Meglitinide analogues for type 2 diabetes mellitus

Parallel artificial liquid membrane extraction coupled with UPLC-ESI-MS/MS method for high-throughput quantitation of repaglinide in diabetic patients

A high-throughput therapeutic monitoring method was developed for repaglinide (RPG) in diabetic patients, combining parallel artificial liquid membrane extraction (PALME) with ultraperformance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). PALME was performed using a 96-well donor plate comprising a donor solution containing a plasma sample, 50 mM phosphate buffer (pH = 8.0), and cetirizine (CTZ) as internal standard. A polypropylene (PP) porous membrane served as a selective support for the liquid membrane (SLM), preventing nonspecific binding produced by other membranes. The extraction was accomplished across SLM made of PP membrane with dodecyl acetate and 1 % trioctylamine (w/w), and the acceptor solution comprised DMSO and 200 mM formic acid (50:50, v/v). The simple workflow for PALME provided analyte enrichment, highly efficient sample cleanup, high throughput analysis, and excellent reproducibility. Method validation met FDA criteria, with a linear plasma calibration range (0.1-100 ng mL-1, r = 0.9995) and a lower limit of quantitation (LLOQ) of 0.1 ng mL-1. Recovery results at 98.9 % affirmed method reliability. The ability to analyze 198 samples per hour, coupled with a reduced amount of solvents, underscores the method's high throughput and eco-friendly profile. The PALME-UPLC-ESI-MS/MS method was successfully applied to therapeutic drug monitoring of RPG in diabetic patients following 2 mg RPG tablet administration, establishing its effectiveness.

Metformin HCl-loaded transethosomal gel; development, characterization, and antidiabetic potential evaluation in the diabetes-induced rat model

Herein we designed, optimized, and characterized the Metformin Hydrochloride Transethosomes (MTF-TES) and incorporate them into Chitosan gel to develop Metformin Hydrochloride loaded Transethosomal gel (MTF-TES gel) that provides a sustained release, improved transdermal flux and improved antidiabetic response of MTF. Design Expert® software (Ver. 12, Stat-Ease, USA) was applied for the statistical optimization of MTF-TES. The formulation with Mean Particle Size Distribution (MPSD) of 165.4 ± 2.3 nm, Zeta Potential (ZP) of -21.2 ± 1.9 mV, Polydispersity Index (PDI) of 0.169 ± 0.033, and MTF percent Entrapment Efficiency (%EE) of 89.76 ± 4.12 was considered to be optimized. To check the chemical incompatibility among the MTF and other formulation components, Fourier Transform Infrared (FTIR) spectroscopy was performed and demonstrated with no chemical interaction. Surface morphology, uniformity, and segregation were evaluated through Transmission Electron Microscopy (TEM). It was revealed that the nanoparticles were spherical and round in form with intact borders. The fabricated MTF-TES has shown sustained release followed by a more pronounced effect in MTF-TES gel as compared to the plain MTF solution (MTFS) at a pH of 7.4. The MTF-TES has shown enhanced permeation followed by MTF-TES gel as compared to the MTFS at a pH of 7.4. In vivo antidiabetic assay was performed and results have shown improved antidiabetic potential of the MTF-TES gel, in contrast to MTF-gel. Conclusively, MTF-TES is a promising anti-diabetic candidate for transdermal drug delivery that can provide sustained MTF release and enhanced antidiabetic effect.

Therapeutic Potential of Quercetin in the Management of Type-2 Diabetes Mellitus

Diabetes Mellitus (DM) is a metabolic disorder that is spreading alarmingly around the globe. Type-2 DM (T2DM) is characterized by low-grade inflammation and insulin resistance and is closely linked to obesity. T2DM is mainly controlled by lifestyle/dietary changes and oral antidiabetic drugs but requires insulin in severe cases. Many of the drugs that are currently used to treat DM are costly and present adverse side effects. Several cellular, animal, and clinical studies have provided compelling evidence that flavonoids have therapeutic potential in the management of diabetes and its complications. Quercetin is a flavonoid, present in various natural sources, which has demonstrated in vitro and in vivo antidiabetic properties. It improves oral glucose tolerance, as well as pancreatic β-cell function to secrete insulin. It inhibits the α-glucosidase and DPP-IV enzymes, which prolong the half-life of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Quercetin also suppresses the release of pro-inflammatory markers such as IL-1β, IL-4, IL-6, and TNF-α. Further studies are warranted to elucidate the mode(s) of action of quercetin at the molecular level. This review demonstrates the therapeutic potential of quercetin in the management of T2DM.

Diabetes and Its Complications: Therapies Available, Anticipated and Aspired

Worldwide, diabetes ranks among the ten leading causes of mortality. Prevalence of diabetes is growing rapidly in low and middle income countries. It is a progressive disease leading to serious co-morbidities, which results in increased cost of treatment and over-all health system of the country. Pathophysiological alterations in Type 2 Diabetes (T2D) progressed from a simple disturbance in the functioning of the pancreas to triumvirate to ominous octet to egregious eleven to dirty dozen model. Due to complex interplay of multiple hormones in T2D, there may be multifaceted approach in its management. The 'long-term secondary complications' in uncontrolled diabetes may affect almost every organ of the body, and finally may lead to multi-organ dysfunction. Available therapies are inconsistent in maintaining long term glycemic control and their long term use may be associated with adverse effects. There is need for newer drugs, not only for glycemic control but also for prevention or mitigation of secondary microvascular and macrovascular complications. Increased knowledge of the pathophysiology of diabetes has contributed to the development of novel treatments. Several new agents like Glucagon Like Peptide - 1 (GLP-1) agonists, Dipeptidyl Peptidase IV (DPP-4) inhibitors, amylin analogues, Sodium-Glucose transport -2 (SGLT- 2) inhibitors and dual Peroxisome Proliferator-Activated Receptor (PPAR) agonists are available or will be available soon, thus extending the range of therapy for T2D, thereby preventing its long term complications. The article discusses the pathophysiology of diabetes along with its comorbidities, with a focus on existing and novel upcoming antidiabetic drugs which are under investigation. It also dives deep to deliberate upon the novel therapies that are in various stages of development. Adding new options with new mechanisms of action to the treatment armamentarium of diabetes may eventually help improve outcomes and reduce its economic burden.

SCORE-IT (Selecting Core Outcomes for Randomised Effectiveness trials In Type 2 diabetes): a systematic review of registered trials

Background

Outcomes measured in clinical trials should be meaningful to patients, healthcare professionals and researchers, yet there is heterogeneity in the outcomes used across trials. This inconsistency impacts on the ability to compare findings and may mean that the results have little importance to healthcare professionals and the patients that they care for. The aim of the present study is to review the outcomes used in registered trials of therapies for type 2 diabetes mellitus as the first step in the development of a core outcome set for effectiveness trials in type 2 diabetes.

Methods

A systematic review of clinicaltrials.gov entries was completed for randomised, open (actively recruiting or in follow-up period), phase 3 and 4 trials of type 2 diabetes mellitus in adults. Trials of the treatment of diabetes complications, co-morbidities, prevention and surgery were excluded. Each trial was screened for eligibility and outcomes extracted from the primary and secondary outcomes data fields and free text study information. The outcomes were recorded verbatim and classified into core outcome domains according to the COMET taxonomy.

Results

A total of 354 trial registrations were reviewed for eligibility and 138 trials included. In total, 1444 outcomes were extracted with a median of eight outcomes per trial (range = 1–60). Outcomes were categorised into 30 different outcome domains according to the COMET taxonomy, but no single domain or outcome was measured in 100% of trials. The majority of trials (88%) included outcomes in the ‘metabolism and nutrition’ domain, such as lipids and lipoproteins (21%), HbA1c (18%), hypoglycaemia (14%), fasting plasma/blood glucose (11%), glycaemic variability (8%), postprandial response (8%) and insulin sensitivity (5%). Only 10% of trials included one or more patient reported outcomes; of these, 29% included the Diabetes Treatment Satisfaction Questionnaire.

Conclusions

There is marked heterogeneity in the outcomes measured in registered therapeutic intervention trials for type 2 diabetes. The use of an agreed set of core outcomes will improve the consistency of reporting in clinical trials for type 2 diabetes.

Trial registration

The core outcome set study, of which this is a part, is registered in the COMET database, http://www.comet-initiative.org/studies/details/956. Registered on 24 January 2017.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2317-5) contains supplementary material, which is available to authorized users.

Monotherapy in patients with type 2 diabetes mellitus

In order to improve the quality of life and to prevent chronic complications related to diabetes mellitus, intensive lifestyle modification and proper medication are needed from the early stage of diagnosis of type 2 diabetes mellitus (T2DM). When using the first medication for diabetic patients, the appropriate treatment should be selected considering the clinical characteristics of the patient, efficacy of the drug, side effects, and cost. In general, the use of metformin as the first treatment for oral hypoglycemic monotherapy is recommended because of its excellent blood glucose-lowering effect, relatively low side effects, long-term proven safety, low risk of hypoglycemia, and low weight gain. If metformin is difficult to use as a first-line treatment, other appropriate medications should be selected in view of the clinical situation. If the goal of achieving glycemic control is not achieved by monotherapy, a combination therapy with different mechanisms of action should be initiated promptly.

Monotherapy in Patients with Type 2 Diabetes Mellitus

In order to improve the quality of life and to prevent chronic complications related to diabetes mellitus, intensive lifestyle modification and proper medication are needed from the early stage of diagnosis of type 2 diabetes mellitus (T2DM). When using the first medication for diabetic patients, the appropriate treatment should be selected considering the clinical characteristics of the patient, efficacy of the drug, side effects, and cost. In general, the use of metformin as the first treatment for oral hypoglycemic monotherapy is recommended because of its excellent blood glucose-lowering effect, relatively low side effects, long-term proven safety, low risk of hypoglycemia, and low weight gain. If metformin is difficult to use as a first-line treatment, other appropriate medications should be selected in view of the clinical situation. If the goal of achieving glycemic control is not achieved by monotherapy, a combination therapy with different mechanisms of action should be initiated promptly.

Meglitinides increase the risk of hypoglycemia in diabetic patients with advanced chronic kidney disease: a nationwide, population-based study

The safety of short-acting meglitinides in diabetic patients with advanced chronic kidney disease (CKD) has not been widely reported. Diabetic patients with advanced CKD who had a serum creatinine level of > 6 mg/dL a hematocrit level of ≦ 28% and received erythropoiesis-stimulating agent treatment between 2000 and 2010, were included in this nationwide study in Taiwan. The outcomes of interest were defined as hypoglycemia and long-term mortality. The risks of hypoglycemia and death were analyzed using Cox proportional hazards models, with end-stage renal disease and anti-diabetic drugs as time-dependent variables. Fresh users and matched non-users of meglitinides (both n = 2,793) were analyzed. The use of meglitinides increased the risk of hypoglycemia (HR, 1.94, p<0.001), as did other anti-diabetic agents. Concomitant use of meglitinide and insuilin will incresase the hypoglycemic risk. (HR, 1.69, p=0.018) Moreover, it was not the use of meglitinides, but the presence of hypoglycemia that predicted mortality. The function curve showed an insignificant trend towards increased hypoglycemic risk in patients aged > 62 and ≤ 33 years from the generalized additive model. This study suggests that the use of short-acting meglitinides could be associated with increased risk of hypoglycemia in diabetic patients with advanced CKD, especially in patients aged > 62 and ≤ 33 years. Meglitinide combined with insulin will increase hypoglycemia in patients with advanced CKD.

Cardiovascular safety of non-insulin pharmacotherapy for type 2 diabetes

Patients with type 2 diabetes mellitus have a twofold increased risk of cardiovascular mortality compared with non-diabetic individuals. There is a growing awareness that glycemic efficacy of anti-diabetic drugs does not necessarily translate to cardiovascular safety. Over the past few years, there has been a number of trials evaluating the cardiovascular effects of anti-diabetic drugs. In this review, we seek to examine the cardiovascular safety of these agents in major published trials. Metformin has with-stood the test of time and remains the initial drug of choice. The sulfonylureas, despite being the oldest oral anti-diabetic drug, has been linked to adverse cardiovascular events and are gradually being out-classed by the various other second-line agents. The glitazones are contraindicated in heart failure. The incretin-based drugs have been at the fore-front of this era of cardiovascular safety trials and their performances have been reassuring, whereas the meglitinides and the alpha-glucosidase inhibitors still lack cardiovascular outcomes data. The sodium glucose cotransporter-2 inhibitors are an exciting new addition that has demonstrated a potential for cardiovascular benefit. Many of the currently available oral anti-diabetic agents have clinically relevant cardiovascular effects. The optimal approach to the reduction of cardiovascular risk in diabetic patients should focus on aggressive management of the standard cardiovascular risk factors rather than purely on intensive glycemic control.

Patients With Type 2 Diabetes: Anesthetic Management in the Ambulatory Setting: Part 2: Pharmacology and Guidelines for Perioperative Management

Type 2 diabetes is a disease of metabolism in which the afflicted patient cannot properly utilize carbohydrates, fats, and proteins. Because the prevalence of type 2 diabetes is rapidly increasing throughout the general population, anesthesia providers must realize that a significant percentage of their patients will present with the disease. Anesthesia providers should have an intimate knowledge of the comorbidities and complications that are associated with type 2 diabetes and know the specific pharmacokinetics and pharmacodynamics of the drugs used to treat the disease. Part 1 of this series on the anesthetic management of type 2 diabetes in the ambulatory theater addressed the pathology of diabetes and its comorbid disease states. Part 2 of the series now focuses on the pharmacology associated with the many medications used to treat the disorder and the most recent guidelines for blood glucose management recommended for patients in an ambulatory surgery setting.

Insulin secretagogues for prevention or delay of type 2 diabetes mellitus and its associated complications in persons at increased risk for the development of type 2 diabetes mellitus

BACKGROUND

The projected rise in the incidence of type 2 diabetes mellitus (T2DM) could develop into a substantial health problem worldwide. Whether insulin secretagogues (sulphonylureas and meglitinide analogues) are able to prevent or delay T2DM and its associated complications in people at risk for the development of T2DM is unknown.

OBJECTIVES

To assess the effects of insulin secretagogues on the prevention or delay of T2DM and its associated complications in people with impaired glucose tolerance, impaired fasting blood glucose, moderately elevated glycosylated haemoglobin A1c (HbA1c) or any combination of these.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform, and the reference lists of systematic reviews, articles and health technology assessment reports. We asked investigators of the included trials for information about additional trials. The date of the last search of all databases was April 2016.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with a duration of 12 weeks or more comparing insulin secretagogues with any pharmacological glucose-lowering intervention, behaviour-changing intervention, placebo or no intervention in people with impaired fasting glucose, impaired glucose tolerance, moderately elevated HbA1c or combinations of these.

DATA COLLECTION AND ANALYSIS

Two review authors read all abstracts and full-text articles/records, assessed quality and extracted outcome data independently. One review author extracted data which were checked by a second review author. We resolved discrepancies by consensus or the involvement of a third review author. For meta-analyses we used a random-effects model with investigation of risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, using 95% confidence intervals (CIs) for effect estimates. We carried out trial sequential analyses (TSAs) for all outcomes that could be meta-analysed. We assessed the overall quality of the evidence by using the GRADE instrument.

MAIN RESULTS

We included six RCTs with 10,018 participants; 4791 participants with data on allocation to intervention groups were randomised to a second- or third-generation sulphonylurea or a meglitinide analogue as monotherapy and 29 participants were randomised to a second-generation sulphonylurea plus metformin. Three trials investigated a second-generation sulphonylurea, two trials investigated a third-generation sulphonylurea and one trial a meglitinide analogue. A total of 4873 participants with data on allocation to control groups were randomised to a comparator group; 4820 participants were randomised to placebo, 23 to diet and exercise, and 30 participants to metformin monotherapy. One RCT of nateglinide contributed 95% of all participants. The duration of the intervention varied from six months to five years. We judged none of the included trials as at low risk of bias for all 'Risk of bias' domains.All-cause and cardiovascular mortality following sulphonylurea (glimepiride) treatment were rarely observed (very low-quality evidence). The RR for incidence of T2DM comparing glimepiride monotherapy with placebo was 0.75; 95% CI 0.54 to 1.04; P = 0.08; 2 trials; 307 participants; very low-quality evidence. One of the trials reporting on the incidence of T2DM did not define the diagnostic criteria used. The other trial diagnosed T2DM as two consecutive fasting blood glucose values ≥ 6.1 mmol/L. TSA showed that only 4.5% of the diversity-adjusted required information size was accrued so far. No trial reported data on serious adverse events, non-fatal myocardial infarction (MI), non-fatal stroke, congestive heart failure (HF), health-related quality of life or socioeconomic effects.One trial with a follow-up of five years compared a meglitinide analogue (nateglinide) with placebo. A total of 310/4645 (6.7%) participants allocated to nateglinide died compared with 312/4661 (6.7%) participants allocated to placebo (hazard ratio (HR) 1.00; 95% CI 0.85 to 1.17; P = 0.98; moderate-quality evidence). The two main criteria for diagnosing T2DM were a fasting plasma glucose level ≥ 7.0 mmol/L or a 2-hour post challenge glucose ≥ 11.1 mmol/L. T2DM developed in 1674/4645 (36.0%) participants in the nateglinide group and in 1580/4661 (33.9%) in the placebo group (HR 1.07; 95% CI 1.00 to 1.15; P = 0.05; moderate-quality evidence). One or more serious adverse event was reported in 2066/4602 (44.9%) participants allocated to nateglinide compared with 2089/4599 (45.6%) participants allocated to placebo. A total of 126/4645 (2.7%) participants allocated to nateglinide died because of cardiovascular disease compared with 118/4661 (2.5%) participants allocated to placebo (HR 1.07; 95% CI 0.83 to 1.38; P = 0.60; moderate-quality evidence). Comparing participants receiving nateglinide with those receiving placebo for the outcomes MI, non-fatal stroke and HF gave the following event rates: MI 116/4645 (2.5%) versus 122/4661 (2.6%), stroke 100/4645 (2.2%) versus 110/4661 (2.4%) and numbers hospitalised for HF 85/4645 (1.8%) versus 100/4661 (2.1%) - (HR 0.85; 95% CI 0.64 to 1.14; P = 0.27). The quality of the evidence was moderate for all these outcomes. Health-related quality of life or socioeconomic effects were not reported.

AUTHORS' CONCLUSIONS

There is insufficient evidence to demonstrate whether insulin secretagogues compared mainly with placebo reduce the risk of developing T2DM and its associated complications in people at increased risk for the development of T2DM. Most trials did not investigate patient-important outcomes.

Increased Serum Insulin Exposure Does Not Affect Age or Stage of Pancreatic Adenocarcinoma Diagnosis in Patients With Diabetes Mellitus

OBJECTIVES

In considering whether medications that increase insulin levels accelerate pancreatic adenocarcinoma (PC) development, we hypothesized that PC patients with diabetes mellitus (DM) who used exogenous insulin or insulin-stimulating medications should have an earlier age at diagnosis or present with more advanced disease.

METHODS

Patients enrolled in our PC registry from June 1, 2003, to May 31, 2012, were stratified according to treatment solely with insulin, insulin-stimulating medications, or insulin-independent medications. Age at PC diagnosis, PC stage, and years between DM and PC diagnoses were analyzed among the cohorts.

RESULTS

Of 122 DM patients (mean age, 67.4 ± 10.2 years), the mean ages at PC diagnosis within the insulin-only (n = 40), insulin-stimulating (n = 11), insulin-independent (n = 71), and non-DM (n = 321) cohorts were 68.7 ± 10.5, 69.6 ± 10.8, 66.3 ± 9.7, and 65.5 ± 10.5 years, respectively. No significant difference among the age at PC diagnosis was observed based on duration or type of DM treatment. There was no correlation between PC stage and increased insulin exposure.

CONCLUSIONS

Anti-DM medications that increase exposure to insulin do not appear to accelerate PC development using outcomes of mean age at PC diagnosis, PC stage, or duration between DM and PC diagnoses.

Drug-related risk of severe hypoglycaemia in observational studies: a systematic review and meta-analysis

BACKGROUND

Diabetes mellitus (DM) leads to multiple complications, including severe hypoglycaemia events (SHEs). SHEs can impact a patient's quality of life and compliance and may directly result in additional costs to the health care system. The aim of this review was to evaluate the risk of severe hypoglycaemia in patients with type 1 (T1) and 2 (T2) DM as observed in everyday clinical practice for various drug regimens.

METHODS

We conducted a systematic review of observational (retrospective or prospective) studies in the MEDLINE, Embase, and Cochrane Library databases that covered at least 100 children or adults with T1/T2 DM. In T1 DM, basal-bolus/pre-mix insulin (human or analogue) and insulin pump were reviewed, and in T2 DM, basal-bolus/pre-mix insulin (human or analogue), oral antidiabetic drugs supported with basal insulin (human or analogue), sulfonylureas in monotherapy, and combined oral treatment were reviewed. In order to estimate SHE rates, we extracted data on the time horizon of the study, number of patients, number of SHEs, and number of patients experiencing at least one SHE. We used a random effects model to estimate the annual SHE rate. We considered the risk for other antidiabetic medications in T2 DM to be negligible and the results of our main review yielded no observational data for premixes in T1 DM so they were assessed based on relative rates taken from additional systematic reviews. The study, being a desk research, did not involve any human subjects (including human material or human data) and no ethical committee approval was asked for. For the same reason there was no need to collect informed consent for participation in the study.

RESULTS

We identified 76 observational studies encompassing 707,722.30 patient-years. The estimated annual SHE rate varied from 0.168 (95 % CI 0.123-0.237) for insulin pump up to 1.628 for biphasic human insulin in T1 DM patients, and from 0.0035 for oral antidiabetic drugs up to 0.554 (95 % CI 0.157-7.534) for basal-bolus with human insulin in T2 DM patients.

CONCLUSIONS

Our review indicates that SHE rates differ between patients depending on treatment regimen. However, SHEs are also driven by other factors. Proper modelling techniques are needed to use various types of information in published studies.

WITHDRAWN: Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

The Cochrane Metabolic and Endocrine Disorders Group withdrew this review as of Issue 7, 2015 because of the involvement of one author (SS Lund) being employed in a pharmaceutical company. The authors of the review and the Cochrane Metabolic and Endocrine Disorders Group did not find that this was a breach of the rules of the Cochrane Collaboration at the time when it was published. However, after the publication of the review, the Cochrane Collaboration requested withdrawal of the review due to the employment of the author. A new protocol for a review to cover this topic will be published. This will have a new title and a markedly improved protocol fulfilling new and important developments and standards within the Cochrane Collaboration as well as an improved inclusion and search strategy making it necessary to embark on a completely new review project.

The editorial group responsible for this previously published document have withdrawn it from publication.

Glucose Control and Cardiovascular Outcomes in Clinical Trials of Sodium Glucose Co-transporter 2 Inhibitor Treatments in Type 2 Diabetes

Currently available medications for the treatment of type 2 diabetes have limitations, and many patients do not achieve glycaemic control. Recently, a new approach has emerged using sodium glucose co-transporter 2 (SGLT2) inhibitors that decrease glucose reabsorption in the kidneys, increasing urinary glucose excretion. These agents offer the potential to improve glycaemic control independently of insulin pathways while avoiding hypoglycaemia. Two drugs of this class, canagliflozin and dapagliflozin, have been approved by the US Food and Drug Administration (FDA); another, empagliflozin, has been filed for regulatory approval and several others are in advanced development. These drugs have been shown to effectively reduce blood glucose, fasting plasma glucose and glycated haemoglobin (HbA_1C) levels in phase III clinical trials when used as monotherapy and as add-on therapy to other diabetes medications, including insulin. Another advantage of the SGLT2 inhibitors over existing treatments is the improvement in cardiovascular risk factors, particularly in terms of reductions in blood pressure and body weight. SGLT2 inhibitors have been generally well tolerated. While more long-term safety data are required to elucidate the benefit-risk profile of SGLT2 inhibitors, the rationale for their use in type 2 diabetes therapy is strong.

Seasonal variations in glycemic control of type 2 diabetes in Korean women

BACKGROUND AND AIMS

Seasonal variations in lifestyle, such as food intake and physical activity, have been reported. Glycemic control in type 2 diabetes mellitus (T2DM) may be affected by such changes. We investigated seasonal variations in glycemic control, food intake, and physical activity in type 2 diabetic patients.

METHODS

This prospective observational study included 37 Korean female patients who had <8.0 % hemoglobin A1c (HbA1c) and managed diabetes by oral anti-diabetic drugs or lifestyle modification only. Participants underwent four or five assessments, including total physical activity (household, leisure-time, and occupational activity) (metabolic equivalent of test-h/day), food intake (kcal/day), HbA1c, and anthropometry every 3 months (August, November, February, May, and August in the Northern Hemisphere) over 1 year. When anti-diabetic drugs were changed, we analyzed the data just before the changes.

RESULTS

The mean HbA1c levels (%) of August and November in 2008, and February, May, and August in 2009 were 7.0 ± 0.1, 6.9 ± 0.1, 7.2 ± 0.2, 7.4 ± 0.2, and 7.2 ± 0.2, respectively (P = 0.018). The change of HbA1c was nearly 0.5 % for the 1-year period. From August to May of the following year, there were also seasonal variations in food intake (1,872 ± 143, 1,739 ± 97, 1,673 ± 86, 1,561 ± 132, respectively; P = 0.013), and total physical activity [7.7 (3.7-14.6), 6.3 (2.8-10.4), 5.1 (2.7-12.6), and 11.2 (4.7-20.5), respectively; P = 0.048]. However, the seasonal variations of HbA1c and total physical activity became non-significant when farmers were excluded.

CONCLUSIONS

These data suggested that glycemic control, total physical activity, and food intake varied seasonally in Korean T2DM patients. These seasonal variations should be considered in education for glycemic control.

Complications of diabetes therapy

Current strategies for the treatment of type 2 diabetes mellitus promote individualized plans to achieve target glucose levels on a patient-by-patient basis while minimizing treatment related risks. Maintaining glycemic control over time is a significant challenge because of the progressive nature of diabetes as a result of declining β-cell function. This article identifies complications of non-insulin treatments for diabetes. The major classes of medications are reviewed with special focus on target population, mechanism of action, effect on weight, cardiovascular outcomes and additional class-specific side effects including effects on bone. Effects on β-cell function are also highlighted.

Management of diabetic complications: a chemical constituents based approach

ETHNOPHARMACOLOGICAL RELEVANCE

Long term hyperglycemia leads to development of complications associated with diabetes. Diabetic complications are now a global health problem without effective therapeutic approach. Hyperglycemia and oxidative stress are important components for the development of diabetic complications. Over the past few decades, herbal medicines have attracted much attention as potential therapeutic agents in the prevention and treatment of diabetic complications due to their multiple targets and less toxic side effects. This review aims to assess the current available knowledge of medicinal herbs for attenuation and management of diabetic complications and their underlying mechanisms.

MATERIAL AND METHODS

Bibliographic investigation was carried out by scrutinizing classical text books and peer reviewed papers, consulting worldwide accepted scientific databases (SCOPUS, PUBMED, SCIELO, NISCAIR, Google Scholar) to retrieve available published literature. The inclusion criteria for the selection of plants were based upon all medicinal herbs and their active compounds with attributed potentials in relieving diabetic complications. Moreover, plants which have potential effect in ameliorating oxidative stress in diabetic animals have been included.

RESULTS

Overall, 238 articles were reviewed for plant literature and out of the reviewed literature, 127 articles were selected for the study. Various medicinal plants/plant extracts containing flavonoids, alkaloids, phenolic compounds, terpenoids, saponins and phytosterol type chemical constituents were found to be effective in the management of diabetic complications. This effect might be attributed to amelioration of persistent hyperglycemia, oxidative stress and modulation of various metabolic pathways involved in the pathogenesis of diabetic complications.

CONCLUSION

Screening chemical candidate from herbal medicine might be a promising approach for new drug discovery to treat the diabetic complications. There is still a dire need to explore the mechanism of action of various plant extracts and their toxicity profile and to determine their role in therapy of diabetic complications. Moreover, a perfect rodent model which completely mimics human diabetic complications should be developed.

Effect of a high-fat diet on glucose/lipid metabolism and GLP-1 secretion in rats with type 2 diabetes after gastric bypass surgery

AIM: To assess the effect of a high-fat diet on glucose/lipid metabolism and glucagon-like peptide-1 (GLP-1) secretion in rats with type 2 diabetes after gastric bypass surgery.

METHODS: Twenty-four SD rats were used to induce type 2 diabetes and then randomly divided into either a control group ( n = 10) or a high-fat diet group ( n = 10). After gastric bypass surgery, the control group and high-fat diet group were fed a normal diet and a high-fat diet for 8 wk, respectively. Food intake, body weight, fasting plasma glucose and the levels of GLP-1 were measured.

RESULTS: The body weight and average food intake first decreased and then gradually increased in both groups. At week 10 after surgery, there was a significant difference in body weight between the control group and high fat diet group (302.4 g ± 34.1 g vs 334.2 g ± 47.5 g, P < 0.05). Fasting plasma glucose gradually decreased after surgery in both groups; however, fasting plasma glucose began to increase with the prolongation of time in the high-fat diet group. At week 8, fasting plasma glucose was higher in the high-fat diet group than in the control group. At week 4 after surgery, insulin level increased and insulin resistance index decreased in both groups. The level of GLP-1 at week 10 after surgery significantly increased in the high-fat diet group compared to the control group (39.33 pmol/L ± 2.77 pmol/L vs 22.69 pmol/L ± 3.87 pmol/L, P < 0.05).

CONCLUSION: Gastric bypass reduces blood glucose in rats with type 2 diabetes. A serious disturbance of carbohydrate metabolism stimulated by a high fat diet was not observed in rats after gastric bypass, and the underlying mechanism may be related to increased secretion of GLP-1.

Risk vs benefit in diabetes pharmacotherapy: a rational approach to choosing pharmacotherapy in type 2 diabetes

Type 2 diabetes now affects more than 1 in 10 US adults and is a leading cause of morbidity, mortality, and healthcare expense. There are increasing numbers of available pharmacotherapies, with established agents as well as newer drugs developed from hormones in the incretin pathway, among others. New data are accumulating continuously with respect to potential benefits of both long-standing and new agents, as well as risks identified through post-marketing surveillance. Here we review the commonly prescribed pharmacotherapy options with attention to recently published information and provide a rational approach to choice of therapy.

Pharmacokinetics of a fixed-dose combination of mitiglinide and metformin versus concurrent administration of individual formulations in healthy subjects: a randomized, open-label, two-treatment, two-period, two-sequence, single-dose, crossover study

BACKGROUND

In the treatment of diabetes mellitus, combined drugs with different mechanisms of action can be effective when adequate glycaemic control is difficult with monotherapy. A fixed-dose combination (FDC) tablet of mitiglinide and metformin has been developed as a second-line treatment for type 2 diabetes.

OBJECTIVES

The objective of this study was to compare the pharmacokinetics and safety of a FDC and a free combination of mitiglinide and metformin in healthy male subjects.

METHODS

A randomized, open-label, two-period, two-treatment, single-dose, crossover study was conducted in 24 healthy Korean male subjects. In one period, a FDC tablet of mitiglinide and metformin (10 mg/500 mg) was administered, and in the other period, corresponding doses of individual formulations were administered.

RESULTS

Twenty-four subjects were enrolled and 19 subjects completed the study. The geometric mean ratios (90 % confidence interval) of the maximum plasma concentration (C(max)) and area under the plasma concentration-time curve from time zero to the time of the last measurable concentration (AUC(last)) were 0.9694 (0.8120, 1.1573) and 0.8951 (0.8440, 0.9494) for mitiglinide, and 1.0235 (0.9373, 1.1057) and 1.0542 (0.9697, 1.1460) for metformin, which were within the bioequivalence range. Among the 23 subjects who received study drugs, 15 subjects experienced 34 adverse events (AEs). The most frequently reported AEs were feeling hot and compensatory sweating. There were no serious AEs and no significant differences in the incidence of AEs between the two treatments.

CONCLUSION

A FDC tablet of mitiglinide and metformin was generally well tolerated in healthy male subjects. Administration of a FDC tablet and concomitant administration of individual formulations did not show significantly different pharmacokinetic profiles.

Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a growing health problem worldwide. Whether sulphonylureas show better, equal or worse therapeutic effects in comparison with other antidiabetic interventions for patients with T2DM remains controversial.

OBJECTIVES

To assess the effects of sulphonylurea monotherapy versus placebo, no intervention or other antidiabetic interventions for patients with T2DM.

SEARCH METHODS

We searched publications in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, LILACS and CINAHL (all until August 2011) to obtain trials fulfilling the inclusion criteria for our review.

SELECTION CRITERIA

We included clinical trials that randomised patients 18 years old or more with T2DM to sulphonylurea monotherapy with a duration of 24 weeks or more.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias. The primary outcomes were all-cause and cardiovascular mortality. Secondary outcomes were other patient-important outcomes and metabolic variables. Where possible, we used risk ratios (RR) with 95% confidence intervals (95% CI) to analyse the treatment effect of dichotomous outcomes. We used mean differences with 95% CI to analyse the treatment effect of continuous outcomes. We evaluated the risk of bias. We conducted trial sequential analyses to assess whether firm evidence could be established for a 10% relative risk reduction (RRR) between intervention groups.

MAIN RESULTS

We included 72 randomised controlled trials (RCTs) with 22,589 participants; 9707 participants randomised to sulphonylureas versus 12,805 participants randomised to control interventions. The duration of the interventions varied from 24 weeks to 10.7 years. We judged none of the included trials as low risk of bias for all bias domains. Patient-important outcomes were seldom reported.First-generation sulphonylureas (FGS) versus placebo or insulin did not show statistical significance for all-cause mortality (versus placebo: RR 1.46, 95% CI 0.87 to 2.45; P = 0.15; 2 trials; 553 participants; high risk of bias (HRB); versus insulin: RR 1.18, 95% CI 0.88 to 1.59; P = 0.26; 2 trials; 1944 participants; HRB). FGS versus placebo showed statistical significance for cardiovascular mortality in favour of placebo (RR 2.63, 95% CI 1.32 to 5.22; P = 0.006; 2 trials; 553 participants; HRB). FGS versus insulin did not show statistical significance for cardiovascular mortality (RR 1.36, 95% CI 0.68 to 2.71; P = 0.39; 2 trials; 1944 participants; HRB). FGS versus alpha-glucosidase inhibitors showed statistical significance in favour of FGS for adverse events (RR 0.63, 95% CI 0.52 to 0.76; P = 0.01; 2 trials; 246 participants; HRB) and for drop-outs due to adverse events (RR 0.28, 95% CI 0.12 to 0.67; P = 0.004; 2 trials; 246 participants; HRB).Second-generation sulphonylureas (SGS) versus metformin (RR 0.98, 95% CI 0.61 to 1.58; P = 0.68; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 0.92, 95% CI 0.60 to 1.41; P = 0.70; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.79 to 1.18; P = 0.72; 4 trials; 1642 participants; HRB), meglitinides (RR 1.44, 95% CI 0.47 to 4.42; P = 0.52; 7 trials; 2038 participants; HRB), or incretin-based interventions (RR 1.39, 95% CI 0.52 to 3.68; P = 0.51; 2 trials; 1503 participants; HRB) showed no statistically significant effects regarding all-cause mortality in a random-effects model. SGS versus metformin (RR 1.47; 95% CI 0.54 to 4.01; P = 0.45; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 1.30, 95% CI 0.55 to 3.07; P = 0.55; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.73 to 1.28; P = 0.80; 4 trials; 1642 participants; HRB) or meglitinide (RR 0.97, 95% CI 0.27 to 3.53; P = 0.97; 7 trials, 2038 participants, HRB) showed no statistically significant effects regarding cardiovascular mortality. Mortality data for the SGS versus placebo were sparse. SGS versus thiazolidinediones and meglitinides did not show statistically significant differences for a composite of non-fatal macrovascular outcomes. SGS versus metformin showed statistical significance in favour of SGS for a composite of non-fatal macrovascular outcomes (RR 0.67, 95% CI 0.48 to 0.93; P = 0.02; 3018 participants; 3 trials; HRB). The definition of non-fatal macrovascular outcomes varied among the trials. SGS versus metformin, thiazolidinediones and meglitinides showed no statistical significance for non-fatal myocardial infarction. No meta-analyses could be performed for microvascular outcomes. SGS versus placebo, metformin, thiazolidinediones, alpha-glucosidase inhibitors or meglitinides showed no statistical significance for adverse events. SGS versus alpha-glucosidase inhibitors showed statistical significance in favour of SGS for drop-outs due to adverse events (RR 0.48, 95% CI 0.24 to 0.96; P = 0.04; 9 trials; 870 participants; HRB). SGS versus meglitinides showed no statistical significance for the risk of severe hypoglycaemia. SGS versus metformin and thiazolidinediones showed statistical significance in favour of metformin (RR 5.64, 95% CI 1.22 to 26.00; P = 0.03; 4 trials; 3637 participants; HRB) and thiazolidinediones (RR 6.11, 95% CI 1.57 to 23.79; P = 0.009; 6 trials; 5660 participants; HRB) for severe hypoglycaemia.Third-generation sulphonylureas (TGS) could not be included in any meta-analysis of all-cause mortality, cardiovascular mortality or non-fatal macro- or microvascular outcomes. TGS versus thiazolidinediones showed statistical significance regarding adverse events in favour of TGS (RR 0.88, 95% CI 0.78 to 0.99; P = 0.03; 3 trials; 510 participants; HRB). TGS versus thiazolidinediones did not show any statistical significance for drop-outs due to adverse events. TGS versus other comparators could not be performed due to lack of data.For the comparison of SGS versus FGS no meta-analyses of all-cause mortality, cardiovascular mortality, non-fatal macro- or microvascular outcomes, or adverse events could be performed.Health-related quality of life and costs of intervention could not be meta-analysed due to lack of data.In trial sequential analysis, none of the analyses of mortality outcomes, vascular outcomes or severe hypoglycaemia met the criteria for firm evidence of a RRR of 10% between interventions.

AUTHORS' CONCLUSIONS

There is insufficient evidence from RCTs to support the decision as to whether to initiate sulphonylurea monotherapy. Data on patient-important outcomes are lacking. Therefore, large-scale and long-term randomised clinical trials with low risk of bias, focusing on patient-important outcomes are required.

Diabetes Mellitus: New Challenges and Innovative Therapies

Diabetes is a common chronic disease affecting an estimated 285 million adults worldwide. The rising incidence of diabetes, metabolic syndrome, and subsequent vascular diseases is a major public health problem in industrialized countries. This chapter summarizes current pharmacological approaches to treat diabetes mellitus and focuses on novel therapies for diabetes mellitus that are under development.

There is great potential for developing a new generation of therapeutics that offer better control of diabetes, its co-morbidities and its complications. Preclinical results are discussed for new approaches including AMPK activation, the FGF21 target, cell therapy approaches, adiponectin mimetics and novel insulin formulations. Gene-based therapies are among the most promising emerging alternatives to conventional treatments. Therapies based on gene silencing using vector systems to deliver interference RNA to cells (i.e. against VEGF in diabetic retinopathy) are also a promising therapeutic option for the treatment of several diabetic complications.

In conclusion, treatment of diabetes faces now a new era that is characterized by a variety of innovative therapeutic approaches that will improve quality of life in the near future.

Choice of therapy in patients with type 2 diabetes inadequately controlled with metformin and a sulphonylurea: a systematic review and mixed-treatment comparison meta-analysis

BACKGROUND

Metformin and a sulphonylurea are often used in combination for the treatment of type 2 diabetes mellitus. We conducted a systematic review and meta-analysis to evaluate the comparative safety and efficacy of all available classes of antihyperglycemic therapies in patients with type 2 diabetes inadequately controlled with metformin and sulphonylurea combination therapy.

METHODS

MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, BIOSIS Previews, PubMed and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials published in English from 1980 to November 2009. Additional citations were obtained from the grey literature and conference proceedings and through stakeholder feedback. Two reviewers independently selected the studies, extracted the data and assessed risk of bias. Key outcomes of interest were hemoglobin A1c, body weight, hypoglycemia, patients' satisfaction with treatment, quality of life, long-term diabetes-related complications, withdrawals due to adverse events, serious adverse events and mortality. Mixed-treatment comparison meta-analyses were conducted to calculate mean differences between drug classes for changes in hemoglobin A1c and body weight. When appropriate, pairwise meta-analyses were used to estimate differences for other outcomes.

RESULTS

We identified 33 randomized controlled trials meeting the inclusion criteria. The methodologic quality of the studies was generally poor. Insulins (basal, biphasic, bolus), dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) analogues and thiazolidinediones (TZDs) all produced statistically significant reductions in hemoglobin A1c in combination with metformin and a sulphonylurea (-0.89% to -1.17%), whereas meglitinides and alpha-glucosidase inhibitors did not. Biphasic insulin, bolus insulin, and TZDs were associated with weight gain (1.85-5.00 kg), whereas DPP-4 inhibitors and alpha-glucosidase inhibitors were weight-neutral, and GLP-1 analogues were associated with modest weight loss. Treatment regimens containing insulin were associated with increased hypoglycemia relative to comparators, but severe hypoglycemia was rare across all treatments.

INTERPRETATION

Third-line agents for the treatment of type 2 diabetes are similar in terms of glycemic control but differ in their propensity to cause weight gain and hypoglycemia. Longer-term studies with larger sample sizes are required to determine if any of the drug classes are superior with regard to reducing diabetes-related complications.

Safety and tolerability of glucagon-like peptide-1 receptor agonists in the treatment of type 2 diabetes

Conventional pharmacotherapies for type 2 diabetes effectively lower blood glucose levels but are associated with side effects that preclude their optimal use or raise safety concerns. Novel treatments based on the endogenous hormone glucagon-like peptide-1 (GLP-1) may overcome some of these obstacles. The GLP-1 receptor agonists, exenatide and liraglutide, have a lower risk of hypoglycaemia than some conventional agents and can provide significant weight loss. Although they can cause gastrointestinal symptoms, effects are transient and can be reduced by gradual dose escalation. No cardiac safety issues have been reported and animal studies suggest that they may confer cardiovascular benefits. Pancreatitis has occurred among patients receiving GLP-1 receptor agonists, but it is unclear whether this is drug-related or due to the increased risk of pancreatitis in type 2 diabetes. Despite findings in rodents that GLP-1 receptor activation of thyroid C-cells results in calcitonin release and C-cell pathology, such effects have not been seen with long-term exposure in humans. Immunogenicity does not appear to be a safety concern. In summary, currently available data indicate that GLP-1 receptor agonists provide an effective and generally well tolerated therapeutic option for the management of type 2 diabetes.

Management of diabetes across the course of disease: minimizing obesity-associated complications

Obesity increases the risk for developing type 2 diabetes mellitus (T2DM) and this in turn correlates with an elevated probability of long-term diabetes complications once diabetes is established. Interventions aimed at lowering weight via changes in diet and lifestyle have repeatedly been shown to improve glycemic control in patients with T2DM and even to reverse early disease. Weight gain, a potential side effect of treatment for patients with T2DM, is also an important concern, and it has been noted that weight increases associated with antidiabetes therapy may blunt cardiovascular risk reductions achieved by decreasing blood glucose. Among older agents, metformin and acarbose have the lowest risk for weight gain, while sulfonylureas, meglitinides, and thiazolidinediones are all associated with weight increases. Clinical trial results have also consistently demonstrated that treatment with glucagon-like peptide-1 receptor agonists and amylin lowers weight, and that dipeptidyl peptidase-4 inhibitors are weight neutral in patients with T2DM. Conventional human insulin formulations are known to increase weight in patients with T2DM. However, some insulin analogs, particularly insulin detemir, have lower liability for this adverse event. The use of both pharmacologic and surgical therapies aimed at treating obesity rather than lowering blood glucose have the potential to improve glycemic control and even resolve T2DM in some patients.

Interventions for latent autoimmune diabetes (LADA) in adults

BACKGROUND

Latent autoimmune diabetes in adults (LADA) is a slowly developing type 1 diabetes.

OBJECTIVES

To compare interventions used for LADA.

SEARCH STRATEGY

Studies were obtained from searches of electronic databases, supplemented by handsearches, conference proceedings and consultation with experts. Date of last search was December 2010.

SELECTION CRITERIA

Randomised controlled trials (RCT) and controlled clinical trials (CCT) evaluating interventions for LADA or type 2 diabetes with antibodies were included.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. Studies were summarised using meta-analysis or descriptive methods.

MAIN RESULTS

Searches identified 13,306 citations. Fifteen publications (ten studies) were included, involving 1019 participants who were followed between three months to 10 years (1060 randomised). All studies had a high risk of bias. Sulphonylurea (SU) with insulin did not improve metabolic control significantly more than insulin alone at three months (one study, n = 15) and at 12 months (one study, n = 14) of treatment and follow-up. SU (with or without metformin) gave poorer metabolic control compared to insulin alone (mean difference in glycosylated haemoglobin A1c (HbA1c) from baseline to end of study, for insulin compared to oral therapy: -1.3% (95% confidence interval (CI) -2.4 to -0.1; P = 0.03, 160 participants, four studies, follow-up/duration of therapy: 12, 30, 36 and 60 months; however, heterogeneity was considerable). In addition, there was evidence that SU caused earlier insulin dependence (proportion requiring insulin at two years was 30% in the SU group compared to 5% in conventional care group (P < 0.001); patients classified as insulin dependent was 64% (SU group) and 12.5% (insulin group, P = 0.007). No intervention influenced fasting C-peptide, but insulin maintained stimulated C-peptide better than SU (one study, mean difference 7.7 ng/ml (95% CI 2.9 to 12.5)). In a five year follow-up of GAD65 (glutamic acid decarboxylase formulated with aluminium hydroxide), improvements in fasting and stimulated C-peptide levels (20 μg group) were maintained after five years. Short term (three months) follow-up in one study (n = 74) using Chinese remedies did not demonstrate a significant difference in improving fasting C-peptide levels compared to insulin alone (0.07 µg/L (95% CI -0.05 to 0.19). One study using vitamin D with insulin showed steady fasting C-peptide levels in the vitamin D group but declining fasting C-peptide levels (368 to 179 pmol/L, P = 0.006) in the insulin alone group at 12 months follow-up. Comparing studies was difficult as there was a great deal of heterogeneity in the studies and in their selection criteria. There was no information regarding health-related quality of life, complications of diabetes, cost or health service utilisation, mortality and limited evidence on adverse events (studies on oral agents or insulin reported no adverse events in terms of severe hypoglycaemic episodes).

AUTHORS' CONCLUSIONS

Two studies show SU leading to earlier insulin dependence and a meta-analysis of four studies with considerable heterogeneity showed poorer metabolic control if SU is prescribed for patients with LADA compared to insulin. One study showed that vitamin D with insulin may protect pancreatic beta cells in LADA. Novel treatments such as GAD65 in certain doses (20 μg) have been suggested to maintain fasting and stimulated C-peptide levels. However, there is no significant evidence for or against other lines of treatment of LADA.

Management of type 2 diabetes: new and future developments in treatment

The increasing prevalence, variable pathogenesis, progressive natural history, and complications of type 2 diabetes emphasise the urgent need for new treatment strategies. Longacting (eg, once weekly) agonists of the glucagon-like-peptide-1 receptor are advanced in development, and they improve prandial insulin secretion, reduce excess glucagon production, and promote satiety. Trials of inhibitors of dipeptidyl peptidase 4, which enhance the effect of endogenous incretin hormones, are also nearing completion. Novel approaches to glycaemic regulation include use of inhibitors of the sodium-glucose cotransporter 2, which increase renal glucose elimination, and inhibitors of 11β-hydroxysteroid dehydrogenase 1, which reduce the glucocorticoid effects in liver and fat. Insulin-releasing glucokinase activators and pancreatic-G-protein-coupled fatty-acid-receptor agonists, glucagon-receptor antagonists, and metabolic inhibitors of hepatic glucose output are being assessed. Early proof of principle has been shown for compounds that enhance and partly mimic insulin action and replicate some effects of bariatric surgery.

A review of diabetes treatment adherence and the association with clinical and economic outcomes

BACKGROUND

The benefits of drug therapy to diabetic patients in terms of glycemic control, microvascular complications, cardiovascular event risk, mortality, and quality of life have been well established by clinical trial data. However, it has been a challenge to quantify the relationship between adherence and outcomes such as glycemic control, disease-related events, hospitalizations, cost, and quality of life.

OBJECTIVE

This article provides a comprehensive summary of empirical studies that examine the associations between adherence and glycemic control, health care utilization, quality of life, and mortality in patients with diabetes. It is intended to provide a framework for researchers interested in conducting studies to improve their understanding of the value of medication adherence for patients with diabetes.

METHODS

Relevant published articles were identified through searches of the National Center for Biotechnology PubMed database. Medical subject heading (MESH) terms diabetes mellitus, hypoglycemic agents, and insulin, were each combined with the MESH term medication adherence and with the subheadings economics, prevention and control, psychology, statistics and numerical data, therapy, adverse effects, therapeutic use, and administration and dosage, where available. Studies were included if they met the following criteria: (1) analyzed empirical data on some measure of patient adherence to diabetes pharmacotherapy; (2) described methods for measuring patient adherence; (3) evaluated economic, clinical, or humanistic outcomes related to diabetes; and (4) had as a goal of the research to evaluate the link between patient adherence and outcomes (as a primary or secondary objective). The data from the articles meeting these criteria were then abstracted, including mention of the specific interventions being compared, specific methods for measuring adherence, outcomes compared between adherent and nonadherent patients and how these outcomes were measured, and information on variables that were adjusted for in predictive and causal multivariable models.

RESULTS

A total of 37 articles that met all 4 criteria in this review underwent data extraction. Of these studies, 22 (59%) used objective measures to assess adherence, with 1 study using pill counts to assess adherence and 21 using either pharmacy claims or similar refill records to assess refill behavior. The remaining 15 (41%) studies used a wide variety of subjective patient-reported adherence assessments. The majority (13/23 [57%]) of the glycemic control studies reported that improved adherence was associated with better glycemic control. The ability to draw a distinction between adherence and glycemic control tended to occur more frequently [7/9 (78%)] among studies that characterized adherence in terms of prescription refills compared with studies that used various constructs for patient-reported adherence measures.

CONCLUSIONS

Based on the literature, better adherence was found to be associated with improved glycemic control and decreased health care resource utilization. There was no consistent association between improved adherence and decreased health care costs. Little data were available on the association between adherence and quality of life.

Comparative effectiveness and safety of medications for type 2 diabetes: an update including new drugs and 2-drug combinations

BACKGROUND

Given the increase in medications for type 2 diabetes mellitus, clinicians and patients need information about their effectiveness and safety to make informed choices.

PURPOSE

To summarize the benefits and harms of metformin, second-generation sulfonylureas, thiazolidinediones, meglitinides, dipeptidyl peptidase-4 (DPP-4) inhibitors, and glucagon-like peptide-1 receptor agonists, as monotherapy and in combination, to treat adults with type 2 diabetes.

DATA SOURCES

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched from inception through April 2010 for English-language observational studies and trials. The MEDLINE search was updated to December 2010 for long-term clinical outcomes.

STUDY SELECTION

Two reviewers independently screened reports and identified 140 trials and 26 observational studies of head-to-head comparisons of monotherapy or combination therapy that reported intermediate or long-term clinical outcomes or harms.

DATA EXTRACTION

Two reviewers following standardized protocols serially extracted data, assessed applicability, and independently evaluated study quality.

DATA SYNTHESIS

Evidence on long-term clinical outcomes (all-cause mortality, cardiovascular disease, nephropathy, and neuropathy) was of low strength or insufficient. Most medications decreased the hemoglobin A(1c) level by about 1 percentage point and most 2-drug combinations produced similar reductions. Metformin was more efficacious than the DPP-4 inhibitors, and compared with thiazolidinediones or sulfonylureas, the mean differences in body weight were about -2.5 kg. Metformin decreased low-density lipoprotein cholesterol levels compared with pioglitazone, sulfonylureas, and DPP-4 inhibitors. Sulfonylureas had a 4-fold higher risk for mild or moderate hypoglycemia than metformin alone and, in combination with metformin, had more than a 5-fold increased risk compared with metformin plus thiazolidinediones. Thiazolidinediones increased risk for congestive heart failure compared with sulfonylureas and increased risk for bone fractures compared with metformin. Diarrhea occurred more often with metformin than with thiazolidinediones.

LIMITATIONS

Only English-language publications were reviewed. Some studies may have selectively reported outcomes. Many studies were small, were of short duration, and had limited ability to assess clinically important harms and benefits.

CONCLUSION

Evidence supports metformin as a first-line agent to treat type 2 diabetes. Most 2-drug combinations similarly reduce hemoglobin A(1c) levels, but some increased risk for hypoglycemia and other adverse events.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

Second-line therapy in patients with type 2 diabetes inadequately controlled with metformin monotherapy: a systematic review and mixed-treatment comparison meta-analysis

BACKGROUND

Although there is general agreement that metformin should be used as first-line pharmacotherapy in patients with type 2 diabetes, uncertainty remains regarding the choice of second-line therapy once metformin is no longer effective. We conducted a systematic review and meta-analysis to assess the comparative safety and efficacy of all available classes of antihyperglycemic therapies in patients with type 2 diabetes inadequately controlled on metformin monotherapy.

METHODS

MEDLINE, EMBASE, BIOSIS Previews, PubMed and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials published in English from 1980 to October 2009. Additional citations were obtained from grey literature and conference proceedings and through stakeholder feedback. Two reviewers independently selected studies, extracted data and assessed risk of bias. Key outcomes of interest were hemoglobin A1c, body weight, hypoglycemia, quality of life, long-term diabetes-related complications, serious adverse drug events and mortality. Mixed-treatment comparison and pairwise meta-analyses were conducted to pool trial results, when appropriate.

RESULTS

We identified 49 active and non-active controlled randomized trials that compared 2 or more of the following classes of antihyperglycemic agents and weight-loss agents: sulfonylureas, meglitinides, thiazolidinediones (TZDs), dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) analogues, insulins, alpha-glucosidase inhibitors, sibutramine and orlistat. All classes of second-line antihyperglycemic therapies achieved clinically meaningful reductions in hemoglobin A1c (0.6% to 1.0%). No significant differences were found between classes. Insulins and insulin secretagogues were associated with significantly more events of overall hypoglycemia than the other agents, but severe hypoglycemia was rarely observed. An increase in body weight was observed with the majority of second-line therapies (1.8 to 3.0 kg), the exceptions being DPP-4 inhibitors, alpha-glucosidase inhibitors and GLP-1 analogues (0.6 to -1.8 kg). There were insufficient data available for diabetes complications, mortality or quality of life.

INTERPRETATION

DPP-4 inhibitors and GLP-1 analogues achieved improvements in glycemic control similar to those of other second-line therapies, although they may have modest benefits in terms of weight gain and overall hypoglycemia. Further long-term trials of adequate power are required to determine whether newer drug classes differ from older agents in terms of clinically meaningful outcomes.

Updated review: improved glycemic control with repaglinide-metformin in fixed combination for patients with type 2 diabetes

As the prevalence of type 2 diabetes continues to rise, new drug therapies will need to be explored to prevent morbidity and mortality associated with diabetes as well as growing health care costs. Type 2 diabetes is characterized by decreased insulin secretion and sensitivity. Numerous oral medications are currently approved for the treatment of type 2 diabetes. A treat-to-failure approach has traditionally been adopted with step-wise additions of oral medications; however, a growing frequency of treatment failures with monotherapy has led to the use of combination therapies earlier in the treatment of type 2 diabetes. One such combination regimen is repaglinide (a prandial glucose optimizer that increases insulin release) plus metformin (an insulin sensitizer that inhibits hepatic glucose output and increases peripheral glucose uptake while minimizing weight gain). Findings from several clinical trials have shown repaglinide plus metformin combination therapy to be superior to either monotherapy with significant reductions in hemoglobin A1C and fasting glucose values. Repaglinide used in combination also has shown less incidence of hypoglycemia compared with other combination therapies such as sulphonylureas plus metformin. Repaglinide plus metformin combination therapy appears to be a valuable therapeutic option for type 2 diabetic patients seeking a less complex drug regimen while potentially achieving better glucose control if currently inadequately controlled on monotherapy.

Emerging treatment options for type 2 diabetes

Type 2 diabetes mellitus (T2DM) is rapidly increasing in prevalence and is a major public health problem. It is a progressive disease which commonly requires multiple pharmacotherapy. Current options for treatment may have undesirable side effects (particularly weight gain and hypoglycaemia) and contraindications, and little effect on disease progression. Incretin based therapy is one of several newer therapies to improve glycaemia and is available in two different forms, dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide-1 (GLP-1) agonists. Use of these agents results in a 'glucose-dependant' increase in insulin secretion and glucagon suppression resulting in improved glycaemia with low incidence of hypoglycaemia. DPP-4 inhibitors are oral drugs which are weight neutral, while GLP-1 agonists are injected subcutaneously and help promote weight loss while improving glycaemia. GLP-1 agonists have also been shown to increase beta cell mass in rat models. Bariatric surgery is another option for the obese patient with T2DM, with blood glucose normalizing in over half of the patients following surgery. Other therapies in development for the treatment of T2DM include sodium-glucose transporter 2 (SGLT-2) inhibitors, glucagon receptor antagonists, glucokinase activators and sirtuins. In this article, we will review the various existing and emerging treatment options for T2DM.

Oral Hypoglycemic Drugs: Pathophysiological Basis of Their Mechanism of ActionOral Hypoglycemic Drugs: Pathophysiological Basis of Their Mechanism of Action

Type 2 diabetes is a syndrome characterized by relative insulin deficiency, insulin resistance and increased hepatic glucose output. Medications used to treat the disease are designed to correct one or more of these metabolic abnormalities. Current recommendations of the American Diabetes Association (ADA) and European Association for the Study of Diabetes (EASD) include diet and exercise as first-line therapy plus hypoglycemic drugs. Actually there are seven distinct classes of anti-hyperglicemic agents, each of them displaying unique pharmacologic properties. The aim of this review is to describe the pathophysiological basis of their mechanism of action, a necessary step to individualize treatment of diabetic people, taking into proper consideration potential benefits and secondary effects of drugs.

Repaglinide/metformin fixed-dose combination to improve glycemic control in patients with type 2 diabetes: an update

Type 2 diabetes is a progressive disease associated with high levels of morbidity and mortality and for which there is both a large and growing prevalence worldwide. Lifestyle advice plus metformin is commonly recommended initially to manage hyperglycemia and to minimize the risk of vascular complications. However, additional agents are required when glycemic targets cannot be achieved or maintained due to the progressive nature of the disease. Repaglinide/metformin fixed-dose combination (FDC) therapy (PrandiMet(®); Novo Nordisk, Bagsværd, Denmark) has been approved for use in the USA. This FDC is a rational second-line therapy given the complementary mechanisms of action of the components. Repaglinide is a rapidly absorbed, short-acting insulin secretagogue targeting postprandial glucose excursions; metformin is an insulin sensitizer with a longer duration of action that principally regulates basal glucose levels. A pivotal, 26-week, randomized study with repaglinide/metformin FDC therapy has been conducted in patients experiencing suboptimal control with previous oral antidiabetes therapy. Repaglinide/metformin FDC improved glycemic control and weight neutrality without adverse effects on lipid profiles. There were no major hypoglycemic episodes and patients expressed greater satisfaction with repaglinide/metformin FDC than previous treatments. Repaglinide/metformin FDC is expected to be more convenient than individual tablets for patients taking repaglinide and metformin in loose combination, and it is expected to improve glycemic control in patients for whom meglitinide or metformin monotherapies provide inadequate control.

Diabetes mellitus: new challenges and innovative therapies

Diabetes mellitus is a widespread disease prevalence and incidence of which increases worldwide. The introduction of insulin therapy represented a major breakthrough in type 1 diabetes; however, frequent hyper- and hypoglycemia seriously affects the quality of life of these patients. New therapeutic approaches, such as whole pancreas transplant or pancreatic islet transplant, stem cell, gene therapy and islets encapsulation are discussed in this review. Regarding type 2 diabetes, therapy has been based on drugs that stimulate insulin secretion (sulphonylureas and rapid-acting secretagogues), reduce hepatic glucose production (biguanides), delay digestion and absorption of intestinal carbohydrate (alpha-glucosidase inhibitors) or improve insulin action (thiazolidinediones). This review is also focused on the newer therapeutically approaches such as incretin-based therapies, bariatric surgery, stem cells and other emerging therapies that promise to further extend the options available. Gene-based therapies are among the most promising emerging alternatives to conventional treatments. Some of these therapies rely on genetic modification of non-differentiated cells to express pancreatic endocrine developmental factors, promoting differentiation of non-endocrine cells into β-cells, enabling synthesis and secretion of insulin in a glucose-regulated manner. Alternative therapies based on gene silencing using vector systems to deliver interference RNA to cells (i.e. against VEGF in diabetic retinopathy) are also a promising therapeutic option for the treatment of several diabetic complications. In conclusion, treatment of diabetes faces now a new era that is characterized by a variety of innovative therapeutic approaches that will improve quality-life and allow personalized therapy-planning in the near future.

DPP-4 inhibitors in clinical practice

Type 2 diabetes is a very common worldwide disorder, with major consequences for patients, society, and health care services. Good glycemic control is an important aspect of diabetes management because it has a significant impact on diabetes-related microvascular and possibly macrovascular complications. Based on our understanding of the pathogenesis of diabetes, multiple pharmacological interventions have been developed in the past 60 years. Although effective, none have had a lasting effect on glycemic control because of the progressive nature of type 2 diabetes requiring combination therapies and insulin treatment. In addition, several pharmacologic interventions have undesirable side effects, including hypoglycemia and weight gain. Drugs targeting the incretin pathway are the latest addition to the available antidiabetes agents. Incretin-based therapy is either delivered orally (dipeptidyl peptidase-4 [DPP-4]) inhibitors or injected subcutaneously (glucagon-like peptide-1 [GLP-1] mimetics and analogues). Dipeptidyl peptidase-4 inhibitors are effective either as a single or combination therapy in lowering glycated hemoglobin, fasting and postprandial glucose levels, with a low incidence of hypoglycemia and no weight gain. There are 3 DPP-4 inhibitors currently available (sitagliptin, saxagliptin, and vildagliptin), with more expected to be available in the future. In this article, we review the scientific background for incretin-based therapy and the available evidence regarding the role and efficacy of DPP-4 inhibitors in the treatment of patients with type 2 diabetes.

Glycaemic control in type 2 diabetes: targets and new therapies

Type 2 diabetes mellitus (T2DM) is a worldwide public health challenge. Despite the availability of many antidiabetes agents and pharmacotherapies targeting cardiovascular risk factors, the morbidity, mortality and economic consequences of T2DM are still a great burden to patients, society, health care systems and the economy. The need for new therapies for glycaemic control is compounded by the fact that existing treatments have limitations either because of their side effects (particularly weight gain and hypoglycaemia) or contraindications that limit their use. Furthermore, none of the current therapies have a significant impact on disease progression. Incretin-based therapies offer a new therapeutic approach to the management of T2DM, and there are also several even newer therapies in development. There are two groups of incretin-based therapies currently available; dipeptidyl peptidase-4 (DPP-4) inhibitors and GLP-1 analogues/mimetics. The former are given orally while the latter subcutaneously. These drugs result in glucose-dependent insulin secretion and glucose-dependent glucagon suppression, with consequent low risk of hypoglycaemia when used as mono- or combination therapy (except when used with sulphonylureas). In addition, they are either weight neutral in the case of DPP-4 inhibitors or cause weight loss in the case of incretin mimetics/analogues. Furthermore, animal studies have shown that these agents prolong beta cell survival which offers the theoretical possibility of slowing the progression to T2DM. In this article we will review the currently available antidiabetes agents with particular emphasis on incretin-based and future therapies. In addition, we will review and discuss the evidence relating to glycaemic control and cardiovascular disease.

Combining insulin with metformin or an insulin secretagogue in non-obese patients with type 2 diabetes: 12 month, randomised, double blind trial

OBJECTIVES

To study the effect of insulin treatment in combination with metformin or an insulin secretagogue, repaglinide, on glycaemic regulation in non-obese patients with type 2 diabetes.

DESIGN

Randomised, double blind, double dummy, parallel trial.

SETTING

Secondary care in Denmark between 2003 and 2006.

PARTICIPANTS

Non-obese patients (BMI </=27) with preserved beta cell function.

INTERVENTIONS

After a four month run-in period with repaglinide plus metformin combination therapy, patients with a glycated haemoglobin (HbA(1c)) concentration of 6.5% or more were randomised to repaglinide 6 mg or metformin 2000 mg. All patients also received biphasic insulin aspart 70/30 (30% soluble insulin aspart and 70% intermediate acting insulin aspart) 6 units once a day before dinner for 12 months. Insulin dose was adjusted aiming for a fasting plasma glucose concentration of 4.0-6.0 mmol/l. The target of HbA(1c) concentration was less than 6.5%. Treatment was intensified to two or three insulin injections a day if glycaemic targets were not reached.

MAIN OUTCOME MEASURE

HbA(1c) concentration.

RESULTS

Of the 459 patients who were eligible, 102 were randomised, and 97 completed the trial. Patients had had type 2 diabetes for approximately 10 years. At the end of treatment, HbA(1c) concentration was reduced by a similar amount in the two treatment groups (insulin plus metformin: mean (standard deviation) HbA(1c) 8.15% (1.32) v 6.72% (0.66); insulin plus repaglinide: 8.07% (1.49) v 6.90% (0.68); P=0.177). Total daily insulin dose and risk of hypoglycaemia were also similar in the two treatment groups. Weight gain was less with metformin plus biphasic insulin aspart 70/30 than with repaglinide plus biphasic insulin aspart 70/30 (difference in mean body weight between treatments -2.51 kg, 95% confidence interval -4.07 to -0.95).

CONCLUSIONS

In non-obese patients with type 2 diabetes and poor glycaemic regulation on oral hypoglycaemic agents, overall glycaemic regulation with insulin in combination with metformin was equivalent to that with insulin plus repaglinide. Weight gain seemed less with insulin plus metformin than with insulin plus repaglinide.

TRIAL REGISTRATION

NCT00118963.

The role of surrogate endpoints in the evaluation of efficacy and safety of therapeutic interventions in diabetes mellitus

In this paper, we examine the concept of surrogate endpoints (i.e. substitute outcome measures) and review their use in clinical trials involving therapies for diabetes mellitus using the example of metformin. Trials such as DCCT and UKPDS, in which patient-important endpoints were evaluated, are relatively rare in diabetology. Clinical decisions, therefore, are often based on evidence obtained using surrogate outcomes, usually fasting or postprandial glycemia or glycated hemoglobin level. In contrast to patient-important endpoints, surrogates do not describe direct clinical benefit to the patient. However, a proven association between a surrogate and patient-important endpoint is essential to draw appropriate therapeutic conclusions. In the process of new drug development, the duration of follow-up, sample size and methodology of the studies initially available are often inadequate to demonstrate the effect of the intervention on patient-important endpoints. Evidence concerning the effect of an intervention on surrogate outcomes usually comes first, followed only later by reports describing its influence on patient-important endpoints. Metformin may serve as an example in several ways. The first publications reported beneficial effects on glycemic control and body weight. Outcomes from the subsequent UKPDS study suggested the patient-important efficacy of metformin measured as a reduction in mortality and a decrease in the incidence of diabetic complications, including myocardial infarction. This reasoning process worked for some but not all strategies. It is particularly questionable whether a change in surrogate endpoint was associated with a potential deterioration in patient-important outcomes. Defining the general relationship between surrogates widely used as measures of metabolic control and patient-important endpoints remains an important challenge in contemporary diabetology.

Dipeptidyl peptidase-4 (DPP-4) inhibitors for type 2 diabetes mellitus

BACKGROUND

In type 2 diabetes mellitus there is a progressive loss of beta-cell function. One new approach yielding promising results is the use of the orally active dipeptidyl peptidase-4 (DPP-4) inhibitors like sitagliptin and vildagliptin.

OBJECTIVES

To assess the effects of dipeptidyl peptidase-4 (DPP-4) inhibitors for type 2 diabetes mellitus.

SEARCH STRATEGY

Studies were obtained from computerised searches of MEDLINE, EMBASE and The Cochrane Library.

SELECTION CRITERIA

Studies were included if they were randomised controlled trials in adult people with type 2 diabetes mellitus and had a trial duration of at least 12 weeks.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed risk of bias and extracted data. Pooling of studies was performed by means of fixed-effect meta-analysis.

MAIN RESULTS

Twenty-five studies of good quality were identified, 11 trials evaluated sitagliptin and 14 trials vildagliptin treatment. Altogether, 6743 patients were randomised in sitagliptin and 6121 patients in vildagliptin studies, respectively. Sitagliptin and vildagliptin studies ranged from 12 to 52 weeks duration. No data were published on mortality, diabetic complications, costs of treatment and health-related quality of life. Sitagliptin and vildagliptin therapy in comparison with placebo resulted in an HbA1c reduction of approximately 0.7% and 0.6%, respectively. Data on comparisons with active comparators were limited but indicated no improved metabolic control following DPP-4 intervention in contrast to other hypoglycaemic agents. Sitagliptin and vildagliptin therapy did not result in weight gain but weight loss was more pronounced following placebo interventions. No definite conclusions could be drawn from published data on sitagliptin and vildagliptin effects on measurements of beta-cell function. Overall, sitagliptin and vildagliptin were well tolerated, no severe hypoglycaemia was reported in patients taking sitagliptin or vildagliptin. All-cause infections increased significantly after sitagliptin treatment but did not reach statistical significance following vildagliptin therapy. All published randomised controlled trials of at least 12 weeks treatment with sitagliptin and vildagliptin only reported routine laboratory safety measurements

AUTHORS' CONCLUSIONS

DPP-4 inhibitors have some theoretical advantages over existing therapies with oral antidiabetic compounds but should currently be restricted to individual patients. Long-term data especially on cardiovascular outcomes and safety are urgently needed before widespread use of these new agents. More information on the benefit-risk ratio of DPP-4 inhibitor treatment is necessary especially analysing adverse effects on parameters of immune function. Also, long-term data are needed investigating patient-oriented parameters like health-related quality of life, diabetic complications and all-cause mortality.

A review of nateglinide in the management of patients with type 2 diabetes

Impaired insulin secretion occurs early in the pathogenesis of type 2 diabetes mellitus (T2DM) and is chronic and progressive, resulting initially in impaired glucose tolerance (IGT) and eventually in T2DM. As most patients with T2DM have both insulin resistance and insulin deficiency, therapy for T2DM should aim to control not only fasting, but also postprandial plasma glucose levels. While oral glucose-lowering treatment with metformin and thiazolidinediones corrects fasting plasma glucose, these agents do not address the problem of mealtime glucose spikes that have been shown to trigger atherogenic processes. Nateglinide is a derivative of the amino acid D-phenylalanine, which acts directly on the pancreatic beta-cells to stimulate insulin secretion. Nateglinide monotherapy controls significantly mealtime hyperglycemia and results in improved overall glycemic control in patients with T2DM by reducing glycosylated hemoglobin (HbA1c) levels. The combination of nateglinide with insulin-sensitising agents, such as metformin and thiazolidinediones, targets both insulin deficiency and insulin resistance and results in reductions in HbA1c that could not be achieved by monotherapy with other antidiabetic agents. In prediabetic subjects with IGT, nateglinide restores early insulin secretion and reduces postprandial hyperglycemia. Nateglinide has an excellent safety and tolerability profile and provides a lifetime flexibility that other antidiabetic agents could not accomplish. The aim of this review is to identify nateglinide as an effective "gate-keeper" in T2DM, since it restores early-phase insulin secretion and prevents mealtime glucose spikes throughout the day and to evaluate the results of ongoing research into its potential role in delaying the progression to overt diabetes and reducing its complications and mortality.