Pathophysiologic approach to therapy in patients with newly diagnosed type 2 diabetes

Phenotypes of prediabetes and stratification of cardiometabolic risk

Prediabetes is associated with increased risks of type 2 diabetes, cardiovascular disease, dementia, and cancer, and its prevalence is increasing worldwide. Lifestyle and pharmacological interventions in people with prediabetes can prevent the development of diabetes and possibly cardiovascular disease. However, prediabetes is a highly heterogeneous metabolic state, both with respect to its pathogenesis and prediction of disease. Improved understanding of these features and precise phenotyping of prediabetes could help to improve stratification of disease risk. In this Personal View, we focus on the extreme metabolic phenotypes of metabolically healthy obesity and metabolically unhealthy normal weight, insulin secretion failure, insulin resistance, visceral obesity, and non-alcoholic fatty liver disease. We present new analyses aimed at improving characterisation of phenotypes in lean, overweight, and obese people with prediabetes. We discuss evidence from lifestyle intervention studies to explore whether these phenotypes can also be used for individualised prediction and prevention of cardiometabolic diseases.

Clinical Considerations for Use of Initial Combination Therapy in Type 2 Diabetes

Type 2 diabetes is a progressive disorder characterized by increasing hyperglycemia and the need to gradually intensify therapy in order to achieve and maintain glycemic control. Early initiation of combination therapy has been proposed as an approach to achieve glycemic goals earlier and delay the deterioration of glycemic control and with possible better preservation of β-cell function. We discuss in this article the pros and cons of this approach, focusing on individuals with HbA1c at diagnosis of 7.5-9.0%, where difference of opinion still exists on management. Initial combination therapy is proposed to lead to better and faster achievement of glycemic targets versus monotherapy and to impede clinical inertia and may possibly slow the deterioration of β-cell function. However, treating patients with sequential therapy is proposed to allow one to fully assess the efficacy and risk-to-benefit ratio of each drug as it is added. Furthermore, there is no evidence to support that rapid addition and titration of medications according to the glycemic profile achieved are inferior to initial combination therapy if glycemic targets are attained in a timely manner. Initial combination therapy is argued to postpone clinical inertia to the next decision point but does not eliminate it. Additionally, it may have been the agents chosen and not the timing of their initiation that led to improved β-cell function in the studies of initial combination therapy, and there are no data currently comparing use of the same drugs initiated simultaneously or sequentially. Heightened awareness of providers, individualization of therapy and setting, and reaching glycemic targets remain the mainstays of care.

Mild hyperglycemia triggered islet function recovery in streptozotocin-induced insulin-deficient diabetic rats

Aims/Introduction

Moderate elevation of glucose level has been shown to effectively promote β‐cell replication in various models in vitro and in normal rodents. Here, we aimed to test the effect of moderately elevated glucose on β‐cell mass expansion and islet function recovery in diabetic animal models.

Materials and Methods

A single high dose of streptozotocin was given to induce insulin‐deficient diabetes in adult male Sprague–Dawley rats. Then, 48 h after streptozotocin injection, newly diabetic rats were randomly divided into three groups: (i) no treatment to maintain hyperglycemia; (ii) daily exogenous long‐acting human insulin analog injection that maintained mild hyperglycemia (15 mmol/L < blood glucose < 18 mmol/L); (iii) daily exogenous long‐acting human insulin analog injection to restore normoglycemia (blood glucose <8 mmol/L) as a control. Islet function, β‐cell regeneration and β‐cell replication were monitored during the entire analysis period.

Results

A single high dose of streptozotocin induced massive loss of β‐cells, resulting in irreversible hyperglycemia. Mild hyperglycemia markedly promoted β‐cell proliferation, leading to robust β‐cell regeneration. Importantly, rats that maintained mild hyperglycemia showed nearly normal glucose‐stimulated insulin secretion, glucose disposal and random blood glucose levels, suggesting almost full restoration of the islet function. Normalization of blood glucose levels profoundly blunted β‐cell replication, regeneration and islet function recovery observed in mild hyperglycemia.

Conclusions

Our research provides a feasible approach to stimulate in situ β‐cell regeneration in diabetic rats, offering new perspectives for diabetes therapy.

Mechanisms of Diabetes-Induced Liver Damage: The role of oxidative stress and inflammation

Diabetes mellitus is a non-communicable disease that occurs in both developed and developing countries. This metabolic disease affects all systems in the body, including the liver. Hyperglycaemia, mainly caused by insulin resistance, affects the metabolism of lipids, carbohydrates and proteins and can lead to non-alcoholic fatty liver disease, which can further progress to non-alcoholic steatohepatitis, cirrhosis and, finally, hepatocellular carcinomas. The underlying mechanism of diabetes that contributes to liver damage is the combination of increased oxidative stress and an aberrant inflammatory response; this activates the transcription of pro-apoptotic genes and damages hepatocytes. Significant involvement of pro-inflammatory cytokines-including interleukin (IL)-1β, IL-6 and tumour necrosis factor-α-exacerbates the accumulation of oxidative damage products in the liver, such as malondialdehyde, fluorescent pigments and conjugated dienes. This review summarises the biochemical, histological and macromolecular changes that contribute to oxidative liver damage among diabetic individuals.

Sodium-glucose cotransporter-2 inhibitor combination therapy to optimize glycemic control and tolerability in patients with type 2 diabetes: focus on dapagliflozin-metformin

In type 2 diabetes (T2D), early combination therapy using agents that target a number of the underlying pathophysiologic defects contributing to hyperglycemia may improve patient outcomes. For many patients, the combination of metformin with a sodium-glucose cotransporter-2 (SGLT-2) inhibitor may be a good option because these agents have complementary mechanisms of action, neutral-to-positive effects on body weight, and a low risk of hypoglycemia. This review focuses on the combination of metformin with dapagliflozin, a member of the SGLT-2 inhibitor class of antidiabetes agents. In clinical trials, the combination of dapagliflozin with metformin produced significant and sustained reductions in glycated hemoglobin and body weight in a broad range of adult patients with T2D, including those initiating pharmacotherapy and those with more advanced disease. These reductions were accompanied by modest decreases in blood pressure. Dapagliflozin as add-on therapy to metformin was well tolerated and associated with low rates of hypoglycemia. Genital infections and, in some studies, urinary tract infections were more frequent with dapagliflozin than with placebo. Early combination therapy with dapagliflozin and metformin may be a safe and appropriate treatment option that enables patients with T2D to achieve individualized glycemic goals as either initial combination therapy in treatment-naïve patients or as dapagliflozin add-on in patients inadequately controlled with metformin therapy.

Postural variation of pulmonary diffusing capacity as a marker of lung microangiopathy in Indian patients with type 2 diabetes mellitus

INTRODUCTION

Diabetes mellitus (DM) is characterized by the presence of chronic hyperglycemia and formation of advanced glycation end products (AGEs). Interaction between AGE and its receptor leads to endothelial damage and microangiopathy. This study was undertaken to investigate the possibility of using a postural variation of diffusing capacity as an early marker of lung microangiopathy and its correlation with the level of adhesion molecules, HbA1c, duration of diabetes, and insulin resistance in type 2 DM (T2DM) patients with and without microangiopathy.

MATERIALS AND METHODS

Forty patients having T2DM without any microangiopathy (n = 20) as well as with microangiopathy (n = 20), and 22 age and sex matched healthy controls were enrolled in this cross-sectional study. Measurement of lung volumes and capacities were done. DLco was measured in sitting and supine position. Levels of vascular cell adhesion molecule-1 (VCAM-1), E-selectin, fasting glucose, and insulin were estimated in plasma of the patients and compared with controls.

RESULTS

Restrictive type of ventilatory change was observed in DM patients. Diffusing capacity (% predicted) in the supine position (P < 0.0001), postural change in DLco (P < 0.0001), and coefficient of diffusion were significantly less in DM patients as compared to controls. Plasma levels of VCAM-1 were significantly higher in DM patients without microangiopathy and negatively correlated (r = -0.4054, P = 0.0094) with Δ DLco in all diabetic subjects. All patients had significantly higher insulin resistance.

CONCLUSION

Lack of postural increase in diffusing capacity in type 2 diabetic patients along with increased VCAM-1 levels could reflect the presence of an early microangiopathy of the small pulmonary vessels.

Not all fats are created equal: adipose vs. ectopic fat, implication in cardiometabolic diseases

Adipose tissue is a recognized endocrine organ that acts not only as a fuel storage but also is able to secrete adipokines that can modulate inflammation. Most of the fat is composed of white adipocytes (WAT), although also brown/beige adipocytes (BAT/BeAT) have been found in humans. BAT is located close to the neck but also among WAT in the epicardial fat and perivascular fat. Adipocyte hypertrophy and infiltration of macrophages impair adipose tissue metabolism determining "adiposopathy" (i.e., sick fat) and increasing the risk to develop metabolic and cardiovascular diseases. The purpose of this review was to search and discuss the available literature on the impact of different types of fat and fat distribution on cardiometabolic risk. Visceral fat, but also ectopic fat, either in liver, muscle and heart, can increase the risk to develop insulin resistance, type 2 diabetes and cardiovascular diseases. Results recently published showed that BAT could have an impact on cardiometabolic risk, not only because it is implicated in energy metabolism but also because it can modulate glucose and lipid metabolism. Therapeutical interventions that can increase energy expenditure, successfully change fat distribution and reduce ectopic fat, also through BAT activation, were discussed.

Improving Effect of the Acute Administration of Dietary Fiber-Enriched Cereals on Blood Glucose Levels and Gut Hormone Secretion

Dietary fiber improves hyperglycemia in patients with type 2 diabetes through its physicochemical properties and possible modulation of gut hormone secretion, such as glucagon-like peptide 1 (GLP-1). We assessed the effect of dietary fiber-enriched cereal flakes (DC) on postprandial hyperglycemia and gut hormone secretion in patients with type 2 diabetes. Thirteen participants ate isocaloric meals based on either DC or conventional cereal flakes (CC) in a crossover design. DC or CC was provided for dinner, night snack on day 1 and breakfast on day 2, followed by a high-fat lunch. On day 2, the levels of plasma glucose, GLP-1, glucose-dependent insulinotropic polypeptide (GIP), and insulin were measured. Compared to CC, DC intake exhibited a lower post-breakfast 2-hours glucose level (198.5±12.8 vs. 245.9±15.2 mg/dL, P<0.05) and a lower incremental peak of glucose from baseline (101.8±9.1 vs. 140.3±14.3 mg/dL, P<0.001). The incremental area under the curve (iAUC) of glucose after breakfast was lower with DC than with CC (P<0.001). However, there were no differences in the plasma insulin, glucagon, GLP-1, and GIP levels. In conclusion, acute administration of DC attenuates postprandial hyperglycemia without any significant change in the representative glucose-regulating hormones in patients with type 2 diabetes (ClinicalTrials.gov. NCT 01997281).

The Time Is Right for a New Classification System for Diabetes: Rationale and Implications of the β-Cell-Centric Classification Schema

The current classification system presents challenges to the diagnosis and treatment of patients with diabetes mellitus (DM), in part due to its conflicting and confounding definitions of type 1 DM, type 2 DM, and latent autoimmune diabetes of adults (LADA). The current schema also lacks a foundation that readily incorporates advances in our understanding of the disease and its treatment. For appropriate and coherent therapy, we propose an alternate classification system. The β-cell-centric classification of DM is a new approach that obviates the inherent and unintended confusions of the current system. The β-cell-centric model presupposes that all DM originates from a final common denominator-the abnormal pancreatic β-cell. It recognizes that interactions between genetically predisposed β-cells with a number of factors, including insulin resistance (IR), susceptibility to environmental influences, and immune dysregulation/inflammation, lead to the range of hyperglycemic phenotypes within the spectrum of DM. Individually or in concert, and often self-perpetuating, these factors contribute to β-cell stress, dysfunction, or loss through at least 11 distinct pathways. Available, yet underutilized, treatments provide rational choices for personalized therapies that target the individual mediating pathways of hyperglycemia at work in any given patient, without the risk of drug-related hypoglycemia or weight gain or imposing further burden on the β-cells. This article issues an urgent call for the review of the current DM classification system toward the consensus on a new, more useful system.

Prescribing practices and clinical predictors of glucose-lowering therapy within the first year in people with newly diagnosed Type 2 diabetes

AIM

To examine prescribing practices and predictors of glucose-lowering therapy within the first year following diagnosis of Type 2 diabetes mellitus in a clinical care setting.

METHODS

We followed people enrolled in the Danish Centre for Strategic Research in Type 2 Diabetes (DD2) cohort from outpatient hospital clinics and general practices throughout Denmark in 2010-2013. We used Poisson regression to compute age- and gender-adjusted risk ratios (RRs).

RESULTS

Among 1158 new Type 2 diabetes mellitus patients, 302 (26%) did not receive glucose-lowering therapy within the first year, 723 (62%) received monotherapy [685 (95%) with metformin], and 133 (12%) received more than one drug. Predictors of receiving any vs. no therapy and combination vs. monotherapy were: age < 40 years [RR: 1.29 (95% CI: 1.16-1.44) and 3.60 (95% CI: 2.36-5.50)]; high Charlson Comorbidity Index [RRs: 1.20 (95% CI: 1.05-1.38) and 2.08 (95% CI: 1.16-3.72)]; central obesity [RRs: 1.23 (95% CI: 1.04-1.44) and 1.93 (95% CI: 0.76-4.94)]; fasting blood glucose of ≥ 7.5 mmol/l [RRs: 1.25 (95% CI: 1.10-1.42) and 1.94 (95% CI: 1.02-3.71)]; and HbA1c ≥ 59 mmol/mol (≥ 7.5%) [RR: 1.26 (95% CI: 1.20-1.32) and 2.86 (95% CI: 1.97-4.14)]. Weight gain ≥ 30 kg since age 20, lack of physical exercise and C-peptide of < 300 pmol/l also predicted therapy.

CONCLUSIONS

Comorbidity, young age, central obesity and poor baseline glycaemic control are important predictors of therapy one year after Type 2 diabetes mellitus debut.

Randomized, Double-Blind Trial of Triple Therapy With Saxagliptin Add-on to Dapagliflozin Plus Metformin in Patients With Type 2 Diabetes

OBJECTIVE

The objective of this study was to assess the efficacy and safety of triple therapy with saxagliptin add-on versus placebo add-on to dapagliflozin plus metformin in adults with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Patients on stable metformin (≥1,500 mg/day) for ≥8 weeks with glycated hemoglobin (HbA1c) 8.0-11.5% (64-102 mmol/mol) at screening received open-label dapagliflozin (10 mg/day) plus metformin immediate release (IR) for 16 weeks. Patients with inadequate glycemic control (HbA1c 7-10.5% [53-91 mmol/mol]) were then randomized to receive placebo (n = 153) or saxagliptin 5 mg/day (n = 162) in addition to background dapagliflozin plus metformin IR. The primary efficacy end point was change in HbA1c from baseline to week 24.

RESULTS

There was a significantly greater reduction in HbA1c at 24 weeks with saxagliptin add-on (-0.51% [-5.6 mmol/mol]) versus placebo (-0.16% [-1.7 mmol/mol]) add-on to dapagliflozin plus metformin (difference, -0.35% [95% CI -0.52% to -0.18%] and -3.8 [-5.7 to -2.0 mmol/mol], respectively; P < 0.0001). Reductions in fasting plasma glucose and 2-h postprandial glucose were similar between treatment arms. A larger proportion of patients achieved HbA1c <7% (53 mmol/mol) with saxagliptin add-on (35.3%) versus placebo add-on (23.1%) to dapagliflozin plus metformin. Adverse events were similar between treatment groups. Episodes of hypoglycemia were infrequent in both treatment arms, and there were no episodes of major hypoglycemia.

CONCLUSIONS

Triple therapy with the addition of saxagliptin to dapagliflozin plus metformin was well tolerated and produced significant improvements in HbA1c in patients with type 2 diabetes inadequately controlled with dapagliflozin plus metformin.

Durability and tolerability of dapagliflozin over 52 weeks as add-on to metformin and sulphonylurea in type 2 diabetes

AIMS

To evaluate the safety and efficacy of dapagliflozin as add-on therapy to metformin plus sulphonylurea over 52 weeks.

METHODS

Patients with type 2 diabetes mellitus (T2DM) using sulphonylurea and metformin received dapagliflozin 10 mg/day or placebo added to therapy for 52 weeks (24-week randomized, double-blind period plus 28-week double-blind extension).

RESULTS

A total of 219 patients were randomized 1 : 1 to dapagliflozin or placebo. Over 52 weeks, glycated haemoglobin (HbA1c) and fasting plasma glucose levels showed greater improvement from baseline with dapagliflozin (-0.8% and -1.5 mmol/l) than with placebo (-0.1% and 0.6 mmol/l). More patients achieved HbA1c <7.0% with dapagliflozin (27.3%) than with placebo (11.3%) at 52 weeks. Dapagliflozin was associated with greater reductions in body weight and systolic blood pressure (-2.9 kg and -1.0 mmHg) compared with placebo (-1.0 kg and 1.1 mmHg). Greater increases in total, LDL and HDL cholesterol and decreases in triglycerides were observed with dapagliflozin (3.4, 4.8, 6.9 and -8.0%, respectively) versus placebo (1.4, 0.9, 0.6 and 2.9%, respectively). Fewer patients were rescued for failing to reach glycaemic targets with dapagliflozin (9.3%) than with placebo (44.4%). Adverse events and serious adverse events were similar between groups (dapagliflozin: 69.7 and 6.4%; placebo: 73.4 and 7.3%). More hypoglycaemic events were observed with dapagliflozin (15.6%) than with placebo (8.3%). Genital infections were reported in more patients in the dapagliflozin (10.1%) than in the placebo group (0.9%) and urinary tract infection frequency was similar in the two groups (10.1 and 11.0%).

CONCLUSION

Dapagliflozin as add-on to metformin plus a sulphonylurea was well tolerated and improvement in glycaemic control was maintained over 52 weeks.

The potential role of sodium glucose co-transporter 2 inhibitors in the early treatment of type 2 diabetes mellitus

BACKGROUND

Sodium glucose co-transporter 2 (SGLT2) inhibitors are a new class of pharmacologic agents developed for the treatment of type 2 diabetes mellitus (T2DM). Their unique mechanism of action is independent of pancreatic beta-cell function or the degree of insulin resistance, giving these agents the potential for use in combination with any of the existing classes of glucose-lowering agents, including insulin. This makes SGLT2 inhibitors an option for patients with long-standing T2DM, but they also have a promising role for early intervention in T2DM, and that role is explored in this review.

METHODS

A literature search was performed to identify relevant English language articles relating to SGLT2 inhibitors, particularly dapagliflozin, canagliflozin and empagliflozin.

RESULTS

Clinical trials of dapagliflozin, canagliflozin and empagliflozin, given as monotherapy or in combination with other glucose-lowering agents, reported clinically significant improvements in glycaemic control, body weight and systolic blood pressure. SGLT2 inhibitors were well tolerated and had a generally favourable safety profile. Few serious adverse events have been reported to date. The frequency of hypoglycaemic events was low, similar to that of placebo, and the choice of co-administered glucose-lowering agent was the major determinant of hypoglycaemic risk. Increased genital and urinary tract infections were consistently reported with SGLT2 inhibitors.

CONCLUSIONS

SGLT2 inhibitors, with their unique insulin-independent mode of action, could have a significant impact on the early management of T2DM, by addressing some of the specific risk factors associated with this disease. SGLT2 inhibitors induce beneficial changes in a number of cardiovascular risk factors, such as lowering blood pressure and body weight, in addition to improved glycaemic control, although information on clinical cardiovascular outcomes is currently limited.

Biocompatible polymeric nanocomplexes as an intracellular stimuli-sensitive prodrug for type-2 diabetes combination therapy

Combination therapy is usually considered as a promising strategy owing to its advantages such as reduced doses, minimized side effects and improved therapeutic efficiency in a variety of diseases including diabetes. Here we synthesized a new highly intracellular stimuli-sensitive chitosan-graft-metformin (CS-MET) prodrug by imine reaction between oxidative chitosan and metformin for type 2 diabetes (T2D) therapy. Hypothetically, CS-MET functions dually as an anti-diabetes prodrug as well as a gene delivery vector without superfluous materials. CS-MET formed nanocomplexes with therapeutic gene through electrostatic interactions and entered cells by Organic Cation Transporter (OCT)-independent endocytosis. The incorporation of metformin into chitosan has been found to increase endosomal escape via the proton sponge effect. When vector carrying a short-hairpin RNA (shRNA) silencing sterol regulatory element-binding protein (SREBP), a major transcription factor involved in de novo lipogenisis, it reduced the SREBP mRNA and proteins efficiently. Furthermore, by intraperitoneal injection, CS-MET/shSREBP nanocomplexes effectively knocked down SREBP in livers of western-type diet (WD)-induced obese C57BL/6J mice, markedly reversed insulin resistance and alleviated the fatty liver phenotype without obvious toxic effects. Thus we were able to show that the intracellular stimuli-sensitive CS-MET prodrug renders a potential platform to increase the anti-diabetes activity with synergistic enhancement of gene therapy.

Computational pharmacokinetics and in vitro-in vivo correlation of anti-diabetic synergistic phyto-composite blend

Despite tremendous strides in modern medicine stringent control over insulin resistance or restoration of normoglycemia has not yet been achieved. With the growth of molecular biology, omics technologies, docking studies, and in silico pharmacology, modulators of enzymes and receptors affecting the molecular pathogenesis of the disease are being considered as the latest targets for anti-diabetic therapy. Therapeutic molecular targets are now being developed basing on the up or down regulation of different signaling pathways affecting the disease. Phytosynergistic anti-diabetic therapy is in vogue both with classical and non-classical medicinal systems. However its chemo-profiling, structural and pharmacokinetic validation awaits providing recognition to such formulations for international acceptance. Translational health research with its focus on benchside product development and its sequential transition to patient bedside puts the pharma RDs to a challenge to develop bio-waiver protocols. Pharmacokinetic simulation models and establishment of in vitro-in vivo correlation can help to replace in vivo bioavailability studies and provide means of quality control for scale up and post approval modification. This review attempts to bring different shades highlighting phyto-synergy, molecular targeting of antidiabetic agents via different signaling pathways and bio-waiver studies under a single umbrella.

Pioglitazone treatment and cardiovascular event and death in subjects with type 2 diabetes without established cardiovascular disease (JDDM 36)

AIMS

The protective association of pioglitazone with cardiovascular events and death was investigated over 6-years in large-scale type 2 diabetic subjects without established cardiovascular disease in a primary care setting.

METHODS

A six-year observational cohort study including 2864 subjects with type 2 diabetes without established cardiovascular disease was performed. The primary endpoint was a composite of first occurrence of cardiovascular disease or death. The effect of pioglitazone use at a baseline year with a Cox proportional hazard model and the time-dependent use in each one-year examination interval with a pooled logistic regression model were analyzed.

RESULTS

Baseline use of pioglitazone (n=493) did not show a statistically protective effect on the primary endpoint (n=175), although it tended to reduce the risk (adjusted hazard ratio 0.67 [95% CI: 0.43-1.05]). However, pooled logistic regression analysis indicated a significant protective association of pioglitazone with the primary endpoint (0.58 [0.38 to 0.87] and cardiovascular disease (0.54 [0.33-0.88]), independent of concurrent levels of blood glucose, blood pressure, lipids, albuminuria, and renal function. In particular, this protective association was observed in those with diabetic nephropathy regardless of the daily dose of pioglitazone. Among a total of 898 subjects who took pioglitazone during the period, 43% experienced a discontinuation at least once; however, serious adverse effects were rare.

CONCLUSIONS

This observational study indicated a protective association of pioglitazone with cardiovascular disease and death in type 2 diabetic subjects without established vascular disease, particularly those with nephropathy.

Treating patients with diabetes of long duration: GLP-1 receptor agonists and insulin in combination

Patients with long-standing type 2 diabetes mellitus (T2DM) can be clinically challenging for physicians to treat because these patients often lack sufficient β-cell function to respond to some oral glucose-lowering agents, may have profound comorbidities, and may have renal impairment that limits the use of traditional agents. These complications, in addition to older age, also increase the risk of hypoglycemia, which can be a major barrier to treatment success. Individualizing treatment targets to balance the benefits of glycemic control with risks of hypoglycemia is the first step to successfully treating these patients. Careful selection of combination therapy strategies to address limited β-cell function, renal function, and cardiovascular status, along with attention to selection of agents associated with lower risk of hypoglycemia, is important. Basal insulin analogs are often used in patients with long-standing diabetes to address insulinopenic states. Incretin-based therapies, particularly GLP-1 receptor agonists, provide postprandial control with lower risks of hypoglycemia than prandial insulin. The author discusses the management of patients with long-standing diabetes who may have limited β-cell function and require transition to insulin therapy with gradual intensification.

Type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is an expanding global health problem, closely linked to the epidemic of obesity. Individuals with T2DM are at high risk for both microvascular complications (including retinopathy, nephropathy and neuropathy) and macrovascular complications (such as cardiovascular comorbidities), owing to hyperglycaemia and individual components of the insulin resistance (metabolic) syndrome. Environmental factors (for example, obesity, an unhealthy diet and physical inactivity) and genetic factors contribute to the multiple pathophysiological disturbances that are responsible for impaired glucose homeostasis in T2DM. Insulin resistance and impaired insulin secretion remain the core defects in T2DM, but at least six other pathophysiological abnormalities contribute to the dysregulation of glucose metabolism. The multiple pathogenetic disturbances present in T2DM dictate that multiple antidiabetic agents, used in combination, will be required to maintain normoglycaemia. The treatment must not only be effective and safe but also improve the quality of life. Several novel medications are in development, but the greatest need is for agents that enhance insulin sensitivity, halt the progressive pancreatic β-cell failure that is characteristic of T2DM and prevent or reverse the microvascular complications. For an illustrated summary of this Primer, visit: http://go.nature.com/V2eGfN.

Influence of glycemic control on gain in VO2 peak, in patients with type 2 diabetes enrolled in cardiac rehabilitation after an acute coronary syndrome. The prospective DARE study

Background

Gain in VO2 peak after cardiac rehabilitation (CR) following an acute coronary syndrome (ACS), is associated with reduced mortality and morbidity. We have previously shown in CR, that gain in VO2 peak is reduced in Type 2 diabetic patients and that response to CR is impaired by hyperglycemia.

Methods

We set up a prospective multicenter study (DARE) whose primary objective was to determine whether good glycemic control during CR may improve the gain in VO2 peak. Sixty four type 2 diabetic patients, referred to CR after a recent ACS, were randomized to insulin intensive therapy or a control group with continuation of the pre-CR antidiabetic treatment. The primary objective was to study the effect of glycemic control during CR on the improvement of peak VO2 by comparing first the 2 treatment groups (insulin intensive vs. control) and second, 2 pre-specified glycemic control groups according to the final fructosamine level (below and above the median).

Results

At the end of the CR program, the gain in VO2 peak and the final fructosamine level (assessing glycemic level during CR) were not different between the 2 treatment groups. However, patients who had final fructosamine level below the median value, assessing good glycemic control during CR, showed significantly higher gain in VO2 peak (3.5 ± 2.4 vs. 1.7 ± 2.4 ml/kg/min,p = 0.014) and ventilatory threshold (2.7 ± 2.5 vs. 1.2 ± 1.9 ml/kg/min,p = 0.04) and a higher proportion of good CR-responders (relative gain in VO2 peak ≥ 16 %): 66 % vs. 36 %, p = 0.011. In multivariate analysis, gain in VO2 peak was associated with final fructosamine level (p = 0.010) but not with age, gender, duration of diabetes, type of ACS, insulin treatment or basal fructosamine.

Conclusions

The DARE study shows that, in type 2 diabetes, good glycemic control during CR is an independent factor associated with gain in VO2 peak. This emphasizes the need for good glycemic control in CR for type 2 diabetic patients.

Trial registration

Trial registered as NCT00354237 (19 July 2006).

Therapeutic Use of Metformin in Prediabetes and Diabetes Prevention

People with elevated, non-diabetic, levels of blood glucose are at risk of progressing to clinical type 2 diabetes and are commonly termed 'prediabetic'. The term prediabetes usually refers to high-normal fasting plasma glucose (impaired fasting glucose) and/or plasma glucose 2 h following a 75 g oral glucose tolerance test (impaired glucose tolerance). Current US guidelines consider high-normal HbA1c to also represent a prediabetic state. Individuals with prediabetic levels of dysglycaemia are already at elevated risk of damage to the microvasculature and macrovasculature, resembling the long-term complications of diabetes. Halting or reversing the progressive decline in insulin sensitivity and β-cell function holds the key to achieving prevention of type 2 diabetes in at-risk subjects. Lifestyle interventions aimed at inducing weight loss, pharmacologic treatments (metformin, thiazolidinediones, acarbose, basal insulin and drugs for weight loss) and bariatric surgery have all been shown to reduce the risk of progression to type 2 diabetes in prediabetic subjects. However, lifestyle interventions are difficult for patients to maintain and the weight loss achieved tends to be regained over time. Metformin enhances the action of insulin in liver and skeletal muscle, and its efficacy for delaying or preventing the onset of diabetes has been proven in large, well-designed, randomised trials, such as the Diabetes Prevention Program and other studies. Decades of clinical use have demonstrated that metformin is generally well-tolerated and safe. We have reviewed in detail the evidence base supporting the therapeutic use of metformin for diabetes prevention.

Short commentary on empagliflozin and its potential clinical impact

Sodium glucose cotransporter type 2 (SGLT2) inhibitors are a new class of drug developed to treat type 2 diabetes mellitus (T2DM). They target the kidney by reducing renal glucose reabsorption and promoting urinary glucose excretion, which reduces hyperglycemia in individuals with T2DM. The SGLT2 inhibitor empagliflozin has gained approval in the EU and in the USA for the treatment of adults with T2DM (there is no current indication in type 1 diabetes). Empagliflozin has shown a good efficacy and safety profile from clinical trials when given as monotherapy, and as an add-on therapy to other glucose-lowering agents. This short commentary reviews the key efficacy and safety data from empagliflozin phase III trials and examines the potential role this agent may have in the management of T2DM.

Evaluation of the long-term durability and glycemic control of fasting plasma glucose and glycosylated hemoglobin for pioglitazone in Japanese patients with type 2 diabetes

BACKGROUND

This study applied a pharmacodynamic model-based approach to evaluate the long-term durability and glycemic control of pioglitazone in comparison with other oral glucose-lowering drugs in Japanese type 2 diabetes mellitus (T2DM) patients.

SUBJECTS AND METHODS

Japanese T2DM patients were enrolled in a prospective, randomized, open-label, blinded-end point study and received pioglitazone with or without other oral glucose-lowering drugs (excluding another thiazolidinedione [TZD]) (n=293) or oral glucose-lowering drugs excluding TZD (n=294). Treatment was adjusted to achieve glycosylated hemoglobin (HbA1c) <6.9%, and samples for fasting plasma glucose (FPG) and HbA1c were collected over 2.5-4 years. A simultaneous cascading indirect response model structure was applied to describe the time course of FPG and HbA1c. HbA1c levels were described using both an FPG-dependent and an FPG-independent function. To account for titration, drug effects for both treatment groups were implemented using a time-dependent Emax model.

RESULTS

Pioglitazone was superior in both time to maximum effect and the magnitude of reduction achieved in FPG and HbA1c. A greater reduction in median FPG (-21 mg/dL vs. -9 mg/dL) was observed with pioglitazone (P<0.05). Maximum drug effect for FPG was predicted to occur earlier (11 months) for pioglitazone than for the control group (14 months). The simulated additional reduction in FPG and HbA1c achieved with pioglitazone was predicted to be maintained beyond the currently observed study duration.

CONCLUSIONS

Pioglitazone was found to result in improved glycemic control and durability compared with control treatment. This model-based approach enabled the quantification of differences in FPG and HbA1c for both treatment groups and simulation to evaluate longer-term durability on FPG and HbA1c.

Initial combination of empagliflozin and linagliptin in subjects with type 2 diabetes

OBJECTIVE

To evaluate the efficacy and safety of empagliflozin/linagliptin in subjects with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Subjects not receiving antidiabetes therapy for ≥12 weeks were randomized to empagliflozin 25 mg/linagliptin 5 mg (n = 137), empagliflozin 10 mg/linagliptin 5 mg (n = 136), empagliflozin 25 mg (n = 135), empagliflozin 10 mg (n = 134), or linagliptin 5 mg (n = 135) for 52 weeks. The primary end point was change from baseline in HbA1c at week 24.

RESULTS

Mean HbA1c at baseline was 7.99-8.05% (64 mmol/mol). At week 24, adjusted mean (SE) changes from baseline in HbA1c with empagliflozin 25 mg/linagliptin 5 mg, empagliflozin 10 mg/linagliptin 5 mg, empagliflozin 25 mg, empagliflozin 10 mg, and linagliptin 5 mg were -1.08 (0.06)% (-11.8 [0.7] mmol/mol), -1.24 (0.06)% (-13.6 [0.7] mmol/mol), -0.95 (0.06)% (-10.4 [0.7] mmol/mol), -0.83 (0.06)% (-9.1 [0.7] mmol/mol), and -0.67 (0.06)% (-7.3 [0.7] mmol/mol), respectively. Reductions in HbA1c were significantly greater for empagliflozin 25 mg/linagliptin 5 mg compared with linagliptin 5 mg (P < 0.001) but not compared with empagliflozin 25 mg and were significantly greater for empagliflozin 10 mg/linagliptin 5 mg compared with the individual components (P < 0.001 for both). At week 24, 55.4%, 62.3%, 41.5%, 38.8%, and 32.3% of subjects with baseline HbA1c ≥7% (≥53 mmol/mol) reached HbA1c <7% with empagliflozin 25 mg/linagliptin 5 mg, empagliflozin 10 mg/linagliptin 5 mg, empagliflozin 25 mg, empagliflozin 10 mg, and linagliptin 5 mg, respectively. Efficacy was maintained at week 52. The proportion of subjects with adverse events (AEs) over 52 weeks was similar across groups (68.9-81.5%), with no confirmed hypoglycemic AEs.

CONCLUSIONS

Reductions from baseline in HbA1c with empagliflozin/linagliptin were significantly different versus linagliptin and empagliflozin 10 mg but not versus empagliflozin 25 mg. Empagliflozin/linagliptin was well tolerated.

β-cell dysfunction: Its critical role in prevention and management of type 2 diabetes

Type 2 diabetes (T2DM) is characterized by insulin resistance and β-cell dysfunction. Although, in contrast to type 1 diabetes, insulin resistance is assumed to be a major pathophysiological feature of T2DM, T2DM never develops unless β-cells fail to compensate insulin resistance. Recent studies have revealed that a deficit of β-cell functional mass is an essential component of the pathophysiology of T2DM, implying that β-cell deficit is a common feature of both type 1 and type 2 diabetes. β-cell dysfunction is present at the diagnosis of T2DM and progressively worsens with disease duration. β-cell dysfunction is associated with worsening of glycemic control and treatment failure; thus, it is important to preserve or recover β-cell functional mass in the management of T2DM. Since β-cell regenerative capacity appears somewhat limited in humans, reducing β-cell workload appears to be the most effective way to preserve β-cell functional mass to date, underpinning the importance of lifestyle modification and weight loss for the treatment and prevention of T2DM. This review summarizes the current knowledge on β-cell functional mass in T2DM and discusses the treatment strategy for T2DM.

Initial combination of linagliptin and metformin compared with linagliptin monotherapy in patients with newly diagnosed type 2 diabetes and marked hyperglycaemia: a randomized, double-blind, active-controlled, parallel group, multinational clinical trial

AIMS

To evaluate glucose-lowering treatment strategies with linagliptin and metformin in people with newly diagnosed type 2 diabetes and marked hyperglycaemia, a prevalent population for which few dedicated studies of oral antidiabetes drugs have been conducted.

METHODS

A total of 316 patients, with type 2 diabetes diagnosed for ≤12 months and with glycated haemoglobin (HbA1c) concentration in the range 8.5-12.0%, were randomized 1:1 to double-blind, free-combination treatment with linagliptin 5 mg once daily and metformin twice daily (uptitrated to 2000 mg/day maximum) or to linagliptin monotherapy. The primary endpoint was change in HbA1c concentration from baseline at week 24 (per-protocol completers' cohort: n = 245).

RESULTS

The mean (standard deviation) age and HbA1c at baseline were 48.8 (11.0) years and 9.8 (1.1)%, respectively. At week 24, the mean ± standard error (s.e.) HbA1c decreased from baseline by -2.8 ± 0.1% with linagliptin/metformin and -2.0 ± 0.1% with linagliptin; a treatment difference of -0.8% (95% confidence interval -1.1 to -0.5; p <0.0001). Similar results were observed in a sensitivity analysis based on intent-to-treat principles: adjusted mean ± s.e. changes in HbA1c of -2.7 ± 0.1% and -1.8 ± 0.1%, respectively; treatment difference of -0.9% (95% CI -1.3 to -0.6; p <0.0001). A treatment response of HbA1c <7.0% was achieved by 61 and 40% of patients in the linagliptin/metformin and linagliptin groups, respectively. Few patients experienced drug-related adverse events (8.8 and 5.7% of patients in the linagliptin/metformin and linagliptin groups, respectively). Hypoglycaemia occurred in 1.9 and 3.2% of patients in the linagliptin/metformin and linagliptin groups, respectively (no severe episodes). Body weight decreased significantly with the combination therapy (-1.3 kg between-group difference; p =0.0033).

CONCLUSIONS

Linagliptin in initial combination with metformin in patients with newly diagnosed type 2 diabetes and marked hyperglycaemia, an understudied group, elicited significant improvements in glycaemic control with a low incidence of hypoglycaemia, weight gain or other adverse effects. These results support early combination treatment strategies and suggest that newly diagnosed patients with marked hyperglycaemia may be effectively managed with oral, non-insulin therapy.

Safety and efficacy of dulaglutide, a once weekly GLP-1 receptor agonist, for the management of type 2 diabetes

BACKGROUND

Type 2 diabetes (T2D) is an increasingly common endocrine disorder that is characterized by chronic hyperglycemia and tissue compartment abnormalities, including macrovascular and microvascular complications. More than 90% of patients with T2D will be diagnosed and treated in the primary care setting. One of the relatively recent additions to the increasing array of approved antidiabetic medications is the glucagon-like peptide-1 receptor agonist class. Mechanisms of action for glucagon-like peptide-1 receptor agonists include: 1) stimulation of insulin secretion through β-cells, though only when glucose levels are elevated (hence, minimizing risk for hypoglycemia); 2) blunting of glucagon secretion; 3) increased satiety; and 4) decreased rate of release of gastric contents into the small intestine, thereby reducing glycemic load. Recent T2D treatment guidelines encourage individualization of therapy. Many patients still do not achieve optimal glycemic control. Therefore, other treatment options are important.

METHODS

A literature search was performed using PubMed and MEDSCAPE to retrieve abstracts and articles pertinent to topics discussed in this review. Original research articles, reviews, and clinical trial manuscripts were identified based on relevance. Only English language articles were considered. Results In 3 phase 3 registration trials in patients with T2D, once-weekly dulaglutide demonstrated superior efficacy at the primary endpoint to metformin as monotherapy, to sitagliptin as add-on to metformin, and to exenatide twice daily as add-on to metformin and pioglitazone. The safety profile of dulaglutide in these trials is similar to currently available glucagon-like peptide-1 receptor agonists, characterized predominantly by gastrointestinal symptoms (ie, nausea, vomiting, and diarrhea). Based on these results, once-weekly dulaglutide should be a relevant additional treatment option for the management of T2D.

Metformin supports the antidiabetic effect of a sodium glucose cotransporter 2 inhibitor by suppressing endogenous glucose production in diabetic mice

Combined use of metformin and a sodium glucose cotransporter 2 inhibitor (SGLT2I) is a promising treatment strategy for type 2 diabetes. The mechanism by which combination treatment provides better glycemic control than metformin or SGLT2I monotherapy remains elusive. Therefore, we investigated the physiological mechanism by which both compounds lower blood glucose concentrations in diabetic mice. We compared the potential of metformin and the SGLT2I AVE2268 alone or in combination to mitigate hyperglycemia and modulate glucose fluxes in db/db and diabetic Tallyho/JngJ mice. SGLT2I treatment alone elicited a rapid decline in circulating blood glucose levels, which appeared to induce endogenous glucose production. Supplementation of metformin dampened this counterresponse, and therefore, combination therapy more efficiently maintained glycemic control. Finally, combination treatment blunted postprandial glucose excursions and improved HbA1c levels within 2 weeks. We conclude that coapplication of metformin enhances the glucose-lowering actions of SGLT2I by restraining endogenous glucose production, which may provide long-term improvement of glycemic control in type 2 diabetic patients.

Addressing unmet medical needs in type 2 diabetes: a narrative review of drugs under development

The global burden of type 2 diabetes is increasing worldwide, and successful treatment of this disease needs constant provision of new drugs. Twelve classes of antidiabetic drugs are currently available, and many new drugs are under clinical development. These include compounds with known mechanisms of action but unique properties, such as once-weekly DPP4 inhibitors or oral insulin. They also include drugs with new mechanisms of action, the focus of this review. Most of these compounds are in Phase 1 and 2, with only a small number having made it to Phase 3 at this time. The new drug classes described include PPAR agonists/modulators, glucokinase activators, glucagon receptor antagonists, anti-inflammatory compounds, G-protein coupled receptor agonists, gastrointestinal peptide agonists other than GLP-1, apical sodium-dependent bile acid transporter (ASBT) inhibitors, SGLT1 and dual SGLT1/SGLT2 inhibitors, and 11beta- HSD1 inhibitors.

We can change the natural history of type 2 diabetes

As diabetes develops, we currently waste the first ∼10 years of the natural history. If we found prediabetes and early diabetes when they first presented and treated them more effectively, we could prevent or delay the progression of hyperglycemia and the development of complications. Evidence for this comes from trials where lifestyle change and/or glucose-lowering medications decreased progression from prediabetes to diabetes. After withdrawal of these interventions, there was no "catch-up"-cumulative development of diabetes in the previously treated groups remained less than in control subjects. Moreover, achieving normal glucose levels even transiently during the trials was associated with a substantial reduction in subsequent development of diabetes. These findings indicate that we can change the natural history through routine screening to find prediabetes and early diabetes, combined with management aimed to keep glucose levels as close to normal as possible, without hypoglycemia. We should also test the hypothesis with a randomized controlled trial.

Importance of Beta Cell Function for the Treatment of Type 2 Diabetes

Type 2 diabetes (T2DM) is characterized by insulin resistance and beta cell dysfunction. Recent evidence has emerged that beta cell dysfunction is a common pathogenetic feature of both type 1 and type 2 diabetes, and T2DM never develops without beta cell dysfunction. Therefore, treatment of T2DM should aim to restore beta cell function. Although the treatment of T2DM has greatly improved over the past few decades, remaining issues in the current treatment of T2DM include (1) hypoglycemia; (2) body weight gain; (3) peripheral hyperinsulinemia and (4) postprandial hyperglycemia, which are all associated with inappropriate insulin supplementation, again underpinning the important role of endogenous and physiological insulin secretion in the management of T2DM. This review summarizes the current knowledge on beta cell function in T2DM and discusses the treatment strategy for T2DM in relation to beta cell dysfunction.

Pathophysiological and pharmacological rationale for the use of exenatide once weekly in patients with type 2 diabetes

INTRODUCTION

A new formulation of exenatide has become available recently that is the first antidiabetic medication for type 2 diabetes mellitus (T2DM) dosed on a weekly schedule. This review summarizes the pharmacology, efficacy, and safety of exenatide once weekly (exenatide QW). The results are interpreted in terms of the pathophysiology of T2DM, as well as the pharmacology of the new formulation.

METHODS

Relevant literature on exenatide QW and diabetes was identified through PubMed database searches from inception until September 2013.

DISCUSSION

In the new once-weekly formulation of exenatide, the exenatide molecule is dispersed in microspheres. Following subcutaneous injection, these microspheres degrade in situ and slowly release active agent. In clinical trials, therapy with exenatide QW as monotherapy or in combination with other antidiabetic treatments was associated with reductions in glycated hemoglobin (-1.3% to -1.9%), fasting plasma glucose (-32 to -41 mg/dL), and body weight (-2.0 to -3.7 kg). These outcomes were achieved without an associated increase in the rate of hypoglycemic episodes, except when exenatide QW was used in combination with sulfonylureas. The primary tolerability issues in the trials were gastrointestinal adverse events, particularly during the first weeks of use, although the rate of nausea during startup with exenatide QW was lower than that with the related agents, exenatide twice daily and liraglutide once daily.

CONCLUSIONS

Exenatide QW may be particularly well suited to patients who desire the benefits associated with glucagon-like peptide-1 receptor agonists, including significant glycemic control, low risk of hypoglycemia, and moderate weight loss, but prefer the convenience of once-weekly dosing.

Drug treatment of type 2 diabetes mellitus in patients for whom metformin is contraindicated

Metformin is considered an initial drug of choice for type 2 diabetes mellitus by leading recommendations. When contraindications to its use exist or patients cannot tolerate it due to adverse effects, clinicians have a variety of other classes of agents to treat hyperglycemia associated with type 2 diabetes mellitus. Each class of agent has its own benefit and safety profile. There are numerous factors to consider when selecting another agent in lieu of metformin including, but not limited to, overall efficacy in A1c reduction, adverse effect profile, cost, and patient preference. The number of factors influencing the decision process presents challenges and often no one specific agent is ideal. Each pharmacotherapeutic class of agents alternative to metformin for the treatment of hyperglycemia in type 2 diabetes mellitus as initial monotherapy is reviewed.

Exenatide extended-release: a once weekly treatment for patients with type 2 diabetes

BACKGROUND

This article reviews the clinical efficacy, safety, and patient outcomes literature on the first once weekly treatment for type 2 diabetes mellitus (T2DM), exenatide extended-release (ER).

METHODS

Relevant literature on exenatide ER and T2DM was identified through PubMed database searches from inception until April 2014.

RESULTS

Exenatide ER is the first medication for the treatment of T2DM dosed on a weekly schedule. Exenatide ER is a glucagon-like peptide-1 (GLP-1) receptor agonist, the third to be approved in the US, and is associated with a low risk of hypoglycemia, may result in weight loss, and has proven to be a safe and effective treatment for T2DM. Exenatide ER reduces A1c levels by decreasing fasting and postprandial hyperglycemia. The most common adverse events are gastrointestinal in nature, which are lesser in frequency than those observed with short-acting exenatide. Exenatide ER has been shown to be more effective than exenatide twice daily and slightly less efficacious than liraglutide. Exenatide ER is useful as monotherapy and in combination with other oral antidiabetic drugs.

CONCLUSION

Once weekly treatment options for diabetes such as exenatide ER have the potential to offer substantial convenience for patients who have high medication burden and poor medication adherence.

Impact of glycemic control on healthcare resource utilization and costs of type 2 diabetes: current and future pharmacologic approaches to improving outcomes

BACKGROUND

The incidence and prevalence of type 2 diabetes continue to grow in the United States and worldwide, along with the growing prevalence of obesity. Patients with type 2 diabetes are at greater risk for comorbid cardiovascular (CV) disease (CVD), which dramatically affects overall healthcare costs.

OBJECTIVES

To review the impact of glycemic control and medication adherence on morbidity, mortality, and healthcare costs of patients with type 2 diabetes, and to highlight the need for new drug therapies to improve outcomes in this patient population.

METHODS

This comprehensive literature search was conducted for the period between 2000 and 2013, using MEDLINE, to identify published articles that report the associations between glycemic control, medication adherence, CV morbidity and mortality, and healthcare utilization and costs. Search terms included "type 2 diabetes," "adherence," "compliance," "nonadherence," "drug therapy," "resource use," "cost," and "cost-effectiveness."

DISCUSSION

Despite improvements in the management of CV risk factors in patients with type 2 diabetes, outcomes remain poor. The costs associated with the management of type 2 diabetes are increasing dramatically as the prevalence of the disease increases. Medication adherence to long-term drug therapy remains poor in patients with type 2 diabetes and contributes to poor glycemic control in this patient population, increased healthcare resource utilization and increased costs, as well as increased rates of comorbid CVD and mortality. Furthermore, poor adherence to established evidence-based guidelines for type 2 diabetes, including underdiagnosis and undertreatment, contributes to poor outcomes. New approaches to the treatment of patients with type 2 diabetes currently in development have the potential to improve medication adherence and consequently glycemic control, which in turn will help to reduce associated costs and healthcare utilization.

CONCLUSIONS

As the prevalence of type 2 diabetes and its associated comorbidities grows, healthcare costs will continue to increase, indicating a need for better approaches to achieve glycemic control and manage comorbid conditions. Drug therapies are needed that enhance patient adherence and persistence levels far above levels reported with currently available drugs. Improvements in adherence to treatment guidelines and greater rates of lifestyle modifications also are needed. A serious unmet need exists for greatly improved patient outcomes, more effective and more tolerable drugs, as well as marked improvements in adherence to treatment guidelines and drug therapy to positively impact healthcare costs and resource use.