Efficacy, dose-response relationship and safety of once-daily extended-release metformin (Glucophage XR) in type 2 diabetic patients with inadequate glycaemic control despite prior treatment with diet and exercise: results from two double-blind, placebo-controlled studies

Bioequivalence of Related GelShieldⓇ Sustained-Release Formulations of Metformin: A Pooled Pharmacokinetic Analysis

PURPOSE

GlucophageⓇ (Merck Healthcare KGaA, Darmstadt, Germany) is the originator brand of metformin hydrochloride, an oral antidiabetic drug. Metformin is recommended in guidelines as first-line treatment of type 2 diabetes mellitus and increasingly in related insulin-resistant conditions, such as prediabetes and polycystic ovary syndrome. The GelShieldⓇ sustained-release formulation tablet of GlucophageⓇ has been improved from the historic version marketed in 2000. Bioequivalence has been demonstrated stepwise along this evolution; however, a head-to-head evaluation between the initial and the current version is missing. This analysis aims to close this gap and to determine bioequivalence between related originator GelShieldⓇ sustained-release formulations of metformin, GlucophageⓇ (GXR 500 mg), from Europe and the United States.

METHODS

Data from seven randomized crossover bioequivalence studies in 361 healthy participants of Asian and non-Asian ethnicity from Europe, the United States, and Asia were considered. All evaluated a single oral dose of 500 mg of the test and reference formulation in healthy male and female participants in fed and fasted state. Bioequivalence was evaluated by means of a combined bridging analysis of available data on the current round tablet from Europe (rGXR EU) and the historic oblong tablet from the United States (oGXR US) in healthy Asian and non-Asian participants under fed and fasting conditions. Bioequivalence between the two formulations was assessed statistically with a mixed effects model for AUC0-t, Cmax, and AUC0-inf.

FINDINGS

In all studies, bioequivalence between the respective test and reference formulations of GXR was shown. Statistical analysis of pooled pharmacokinetic data of 2 (primary pooling set) or 3 studies (secondary pooling set) demonstrated bioequivalence between rGXR EU and oGXR US via bridging with oGXR EU. The 90% CI for the geometric mean ratio of all pharmacokinetic parameters was within the bioequivalence range of 0.80 to 1.25. In the primary pooling set, geometric least squares mean ratios in the fed group ranged from 0.9931 (90% CI, 0.9151-1.0778) for AUC0-inf to 1.1344 (90% CI, 1.0711-1.2014) for Cmax; results in the fasted group were similar. The secondary pooling set, which added a study in Asians, confirmed these findings.

IMPLICATIONS

Bioequivalence was determined between sustained-release formulations of GlucophageⓇ from Europe and the United States under fasted and fed conditions in healthy men and women, including different ethnicities. The efficacy and safety of GlucophageⓇ XR can be claimed along the evolution from oGXR US, via oGXR EU to rGXR EU, and in several ethnicities and production sites.

Systemic antibiotics adjuvants to scaling and root planing in type 2 diabetic and periodontitis individuals: Systematic review with network meta-analysis

Targeting inflammatory pathways is considered a common strategy to control type 2 diabetes (T2D) and periodontitis. This overview was to validate systemic antibiotics as an adjuvant to scaling and root planing (SRP) for the treatments of periodontal patients with T2D. Literature searches were conducted using Web of Science, PubMed, Cochrane, and EMBASE. Randomized trials comparing SRP and systemic antibiotics on glycated hemoglobin (HbA1c) and probing pocket depth (PPD) in adults with T2D and periodontitis were analyzed using network meta-analysis and meta-regression. At 3-month postintervention, meta-analyses of 16 studies revealed that SRP and SRP plus systemic antibiotics (SRPa) had similar significant effects in reducing HbA1c levels of - 0.72% and - 0.96% respectively. While SRP and SRPa also, respectively, reduced PPD of - 0.67 and - 0.89 mm, SRPa showed a better reduction than SRP. At 6-month postintervention, meta-analyses of 7 trials revealed that only SRP was effective in reducing HbA1c levels (-0.29%) but not SRPa. Although both SRP and SRPa still significantly reduced PPD by - 0.56 and - 0.81 mm, respectively, there was no difference between them. The current overview suggested that routine SRP alone is highly recommended for patients with T2D and periodontitis, since systemic antibiotics as an adjuvant provide a rather short-term effect.

Choice of Glucose-Lowering Drugs as Initial Monotherapy for Type 2 Diabetes Patients with Contraindications or Intolerance to Metformin: A Systematic Review and Meta-Analysis

BACKGROUND

There are multiple glucose-lowering drugs available as alternative initial monotherapy for type 2 diabetes patients with contraindications or intolerance to metformin. However, little comparative and systematic data are available for them as initial monotherapy. This study estimated and compared the treatment effects of glucose-lowering drugs as initial monotherapy for type 2 diabetes.

METHODS

PubMed, Web of Science, Embase, CNKI, Chongqing VIP, and WanFang Data from 1 January 1990 until 31 December 2020 were searched for randomized controlled trials which compared a glucose-lowering drug with placebo/lifestyle-intervention for type 2 diabetes. Drug classes included metformin, sulfonylureas (SUs), thiazolidinediones (TZDs), glinides (NIDEs), α-glucosidase inhibitors (AGIs), dipeptidyl peptidase-4 inhibitors (DPP-4is), sodium-glucose cotransporter-2 inhibitors (SGLT2is), insulins (INSs), and glucagon-like peptide-1 receptor agonists (GLP-1RAs).

RESULTS

A total of 185 trials were included, identifying 38,376 patients from 56 countries across six continents. When choosing an initial drug monotherapy alternative to metformin, SUs were most efficacious in reducing HbA1c (-1.39%; 95% CI -1.63, -1.16) and FPG (-2.70 mmol/L; 95% CI -3.18, -2.23), but increased hypoglycemia risks (5.44; 95% CI 2.11, 14.02). GLP-1RAs were most efficacious in reducing BMI (-1.05 kg/m²; 95% CI -1.81, -0.29) and TC (-0.42 mmol/L; 95% CI -0.61, -0.22). TZDs were most efficacious in increasing HDL-C (0.12 mmol/L; 95% CI 0.07, 0.17). SGLT2is were most efficacious in lowering SBP (-4.18 mmHg; 95% CI -4.84, -3.53). While AGIs conferred higher risk of AE-induced discontinuations (2.57; 95% CI 1.64, 4.03). Overall, only GLP-1RAs showed an integrated beneficial effect on all outcomes. Our results also confirmed the intraclass differences in treatment effects across drugs. Most trials were short-term, and no significant differences in mortality, total vascular events, myocardial infarction, heart failure, stroke, or diabetic nephropathy were observed across drug classes.

CONCLUSIONS

Our results suggest a potential treatment hierarchy for decision-makers, with GLP-1RAs being the preferred alternative therapy to metformin regarding their favorable efficacy and safety profiles.

Gastrointestinal adverse events of metformin treatment in patients with type 2 diabetes mellitus: A systematic review, meta-analysis and meta-regression of randomized controlled trials

INTRODUCTION

Metformin is the first choice drug in the treatment of type 2 diabetes mellitus but its administration may be linked to gastrointestinal adverse events limiting its use.

OBJECTIVES

The objective of this systematic review and meta-analysis was to assess the risk of gastrointestinal adverse events related to metformin use in patients with type 2 diabetes treated with metformin.

METHODS

PUB MED/CINAHL/Web of Science/Scopus were searched from database inception until 08.11.2020 for articles in English and randomized controlled trials related to patients with type 2 diabetes treated with metformin were included.

RESULTS

From 5315 publications, we identified 199 potentially eligible full-text articles. Finally, 71 randomized controlled trials were included in the meta-analysis. In these studies, metformin use was associated with higher risk of abdominal pain, diarrhea and nausea comparing to control. The risks of abdominal pain and nausea were highest comparing to placebo. Bloating risk was only elevated when metformin treatment was compared to DPP4i.

CONCLUSIONS

The risk of gastrointestinal adverse events such as abdominal pain, nausea and diarrhea is higher in type 2 diabetes patients treated with metformin compared to other antidiabetic drugs. There is a higher risk of bloating and diarrhea with metformin immediate-release than with metformin extended release formulation.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021289975, identifier CRD42021289975.

The Hormetic Effect of Metformin: "Less Is More"?

Metformin (MTF) is the first-line therapy for type 2 diabetes (T2DM). The euglycemic effect of MTF is due to the inhibition of hepatic glucose production. Literature reports that the principal molecular mechanism of MTF is the activation of 5′-AMP-activated protein kinase (AMPK) due to the decrement of ATP intracellular content consequent to the inhibition of Complex I, although this effect is obtained only at millimolar concentrations. Conversely, micromolar MTF seems to activate the mitochondrial electron transport chain, increasing ATP production and limiting oxidative stress. This evidence sustains the idea that MTF exerts a hormetic effect based on its concentration in the target tissue. Therefore, in this review we describe the effects of MTF on T2DM on the principal target organs, such as liver, gut, adipose tissue, endothelium, heart, and skeletal muscle. In particular, data indicate that all organs, except the gut, accumulate MTF in the micromolar range when administered in therapeutic doses, unmasking molecular mechanisms that do not depend on Complex I inhibition.

Effects of metformin treatment on pregnancy outcomes in patients with polycystic ovary syndrome

INTRODUCTION

This review covers the current evidence regarding the use of metformin as a therapeutic intervention for optimizing pregnancy outcomes in women with polycystic ovary syndrome (PCOS).

AREAS COVERED

After searching Medline, Embase and CINAHL, all important large clinical trials and observational studies plus systematic reviews, meta-analyses and Cochrane reviews have been summarized here. The results have been compared to culminate in a thorough review and discussion on the use of metformin in relation to reproductive outcomes for women with PCOS. The role of metformin in PCOS is explored both in terms of achieving conception and during pregnancy. The existing evidence around metformin use is summarized both during the preconceptual period and during pregnancy, in relation to reproductive outcomes.

EXPERT OPINION

Metformin is a widely used medication, often prescribed to improve reproductive outcomes for women with PCOS. However, the evidence remains equivocal regarding its efficacy both in optimizing fertility and pregnancy outcomes. More research is required with special emphasis on metformin use within different populations, including ethnic groups and women with varying BMI ranges.

Effects of Increasing Metformin Dose vs Adding/Switching to Dipeptidyl Peptidase-4 Inhibitors on Glycemic Control in Patients with Type 2 Diabetes

INTRODUCTION

Metformin has dose-dependent hypoglycemic effects on patients with type 2 diabetes (T2D). In Japan, metformin has been prescribed at lower doses than in Western countries. We analyzed the effect of increasing the metformin dose on glycemic control and compared it to a combination therapy with dipeptidyl peptidase-4 inhibitors (DPP-4i) and a replacement therapy with DPP-4i.

METHODS

This is a cohort study using a Japanese claims database. Patients with T2D who had been initially treated with low-dose metformin (≥ 500 mg/day and < 1000 mg/day) and then given a prescription change by increasing metformin to a higher dose (≥ 1000 mg/day) (increased-dose), adding DPP-4i (drug-added), or switching to DPP-4i (drug-switched) were included in this study. The primary outcome was the change in HbA1c levels at 12 months from the baseline period.

RESULTS

Among 2,726,437 patients with T2D, 494 were included. Of these patients, 226, 240, and 28 patients were classified as increased-dose, drug-added, and drug-switched groups, respectively. The HbA1c levels at 12 months from the index significantly decreased compared to that during the baseline period. The change was the highest in the drug-added group (- 1.06%), followed by the increased-dose (- 0.91%) and the drug-switched groups (- 0.37%). Among the subset of patients who did not receive any antidiabetic drugs other than metformin or DPP-4i, the highest change in HbA1c levels was observed in the increased-dose group (- 0.84%), followed by the drug-added (- 0.67%) and the drug-switched (- 0.42%) groups. The order of decrease from baseline remained the same for all the study groups after the propensity score weighting adjustment.

CONCLUSION

The effect on glycemic control when increasing the metformin dose was studied in patients who had been receiving low-dose metformin. Increasing metformin dosage shows effectiveness and could be one of the next treatment options in patients who were prescribed low-dose metformin as the first-line treatment.

Association of metformin monotherapy or combined therapy with cardiovascular risks in patients with type 2 diabetes mellitus

Background

Metformin is a first-line drug in type 2 diabetes mellitus (T2DM) treatment, yet whether metformin may increase all-cause or cardiovascular mortality of T2DM patients remains inconclusive.

Methods

We searched PubMed and Embase for data extracted from inception to July 14, 2020, with a registration in PROSPERO (CRD42020177283). This study included randomized controlled trials (RCT) assessing the cardiovascular effects of metformin for T2DM. This study is followed by PRISMA and Cochrane guideline. Risk ratio (RR) with 95% CI was pooled across trials by a random-effects model. Primary outcomes include all-cause mortality and cardiovascular mortality.

Results

We identified 29 studies that randomly assigned patients with 371 all-cause and 227 cardiovascular death events. Compared with untreated T2DM patients, metformin-treated patients was not associated with lower risk of all-cause mortality (RR: 0.98; 95%CI: 0.69–1.38; P = 0.90), cardiovascular mortality (RR: 1.13; 95% CI: 0.60, 2.15; P = 0.70), macrovascular events (RR: 0.87; 95%CI: 0.70–1.07; P = 0.19), heart failure (RR: 1.02; 95% CI:0.61–1.71; P = 0.95), and microvascular events (RR: 0.78; 95% CI:0.54–1.13; P = 0.19). Combination of metformin with another hypoglycemic drug was associated with higher risk of all-cause mortality (RR: 1.49; 95% CI: 1.02, 2.16) and cardiovascular mortality (RR: 2.21; 95% CI: 1.22, 4.00) compared with hypoglycemic drug regimens with no metformin.

Conclusion

The combination of metformin treatment may impose higher risk in all-cause and cardiovascular mortality. This finding, at least in part, shows no evidence for benefits of metformin in combination in terms of all-cause/cardiovascular mortality and cardiovascular events for T2DM. However, the conclusion shall be explained cautiously considering the limitations from UK Prospective Diabetes Study (UKPDS).

Pharmacological treatment of hyperglycemia in type 2 diabetes

Diabetes mellitus is a major public health problem, affecting about 10% of the population. Pharmacotherapy aims to protect against microvascular complications, including blindness, end-stage kidney disease, and amputations. Landmark clinical trials have demonstrated that intensive glycemic control slows progression of microvascular complications (retinopathy, nephropathy, and neuropathy). Long-term follow-up has demonstrated that intensive glycemic control also decreases risk of macrovascular disease, albeit rigorous evidence of macrovascular benefit did not emerge for over a decade. The US FDA's recent requirement for dedicated cardiovascular outcome trials ushered in a golden age for understanding the clinical profiles of new type 2 diabetes drugs. Some clinical trials with sodium-glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide 1 (GLP1) receptor agonists reported data demonstrating cardiovascular benefit (decreased risk of major adverse cardiovascular events and hospitalization for heart failure) and slower progression of diabetic kidney disease. This Review discusses current guidelines for use of the 12 classes of drugs approved to promote glycemic control in patients with type 2 diabetes. The Review also anticipates future developments with potential to improve the standard of care: availability of generic dipeptidylpeptidase-4 (DPP4) inhibitors and SGLT2 inhibitors; precision medicine to identify the best drugs for individual patients; and new therapies to protect against chronic complications of diabetes.

Comparison of Clinical Efficacy and Safety of Metformin Sustained-Release Tablet (II) (Dulening) and Metformin Tablet (Glucophage) in Treatment of Type 2 Diabetes Mellitus

OBJECTIVES

This study investigated the clinical efficacy and safety of metformin hydrochloride sustained-release (SR) tablet (II) produced by Dulening and the original metformin hydrochloride tablet produced by Glucophage in the treatment of type 2 diabetes mellitus (T2DM).

METHODS

This randomized, open and parallel controlled clinical trial consecutively recruited a total of 886 patients with T2DM in 40 clinical centers between May 2016 and December 2018. These patients were randomly assigned to the Dulening group (n=446), in which patients were treated with Dulening metformin SR tablets, and the Glucophage group (n=440), in which patients were treated with Glucophage metformin tablets, for 16 weeks. The changes in the levels of glycated hemoglobin (HbAc1) and fasting blood glucose (FBG) as well as weight loss were compared between these two groups. Also, the overall incidence of adverse drug reactions (ADRs) and the incidence of ADR of the gastrointestinal system observed in patients of these two groups were also compared.

RESULTS

There were no significant differences in demographic and basal clinical characteristics between these two groups. The Dulening and Glucophage groups showed comparable levels of decrease in HbA1c levels, FBG and weight loss after 12-week treatment (all p>0.05). The Dulening group had a significantly lower overall incidence of ADRs as well as gastrointestinal ADR than the Glucophage group.

CONCLUSIONS

Metformin SR tablets (II) and the original metformin tablets exhibit similar therapeutic efficacy in the treatment of T2DM, but metformin SR tablets (II) has the significantly lower incidence of ADRs than the original metformin tablets.

Age, sex, disease severity, and disease duration difference in placebo response: implications from a meta-analysis of diabetes mellitus

BACKGROUND

The placebo response in patients with diabetes mellitus is very common. A systematic evaluation needs to be updated with the current evidence about the placebo response in diabetes mellitus and the associated factors in clinical trials of anti-diabetic medicine.

METHODS

Literature research was conducted in Medline, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov for studies published between the date of inception and June 2019. Randomized placebo-controlled trials conducted in type 1and type 2 diabetes mellitus (T1DM/T2DM) were included. Random-effects model and meta-regression analysis were accordingly used. This meta-analysis was registered in PROSPERO as CRD42014009373.

RESULTS

Significantly weight elevation (effect size (ES) = 0.33 kg, 95% CI, 0.03 to 0.61 kg) was observed in patients with placebo treatments in T1DM subgroup while significantly HbA1c reduction (ES = - 0.12%, 95% CI, - 0.16 to - 0.07%) and weight reduction (ES = - 0.40 kg, 95% CI, - 0.50 to - 0.29 kg) were observed in patients with placebo treatments in T2DM subgroup. Greater HbA1c reduction was observed in patients with injectable placebo treatments (ES = - 0.22%, 95% CI, - 0.32 to - 0.11%) versus oral types (ES = - 0.09%, 95% CI, - 0.14 to - 0.04%) in T2DM (P = 0.03). Older age (β = - 0.01, 95% CI, - 0.02 to - 0.01, P < 0.01) and longer diabetes duration (β = - 0.02, 95% CI, - 0.03 to - 0.21 × 10^-2, P = 0.03) was significantly associated with more HbA1c reduction by placebo in T1DM. However, younger age (β = 0.02, 95% CI, 0.01 to 0.03, P = 0.01), lower male percentage (β = 0.01, 95% CI, 0.22 × 10^-2, 0.01, P < 0.01), higher baseline BMI (β = - 0.02, 95% CI, - 0.04 to - 0.26 × 10^-2, P = 0.02), and higher baseline HbA1c (β = - 0.09, 95% CI, - 0.16 to - 0.01, P = 0.02) were significantly associated with more HbA1c reduction by placebo in T2DM. Shorter diabetes duration (β = 0.06, 95% CI, 0.06 to 0.10, P < 0.01) was significantly associated with more weight reduction by placebo in T2DM. However, the associations between baseline BMI, baseline HbA1c, and placebo response were insignificant after the adjusted analyses.

CONCLUSION

The placebo response in diabetes mellitus was systematically outlined. Age, sex, disease severity (indirectly reflected by baseline BMI and baseline HbA1c), and disease duration were associated with placebo response in diabetes mellitus. The association between baseline BMI, baseline HbA1c, and placebo response may be the result of regression to the mean.

Effect of Changes in Patient's Self-management Strategies on Clinical Outcomes: Evidence from a Cohort Study of Patients with Diabetes, Hypertension, and Hyperlipidemia

BACKGROUND

Self-management has become the dominant care model for chronic disease management. This study aimed to investigate the effect of changes in self-management strategies on the clinical outcomes of chronic diseases.

METHODS

Two hundred ninety-seven patients with one or more chronic disease (diabetes, dyslipidemia, or hypertension) were registered and followed in this prospective cohort study. We compared differences in the changes in clinical outcomes from baseline to 6 months according to the improvement of self-management strategies by analysis of covariance.

RESULTS

Diabetic patients with improved self-management strategies showed a significantly greater change in HbA1c levels compared to patients without improvement of self-management strategies (group difference in HbA1c = 0.51%). In hypertensive patients, systolic and diastolic blood pressure (BP) showed a significant decline in the patients with improved self-management strategies (group difference in systolic BP = 6.2 mmHg and in diastolic BP = 5.5 mmHg). Clinical outcomes improved significantly when self-management strategies improved in people with a poor self-management strategy at baseline.

CONCLUSIONS

This study suggests that improvements in self-management strategies are associated with an improvement in clinical outcomes among patients with chronic diseases, especially for those with an initially poor self-management strategy.

In Vitro Dissolution and In Vivo Bioequivalence Evaluation of Two Metformin Extended-Release Tablets

The objective of the present study was to evaluate the bioequivalence between generic and branded metformin extended-release (ER) tablets in Chinese subjects. We tested bioequivalence in vitro and in vivo using a comparative dissolution study and a comparative pharmacokinetic trial. Safety assessments were conducted throughout the entire trial period. The dissolution profiles of the generic formulation expressed obvious extended-release properties, similar to those of the branded formulation (f₂ > 60.0%). Consistent with the result of the in vitro study, no remarkable differences were found in terms of pharmacokinetic profiles between generic and branded formulations. The 90% confidence intervals of Ln AUC_0-36 h , Ln AUC_0-∞ , and Ln C_max from generic formulation versus branded formulation were 91.4% to 105.0%, 91.3% to 104.7%, and 101.2% to 119.4%, respectively. During the entire trial period, 4 subjects experienced 11 adverse events. All these were mild and spontaneously resolved. The results obtained from the present study suggest that the generic and branded metformin ER tablets were bioequivalent in Chinese subjects.

Optimization of Metformin in the GRADE Cohort: Effect on Glycemia and Body Weight

OBJECTIVE

We evaluated the effect of optimizing metformin dosing on glycemia and body weight in type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was a prespecified analysis of 6,823 participants in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE) taking metformin as the sole glucose-lowering drug who completed a 4- to 14-week (mean ± SD 7.9 ± 2.4) run-in in which metformin was adjusted to 2,000 mg/day or a maximally tolerated lower dose. Participants had type 2 diabetes for <10 years and an HbA_1c ≥6.8% (51 mmol/mol) while taking ≥500 mg of metformin/day. Participants also received diet and exercise counseling. The primary outcome was the change in HbA_1c during run-in.

RESULTS

Adjusted for duration of run-in, the mean ± SD change in HbA_1c was -0.65 ± 0.02% (-7.1 ± 0.2 mmol/mol) when the dose was increased by ≥1,000 mg/day, -0.48 ± 0.02% (-5.2 ± 0.2 mmol/mol) when the dose was unchanged, and -0.23 ± 0.07% (-2.5 ± 0.8 mmol/mol) when the dose was decreased (n = 2,169, 3,548, and 192, respectively). Higher HbA_1c at entry predicted greater reduction in HbA_1c (P < 0.001) in univariate and multivariate analyses. Weight loss adjusted for duration of run-in averaged 0.91 ± 0.05 kg in participants who increased metformin by ≥1,000 mg/day (n = 1,894).

CONCLUSIONS

Optimizing metformin to 2,000 mg/day or a maximally tolerated lower dose combined with emphasis on medication adherence and lifestyle can improve glycemia in type 2 diabetes and HbA_1c values ≥6.8% (51 mmol/mol). These findings may help guide efforts to optimize metformin therapy among persons with type 2 diabetes and suboptimal glycemic control.

Use of oral antidiabetic drugs in Japanese working-age patients with type 2 diabetes mellitus: dosing pattern for metformin initiators

Objective: To determine the pattern of antidiabetic drug use, with a particular focus on the metformin dose, among patients with type 2 diabetes mellitus (T2DM) in a Japanese working population.Methods: We used an administrative claims database linked to yearly health check-up data from large corporations. Data were collected for T2DM patients who began using an antidiabetic drug between 2014 and 2017 (n = 20,401). We evaluated the type of antidiabetic drug used and the characteristics of the patients using each type of drug. Among the metformin users, we assessed the titration in its dose or treatment during the 12 month period after initiation at 3 month intervals.Results: Among 20,401 new antidiabetic users, the most frequently used agents during the study period were dipeptidyl peptidase-4 inhibitors (DPP4is; 47.4%), followed by biguanides (18.5%) and sodium glucose cotransporter-2 inhibitors (SGLT2is; 6.7%). Most patients who initiated with metformin were prescribed 500 mg or less daily (72.9%); only 2.0% were prescribed a daily dose of >1000 mg. Moreover, 27% remained on the same daily dose during the 1 year follow-up, whereas another 29.9% discontinued their antidiabetic treatment altogether.Conclusions: A unique pattern of prescription was observed amongst Japanese patients with T2DM, and DPP4is, rather than metformin, were predominantly used as the first-line treatment. SGLT2is were infrequently prescribed. Metformin was prescribed at a daily dose of ≤500 mg in many patients. Greater efforts are needed to assess the comparative effectiveness of these treatment strategies.

Observational study of the efficacy of prolonged-release metformin in people with prediabetes

Objectives: Prediabetes is characterized by elevation of indices of blood glucose that is insufficient to provoke a diagnosis of type 2 diabetes, but markedly increases the risk of developing type 2 diabetes in the future. Lifestyle interventions are the main therapeutic intervention for the management of prediabetes. Current guidelines also support treatment of prediabetes with metformin for selected subgroups of patients, and metformin has a therapeutic indication for this use in a number of countries.Methods: We performed an observational, non-interventional study of the effects on glycaemia of prolonged-release metformin (Glucophage XR, referred to henceforth as metformin XR) in 686 subjects with prediabetes. Metformin was prescribed according to physicians' usual care practices, and the study duration was 12 weeks.Results: Mean (SD) fasting plasma glucose (FPG) at baseline was 6.2 (0.4) mmol/L [111 (8) mg/dL) and was reduced by -0.55 (0.7) mmol/L [-10 (13) mg/dL] after 12 weeks of metformin XR. FPG was normalized to below the American Diabetes Association cut-off for the diagnosis of prediabetes (<5.7 mmol/L [100 mg/dL]) in 43% of subjects. Increasing age, increasing body mass index, not following a weight-loss diet and alcohol use predicted a lower probability of normalized FPG. Metformin was well tolerated, with most side effects occurring in the gastrointestinal system, as expected.Conclusions: Metformin XR normalized FPG in about two-fifths of subjects with prediabetes. These real-world data add further support a role for metformin in the management of prediabetes, in line with current guidelines in this area.

What is new in the landscape of insulin-sensitizing agents for polycystic ovary syndrome treatment

Polycystic ovary syndrome, the most common gynecological endocrinopathy, is burdened with a state of hyperinsulinemia and insulin resistance in 50–80% of affected women. Wherever the origin of these metabolic abnormalities lies, their pathogenetic role in determining, perpetuating, and worsening the clinical traits of the syndrome is ascertained. Many studies have already highlighted possible mechanisms: hyperinsulinemia and insulin resistance may contribute to hyperandrogenemia, chronic anovulation, and other comorbidities of the syndrome by differentially affecting the endocrine glands (ovaries, adrenals, and pituitary) and peripheral tissues (fat mass and skeletal muscle). Based on these evidences, in the past years, thorough research has been focused on the possible role of insulin-sensitizing agents in the treatment of polycystic ovary syndrome. Many compounds were tested to verify their efficacy against polycystic ovary syndrome–related metabolic dysfunction, both relying on previous acquired experiences in the field of diabetes mellitus and experimenting new agents, in particular, those belonging to the class of nutraceuticals. We sought to summarize the most relevant aspects of insulin-sensitizing treatments in polycystic ovary syndrome, by reporting the relevant literature on this topic and by keeping an attentive eye on the newly published international guidelines on polycystic ovary syndrome 2018. This overview encompasses metformin, thiazolidinediones, inositols, alpha-lipoic acid, and GLP1-R analogues. Starting from the analysis of the mechanisms of action, we anchored to the state of the art of the use of these drugs in polycystic ovary syndrome, to the most recent evidences for clinical practice and to the remaining open questions around indications, dose, treatment schedules, and side effects.

Mechanisms of action of metformin with special reference to cardiovascular protection

Management guidelines continue to identify metformin as initial pharmacologic antidiabetic therapy of choice for people with type 2 diabetes without contraindications, despite recent randomized trials that have demonstrated significant improvements in cardiovascular outcomes with newer classes of antidiabetic therapies. The purpose of this review is to summarize the current state of knowledge of metformin's therapeutic actions on blood glucose and cardiovascular clinical evidence and to consider the mechanisms that underlie them. The effects of metformin on glycaemia occur mainly in the liver, but metformin-stimulated glucose disposal by the gut has emerged as an increasingly import site of action of metformin. Additionally, metformin induces increased secretion of GLP-1 from intestinal L-cells. Clinical cardiovascular protection with metformin is supported by three randomized outcomes trials (in newly diagnosed and late stage insulin-treated type 2 diabetes patients) and a wealth of observational data. Initial evidence suggests that cotreatment with metformin may enhance the impact of newer incretin-based therapies on cardiovascular outcomes, an important observation as metformin can be combined with any other antidiabetic agent. Multiple potential mechanisms support the concept of cardiovascular protection with metformin beyond those provided by reduced blood glucose, including weight loss, improvements in haemostatic function, reduced inflammation, and oxidative stress, and inhibition of key steps in the process of atherosclerosis. Accordingly, metformin remains well placed to support improvements in cardiovascular outcomes, from diagnosis and throughout the course of type 2 diabetes, even in this new age of improved outcomes in type 2 diabetes.

Long-term effects on glycaemic control and β-cell preservation of early intensive treatment in patients with newly diagnosed type 2 diabetes: A multicentre randomized trial

AIM

To determine the effects of early intensive glycaemic control with intensive insulin treatment (IIT) or initial combined oral antidiabetic drug (COAD) therapy on long-term glycaemic control and the preservation of β-cell function in people with type 2 diabetes mellitus (T2DM).

METHODS

Newly diagnosed drug-naïve patients with T2DM from 8 outpatient diabetes centres were randomized to receive either IIT (n = 50; glargine/glulisine) or COAD (n = 47; glimepiride/metformin) as intensive treatment until the termination criteria to ensure euglycaemia were met. After intensive treatment, the patients completed a follow-up period with either lifestyle modification (LSM) alone or rescue therapy to maintain target glycated haemoglobin levels of <7% (53 mmol/mol) up to week 104. The primary outcomes were analysed after excluding participants who were anti-glutamic acid decarboxylase autoantibody-positive.

RESULTS

Both intensive treatment methods were effective for short-term glycaemic control, but improvements in the disposition index (DI) were significantly greater in the IIT group than in the COAD group (P = .021). During the follow-up period after intensive treatment, the two groups significantly differed in rescue method regarding the maintenance of comparable levels of glycaemic control (P = .010) and more participants who received IIT exhibited well-controlled glycaemia with LSM alone. Additionally, the IIT group maintained a higher DI than the COAD group during the follow-up period. Cox regression analysis showed that the IIT method was associated with a 52.5% lower risk of failing to maintain drug-free glycaemic remission compared with the COAD method (P = .015).

CONCLUSIONS

The findings indicate that outpatient clinic-based IIT to ensure euglycaemia in newly diagnosed patients with T2DM might be an effective initial therapeutic option for improvements in β-cell function and glycaemic control over the long term, without serious adverse events.

The Efficacy and Safety of the Chinese Herbal Formula, JTTZ, for the Treatment of Type 2 Diabetes with Obesity and Hyperlipidemia: A Multicenter Randomized, Positive-Controlled, Open-Label Clinical Trial

BACKGROUND AND AIM

Studies have shown an increasing number of type 2 diabetes (T2D) patients with concomitant obesity and hyperlipidemia syndromes, resulting from relevant metabolic disorders. However, there are few medications and therapies, which can thoroughly address these issues. Therefore, the current study evaluated the efficacy and safety of using JTTZ, a Chinese herbal formula, to treat T2D with obesity and hyperlipidemia.

METHODS

A total of 450 participants with T2D (HbA1c ≥ 7.0%; waist circumference ≥ 90 cm and 80 cm in males and females, resp.; and triglycerides (TG) ≥ 1.7 mmol/L) were randomly assigned, in equal proportions, to two groups in this multicenter randomized, positive-controlled, open-label trial. One group received JTTZ formula, and the other received metformin (MET) for 12 consecutive weeks. The primary efficacy outcomes were changes in HbA1c, TG, weight, and waist circumference. Adverse reactions and hypoglycemia were monitored.

RESULTS

HbA1c decreased by 0.75 ± 1.32% and 0.71 ± 1.2% in the JTTZ and MET groups, respectively, after 12 weeks of treatment. TG levels in the JTTZ and MET groups were reduced by 0.64 ± 2.37 mmol/L and 0.37 ± 2.18 mmol/L, respectively. Weight was decreased by 2.47 ± 2.71 kg in the JTTZ group and by 2.03 ± 2.36 kg in the MET group. JTTZ also appeared to alleviate insulin resistance and increase HOMA-β. In addition, symptoms were significantly relieved in participants in the JTTZ group compared to those in the MET group. One case of hypoglycemia was reported in the MET group. No severe adverse events were reported in either group.

CONCLUSIONS

The JTTZ formula led to safe and significant improvements in the blood glucose, blood lipids, and weight levels; relieved symptoms; and enhanced β cell function for T2D patients with obesity and hyperlipidemia. The JTTZ formula has shown that it could potentially be developed as an alternative medicine for patients with T2D, particularly those who cannot tolerate metformin or other hypoglycemic drugs. This trial was registered with Clinicaltrials.gov NCT01471275.

Metformin extended-release versus immediate-release: An international, randomized, double-blind, head-to-head trial in pharmacotherapy-naïve patients with type 2 diabetes

This international, randomized, double-blind trial (NCT01864174) compared the efficacy and safety of metformin extended-release (XR) and immediate-release (IR) in patients with type 2 diabetes. After a 4-week placebo lead-in, pharmacotherapy-naïve adults with glycated haemoglobin (HbA1c) at 7.0% to 9.2% were randomized (1:1) to receive once-daily metformin XR 2000 mg or twice-daily metformin IR 1000 mg for 24 weeks. The primary endpoint was change in HbA1c after 24 weeks. Secondary endpoints were change in fasting plasma glucose (FPG), mean daily glucose (MDG) and patients (%) with HbA1c <7.0% after 24 weeks. Overall, 539 patients were randomized (metformin XR, N = 268; metformin IR, N = 271). Adjusted mean changes in HbA1c, FPG, MDG and patients (%) with HbA1c <7.0% after 24 weeks were similar for XR and IR: -0.93% vs -0.96%; -21.1 vs -20.6 mg/dL (-1.2 vs -1.1 mmol/L); -24.7 vs -27.1 mg/dL (-1.4 vs -1.5 mmol/L); and 70.9% vs 72.0%, respectively. Adverse events were similar between groups and consistent with previous studies. Overall, metformin XR demonstrated efficacy and safety similar to that of metformin IR over 24 weeks, with the advantage of once-daily dosing.

Understanding and overcoming metformin gastrointestinal intolerance

Metformin is the most widely prescribed drug for patients with type 2 diabetes mellitus and the first-line pharmacological option as supported by multiple international guidelines, yet a rather large proportion of patients cannot tolerate metformin in adequate amounts because of its associated gastrointestinal (GI) adverse events (AEs). GI AEs typically encountered with metformin therapy include diarrhoea, nausea, flatulence, indigestion, vomiting and abdominal discomfort, with diarrhoea and nausea being the most common. Although starting at a low dose and titrating slowly may help prevent some GI AEs associated with metformin, some patients are unable to tolerate metformin at all and it may also be difficult to convince patients to start metformin again after a bout of GI AEs. Despite this clinical importance, the underlying mechanisms of the GI intolerance associated with metformin are poorly known. In the present review, we discuss: the epidemiology of metformin-associated GI intolerance and its underlying mechanisms; genotype variability and associated factors affecting metformin GI intolerance, such as comorbidities, co-medications and bariatric surgery; clinical consequences and therapeutic strategies to overcome metformin GI intolerance. These strategies include appropriate titration of immediate-release metformin, use of extended-release metformin, the promise of delayed-release metformin and gut microbiome modulators, as well as alternative pharmacological therapies when metformin cannot be tolerated at all. Given the available data, all efforts should be made to maintain metformin before considering a shift to another drug therapy.

Metformin: New Preparations and Nonglycemic Benefits

Metformin has been widely used for over 5 decades. New preparations have been developed for possible enhancement of efficiency, tolerability, and pleiotropic nonglycemic effects. Extended-release metformin has contributed to adherence and improved gastrointestinal tolerability. Delayed-release metformin acts in the lower gastrointestinal tract and exerts glucose-lowering effects at lower plasma metformin levels, which might suggest use of this biguanide in patients with chronic kidney disease. Metformin is also known to have numerous nonglycemic effects. Results of the UK Prospective Diabetes Study indicate improvements in cardiovascular outcome and reduced total mortality independent of glycemic control. Anticancer effects of metformin have been discussed and many clinical trials are on-going. Metformin is noted for its beneficial effects on lifespan extension and on disorders due to increased insulin resistance. Further investigations, including randomized control trials in nondiabetic individuals, are required to demonstrate the nonglycemic effects of metformin.

Effects of body mass index or dosage on gastrointestinal disorders associated with extended-release metformin in type 2 diabetes: Sub-analysis of a Phase IV open-label trial in Chinese patients

AIM

To determine whether gastrointestinal (GI) tolerability of metformin monotherapy varies according to baseline BMI or at doses >1500mg/day in patients newly diagnosed with type 2 diabetes.

METHODS

We performed a sub-analysis of the safety population from a prospective, multicenter, Phase IV open-label study in which 371 Chinese patients with type 2 diabetes received extended-release metformin monotherapy for 16 weeks. The incidence, severity and duration of GI adverse events (AEs) were compared between normal-weight (BMI<25kg/m(2), n=155) and overweight/obese (BMI≥25kg/m(2), n=216) patients. The primary objective was to determine whether baseline BMI affect the incidence, severity and duration of GI AEs, using Fisher's exact test and Student's t-test. Secondary objectives were to compare these factors according to final metformin dose (≤1500mg/day versus 2000mg/day).

RESULTS

The proportion of patients who reported ≥1 GI AE did not differ significantly between BMI groups (25.2% of the normal-weight group versus 21.3% of the overweight/obese group; p=0.3840). Patients who reported GI AEs in the two BMI groups experienced similar GI AE severity (p=0.5410), mean duration (p=0.3572) and duration distribution (p=0.1347). There was no significant difference in GI AE severity and duration between metformin dosage groups (≤1500mg/day versus 2000mg/day).

CONCLUSIONS

Newly-diagnosed Chinese type 2 diabetes patients of normal weight are no more likely than overweight/obese patients to suffer from increased incidence rates, severity or duration of GI AEs when treated with first-line extended-release metformin monotherapy. Doses of 2000mg/day did not increase the severity or duration of GI AEs.

Genetic variants in transcription factors are associated with the pharmacokinetics and pharmacodynamics of metformin

One-third of type 2 diabetes patients do not respond to metformin. Genetic variants in metformin transporters have been extensively studied as a likely contributor to this high failure rate. Here, we investigate, for the first time, the effect of genetic variants in transcription factors on metformin pharmacokinetics (PK) and response. Overall, 546 patients and healthy volunteers contributed their genome-wide, pharmacokinetic (235 subjects), and HbA1c data (440 patients) for this analysis. Five variants in specificity protein 1 (SP1), a transcription factor that modulates the expression of metformin transporters, were associated with changes in treatment HbA1c (P < 0.01) and metformin secretory clearance (P < 0.05). Population pharmacokinetic modeling further confirmed a 24% reduction in apparent clearance in homozygous carriers of one such variant, rs784888. Genetic variants in other transcription factors, peroxisome proliferator-activated receptor-α and hepatocyte nuclear factor 4-α, were significantly associated with HbA1c change only. Overall, our study highlights the importance of genetic variants in transcription factors as modulators of metformin PK and response.

Efficacy of glimepiride/metformin fixed-dose combination vs metformin uptitration in type 2 diabetic patients inadequately controlled on low-dose metformin monotherapy: A randomized, open label, parallel group, multicenter study in Korea

Aims/Introduction

To compare the efficacy and safety of early combination therapy with glimepiride/metformin to metformin uptitration in reducing glycated hemoglobin (HbA1c) levels in Korean type 2 diabetic patients inadequately controlled on low-dose metformin monotherapy.

Materials and Methods

In a randomized, open label, parallel group, multicenter study, 209 Korean type 2 diabetic patients (HbA1c 7.0–10.0%, on metformin 500–1,000 mg/day) received glimepiride/metformin fixed-dose combination (G/M FDC) or metformin uptitration treatment (Met UP). The primary end-point was the change in HbA1c from baseline to week 24.

Results

G/M FDC therapy provided significantly greater adjusted mean decreases vs Met UP therapy in HbA1c (−1.2 vs −0.8%, P < 0.0001), and fasting plasma glucose (−35.7 vs −18.6 mg/dL, P < 0.0001). A significantly greater proportion of patients with G/M FDC therapy achieved HbA1c < 7% (74.7 vs 46.6%, P < 0.0001) at the end of the study. More patients experienced hypoglycemia with G/M FDC therapy compared with Met UP therapy (41 vs 5.6%, P < 0.0001), but there was no serious hypoglycemia in any group. A modest increase in mean bodyweight occurred in the patients who were treated with G/M FDC therapy (1.0 kg), whereas a slight decrease was observed in the patients who were treated with Met UP therapy (−0.7 kg).

Conclusion

The present study showed that glimepiride/metformin fixed-dose combination therapy was more effective in glycemic control than metformin uptitration, and was well tolerated in type 2 diabetic patients inadequately controlled by low-dose metformin monotherapy in Korea. This trial was registered with ClinicalTrial.gov (no. NCT00612144).

Safety, tolerability, and efficacy of metformin extended-release oral antidiabetic therapy in patients with type 2 diabetes: an observational trial in Asia

BACKGROUND

The aim of the present prospective observational study was to assess the tolerability and antihyperglycemic efficacy of metformin extended-release (MXR) in the routine treatment of patients with type 2 diabetes mellitus (T2DM) from six Asian countries.

METHODS

Data from 3556 patients treated with once-daily MXR for 12 weeks, or until discontinuation, were analyzed.

RESULTS

Treatment with MXR was well tolerated, with 97.4% of patients completing 12 weeks of treatment. Only 3.3% of patients experienced one or more gastrointestinal (GI) side-effects and only 0.7% of patients discontinued for this reason (primary endpoint). The incidence of GI side-effects and related discontinuations appeared to be considerably lower during short-term MXR therapy than during previous treatment (mean 2.71 years' duration), most commonly with immediate-release metformin. A 12-week course of MXR therapy also reduced HbA1c and fasting glucose levels from baseline.

CONCLUSIONS

The present study provides new insights into the incidence of GI side-effects with MXR in Asian patients with T2DM and on the tolerability of MXR in non-Caucasian populations. Specifically, these data indicate that once-daily MXR not only improves measures of glycemic control in Asian patients with T2DM, but also has a favorable GI tolerability profile that may help promote enhanced adherence to oral antidiabetic therapy.

Metformin and its clinical use: new insights for an old drug in clinical practice

Metformin is generally recommended as first-line treatment in type 2 diabetes, especially in overweight patients, but in recent years new indications for its use have emerged. Metformin has been found to be safe and efficacious both as monotherapy and in combination with all oral antidiabetic agents and insulins. If metformin use during pregnancy and the lactation period is supported by few data, it could be indicated for women with polycystic ovary syndrome, since it could diminish circulating androgens and insulin resistance, thus ameliorating the ovulation rate. Metformin seems to reduce cancer risk, which appears to be increased in diabetics, and is a promising agent for oncoprevention and chemotherapy combinations. Moreover, metformin could find a place in the treatment of non-alcoholic fatty liver disease. Lactic acidosis could be decreased by avoiding metformin use in patients with hypovolemia, sepsis, renal impairment, hypoxic respiratory diseases and heart failure, in the preoperative period and before intravenous injection of contrast media.

Long-term safety, tolerability, and weight loss associated with metformin in the Diabetes Prevention Program Outcomes Study

OBJECTIVE

Metformin produced weight loss and delayed or prevented diabetes in the Diabetes Prevention Program (DPP). We examined its long-term safety and tolerability along with weight loss, and change in waist circumference during the DPP and its long-term follow-up.

RESEARCH DESIGN AND METHODS

The randomized double-blind clinical trial of metformin or placebo followed by a 7-8-year open-label extension and analysis of adverse events, tolerability, and the effect of adherence on change in weight and waist circumference.

RESULTS

No significant safety issues were identified. Gastrointestinal symptoms were more common in metformin than placebo participants and declined over time. During the DPP, average hemoglobin and hematocrit levels were slightly lower in the metformin group than in the placebo group. Decreases in hemoglobin and hematocrit in the metformin group occurred during the first year following randomization, with no further changes observed over time. During the DPP, metformin participants had reduced body weight and waist circumference compared with placebo (weight by 2.06 ± 5.65% vs. 0.02 ± 5.52%, P < 0.001, and waist circumference by 2.13 ± 7.06 cm vs. 0.79 ± 6.54 cm, P < 0.001 in metformin vs. placebo, respectively). The magnitude of weight loss during the 2-year double-blind period was directly related to adherence (P < 0.001). Throughout the unblinded follow-up, weight loss remained significantly greater in the metformin group than in the placebo group (2.0 vs. 0.2%, P < 0.001), and this was related to the degree of continuing metformin adherence (P < 0.001).

CONCLUSIONS

Metformin used for diabetes prevention is safe and well tolerated. Weight loss is related to adherence to metformin and is durable for at least 10 years of treatment.

Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus

BACKGROUND

Metformin is an oral anti-hyperglycemic agent that has been shown to reduce total mortality compared to other anti-hyperglycemic agents, in the treatment of type 2 diabetes mellitus. Metformin, however, is thought to increase the risk of lactic acidosis, and has been considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age.

OBJECTIVES

To assess the incidence of fatal and nonfatal lactic acidosis, and to evaluate blood lactate levels, for those on metformin treatment compared to placebo or non-metformin therapies.

SEARCH STRATEGY

A comprehensive search was performed of electronic databases to identify studies of metformin treatment. The search was augmented by scanning references of identified articles, and by contacting principal investigators.

SELECTION CRITERIA

Prospective trials and observational cohort studies in patients with type 2 diabetes of least one month duration were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy.

DATA COLLECTION AND ANALYSIS

The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for non-metformin treatments. The upper limit for the true incidence of cases was calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed-effect model for continuous data.

MAIN RESULTS

Pooled data from 347 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 70,490 patient-years of metformin use or in 55,451 patients-years in the non-metformin group. Using Poisson statistics the upper limit for the true incidence of lactic acidosis per 100,000 patient-years was 4.3 cases in the metformin group and 5.4 cases in the non-metformin group. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to non-metformin therapies.

AUTHORS' CONCLUSIONS

There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments.

Assessment of efficacy and tolerability of once-daily extended release metformin in patients with type 2 diabetes mellitus

AIMS

To determine prospectively the efficacy, tolerability and patient satisfaction of an extended release formulation of metformin (metformin XR) in hospital based outpatients with type 2 diabetes mellitus currently treated with standard metformin.

METHODS

Patients on immediate release standard metformin either alone or combined with other oral agents were switched to extended release metformin XR 500 mg tablets and titrated to a maximum dose of 2000 mg/day Measurements to include glucose and lipid control, blood pressure, body weight, waist circumference, C-reactive protein, adverse events and patient satisfaction were recorded at baseline, three and six months.

RESULTS

Complete data were obtained for 35 of the 61 patients enrolled to the study. At three and six months no changes were reported for any of the cardiovascular risk factors except for lipids where there was a modest rise in plasma triglycerides. These effects were achieved with a reduced dose of metformin XR compared to pre-study dosing with standard metformin (1500 mg +/- 402 vs 1861 +/- 711 p = 0.004). A total of 77% of patients were free of gastrointestinal side effects and 83% of patients stated a preference for metformin XR at the end of the study. Ghost tablets were reported in the faeces by the majority of the patients (54.1%).

CONCLUSIONS

Patients switched to extended release metformin XR derived the same clinical and metabolic benefits as for standard metformin but with reduced dosage, fewer gastrointestinal side effects and a greater sense of well being and satisfaction on medication.

Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus

BACKGROUND

Metformin is an oral anti-hyperglycemic agent that has been shown to reduce total mortality compared to other anti-hyperglycemic agents, in the treatment of type 2 diabetes mellitus. Metformin, however, is thought to increase the risk of lactic acidosis, and has been considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age.

OBJECTIVES

To assess the incidence of fatal and nonfatal lactic acidosis, and to evaluate blood lactate levels, for those on metformin treatment compared to placebo or non-metformin therapies.

SEARCH STRATEGY

A comprehensive search was performed of electronic databases to identify studies of metformin treatment. The search was augmented by scanning references of identified articles, and by contacting principal investigators.

SELECTION CRITERIA

Prospective trials and observational cohort studies in patients with type 2 diabetes of least one month duration were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy.

DATA COLLECTION AND ANALYSIS

The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for non-metformin treatments. The upper limit for the true incidence of cases was calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed-effect model for continuous data.

MAIN RESULTS

Pooled data from 347 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 70,490 patient-years of metformin use or in 55,451 patients-years in the non-metformin group. Using Poisson statistics the upper limit for the true incidence of lactic acidosis per 100,000 patient-years was 4.3 cases in the metformin group and 5.4 cases in the non-metformin group. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to non-metformin therapies.

AUTHORS' CONCLUSIONS

There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments.

Adherence in patients transferred from immediate release metformin to a sustained release formulation: a population-based study

AIM

Metformin is the most commonly prescribed oral agent used in the treatment of type 2 diabetes. It is effective at reducing glycosylated Haemoglobin (HbA1c) and decreasing microvascular and macrovascular disease. However, up to 25% of patients develop gastrointestinal side effects leading to cessation in 5-10% of users. Metformin XL (glucophage SR) is a once a day preparation that delays absorption, leading to decreased peak metformin concentrations. We hypothesised that the XL preparation of metformin would be better tolerated than the standard immediate release (IR) preparation leading to improved adherence to therapy.

METHODS

In a retrospective observational study, we studied adherence and glycaemic control in patients prescribed metformin IR and XL preparations in Tayside, UK.

RESULTS

Metformin XL was used by 137 patients during the study period. Overall adherence was greater in the XL group (80%) compared with the 10,772 patients in the IR group (72%, p = 0.0026). In the 40 patients who changed from metformin IR to metformin XL who had sufficient data to determine adherence, the adherence increased from 62% in the IR group to 81% in the XL group (p < 0.0001). This was associated with an HbA1c reduction from 9.1 to 8.4% (p = 0.0739, n = 29).

CONCLUSIONS

Metformin XL use is associated with increased adherence compared with the IR preparation, although the mechanism for this cannot be determined from this study. In patients intolerant of metformin IR the XL preparation should be considered.

Reducing cardiovascular complications of type 2 diabetes by targeting multiple risk factors

Insulin resistance syndrome is characterized by hyperglycemia, atherogenic dyslipidemia, hypertension, and abdominal obesity. Hyperglycemia is the major risk factor for microvascular complications in type 2 diabetes. However, 70% to 80% of patients with type 2 diabetes will die of macrovascular disease. Atherogenic dyslipidemia-characterized by elevated triglyceride levels, low high-density lipoprotein cholesterol (HDL-c) levels, and a preponderance of small, dense, low-density lipoprotein (LDL) particles-is the major cause of atherosclerosis in individuals with type 2 diabetes. Therefore, treatment of type 2 diabetes must address hyperglycemia to prevent microvascular disease (retinopathy, neuropathy, and nephropathy) and atherogenic dyslipidemia to prevent macrovascular complications. Emerging evidence indicates lipid and glucose homeostasis are interrelated via bile acid-activated nuclear hormone receptor signaling pathways. Agents that act on these pathways could simultaneously address hyperglycemia and dyslipidemia in patients with type 2 diabetes. Recent studies have shown that bile acid sequestrants, including cholestyramine, colestimide, and colesevelam HCl, significantly improve glycemic control and reduce LDL cholesterol levels in patients with type 2 diabetes. This paper will review the effects of bile acid sequestrants on both glucose and lipid metabolism in patients with type 2 diabetes.

Evaluation of adverse events of oral antihyperglycemic monotherapy experienced by a geriatric population in a real-world setting: a retrospective cohort analysis

BACKGROUND AND OBJECTIVE

To evaluate and compare the risk of adverse events (AEs) associated with the use of metformin, sulfonylureas and thiazolidinediones among geriatric patients in a usual care setting.

METHODS

An electronic medical record database was utilized to identify geriatric patients with type 2 diabetes mellitus aged > or =65 years from 1996 to 2005. Patients naive to oral antihyperglycemic drug (OAD) therapy were followed for 395 days post initiation of metformin, sulfonylurea or thiazolidinedione treatment. AEs related to study drugs were evaluated during the follow-up period, and the risks of developing an AE were evaluated and adjusted for differences in baseline characteristics by OAD treatment.

RESULTS

A total of 5438 patients (mean age 73.2 [SD 5.08] years, 56.1% female) were identified. During the follow-up period, 12.5% of patients experienced an AE (8.3% of metformin, 13.9% of sulfonylurea and 19.8% of thiazolidinedione recipients). Sulfonylurea (odds ratio [OR] 1.74; 95% CI 1.41, 2.13) and thiazolidinedione (OR 2.86; 95% CI 2.23, 3.65) recipients were more likely to experience an AE than metformin recipients, after adjustment for baseline demographic and co-morbidity differences. The average time to onset of a metformin AE (175 days) was less than that for sulfonylurea or thiazolidinedione treatment (192 and 201 days, respectively). The most common AEs were abdominal pain with metformin (42.3%) and weight gain >4.5 kg for sulfonylureas (63.2%) and thiazolidinediones (68.2%). Hypoglycaemia occurred in 2.6% and 2.2% of sulfonylurea and thiazolidinedione recipients, respectively.

DISCUSSION AND CONCLUSIONS

Geriatric patients in a real-world setting experienced AEs with metformin, sulfonylurea and thiazolidinedione therapy, although rates differed from those seen in clinical trials, particularly for weight gain and hypoglycaemia. Lactic acidosis occurred at a higher rate with metformin therapy than has been reported in clinical trials, but our results were in the same range for abdominal pain and lower for diarrhoea, nausea/vomiting and dyspepsia. AEs related to sulfonylurea therapy were in the same range as in clinical trials for weight gain but lower for hypoglycaemia, dizziness and headaches. AEs related to thiazolidinedione therapy were more common in our study than in clinical trials, and within the same range for weight gain and elevated liver enzymes but lower for hypoglycaemia and oedema. While AE reporting is likely to be different in a real-world setting than in clinical trials, the observed variances may also be due to the aetiology of diabetes and the physiological response to hypoglycaemia in an older population.

Metformin therapy and clinical uses

Metformin is now established as a first-line antidiabetic therapy for the management of type 2 diabetes. Its early use in treatment algorithms is supported by lack of weight gain, low risk of hypoglycaemia and its mode of action to counter insulin resistance. The drug's anti-atherosclerotic and cardioprotective effects have recently been confirmed in prospective and retrospective studies, and appear to reflect a collection of glucose-independent effects on the vascular endothelium, suppressant effects on glycation, oxidative stress and formation of adhesion molecules, stimulation of fibrinolysis and favourable effects on the lipid profile. Although avoidance of troublesome gastrointestinal tolerability issues requires careful dose titration, the risk of serious adverse events is considered low provided that contra-indications (especially with respect to renal function) are observed. As many of its actions go beyond glucose lowering, emerging evidence indicates potential benefits in other insulin-resistant states and possibly tumour suppression.

Association between oral antidiabetic use, adverse events and outcomes in patients with type 2 diabetes

OBJECTIVE

To quantify adverse events (AEs) associated with the use of metformin (MET), sulphonylureas (SUs) and thiazolidinediones (TZDs) in a usual care setting, and to assess the relationship of AEs to treatment patterns and glycaemic response in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

An electronic medical record database was used to identify patients with type 2 diabetes age >or=18 years from 1996 to 2005. Patients naïve to oral antidiabetic therapy were followed for 395 days postinitiation of MET, SU or TZD treatment. AEs related to study drugs were evaluated during the follow-up period. Baseline and follow-up A1C levels were compared by drug regimen. Associations between the change in A1C, drug regimen changes and AEs were evaluated.

RESULTS

A total of 14,512 patients (mean age 60.8 years, 52.9% female) were identified. During the follow-up period, 12.7% of patients experienced an AE (8.6% MET, 15.9% SU and 19.8% TZD patients). SU and TZD patients were more likely to experience an AE than MET (p < 0.001) patients. AEs did not significantly influence A1C outcomes, although MET and SU patients experiencing an AE were more likely to add-on therapy (odds ratio (OR) = 1.34 and OR = 1.37, respectively; p < 0.05) than those without an AE. MET patients with AEs were more likely to switch therapy (OR = 1.91; p < 0.05) than those without an AE.

CONCLUSIONS

The occurrence of AEs did not significantly impact glycaemic response to therapy. However, AEs may lead to greater treatment switches for patients receiving MET and add-on therapy for MET-treated and SU-treated patients.

The metabolic effects of once daily extended-release metformin in patients with type 2 diabetes: a multicentre study

AIM

To investigate the effects of extended-release metformin (MXR) compared with immediate-release metformin (MIR) on post-prandial glycaemic excursion, chronic glycaemia, lipid profiles, insulin resistance and islet function in type 2 diabetes.

METHODS

A randomised, open-labelled, positive-controlled multicentre study was conducted on 150 Chinese patients with type 2 diabetes. After 2 weeks of run-in period with MIR, 150 subjects were randomised into MXR group and MIR group. The patients in MXR group were assigned to take MXR 1500 mg once daily after dinner, while the patients in MIR group were assigned to continue MIR 500 mg thrice daily after meals for 12 weeks. Standard meal tests were carried out at baseline and at the end of this study. Plasma glucose, serum insulin, HbA1c and lipid profiles were measured. Homeostasis model assessment (HOMA) was used to evaluate insulin resistance index (HOMA-IR) and islet beta-cell function index (HOMA-B).

RESULTS

Either MIR or MXR modestly, but significantly decreased HbA1c levels and body mass index (BMI) after 12 weeks of treatment. However, there were no significant differences between two groups. The post-prandial glycaemia at 120 min after a standard meal in MXR group was higher than in MIR group (11.02 +/- 3.08 mmol/l vs. 9.74 +/- 2.61 mmol/l, p < 0.05). Moreover, no differences in the areas under curve of insulin release response, HOMA-B, HOMA-IR and lipid profiles were found within or between groups after 12 weeks of treatment.

CONCLUSION

The effects of once daily MXR on chronic glycaemia, BMI, lipid profiles, insulin resistance and islet function are comparable with that of thrice daily MIR in oriental population.

Both slow-release and regular-form metformin improve glycemic control without altering plasma visfatin level in patients with type 2 diabetes mellitus

Both slow-release (SR) and regular-release (RR) metformin were effective in the treatment of type 2 diabetes mellitus. We compare the efficacy, safety, and effects on serum adipocytokines and inflammatory markers of both regimens in patients with type 2 diabetes mellitus. A prospective, randomized, double-blind study enrolled 55 patients with type 2 diabetes mellitus, which were randomly assigned to receive either metformin SR or RR (at a maximal dosage of 2000 mg/d for 12 weeks). Glycosylated hemoglobin A1c (HbA1c), fasting plasma glucose, adipocytokines, C-reactive protein, and insulin resistance and pancreatic beta-cell function were measured before and after treatment. Significant decreases (P<.001) in mean HbA1c and fasting plasma glucose levels were observed in each group. However, the mean changes in HbA1c from baseline to end point in the 2 groups were not significantly different. Changes in metabolic parameters were similar except that a decreased total cholesterol level was observed in the metformin RR group. Neither regimen treatment had any influence on insulin resistance, but metformin RR improved beta-cell function. Neither regimen had an effect on serum adipocytokines or inflammatory markers. Once-daily metformin SR was as safe and effective as metformin RR in type 2 diabetic patients. Neither dosage form affected serum adipocytokines and inflammatory markers.

Clomiphene, metformin, or both for infertility in the polycystic ovary syndrome

BACKGROUND

The polycystic ovary syndrome is a common cause of infertility. Clomiphene and insulin sensitizers are used alone and in combination to induce ovulation, but it is unknown whether one approach is superior.

METHODS

We randomly assigned 626 infertile women with the polycystic ovary syndrome to receive clomiphene citrate plus placebo, extended-release metformin plus placebo, or a combination of metformin and clomiphene for up to 6 months. Medication was discontinued when pregnancy was confirmed, and subjects were followed until delivery.

RESULTS

The live-birth rate was 22.5% (47 of 209 subjects) in the clomiphene group, 7.2% (15 of 208) in the metformin group, and 26.8% (56 of 209) in the combination-therapy group (P<0.001 for metformin vs. both clomiphene and combination therapy; P=0.31 for clomiphene vs. combination therapy). Among pregnancies, the rate of multiple pregnancy was 6.0% in the clomiphene group, 0% in the metformin group, and 3.1% in the combination-therapy group. The rates of first-trimester pregnancy loss did not differ significantly among the groups. However, the conception rate among subjects who ovulated was significantly lower in the metformin group (21.7%) than in either the clomiphene group (39.5%, P=0.002) or the combination-therapy group (46.0%, P<0.001). With the exception of pregnancy complications, adverse-event rates were similar in all groups, though gastrointestinal side effects were more frequent, and vasomotor and ovulatory symptoms less frequent, in the metformin group than in the clomiphene group.

CONCLUSIONS

Clomiphene is superior to metformin in achieving live birth in infertile women with the polycystic ovary syndrome, although multiple birth is a complication. (ClinicalTrials.gov number, NCT00068861 [ClinicalTrials.gov].).

Case studies in swelling polymeric gastric retentive tablets

Swelling tablets administered in the fed state have been shown to provide therapeutic advantages in two marketed products, with the duration of delivery characterised with respect to food and tablet size. Metformin extended-release tablets are a diffusion-based swelling tablet demonstrating once-daily efficacy with good gastrointestinal solubility. Ciprofloxacin extended-release tablets are based on an erosional matrix that delivers the drug to the upper gastrointestinal tract over 6 h to provide once-daily efficacy with reduced incidences of nausea and diarrhoea. Furosemide extended-release tablets are another example of an erosional matrix designed to deliver furosemide to the duodenum and upper jejunum over 6 h to provide a more gradual diuresis and naturesis compared with the immediate-release product.

Efficacy, tolerability, and safety of a novel once-daily extended-release metformin in patients with type 2 diabetes

OBJECTIVE

The purpose of this study was to determine the efficacy and safety of a novel extended-release metformin in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Adults with type 2 diabetes (newly diagnosed, treated with diet and exercise only, or previously treated with oral diabetic medications) were randomly assigned to receive one of three extended-release metformin treatment regimens (1,500 mg/day q.d., 1,500 mg/day twice daily, or 2,000 mg/day q.d.) or immediate-release metformin (1,500 mg/day twice daily) in a double-blind 24-week trial.

RESULTS

Significant decreases (P < 0.001) in mean HbA(1c) (A1C) levels were observed by week 12 in all treatment groups. The mean changes from baseline to end point in the two groups given 1,500 mg extended-release metformin (-0.73 and -0.74%) were not significantly different from the change in the immediate-release metformin group (-0.70%), whereas the 2,000-mg extended-release metformin group showed a greater decrease in A1C levels (-1.06%; mean difference [2,000 mg extended-release metformin - immediate-release metformin]: -0.36 [98.4% CI -0.65 to -0.06]). Rapid decreases in fasting plasma glucose levels were observed by week 1, which continued until week 8, and were maintained for the duration of the study. The overall incidence of adverse events was similar for all treatment groups, but fewer patients in the extended-release metformin groups discontinued treatment due to nausea during the initial dosing period than in the immediate-release metformin group.

CONCLUSIONS

Once- or twice-daily extended-release metformin was as safe and effective as twice-daily immediate-release metformin and provided continued glycemic control for up to 24 weeks of treatment.