozin trials included active comparators. All three drugs were shown to be effective in improving glycaemic control, promoting weight loss and lowering blood pressure (BP).

LIMITATIONS

There were no head-to-head trials of the different flozins, and no long-term data on cardiovascular outcomes in this group of patients. Most trials were against placebo. The trials were done in patient groups that were not always comparable, for example in baseline glycated haemoglobin or body mass index. Data on elderly patients were lacking.

CONCLUSIONS

Dapagliflozin, canagliflozin and empagliflozin are effective in improving glycaemic control, with added benefits of some reductions in BP and weight. Adverse effects are urinary and genital tract infections in a small proportion of users. In monotherapy, the three drugs do not appear cost-effective compared with gliclazide or pioglitazone, but may be competitive against sitagliptin (Januvia, Boehringer Ingelheim, Bracknell, UK).

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Treatment of type 2 diabetes mellitus in elderly patients

The prevalence of type 2 diabetes mellitus (DM2) increases markedly with age. Antidiabetic treatment and the objectives of glycaemic control in elderly patients with DM2 should be individualised according to their biopsychosocial characteristics. In elderly patients for whom the benefits of intensive antidiabetic treatment are limited, the basic objectives should be to improve the quality of life, preserve functionality and avoid adverse effects, especially hypoglycaemia. Treatment of DM2 in the elderly was the subject of a consensus document published in 2012 and endorsed by several Spanish scientific societies. Since then, new therapeutic groups and evidence have emerged that warrant an update to this consensus document. The present document focuses on the therapeutic aspects of DM2 in elderly patients, understood as being older than 75 years or frail.

Safety and efficacy of long-term treatment with teneligliptin: Interim analysis of a post-marketing surveillance of more than 10,000 Japanese patients with type 2 diabetes mellitus

BACKGROUND

This post-marketing surveillance examined the safety and efficacy of long-term teneligliptin therapy in Japanese patients.

RESEARCH DESIGN AND METHODS

We report interim results (cut-off date: 28 June 2017) of a 3-year PMS undertaken in subjects with type 2 diabetes mellitus (T2DM). Survey items included demographics, treatments, adverse drug reactions (ADRs), and laboratory variables. A subgroup analysis was also performed across three age groups (<65 years; 65 to <75 years; ≥75 years). Main outcome measures were incidence of ADRs, laboratory variables, and change in glycated hemoglobin (HbA1c) from baseline over time.

RESULTS

Of 11,677 patients registered, data from 10,532 patients (6,338 males/4,194 females) were analyzed for the safety analysis set; the median administration period was 731 days. Overall, ADRs and serious ADRs were reported in 364 (3.46%) and 91 patients (0.86%), respectively. The most common ADRs were all hypoglycemia (0.32%), constipation (0.27%), and hepatic function abnormal (0.24%). No change in mean body weight occurred, and a reduction in mean HbA1c was observed until 2 years. The safety and efficacy profiles did not differ markedly among the three age groups.

CONCLUSIONS

These interim results show that teneligliptin was well tolerated and improved hyperglycemia in Japanese patients with T2DM in clinical practice.

Intensifying Treatment Beyond Monotherapy in Type 2 Diabetes Mellitus: Where Do Newer Therapies Fit?

PURPOSE OF REVIEW

Guidelines for a standard second diabetes medication for the treatment of type 2 diabetes (T2DM) have yet to be established. The rapid increase in the number of newer therapies available makes the choice more difficult. Thus, we reviewed clinical trial evidence evaluating newer therapies available for treatment intensification beyond monotherapy.

RECENT FINDINGS

Head-to-head studies comparing newer therapies versus traditional (i.e., sulfonylurea) approaches consistently find lower incidence of hypoglycemia and weight gain with newer therapies. Glucagon-like peptide-1 (GLP-1) receptor agonists and sodium-glucose co-transporter 2 (SGLT2) inhibitors demonstrate high glycemic efficacy, while merits of dipeptidyl peptidase-4 (DPP-4) inhibitors include their tolerability. Secondary effects (weight loss, cardiovascular outcomes, renal function) are of growing interest with newer therapies. Choices for treatment intensification in T2DM diabetes are numerous. Understanding the comparative evidence of newer treatment choices, as provided in this review, may help guide clinical decision making.

Effect of Long-term Incretin-Based Therapies on Ischemic Heart Diseases in Patients with Type 2 Diabetes Mellitus: A Network Meta-analysis

Patients with type 2 diabetes mellitus (T2DM) experience many cardiovascular complications. Several studies have demonstrated the cardioprotective effects of incretin-based therapies; however, there are few studies on the effects of long-term incretin-based therapies on cardiovascular events. Therefore, the present study conducted a systematic review and network meta-analysis to evaluate the effects of long-term incretin-based therapies on ischaemic diseases. We searched PubMed, CENTRAL, and Clinicaltrial.gov to retrieve randomised control trials reported until December 2016 and enrolled only RCTs with more than a 1-year follow-up. The network meta-analysis was performed using R Software with a GeMTC package. A total of 40 trials were included. Dipeptidyl peptidase 4 inhibitors and glucagon-like peptide-1 agonists were associated with a lower risk of myocardial infarction (MI) than were sulfonylureas (odds ratio [95% credible interval] 0.41 [0.24–0.71] and 0.48 [0.27–0.91], respectively). These results suggested that patients with T2DM receiving long-term incretin-based therapies have a lower risk of MI than do those receiving sulfonylurea-based therapy. These findings highlight the risks of cardiovascular events in patients who receive long-term incretin-based therapies, and may provide evidence for the selection of antidiabetic therapy in the future.

Effectiveness and safety of dipeptidyl peptidase 4 inhibitors in the management of type 2 diabetes in older adults: a systematic review and development of recommendations to reduce inappropriate prescribing

Background

Preventable drug-related hospital admissions can be associated with drugs used in diabetes and the benefits of strict diabetes control may not outweigh the risks, especially in older populations. The aim of this study was to look for evidence on risks and benefits of DPP-4 inhibitors in older adults and to use this evidence to develop recommendations for the electronic decision support tool of the PRIMA-eDS project.

Methods

Systematic review using a staged approach which searches for systematic reviews and meta-analyses first, then individual studies only if prior searches were inconclusive. The target population were older people (≥65 years old) with type 2 diabetes. We included studies reporting on the efficacy and/or safety of DPP-4 inhibitors for the management of type 2 diabetes. Studies were included irrespective of DPP-4 inhibitors prescribed as monotherapy or in combination with any other drug for the treatment of type 2 diabetes. The target intervention was DPP-4 inhibitors compared to placebo, no treatment, other drugs to treat type 2 diabetes or a non-pharmacological intervention.

Results

Thirty studies (reported in 33 publications) were included: 1 meta-analysis, 17 intervention studies and 12 observational studies. Sixteen studies were focused on older adults and 14 studies reported subgroup analyses in participants ≥65, ≥70, or ≥75 years. Comorbidities were reported by 26 studies and frailty or functional status by one study. There were conflicting findings regarding the effectiveness of DPP-4 inhibitors in older adults. In general, DPP-4 inhibitors showed similar or better safety than placebo and other antidiabetic drugs. However, these safety data are mainly based on short-term outcomes like hypoglycaemia in studies with HbA1c control levels recommended for younger people. One recommendation was developed advising clinicians to reconsider the use of DPP-4 inhibitors for the management of type 2 diabetes in older adults with HbA1c <8.5% because of scarce data on clinically relevant benefits of their use. Twenty-two of the included studies were funded by pharmaceutical companies and authored or co-authored by employees of the sponsor.

Conclusions

Other than the surrogate endpoint of improved glycaemic control, data on clinically relevant benefits of DPP-4 inhibitors in the treatment of type 2 diabetes mellitus in older adults is scarce. DPP-4 inhibitors might have a lower risk of hypoglycaemia compared to other antidiabetic drugs but data show conflicting findings for long-term benefits. Further studies are needed that evaluate the risks and benefits of DPP-4 inhibitors for the management of type 2 diabetes mellitus in older adults, using clinically relevant outcomes and including representative samples of older adults with information on their frailty status and comorbidities. Studies are also needed that are independent of pharmaceutical company involvement.

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-017-0571-8) contains supplementary material, which is available to authorized users.

Treatment of type 2 diabetes mellitus in the elderly

The prevalence of type 2 diabetes is expected to increase gradually with the prolongation of population aging and life expectancy. In addition to macrovascular and microvascular complications of elderly patients of diabetes mellitus, geriatric syndromes such as cognitive impairment, depression, urinary incontinence, falling and polypharmacy are also accompanied by aging. Individual functional status in the elderly shows heterogeneity so that in these patients, there are many unanswered questions about the management of diabetes treatment. The goals of diabetes treatment in elderly patients include hyperglycemia and risk factors, as in younger patients. comorbid diseases and functional limitations of individuals should be taken into consideration when setting treatment targets. Thus, treatment should be individualized. In the treatment of diabetes in vulnerable elderly patients, hypoglycemia, hypotension, and drug interactions due to multiple drug use should be avoided. Since it also affects the ability to self-care in these patients, management of other concurrent medical conditions is also important.

Lixisenatide Therapy in Older Patients With Type 2 Diabetes Inadequately Controlled on Their Current Antidiabetic Treatment: The GetGoal-O Randomized Trial

OBJECTIVE

To evaluate the efficacy and safety of lixisenatide versus placebo on glycemic control in older patients with type 2 diabetes uncontrolled on their current antidiabetic treatment.

RESEARCH DESIGN AND METHODS

In this phase III, double-blind, randomized, placebo-controlled, two-arm, parallel-group, multicenter trial, patients aged ≥70 years were randomized to receive once-daily lixisenatide 20 μg or placebo before breakfast concomitantly with their existing antidiabetic therapy (including insulin) for 24 weeks. Patients at risk for malnutrition or with moderate to severe cognitive impairment were excluded. The primary end point was absolute change in HbA_1c from baseline to week 24. Secondary end points included change from baseline to week 24 in 2-h postprandial plasma glucose (PPG) and body weight.

RESULTS

A total of 350 patients were randomized. HbA_1c decreased substantially with lixisenatide (-0.57% [6.2 mmol/mol]) compared with placebo (+0.06% [0.7 mmol/mol]) from baseline to week 24 (P < 0.0001). Mean reduction in 2-h PPG was significantly greater with lixisenatide (-5.12 mmol/L) than with placebo (-0.07 mmol/L; P < 0.0001). A greater decrease in body weight was observed with lixisenatide (-1.47 kg) versus placebo (-0.16 kg; P < 0.0001). The safety profile of lixisenatide in this older population, including rates of nausea and vomiting, was consistent with that observed in other lixisenatide studies. Hypoglycemia was reported in 17.6% of patients with lixisenatide versus 10.3% with placebo.

CONCLUSIONS

In nonfrail older patients uncontrolled on their current antidiabetic treatment, lixisenatide was superior to placebo in HbA_1c reduction and in targeting postprandial hyperglycemia, with no unexpected safety findings.

A systematic literature review on the efficacy-effectiveness gap: comparison of randomized controlled trials and observational studies of glucose-lowering drugs

Aim

To identify a potential efficacy–effectiveness gap and possible explanations (drivers of effectiveness) for differences between results of randomized controlled trials (RCTs) and observational studies investigating glucose-lowering drugs.

Methods

A systematic literature review was conducted in English language articles published between 1 January, 2000 and 31 January, 2015 describing either RCTs or observational studies comparing glucagon-like peptide-1 analogs (GLP-1) with insulin or comparing dipeptidyl peptidase-4 inhibitors (DPP-4i) with sulfonylurea, all with change in glycated hemoglobin (HbA1c) as outcome. Medline, Embase, Current Content, and Biosis were searched. Information on effect estimates, baseline characteristics of the study population, publication year, study duration, and number of patients, and for observational studies, characteristics related to confounding adjustment and selection- and information bias were extracted.

Results

From 312 hits, 11 RCTs and 7 observational studies comparing GLP-1 with insulin, and from 474 hits, 16 RCTs and 4 observational studies comparing DPP-4i with sulfonylurea were finally included. No differences were observed in baseline characteristics of the study populations (age, sex, body mass index, time since diagnosis of type 2 diabetes mellitus, and HbA1c) or effect sizes across study designs. Mean effect sizes ranged from −0.43 to 0.91 and from −0.80 to 1.13 in RCTs and observational studies, respectively, comparing GLP-1 with insulin, and from −0.13 to 2.70 and −0.20 to 0.30 in RCTs and observational studies, respectively, comparing DPP-4i and sulfonylurea. Generally, the identified observational studies held potential flaws with regard to confounding adjustment and selection- and information bias.

Conclusions

Neither potential drivers of effectiveness nor an efficacy–effectiveness gap were identified. However, the limited number of studies and potential problems with confounding adjustment, selection- and information bias in the observational studies, may have hidden a true efficacy-effectiveness gap.

NRF2 activation by antioxidant antidiabetic agents accelerates tumor metastasis

Cancer is a common comorbidity of diabetic patients; however, little is known about the effects that antidiabetic drugs have on tumors. We discovered that common classes of drugs used in type 2 diabetes mellitus, the hypoglycemic dipeptidyl peptidase-4 inhibitors (DPP-4i) saxagliptin and sitagliptin, as well as the antineuropathic α-lipoic acid (ALA), do not increase tumor incidence but increase the risk of metastasis of existing tumors. Specifically, these drugs induce prolonged activation of the nuclear factor E2-related factor 2 (NRF2)-mediated antioxidant response through inhibition of KEAP1-C151-dependent ubiquitination and subsequent degradation of NRF2, resulting in up-regulated expression of metastasis-associated proteins, increased cancer cell migration, and promotion of metastasis in xenograft mouse models. Accordingly, knockdown of NRF2 attenuated naturally occurring and DPP-4i-induced tumor metastasis, whereas NRF2 activation accelerated metastasis. Furthermore, in human liver cancer tissue samples, increased NRF2 expression correlated with metastasis. Our findings suggest that antioxidants that activate NRF2 signaling may need to be administered with caution in cancer patients, such as diabetic patients with cancer. Moreover, NRF2 may be a potential biomarker and therapeutic target for tumor metastasis.

An update on the clinical pharmacology of the dipeptidyl peptidase 4 inhibitor alogliptin used for the treatment of type 2 diabetes mellitus

Alogliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor that is a class of relatively new oral hypoglycaemic drugs used in patients with type 2 diabetes (T2DM), can be used as monotherapy or in combination with other anti-diabetic agents, including metformin, pioglitazone, sulfonylureas and insulin with a considerable therapeutic effect. Alogliptin exhibits favorable pharmacokinetic and pharmacodynamic profiles in humans. Alogliptin is mainly metabolized by cytochrome P450 (CYP2D6) and CYP3A4. Dose reduction is recommended for patients with moderate or worse renal impairment. Side effects of alogliptin include nasopharyngitis, upper-respiratory tract infections and headache. Hypoglycaemia is seen in about 1.5% of the T2DM patients. Rare but severe adverse reactions such as acute pancreatitis, serious hypersensitivity including anaphylaxis, angioedema and severe cutaneous reactions such as Stevens-Johnson syndrome have been reported from post-marketing monitoring. Pharmacokinetic interactions have not been observed between alogliptin and other drugs including glyburide, metformin, pioglitazone, insulin and warfarin. The present review aimed to update the clinical information on pharmacodynamics, pharmacokinetics, adverse effects and drug interactions, and to discuss the future directions of alogliptin.

An update on DPP-4 inhibitors in the management of type 2 diabetes

INTRODUCTION

DPP-4 inhibitors are a class of compounds used for the treatment of type 2 diabetes. The drugs inhibit the degradation of GLP-1, thus amplifying the incretin effect. They have moderate glycemic efficacy, a low propensity of causing hypoglycaemia and are weight neutral. The drugs are often used as second line therapy after metformin. Areas covered: This review summarizes the available compounds in the market and discusses the novel compounds that are currently under development. Several large cardiovascular outcome trials with some of the compounds have been completed, and their results and implications are considered. Fixed dose combination pills are currently the main focus of research and the contribution of these to the care of patients with diabetes is further discussed. Expert opinion: The DPP-4 inhibitors have been a successful class in drug development for diabetes. Taken orally and available as fixed dose combinations with metformin or with SGLT-2 inhibitors, they have reached a large market share of over 7 billion dollars. Other than retagliptin, it does not appear that any additional compound will be launched soon. Currently, the main focus is on the development of additional fixed dose combinations with SGLT-2 inhibitors, but the success of these combinations remains to be seen.

Adverse effects of incretin-based therapies on major cardiovascular and arrhythmia events: meta-analysis of randomized trials

BACKGROUND

Recent cardiovascular outcome trials of incretin-based therapies (IBT) in type 2 diabetes have not demonstrated either benefit or harm in terms of major adverse cardiovascular events (MACE). Earlier meta-analyses showed conflicting results but were limited in methodology. We aimed to perform an updated meta-analysis of all available incretin therapies on the incidence of MACE plus arrhythmia and heart failure.

METHODS

We identified studies published through November 2014 by searching electronic databases and reference lists. We included RCTs in which the intervention group received incretin-based therapies and the control group received placebo or standard treatment; enrolled >100 participants in each group; interventions lasted >24 weeks; and reported data on one or more primary major adverse cardiovascular events endpoints plus terms for arrhythmia and heart failure. We used the Peto method for each CV event for individual IBT treatment.

RESULTS

In this meta-analysis of 100 RCTs involving 54,758 incretin-based therapies users and 48,175 controls, exenatide was associated with increased risk of arrhythmia (OR 2.83; 95% CI, 1.06-7.57); saxagliptin was associated with an increased risk of heart failure (OR 1.23; 95% CI, 1.03-1.46), and sitagliptin was associated with a significantly decreased risk of all cause death compared to active controls (OR 0.39, 95% CI 0.18-0.82).

CONCLUSIONS

In type 2 diabetes, exenatide may increase the risk of arrhythmia, and sitagliptin may reduce the risk of all cause death; however, the subgroup of patients most likely to experience harm or benefit is unclear. Copyright © 2016 John Wiley & Sons, Ltd.

Alogliptin for the treatment of type 2 diabetes: a drug safety evaluation

INTRODUCTION

Dipeptidyl peptidase-4 (DPP-4) inhibitors such as alogliptin are becoming more widely established as treatment options for patients with type 2 diabetes (T2DM) because of their ability to improve glycemic control without increasing the risk of hypoglycemia or weight gain. New therapies with improved safety profiles are needed, especially because of the chronic and progressive nature of T2DM.

AREAS COVERED

In this article, the overall safety and tolerability of alogliptin are evaluated based upon a review of the literature. In particular, adverse events (AEs) that have been of interest for the DPP-4 class of drugs, such as the risk of major cardiovascular (CV) events and acute pancreatitis, will be investigated in detail.

EXPERT OPINION

Alogliptin is generally well-tolerated in a broad range of patient populations including different ethnic groups and the elderly. In the pivotal EXAMINE clinical trial, alogliptin was found not to be associated with an increased risk of major CV events or acute pancreatitis/pancreatic cancer.

Pharmacology and therapeutic implications of current drugs for type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a global epidemic that poses a major challenge to health-care systems. Improving metabolic control to approach normal glycaemia (where practical) greatly benefits long-term prognoses and justifies early, effective, sustained and safety-conscious intervention. Improvements in the understanding of the complex pathogenesis of T2DM have underpinned the development of glucose-lowering therapies with complementary mechanisms of action, which have expanded treatment options and facilitated individualized management strategies. Over the past decade, several new classes of glucose-lowering agents have been licensed, including glucagon-like peptide 1 receptor (GLP-1R) agonists, dipeptidyl peptidase 4 (DPP-4) inhibitors and sodium/glucose cotransporter 2 (SGLT2) inhibitors. These agents can be used individually or in combination with well-established treatments such as biguanides, sulfonylureas and thiazolidinediones. Although novel agents have potential advantages including low risk of hypoglycaemia and help with weight control, long-term safety has yet to be established. In this Review, we assess the pharmacokinetics, pharmacodynamics and safety profiles, including cardiovascular safety, of currently available therapies for management of hyperglycaemia in patients with T2DM within the context of disease pathogenesis and natural history. In addition, we briefly describe treatment algorithms for patients with T2DM and lessons from present therapies to inform the development of future therapies.

Cost-effectiveness of dipeptidyl peptidase-4 inhibitor monotherapy in elderly type 2 diabetes patients in Thailand

BACKGROUND

The management of type 2 diabetes mellitus (T2DM) in elderly population poses many challenges. Dipeptidyl peptidase-4 (DPP-4) inhibitors show particular promise due to excellent tolerability profiles, low risk of hypoglycemia, and little effect on body weight. This study evaluated, from the health care system's perspective, the long-term cost-effectiveness of DPP-4 inhibitor monotherapy vs metformin and sulfonylurea (SFU) monotherapy in Thai elderly T2DM patients.

METHODS

The clinical efficacy was estimated from a systematic review and meta-analysis. Baseline cohort characteristics and cost parameters were obtained from published studies and hospital databases in Thailand. A validated IMS CORE Diabetes Model version 8.5 was used to project clinical and economic outcomes over a lifetime horizon using a 3% annual discount rate. Costs were expressed in 2014 Thai Baht (THB) (US dollar value). Incremental cost-effectiveness ratios were calculated. Base-case assumptions were assessed through several sensitivity analyses.

RESULTS

For treating elderly T2DM patients, DPP-4 inhibitors were more expensive and less effective, ie, a dominated strategy, than the metformin monotherapy. Compared with SFU, treatment with DPP-4 inhibitors gained 0.031 more quality-adjusted life years (QALYs) at a total cost incurred over THB113,701 or US$3,449.67, resulting in an incremental cost-effectiveness ratio of THB3.63 million or US$110,133.50 per QALY. At the acceptable Thai ceiling threshold of THB160,000/QALY (US$4,854.37/QALY), DPP-4 inhibitors were not a cost-effective treatment.

CONCLUSION

DPP-4 inhibitor monotherapy is not a cost-effective treatment for elderly T2DM patients compared with metformin monotherapy and SFU monotherapy, given current resource constraints in Thailand.

Clinical pharmacology of dipeptidyl peptidase 4 inhibitors indicated for the treatment of type 2 diabetes mellitus

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of oral antidiabetic drugs that improve glycaemic control without causing weight gain or increasing hypoglycaemic risk in patients with type 2 diabetes mellitus (T2DM). The eight available DPP-4 inhibitors, including alogliptin, anagliptin, gemigliptin, linagliptin, saxagliptin, sitagliptin, teneligliptin, and vildagliptin, are small molecules used orally with identical mechanism of action and similar safety profiles in patients with T2DM. DPP-4 inhibitors may be used as monotherapy or in double or triple combination with other oral glucose-lowering agents such as metformin, thiazolidinediones, or sulfonylureas. Although DPP-4 inhibitors have the same mode of action, they differ by some important pharmacokinetic and pharmacodynamic properties that may be clinically relevant in some patients. The main differences between the eight gliptins include: potency, target selectivity, oral bioavailability, elimination half-life, binding to plasma proteins, metabolic pathways, formation of active metabolite(s), main excretion routes, dosage adjustment for renal and liver insufficiency, and potential drug-drug interactions. The off-target inhibition of selective DPP-4 inhibitors is responsible for multiorgan toxicities such as immune dysfunction, impaired healing, and skin reactions. As a drug class, the DPP-4 inhibitors have become accepted in clinical practice due to their excellent tolerability profile, with a low risk of hypoglycaemia, a neutral effect on body weight, and once-daily dosing. It is unknown if DPP-4 inhibitors can prevent disease progression. More clinical studies are needed to validate the optimal regimens of DPP-4 inhibitors for the management of T2DM when their potential toxicities are closely monitored.

The Association between Sulfonylurea Use and All-Cause and Cardiovascular Mortality: A Meta-Analysis with Trial Sequential Analysis of Randomized Clinical Trials

BACKGROUND

Sulfonylureas are an effective and inexpensive treatment for type 2 diabetes. There is conflicting data about the safety of these drugs regarding mortality and cardiovascular outcomes. The objective of the present study was to evaluate the safety of the sulfonylureas most frequently used and to use trial sequential analysis (TSA) to analyze whether the available sample was powered enough to support the results.

METHODS AND FINDINGS

Electronic databases were reviewed from 1946 (Embase) or 1966 (MEDLINE) up to 31 December 2014. Randomized clinical trials (RCTs) of at least 52 wk in duration evaluating second- or third-generation sulfonylureas in the treatment of adults with type 2 diabetes and reporting outcomes of interest were included. Primary outcomes were all-cause and cardiovascular mortality. Additionally, myocardial infarction and stroke events were evaluated. Data were summarized with Peto odds ratios (ORs), and the reliability of the results was evaluated with TSA. Forty-seven RCTs with 37,650 patients and 890 deaths in total were included. Sulfonylureas were not associated with all-cause (OR 1.12 [95% CI 0.96 to 1.30]) or cardiovascular mortality (OR 1.12 [95% CI 0.87 to 1.42]). Sulfonylureas were also not associated with increased risk of myocardial infarction (OR 0.92 [95% CI 0.76 to 1.12]) or stroke (OR 1.16 [95% CI 0.81 to 1.66]). TSA could discard an absolute difference of 0.5% between the treatments, which was considered the minimal clinically significant difference. The major limitation of this review was the inclusion of studies not designed to evaluate safety outcomes.

CONCLUSIONS

Sulfonylureas are not associated with increased risk for all-cause mortality, cardiovascular mortality, myocardial infarction, or stroke. Current evidence supports the safety of sulfonylureas; an absolute risk of 0.5% could be firmly discarded.

REVIEW REGISTRATION

PROSPERO CRD42014004330.

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.

Dipeptidyl Peptidase-4 Inhibitors in Diverse Patient Populations With Type 2 Diabetes

PURPOSE

The purpose of this review is to discuss the clinical evidence for dipeptidyl peptidase-4 (DPP-4) inhibitors and to better define their use in treating type 2 diabetes mellitus (T2DM), including in special populations, such as the elderly. DPP-4 inhibitors are incretin-based therapies that can be used as monotherapy or in combination with other antidiabetes medications to treat T2DM. As monotherapy, DPP-4 inhibitors have demonstrated a modest and comparable glycated hemoglobin-lowering effect. As initial dual therapy with other antidiabetes agents, DPP-4 inhibitors significantly improved glycated hemoglobin when compared with monotherapy arms. Similarly, in triple combinations, DPP-4 inhibitors consistently provided additive glycemic benefits. In patients who were continuing insulin, glycemic parameters were improved with the addition of a DPP-4 inhibitor, and they required less insulin uptitration. In clinical trials, the overall occurrence of adverse events was similar between DPP-4 inhibitor groups and controls, and a low occurrence of hypoglycemia was observed, except when used in combination with a sulfonylurea. A neutral effect on weight was maintained, even in combination with insulin. Similar to outcomes observed in younger patients, DPP-4 inhibitors significantly improved glycemic efficacy in older patients, without increasing the risk for hypoglycemia. Efficacy and safety in patients with renal insufficiency are also documented.

CONCLUSION

DPP-4 inhibitors are therapeutically beneficial for a diverse population of patients with T2DM, including elderly patients, based on demonstrated efficacy, tolerability, and a low risk for hypoglycemia.

Trends in Antihyperglycemic Medication Prescriptions and Hypoglycemia in Older Adults: 2002-2013

Background

Over the last decade, several new antihyperglycemic medications have been introduced including those associated with a lower hypoglycemia risk. We aimed to investigate how these medications are being prescribed to older adults in our region.

Methods

We conducted population-based cross-sectional analyses of older adults (mean age 75 years) with treated diabetes in Ontario, Canada from 2002 until 2013, to examine the percentage prescribed insulin, sulphonylureas, alpha-glucosidase inhibitors, metformin, thiazolidinediones, meglitinides, and dipeptidyl peptidase-4 inhibitors. Over the study period, we also examined their hospital encounters for hypoglycemia (emergency room or inpatient encounter).

Results

The mean age of treated patients increased slightly over the study quarters and the proportion that were women declined. With the exception of chronic kidney disease, cancer, dementia, and neuropathy, the percentage with a comorbidity appeared to decline. The percentage of treated patients prescribed metformin, gliclazide and dipeptidyl peptidase-4 inhibitors increased as did combination therapy. Glyburide and thiazolidinedione prescriptions declined, and insulin use remained stable. In those with newly treated diabetes, the majority were prescribed metformin, with smaller percentages prescribed insulin and other oral agents. Although the absolute number of treated patients with a hypoglycemia encounter increased until mid-2006 and then decreased, the overall percentage with an encounter declined over the study period (0.8% with an event in the first quarter, 0.4% with an event in the last quarter).

Conclusions

Antihyperglycemic medications with safer profiles are being increasingly prescribed to older adults. In this setting there has been a decrease in the percentage of treated patients with a hospital encounter for hypoglycemia.

Incretin-based therapies for obesity treatment

Currently, obesity and its associated complications are considered major public health problems worldwide. Because the causes are multifactorial and complex, different treatment methods are used, which include diet and exercise, as well as the use of drugs, although they can have adverse side effects. A new target for the treatment of obesity may be the incretin system, which consists of hormones that seem to contribute to weight loss. In this sense, some studies have shown a relationship between weight loss and drugs related to incretin system, including glucagon-like peptide-1 (GLP-1) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors. The objective of this review is to summarize the association between the incretin system and obesity treatment.

Effects of sulfonylureas on lipids in type 2 diabetes mellitus: a meta-analysis of randomized controlled trials

OBJECTIVE

Previous studies suggested that dyslipidemia was potentially associated with anti-diabetic medications of sulfonylureas (SUs). The results were, however, inconsistent. Therefore, we conducted a meta-analysis of randomized controlled trials (RCTs) to assess the effects of SUs on the level of lipids in patients with type 2 diabetes mellitus (T2DM).

METHODS

We searched PubMed, EMBASE, and CENTRAL databases for RCTs that addressed the effects of second- and/or third-generation SUs used in T2DM patients on lipids profiles with study duration of at least 12 weeks. Two reviewers independently screened literature, collected data, and assessed methodological quality of included studies. The meta-analysis was performed by using the RevMan5.1 software.

RESULTS

A total of 59 RCTs were included, of which 52 were included for final meta-analysis. The results suggested that SUs statistically increased the levels of FFA (SMD = 0.24, 95%CI 0.06 to 0.42) and TG (MD = 0.06, 95%CI 0.02 to 0.10), but decreased HDL-C (MD = -0.07, 95%CI -0.11 to -0.04) and LDL-C (MD = -0.11, 95%CI -0.17 to -0.04); but the SUs had no effect on TC (MD = 0.01, 95%CI -0.05 to 0.08), ApoA1 (MD = 0.01, 95%CI -0.03 to 0.04), and Apo B (MD = -0.01, 95%CI -0.05 to 0.03). When compared to metformin, SUs could increase TC and LDL-C; compared to glinides, SUs increased TC and lowered HDL-C; compared to thiazolidinediones, SUs reduced TC, LDL-C, HDL-C, and increase TG.

CONCLUSIONS

SUs have a small effect on lipids, although they may statistically increase the level of FFA and TG, and decrease LDL-C and HDL-C.

Efficacy and tolerability of saxagliptin compared with glimepiride in elderly patients with type 2 diabetes: a randomized, controlled study (GENERATION)

AIMS

To assess the efficacy and safety of adjunctive saxagliptin vs glimepiride in elderly patients with type 2 diabetes (T2D) and inadequate glycaemic control.

METHODS

In this multinational, randomized, double-blind, phase IIIb/IV study (GENERATION; NCT01006603), patients aged ≥65 years were randomized (1 : 1) to receive saxagliptin 5 mg/day or glimepiride ≤6 mg/day, added to metformin, during a 52-week treatment period. The primary endpoint was achievement of glycated haemoglobin (HbA1c) <7.0% at week 52 without confirmed/severe hypoglycaemia. The key secondary endpoint was incidence of confirmed/severe hypoglycaemia. Safety and tolerability were also assessed.

RESULTS

Of 720 patients randomized (360 in each treatment group; mean age 72.6 years; mean T2D duration 7.6 years), 574 (79.8%) completed the study (saxagliptin 80.3%; glimepiride 79.2%). Similar proportions of patients achieved the primary endpoint with saxagliptin and glimepiride (37.9 vs 38.2%; odds ratio 0.99, 95% confidence interval 0.73, 1.34; p = 0.9415); however, a significant treatment-by-age interaction effect was detected (p = 0.0389): saxagliptin was numerically (but not significantly) superior to glimepiride for patients aged <75 years (39.2 vs 33.3%) and numerically inferior for patients aged ≥75 years (35.9 vs 45.5%). The incidence of confirmed/severe hypoglycaemia was lower with saxagliptin vs glimepiride (1.1 vs 15.3%; nominal p < 0.0001). Saxagliptin was generally well tolerated, with similar incidences of adverse events compared with glimepiride.

CONCLUSION

As avoiding hypoglycaemia is a key clinical objective in elderly patients, saxagliptin is a suitable alternative to glimepiride in patients with T2D aged ≥65 years.

Alogliptin benzoate for management of type 2 diabetes

Dipeptidyl peptidase-4 (DPP-4) inhibitors, a new class of oral hypoglycemic agents, augment glucose-dependent insulin secretion and suppress glucagon levels through enhancement of the action of endogenous incretin by inhibiting DPP-4, an incretin-degrading enzyme. DPP-4 inhibitors are generally well tolerated because of their low risk of hypoglycemia and other adverse events. Moreover, with their potential to improve beta cell function, a core defect of type 2 diabetes, DPP-4 inhibitors are becoming a major component of treatment of type 2 diabetes. Alogliptin benzoate is a newly developed, highly selective DPP-4 inhibitor which has been approved in many countries throughout the world. Once-daily administration of alogliptin as either monotherapy or combination therapy with other oral antidiabetic drugs or insulin has a potent glucose-lowering effect which is similar to that of other DPP-4 inhibitors, with a low risk of hypoglycemia and weight gain. The cardiovascular safety of this drug has been confirmed in a recent randomized controlled trial. This review summarizes the efficacy and safety of alogliptin, and discusses the role of DPP-4 inhibitors in the treatment of type 2 diabetes.