Incretin-based therapy in combination with basal insulin: a promising tactic for the treatment of type 2 diabetes

KCNQ1 variant rs163184 is a potential biomarker of glycemic response to exenatide

Aim: To examine the association between variant rs163184 in the type 2 diabetes mellitus (T2DM) susceptibility gene KCNQ1 and exenatide glycemic response in the Chinese population. Patients & methods: We included 100 T2DM patients from the CONFIDENCE study and investigated the association between rs163184 and glycemic response to exenatide, by using a multivariate linear model with adjustment for baseline glucose status and other covariates. Results: The G allele of rs163184 was associated with a 0.34% (p = 0.016) lower glycosylated hemoglobin reduction after 48 weeks of exenatide treatment. Similar significant associations were observed when glycemic response to exenatide was evaluated with fasting blood glucose or postprandial blood glucose reduction. Conclusion: We found that rs163184 in the gene KCNQ1 was associated with reduced glycemic response to exenatide in T2DM patients. The effect size observed in this study was large enough to be considered clinically relevant in stratified medicine.

Clinical Considerations When Initiating and Titrating Insulin Degludec/Liraglutide (IDegLira) in People with Type 2 Diabetes

Therapeutic inertia is a substantial obstacle to the initiation of insulin therapy in people with uncontrolled type 2 diabetes (T2D). This effect has in part been perpetuated by concerns over the impact of a burdensome regimen and the increased risk of hypoglycemia and body weight gain often associated with insulin use. An effective, yet simple, less burdensome regimen with a lower risk of body weight gain and hypoglycemia compared with an insulin-only regimen, may help to address these concerns more effectively. We review the available clinical and real-world data on IDegLira, a once-daily, injectable, fixed-ratio combination of insulin degludec (degludec) and the glucagon-like peptide-1 receptor agonist (GLP-1RA) liraglutide, in people with T2D. Evidence from the comprehensive DUAL clinical trial program suggests an advantage of IDegLira over traditional insulin therapies in a number of clinical outcomes, including maintenance of glycemic control, achievement of glycemic targets, reducing the risk of hypoglycemia, and body weight loss. These findings were demonstrated in participants with T2D irrespective of prior GLP-1RA and insulin use. Furthermore, the individual components of IDegLira have confirmed safety (degludec) or significant benefit in terms of improvement of cardiovascular risk (liraglutide). As an injectable therapy that is simple to titrate, IDegLira has the potential to optimize the ability to achieve relevant glycemic targets, and offers a suitable treatment option for people with T2D requiring insulin therapy who are at risk of hypoglycemia or weight gain.

IDegLira improves patient-reported outcomes while using a simple regimen with fewer injections and dose adjustments compared with basal-bolus therapy

AIMS

Basal-bolus therapy is associated with greater treatment burden and lower adherence compared with more simplified regimens. This post hoc analysis studied the difference between insulin degludec/liraglutide (IDegLira) and basal-bolus therapy on number of injections, dose adjustments and patient outcomes in the DUAL VII trial.

MATERIALS AND METHODS

DUAL VII was a 26-week, open-label trial in which patients with uncontrolled type 2 diabetes who were using metformin and insulin glargine 100 units/mL (20-50 U) were randomized 1:1 to IDegLira (N = 252) or basal-bolus (insulin glargine U100 + insulin aspart ≤4 times/day) (N = 254). This post hoc analysis reports the observed mean number of injections and cumulative dose adjustments during 26 weeks of treatment. Patient-reported outcomes (Treatment-Related Impact Measure - Diabetes [TRIM-D] and Short Form-36 Health Survey version 2 [SF-36v2]) were collected at scheduled visits and change from baseline scores calculated.

RESULTS

The clinical benefits (non-inferior HbA1c reductions, weight benefit, less hypoglycaemia) of IDegLira vs basal-bolus therapy were achieved with fewer cumulative dose adjustments (16.6 vs 217.2, respectively) and fewer injections (1 vs ≥3 per day, respectively). Patients treated with IDegLira experienced significant improvements across all TRIM-D domains compared with those undergoing basal-bolus therapy. The SF-36v2 showed improvements in both treatment arms with no significant difference between arms in the physical component summary, but there was a significant improvement in patients treated with IDegLira in the mental component summary (P = .0228).

CONCLUSIONS

These findings, combined with the DUAL VII results, suggest that IDegLira, through a more simplified regimen versus basal-bolus therapy, may help improve patient adherence and improve patient outcomes related to diabetes management, treatment burden and mental health, which in turn may assist in the timely achievement of glycaemic control in clinical practice.

Incretin-based medications (GLP-1 receptor agonists, DPP-4 inhibitors) as a means to avoid hypoglycaemic episodes

Hypoglycaemia is common in both type 1 and type 2 diabetes and has both acute and long-term consequences. Therefore, a key to proper glucose-lowering therapy in diabetes is to avoid or prevent hypoglycaemia. Incretin therapy (DPP-4 inhibitors and GLP-1 receptor agonists) offers an advantage in this respect, because it reduces glucose with a low risk of hypoglycaemia, both in monotherapy and in combination with other therapies. The reason for this low risk of hypoglycaemia is the glucose dependency of action of incretin therapy and the sustainment of glucose counter-regulatory hormone responses to hypoglycaemia, in particular the glucagon response. Incretin therapy is also associated with a low risk of hypoglycaemia in patient groups which are especially vulnerable and susceptible for hypoglycaemia, e.g., subjects with renal impairment, elderly subjects and subjects with on-going insulin therapy. This review summarizes how incretin therapy may meet the challenges of hypoglycaemia and suggests that incretin therapy is a therapy of choice to avoid hypoglycaemia, both in the general diabetes population and in subjects with increased risk or vulnerability for hypoglycaemia.

Insulin/Glucagon-Like Peptide-1 Receptor Agonist Combination Therapy for the Treatment of Type 2 Diabetes: Are Two Agents Better Than One?

IN BRIEF Given the progressive nature of type 2 diabetes, treatment intensification is usually necessary to maintain glycemic control. However, for a variety of reasons, treatment is often not intensified in a timely manner. The combined use of basal insulin and a glucagon-like peptide-1 receptor agonist is recognized to provide a complementary approach to the treatment of type 2 diabetes. This review evaluates the efficacy and safety of two co-formulation products, insulin degludec/liraglutide and insulin glargine/lixisenatide, for the treatment of type 2 diabetes inadequately controlled on either component agent alone. We consider the benefits and limitations of these medications based on data from randomized clinical trials and discuss how they may address barriers to treatment intensification.

Type 2 Diabetes Patients Reach Target Glycemic Control Faster Using IDegLira than Either Insulin Degludec or Liraglutide Given Alone

BACKGROUND AND OBJECTIVES

The time-course when changes in glycemic control and body weight were first manifest in patients with type 2 diabetes mellitus (T2DM) treated with a combination of insulin degludec and liraglutide (IDegLira) was assessed, comparing IDegLira to its individual components.

METHODS

Data from weeks 0-12 from two studies were analyzed, one comparing IDegLira to each component (DUAL I), and one comparing IDegLira to insulin degludec titrated to a maximum 50 units (DUAL II). Efficacy endpoints included glycated hemoglobin (HbA1c) and fasting plasma glucose (FPG) reduction, proportion of patients achieving HbA1c [<7.0 % (<53.0 mmol/mol)] and FPG (≤7.2 mmol/L) targets, and proportion achieving HbA1c target without hypoglycemia and without hypoglycemia and weight gain.

RESULTS

Mean HbA1c was lower, and the proportion of patients reaching target HbA1c greater, with IDegLira versus comparators (both studies) at weeks 8 and 12. Proportions of patients reaching target HbA1c without hypoglycemia and without hypoglycemia and weight gain were higher for IDegLira versus insulin degludec, though not versus liraglutide. Mean FPG was lower with IDegLira, and the proportion achieving target FPG higher, versus components (both studies) from weeks 4-12. IDegLira was associated with mean weight reduction from weeks 4-12, although less than with liraglutide alone. Hypoglycemia occurred infrequently in weeks 0-12, with no difference in incidence between IDegLira and insulin degludec in either study.

CONCLUSIONS

IDegLira reduces plasma glucose to a greater extent than its components, measurable within the first 12 weeks of therapy, and without weight gain or an increased hypoglycemia risk versus insulin degludec.

Treatment intensification using long-acting insulin -predictors of future basal insulin supported oral therapy in the DIVE registry

BACKGROUND

In patients with type-2 diabetes receiving oral antidiabetic drugs (OADs), the addition of insulin is frequently required to achieve sufficient control over blood glucose levels. It is, however, difficult to predict if, when and in which patients insulin therapy will be needed. We aimed to identify patient related variables associated with the addition of basal insulin to oral therapy resulting in a basal supported oral therapy (BOT).

METHODS

DIVE (DIabetes Versorgungs-Evaluation) is a prospective, observational, multi-centre diabetes registry established in Germany in 2011. For the present explorative analysis, 31,008 patients with type-2 diabetes prescribed at least one OAD were included. Patients who had previously received insulin and those over 90 years old were excluded. The event of interest was defined as the initiation of BOT during the observational period. Cause-specific Cox proportional hazards models based on a competing risk framework were applied for risk quantification.

RESULTS

Multivariable adjusted hazard ratios demonstrated that longer diabetes duration, higher BMI, poorer glycaemic control, documentation of any micro- or macrovascular comorbidity, the presence of concomitant non-antidiabetic pharmacotherapies, and greater numbers of prescribed OADs increased the likelihood of BOT initiation. On the other hand BOT initiation was less likely in patients with older age and female gender. Analysing the likelihood of OAD termination without initiation of BOT provided supportive evidence for the variables predictive of BOT initiation.

DISCUSSION

Analysis of the DIVE registry has resulted in the identification of a number of factors that may be predictive for the initiation of BOT for type-2 diabetes patients initially prescribed one or more OADs. Poor glycaemic control, the presence of vascular comorbidities and concomitant medications, and a greater number of OADs were all detected to increase the risk of a switch to BOT. Female gender and younger age showed protective properties.

CONCLUSIONS

The close monitoring of patients displaying these characteristics may help to identify individuals who might benefit from early addition of insulin therapy to their oral treatment regimen.

One-year efficacy and safety of a fixed combination of insulin degludec and liraglutide in patients with type 2 diabetes: results of a 26-week extension to a 26-week main trial

AIMS

To confirm, in a 26-week extension study, the sustained efficacy and safety of a fixed combination of insulin degludec and liraglutide (IDegLira) compared with either insulin degludec or liraglutide alone, in patients with type 2 diabetes.

METHODS

Insulin-naïve adults with type 2 diabetes randomized to once-daily IDegLira, insulin degludec or liraglutide, in addition to metformin ± pioglitazone, continued their allocated treatment in this preplanned 26-week extension of the DUAL I trial.

RESULTS

A total of 78.8% of patients (1311/1663) continued into the extension phase. The mean glycated haemoglobin (HbA1c) concentration at 52 weeks was reduced from baseline by 1.84% (20.2 mmol/mol) for the IDegLira group, 1.40% (15.3 mmol/mol) for the insulin degludec group and 1.21% (13.2 mmol/mol) for the liraglutide group. Of the patients on IDegLira, 78% achieved an HbA1c of <7% (53 mmol/mol) versus 63% of the patients on insulin degludec and 57% of those on liraglutide. The mean fasting plasma glucose concentration at the end of the trial was similar for IDegLira (5.7 mmol/l) and insulin degludec (6.0 mmol/l), but higher for liraglutide (7.3 mmol/l). At 52 weeks, the daily insulin dose was 37% lower with IDegLira (39 units) than with insulin degludec (62 units). IDegLira was associated with a significantly greater decrease in body weight (estimated treatment difference, -2.80 kg, p < 0.0001) and a 37% lower rate of hypoglycaemia compared with insulin degludec. Overall, all treatments were well tolerated and no new adverse events or tolerability issues were observed for IDegLira.

CONCLUSIONS

These 12-month data, derived from a 26-week extension of the DUAL I trial, confirm the initial 26-week main phase results and the sustainability of the benefits of IDegLira compared with its components in glycaemic efficacy, safety and tolerability.

The Place of Dipeptidyl Peptidase-4 Inhibitors in Type 2 Diabetes Therapeutics: A "Me Too" or "the Special One" Antidiabetic Class?

Incretin-based therapies, the most recent therapeutic options for type 2 diabetes mellitus (T2DM) management, can modify various elements of the disease, including hypersecretion of glucagon, abnormal gastric emptying, postprandial hyperglycaemia, and, possibly, pancreatic β cell dysfunction. Dipeptidyl peptidase-4 (DPP-4) inhibitors (gliptins) increase glucagon-like peptide-1 (GLP-1) availability and correct the "incretin defect" seen in T2DM patients. Clinical studies have shown good glycaemic control with minimal risk of hypoglycaemia or any other adverse effects, despite the reports of pancreatitis, whose association remains to be proved. Recent studies have been focusing on the putative ability of DPP-4 inhibitors to preserve pancreas function, in particular due to the inhibition of apoptotic pathways and stimulation of β cell proliferation. In addition, other cytoprotective effects on other organs/tissues that are involved in serious T2DM complications, including the heart, kidney, and retina, have been increasingly reported. This review outlines the therapeutic potential of DPP-4 inhibitors for the treatment of T2DM, focusing on their main features, clinical applications, and risks, and discusses the major challenges for the future, in particular the possibility of becoming the preferred therapy for T2DM due to their ability to modify the natural history of the disease and ameliorate nephropathy, retinopathy, and cardiovascular complications.

Post-Glucose Load Plasma α-Dicarbonyl Concentrations Are Increased in Individuals With Impaired Glucose Metabolism and Type 2 Diabetes: The CODAM Study

OBJECTIVE

There is increasing evidence that postprandial glucose excursions play an important role in the development of vascular complications. The underlying mechanism is unknown, but glucose-derived formation of reactive α-dicarbonyl compounds may explain why acute hyperglycemia leads to increased risk for diabetes complications. In the current study, we investigated whether α-dicarbonyls are increased after a glucose load in individuals without or with impaired glucose metabolism (IGM) and type 2 diabetes.

RESEARCH DESIGN AND METHODS

Cross-sectional, linear analyses were performed in the Cohort on Diabetes and Atherosclerosis Maastricht (CODAM [n = 574, 61% men, 60 years old]) study. Individuals with normal glucose metabolism (n = 279), IGM (n = 120), and type 2 diabetes (n = 92) who had complete data on an oral glucose tolerance test (OGTT) and were not on insulin treatment were included in the study population. Plasma α-dicarbonyl (methylglyoxal [MGO], glyoxal [GO], and 3-deoxyglucosone [3-DG]) levels were measured in the fasting state and in samples of the OGTT by ultra-performance liquid chromatography-tandem mass spectrometry.

RESULTS

The presence of both IGM and type 2 diabetes was significantly associated with higher α-dicarbonyl incremental areas under the curve (iAUCs), as calculated from the OGTT (for IGM, MGO β = 0.190 [95% CI 0.106-0.274], GO β = 0.287 [95% CI 0.172-0.401], and 3-DG β = 0.285 [95% CI 0.221-0.349]; for type 2 diabetes, MGO β = 0.293 [95% CI 0.180-0.405], GO β = 0.536 [95% CI 0.382-0.689], and 3-DG β = 0.542 [95% CI 0.456-0.628]). Adjustment for glucose iAUC attenuated these associations. iAUCs of the α-dicarbonyls correlated highly with glucose iAUC but not with fasting glucose levels or HbA1c.

CONCLUSIONS

The increased levels of α-dicarbonyls during an OGTT in individuals with IGM and type 2 diabetes underline the potential importance of α-dicarbonyl stress as a candidate to explain the increased risk of diabetes complications in individuals with postprandial hyperglycemia.

Minimizing Hypoglycemia and Weight Gain with Intensive Glucose Control: Potential Benefits of a New Combination Therapy (IDegLira)

Due to the progressive nature of type 2 diabetes (T2D), the majority of patients require increasing levels of therapy to achieve and maintain good glycemic control. At present, once patients become uncontrolled on oral antidiabetic therapies, the two primary treatment options are glucagon-like peptide-1 receptor agonists (GLP-1RAs) or basal insulin, although earlier use of GLP-1RAs has also been advocated. While both of these drug classes have proven efficacy in treating T2D, there can be limitations to their use in some patients, and resistance to further treatment intensification among both patients and physicians. More recently, treatment incorporating both a GLP-1RA and a basal insulin has been used successfully in the clinic and the first such combination product, IDegLira (insulin degludec + liraglutide), has recently been approved for use in Europe. IDegLira combines insulin degludec and the GLP-1RA liraglutide in a single injection. In both insulin-naïve and basal insulin-treated individuals with T2D, IDegLira has demonstrated greater reductions in glycated hemoglobin (HbA_1c) than either of the individual components, with a low rate of hypoglycemia and weight loss. IDegLira may provide a new option for patients requiring treatment intensification but for whom increased weight or a higher risk of hypoglycemia are barriers. This article discusses the rationale behind combining these two drug classes and reviews the available clinical evidence for the efficacy and safety of IDegLira.

New developments in insulin therapy for type 2 diabetes

Insulin has classically been considered a treatment of last resort for individuals with type 2 diabetes, delayed until all other efforts by the patient and healthcare provider have failed. Recent treatment guidelines recommend the use of insulin, in particular basal insulin, as part of a treatment regimen earlier in the disease process. Many patients are reticent about initiating insulin, so therapies that allow insulin treatment to be more tailored to individual needs are likely to result in greater acceptance and patient adherence with therapy. To meet this need, a range of insulin products are in development that aim to increase absorption rate or prolong the duration of action, reduce peak variability and weight gain associated with insulin treatment, and offer alternative delivery methods. This review describes insulin products in clinical development, new combination therapies, and new devices for insulin delivery.

Hypoglycemia

Hypoglycemia is a common, potentially avoidable consequence of diabetes treatment and is a major barrier to initiating or intensifying antihyperglycemic therapy in efforts to achieve better glycemic control. Therapy regimen and a history of hypoglycemia are the most important predictors of future events. Other risk factors include renal insufficiency, older age, and history of hypoglycemia-associated autonomic failure. Reported rates of hypoglycemia vary considerably among studies because of differences in study design, definitions used, and population included, among other factors. Although occurring more frequently in type 1 diabetes, hypoglycemia also is clinically important in type 2 diabetes. Symptoms experienced by patients vary among individuals, and many events remain undiagnosed. The incidence of severe events is unevenly distributed, with only a small proportion (∼ 5%) of individuals accounting for >50% of events. Consequently, clinicians must be conscientious in obtaining thorough patient histories, because an accurate picture of the frequency and severity of hypoglycemic events is essential for optimal diabetes management. Severe hypoglycemia in particular is associated with an increased risk of mortality, impairments in cognitive function, and adverse effects on patients' quality of life. Economically, hypoglycemia burdens the healthcare system and adversely affects workplace productivity, particularly after a nocturnal event. Ongoing healthcare reform efforts will result in even more emphasis on reducing this side effect of diabetes treatment. Therefore, improving patients' self-management skills and selecting or modifying therapy to reduce the risk of hypoglycemia will increase in importance for clinicians and patients alike.

Evidence-based practice use of incretin-based therapy in the natural history of diabetes

The incretin class of anti-hyperglycemic agents, including glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-inhibitors, is an important addition to the therapeutic armamentarium for the management of appropriate patients with type 2 diabetes mellitus as an adjunct to diet and exercise and/or with the agents metformin, sulfonylureas, thiazolidinediones, or any combination thereof. More recently, US Food and Drug Administration (FDA)-approved indications for incretins were expanded to include use with basal insulin. This review article takes an evidence-based practice approach in discussing the importance of aggressive treatment for diabetes, the principles of incretin physiology and pathophysiology, use of glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors, and patient types and contexts where incretin therapy has been found beneficial, from metabolic syndrome to overt diabetes.

The effect of addition of liraglutide to high-dose intensive insulin therapy: a randomized prospective trial

AIMS

Patients with type 2 diabetes and insulin resistance may require high insulin doses to control hyperglycaemia. The addition of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) to basal insulin therapy has been shown to reduce insulin requirement while reducing insulin-associated weight gain [1,2]. The effect of GLP-1 RA therapy added to intensive (basal/bolus) insulin therapy has not been studied in a prospective trial. This trial evaluated the effect of the addition of liraglutide to high-dose intensive insulin therapy compared with standard insulin up-titration in obese insulin-resistant patients with type 2 diabetes requiring high-dose insulin therapy.

METHODS

Thirty-seven subjects with type 2 diabetes requiring >100 units of insulin daily administered either by continuous subcutaneous insulin infusion (CSII) or by multiple daily injections (MDIs) with or without metformin were randomized to receive either liraglutide plus insulin (LIRA) or intensive insulin only (controls). Liraglutide was initiated at 0.6 mg subcutaneously (sq) per day and increased to either 1.2 or 1.8 mg daily in combination with intensive insulin therapy. Controls received intensive insulin up-titration only.

RESULTS

At 6 months, subjects receiving liraglutide plus insulin experienced statistically significant reductions in HbA1c, weight, insulin dose and glycaemic variability (GV) by continuous glucose monitor (CGM) compared with the control group receiving insulin only.

CONCLUSIONS

Adding liraglutide to intensive high-dose (basal/bolus) insulin therapy results in greater improvement in glycaemic control than insulin therapy alone, with additional benefits of weight loss and reduced GV.

Comparison of insulin lispro protamine suspension versus insulin glargine once daily added to oral antihyperglycaemic medications and exenatide in type 2 diabetes: a prospective randomized open-label trial

AIMS

To compare efficacy and safety of two, once-daily basal insulin formulations [insulin lispro protamine suspension (ILPS) vs. insulin glargine (glargine)] added to oral antihyperglycaemic medications (OAMs) and exenatide BID in suboptimally controlled type 2 diabetes (T2D) patients.

METHODS

This 24-week, open-label, multicentre trial randomized patients to bedtime ILPS (n = 171) or glargine (n = 168). Non-inferiority of ILPS versus glargine was assessed by comparing the upper limit of 95% confidence intervals (CIs) for change in haemoglobin A1c (HbA1c) from baseline to week 24 (adjusted for baseline HbA1c) with non-inferiority margin 0.4%.

RESULTS

Non-inferiority of ILPS versus glargine was demonstrated: least-squares mean between-treatment difference (ILPS minus glargine) (95% CI) was 0.22% (0.06, 0.38). Mean HbA1c reduction was less for ILPS- versus glargine-treated patients (-1.16 ± 0.84 vs. -1.40 ± 0.97%, p = 0.008). Endpoint HbA1c < 7.0% was achieved by 53.7% (ILPS) and 61.7% (glargine) (p = NS). Overall hypoglycaemia rates (p = NS) and severe hypoglycaemia incidence (p = NS) were similar. Nocturnal hypoglycaemia rate was higher in patients treated with ILPS versus glargine (p = 0.004). Weight gain was similar between groups (ILPS: 0.27 ± 3.38 kg; glargine: 0.66 ± 3.93 kg, p = NS). Endpoint total insulin doses were lower in patients treated with ILPS versus glargine (0.30 ± 0.17 vs. 0.37 ± 0.17 IU/kg/day, p < 0.001).

CONCLUSIONS

ILPS was non-inferior to glargine for HbA1c change over 24 weeks, but was associated with less HbA1c reduction and more nocturnal hypoglycaemia. Treat-to-target basal insulin therapy improves glycaemic control and is associated with minimal weight gain when added to OAMs and exenatide BID for suboptimally controlled T2D.

Complementary Approaches to Improving Glucose Control-Insulin and Incretins: Patient Case Studies in Action

PURPOSE

The use of insulin and incretin-based therapies together has recently emerged as a new therapeutic option for patients with type 2 diabetes. This approach can be used across the continuum of diabetes and is supported by clinical trial evidence. To illustrate how these data may apply to clinical care, this supplement uses patient case studies to provide clinical context for diabetes educators. Relevant medical literature was searched and cited. Search terms included insulin, DPP-4 inhibitors, GLP-1 receptor agonists, hypoglycemia, and weight gain.

CONCLUSION

Insulin remains the most potent glucose-lowering agent available for the treatment of type 2 diabetes but has limitations, primarily of hypoglycemia and secondarily of weight gain. The addition of incretin-based therapies complements the glucose-lowering potential of basal insulin, without increasing the risk of hypoglycemia, potentially allowing for lower doses of insulin and without increasing weight gain (DPP-4 inhibitors) or possibly with weight loss (GLP-1 receptor agonists). Incretin-based therapies offer advantages over prandial insulin to address postprandial hyperglycemia.

Insulin plus incretin agent combination therapy in type 2 diabetes: a systematic review

BACKGROUND

Insulin and incretin agents (dipeptidyl peptidase-4 inhibitors [DPP4is] and glucagon-like peptide-1 receptor agonists [GLP1 RAs]) are second-line treatment options in patients with type 2 diabetes (T2D) not achieving glycemic targets with metformin. Combinations of insulin with incretin agents have been explored in randomized controlled trials (RCTs) and retrospective studies. However, the optimal approach is still elusive; numerous combination regimens can be envisioned, differing in composition and in order of addition.

SCOPE

A systematic survey was conducted of RCTs testing insulin/DPP4i or insulin/GLP1 RA regimens. PubMed and other online databases were queried using 'insulin' and the names of all incretin agents available in Canada, along with 'combination', 'concomitant', 'concurrent', and 'add-on'. Web of Science and clinicaltrials.gov were searched to identify unpublished trials.

FINDINGS

Fifteen placebo-controlled or active-comparator RCTs were identified, reporting outcomes for regimens combining insulins and incretin agents available in Canada. DPP4i add-on to insulin therapy (six trials) leads to modest A1c lowering, with weight neutrality. GLP1 RA and insulin combination therapy (GLP1 RA add-on, five trials; insulin add-on, two trials) is associated with significant A1c lowering, with beneficial effects on body weight. A single proof-of-concept trial compared GLP1 RA to DPP4i add-on to insulin, and only one RCT examined simultaneous introduction of an incretin agent with insulin. Adding an incretin agent to established basal insulin therapy may represent a useful alternative to insulin intensification with prandial or premixed insulin. Initial introduction of an incretin agent, with subsequent introduction of insulin, offers potential practical advantages. No study directly comparing order of addition has yet been reported.

CONCLUSIONS

Insulin/incretin combination therapy comprises a variety of efficacious, weight-sparing regimens and may be considered for many patients who do not achieve glycemic targets when treated with insulin or an incretin agent.

Effect of once-daily insulin detemir on oral antidiabetic drug (OAD) use in patients with type 2 diabetes

WHAT IS KNOWN AND OBJECTIVE

There are acknowledged benefits to continuing metformin when initiating insulin, but there appears to be growing concern over the role of sulphonylureas and thiazolidinediones when used in combination with insulin. This analysis investigates the effects of continuing or discontinuing oral antidiabetic drugs (OADs) following the initiation of once-daily insulin detemir.

METHODS

SOLVE is a 24-week, multinational observational study of insulin detemir initiation in patients with type 2 diabetes mellitus treated with one or more OADs.

RESULTS

In the total cohort (n = 17 374), there were significant improvements in HbA1c (-1·3%, 95% CI -1·34; -1·27%) and weight (-0·6 kg, 95% CI -0·65; -0·47 kg), with an increase in the incidence rate of minor hypoglycaemia (+0·256 events ppy, P < 0·001), but not severe hypoglycaemia (-0·038 events ppy, P < 0·001). Study participants had information on OAD use either prior to (n = 17 086) or during insulin initiation (n = 16 346). HbA1c reductions were significantly greater in patients continuing treatment with metformin (-1·3% vs. -1·1%, P < 0·01), thiazolidinediones (-1·3% vs. -1·0%, P < 0·01) and DPP-IV inhibitors (-1·3% vs. -0·9%, P < 0·001). Final insulin doses were significantly greater in patients discontinuing treatment with sulphonylureas (0·29 vs. 0·26 IU/kg, P < 0·001), glinides (0·28 vs. 0·26 IU/kg, P < 0·01), thiazolidinediones (0·31 vs. 0·26 IU/kg, P < 0·001) and DPP-IV inhibitors (0·35 vs. 0·29 IU/kg, P < 0·001) compared with patients continuing these respective agents. All patient subgroups had a mean weight loss irrespective of OAD continuation, apart from those continuing thiazolidinediones (+0·2 kg). The largest improvements in weight were seen following the withdrawal of sulphonylureas and thiazolidinediones (-1·1 and -1·1 kg, respectively).

WHAT IS NEW AND CONCLUSION

Discontinuation (or switching) of OADs at the time of insulin initiation appears to be governed principally by concerns about hypoglycaemia and weight. HbA1c improvements were smaller in patients discontinuing OADs at the time of insulin initiation and may be associated with insufficient insulin titration.

Peripheral adrenoceptors: the impetus behind glucose dysregulation and insulin resistance

It is now accepted that several pharmacological drug treatments trigger clinical manifestations of glucose dysregulation, such as hyperglycaemia, glucose intolerance and insulin resistance, in part through poorly understood mechanisms. Persistent sympathoadrenal activation is linked to glucose dysregulation and insulin resistance, both of which significantly increase the risk of emergent endocrinological disorders, including metabolic syndrome and type 2 diabetes mellitus. Through the use of targeted mutagenesis and pharmacological methods, preclinical and clinical research has confirmed physiological glucoregulatory roles for several peripheral α- and β-adrenoceptor subtypes. Adrenoceptor isoforms in the pancreas (α(2A) and β(2) ), skeletal muscle (α(1A) and β(2) ), liver (α(1A & B) and β(2) ) and adipose tissue (α(1A) and β(1 & 3) ) are convincing aetiological targets that account for both immediate and long-lasting alterations in blood glucose homeostasis. Because significant overlap exists between the therapeutic applications of numerous classes of drugs and their associated adverse side-effects, a better understanding of peripheral adrenoceptor-mediated glucose metabolism is thus warranted. Therefore, at the same time as providing a brief review of glucose homeostasis in the periphery, the present review addresses both functional and pathophysiological roles of the mammalian α(1) , α(2) , and β-adrenoceptor isoforms in whole-body glucose turnover. We highlight evidence relating to the clinical use of common adrenergic drugs and their impacts on glucose metabolism.