Effects of voglibose and nateglinide on glycemic status and coronary atherosclerosis in early-stage diabetic patients

Alpha-Glucosidase Inhibitors in Aging and Aging-Related Diseases: Clinical Applications and Relevant Mechanisms

Aging is a complex and universal process marked by gradual functional declines at the cellular and tissue levels, often leading to a range of aging-related diseases such as diabetes, cardiovascular diseases, and cancer. Delaying the aging process can help prevent, slow down, and alleviate the severity of these various conditions, enhancing overall health and well-being. Alpha-glucosidase inhibitors (AGIs) are a class of widely used antidiabetic drugs that inhibit alpha-glucosidase in the small intestinal mucosa, delaying carbohydrate absorption and reducing postprandial hyperglycemia. Beyond their roles in diabetes treatment, AGIs have shown potential in extending lifespan and effectively treating aging-related diseases by modulating oxidative stress, gut microbiota, inflammatory responses, and nutrient-sensing pathways. This review summarizes recent advancements in the application of AGIs for preventing and treating aging and aging-related diseases, with a focus on their mechanisms and roles in these processes.

The effect of continuous glucose monitoring-guided glycemic control on progression of coronary atherosclerosis in type 2 diabetic patients with coronary artery disease: The OPTIMAL randomized clinical trial

BACKGROUND

Continuous glucose monitoring (CGM) improves glycemic fluctuation and reduces hypoglycemic risk. Whether CGM-guided glycemic control favorably modulates coronary atherosclerosis in patients with type 2 diabetes (T2DM) remains unknown.

METHODS

The OPTIMAL trial was a prospective, randomized, single-center trial in which 94 T2DM patients with CAD were randomized to CGM- or HbA1c-guided glycemic control for 48 weeks (jRCT1052180152). The primary endpoint was the nominal change in total atheroma volume (TAV) measured by serial IVUS. The secondary efficacy measure was the nominal change in maxLCBI4mm on near-infrared spectroscopy imaging.

RESULTS

Among the 94 randomized patients, 82 had evaluable images at 48 weeks. Compared to HbA1c-guided glycemic control, CGM-guided control achieved a greater reduction in %coefficient of variation [-0.1 % (-1.8 to 1.6) vs. -3.3 % (-5.1 to -1.5), p = 0.01] and a greater increase in the duration with glucose between 70 and 180 mg/dL [-1.5 % (-6.0 to 2.9) vs. 6.7 % (1.9 to 11.5), p = 0.02]. TAV increased by 0.11 ± 1.9 mm3 in the HbA1c-guided group and decreased by -3.29 ± 2.00 mm3 in the CGM-guided group [difference = -3.4 mm3 (95%CI: -8.9 to 2.0 mm3), p = 0.22]. MaxLCBI4mm, increased by 90.1 ± 25.6 in the HbA1c-guided group and by 50.6 ± 25.6 in the CGM-guided group (difference = -45.6 (95%CI: -118.1 to 26.7) p = 0.21]. A post-hoc exploratory analysis showed a greater regression of maxLCBI4mm in the CGM-guided group [difference = 20.4 % (95%CI:1.3 to 39.5 %), p = 0.03].

CONCLUSIONS

CGM-guided control for 48 weeks did not slow disease progression in T2DM patients with CAD. A greater regression of lipidic plaque under CGM-guided glycemic control in the post-hoc analysis requires further investigation.

[Evolution of the non-insulin therapeutic strategy in type 2 diabetes]

While the prevalence of diabetes continues to rise worldwide, with 537 million adults aged 20-79-years-old having diabetes in 2021, the development of new therapeutic classes improving not only glycemic control but also kidney function and cardiovascular prevention has revolutionized patient care. Today, the treatment of diabetes is no longer just the treatment of blood sugar level. In this context, the individualized therapeutic strategy has been completely reviewed, with in particular sulfamides indicated much later in the therapeutic strategy, while SGLT2 inhibitors are indicated very early in patients with kidney disease and/or with ischemic heart disease or chronic heart failure, and GLP-1 analogues in obese patients and/or in primary or secondary cardiovascular prevention. As for lifestyle rules and metformin, they remain the cornerstone of treatment. Knowledge of antidiabetic effects in terms of efficacy and hypoglycemic risk, of cardiovascular, nephroprotective and weight effects is essential to optimize the management of diabetic patients today.

Long-term effects of lowering postprandial glucose level on cardiovascular outcomes in early-stage diabetic patients with coronary artery disease: 10-year post-trial follow-up analysis of the DIANA study

AIMS

To elucidate the long-term cardiovascular benefit of lowering postprandial hyperglycemia (PPG) in early-stage T2DM patients.

METHODS

This 10-year post-trial follow-up study included 243 patients from the DIANA (DIAbetes and diffuse coronary Narrowing) study, a multi-center randomized controlled trial which compared the efficacy of one-year life-style and pharmacological (voglibose/nateglinide) intervention lowering PPG on coronary atherosclerosis in 302 early-stage T2DM subjects [impaired glucose tolerance (IGT) or newly-diagnosed T2DM] (UMIN-CTRID#0000107). MACE (all-cause death, non-fatal MI or unplanned coronary revascularization) were compared in (1) three assigned therapies (life-style intervention/vogliose/nateglinide) and (2) patients with and without improvement of PPG (reversion from IGT to NGT or from DM to IGT/NGT on 75 g oral glucose tolerance test).

RESULTS

During the 10-year post-trial observational period, voglibose (HR = 1.07, 95%CI: 0.69-1.66, p = 0.74) or nateglinide (HR = 0.99, 95%CI: 0.64-1.55, p = 0.99) did not reduce MACE. Similarly, achieving the improvement of PPG was not associated with a reduction of MACE (HR = 0.78, 95%CI: 0.51-1.18, p = 0.25). However, in IGT subjects (n = 143), this glycemic management significantly reduced the occurrence of MACE (HR = 0.44, 95%CI: 0.23-0.86, p = 0.01), especially unplanned coronary revascularization (HR = 0.46, 95%CI: 0.22-0.94, p = 0.03).

CONCLUSIONS

The early improvement of PPG significantly reduced MACE and unplanned coronary revascularization in IGT subjects during the post-trial 10-year period.

Effect of insulin secretagogues on major cardiovascular events and all-cause mortality: A meta-analysis of randomized controlled trials

BACKGROUND AND AIM

In 2019, the Italian Society of Diabetology and the Italian Association of Clinical Diabetologists nominated an expert panel to develop guidelines for drug treatment of type 2 diabetes. This expert panel, after identifying the effects of glucose-lowering agents on major adverse cardiovascular events (MACEs) and all-cause mortality as critical outcomes, decided to perform a systematic review and meta-analysis on the effect of insulin secretagogues (sulfonylureas and glinides) with this respect.

METHODS AND RESULTS

A MEDLINE database search was performed to identify all RCTs, up to January 1st, 2020, with duration≥52 weeks, in which insulin secretagogues (glibenclamide, gliclazide, glimepiride, glipizide, chlorpropamide, repaglinide, nateglinide) were compared with either placebo or active comparators. The principal endpoints were MACE (restricted for RCT reporting MACEs within their outcomes) and all-cause mortality (irrespective of the inclusion of MACEs among the pre-specified outcomes). Mantel-Haenszel odds ratio (MH-OR) with 95% Confidence Interval (95% CI) was calculated for all the endpoints considered. Fourteen RCTs were included in the analysis for MACEs (919 in insulin secretagogues and 1,087 in control group). Insulin secretagogues were not significantly associated with an increased risk of MACEs in comparison with controls (MH-OR 1.08 [95% CI 0.96, 1.22], p = 0.20). When considering the 48 RCTs fulfilling criteria for inclusion in the analysis on all-cause mortality, insulin secretagogues were associated with a significantly increased risk of all-cause mortality (MH-OR 1.11 [1.00, 1.23], p = 0.04).

CONCLUSIONS

This meta-analysis suggests that insulin secretagogues are associated with an increased risk of all-cause mortality when compared with placebo or other anti-hyperglycaemic drugs.

The effect of voglibose on metabolic profiles in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of clinical trials

OBJECTIVE

The effect of voglibose on metabolic homeostasis is not well characterized. Therefore, we conducted a systematic review and meta-analysis of clinical trials assessing the effect of voglibose on metabolic profile in patients with type 2 diabetes mellitus (T2DM).

METHODS

Systematic searches were conducted in PubMed, Scopus, Embase, Google Scholar, Web of Science and Cochrane Library to identify clinical trials assessing the effects of voglibose supplementation on cardio-metabolic profile from incept up to 29 July 2019. Data was pooled using fixed- or random-effect models and weighted mean difference (WMD) as the effect size.

RESULTS

Eight clinical trials from 1094 reports, were eligible for inclusion. Pooled findings identified significant reductions in hemoglobin A1c (HbA1c) (WMD= -0.27; 95 %CI -0.49 to -0.05; P = 0.01; I² = 64.8 %) and an increase in LDL-cholesterol levels (WMD=5.97 mg/dl, 95 % CI 0.88, 11.06, P = 0.02; I² = 0.0 %). However, no evidence of effect for voglibose intake on T2DM patients was observed for: fasting blood sugar (FBS) (WMD -7.43 mg/dl; 95 %CI -16.56 to 1.71; P = 0.110; I² = 69.3 %), serum insulin (WMD= -0.15 μU/mL; 95 %CI -0.89 to 0.60; P = 0.70; I² = 0.0 %), total-cholesterol (WMD=2.82 mg/dl, 95 %CI -2.36 to 8.01, P = 0.70; I² = 49.7 %), triglycerides (WMD= -7.07 mg/dl, 95 %CI -21.76 to 7.62, P = 0.34; I² = 0.0 %), HDL-cholesterol levels (WMD= -2.10 mg/dl, 95 %CI -4.48 to 0.27, P = 0.08; I² = 0.0 %,), body mass index (BMI) (WMD=0.09 kg/m², 95 %CI -0.70 to 0.87; P = 0.87; I² = 0.0 %), body weight (WMD= -0.42 kg, 95 %CI -0.84 to 0.00; P = 0.05; I² = 0.0 %), and adiponectin levels (WMD = 0.32 μg/mL, 95 %CI -0.74 to 1.38; P = 0.55; I² = 0.0 %).

CONCLUSIONS

The current meta-analysis identified a decrease in HbA1c and an increase in LDL-cholesterol with administration of voglibose. However, no significant effect was observed on FBS, insulin, bodyweight, BMI, adiponectin, triglycerides, total- and HDL-cholesterol levels.

Recent Updates on Vascular Complications in Patients with Type 2 Diabetes Mellitus

It is well known that patients with type 2 diabetes mellitus (T2DM) are at an increased risk of morbidity and mortality from atherosclerotic cardiovascular (CV) complications. Previously, the concept that diabetes mellitus (DM) is a "coronary artery disease (CAD) risk equivalent" was widely accepted, implying that all DM patients should receive intensive management. However, considerable evidence exist for wide heterogeneity in the risk of CV events among T2DM patients and the concept of a "CAD risk equivalent" has changed. Recent guidelines recommend further CV risk stratification in T2DM patients, with treatment tailored to the risk level. Although imaging modalities for atherosclerotic cardiovascular disease (ASCVD) have been used to improve risk prediction, there is currently no evidence that imaging-oriented therapy improves clinical outcomes. Therefore, controversy remains whether we should screen for CVD in asymptomatic T2DM. The coexistence of T2DM and heart failure (HF) is common. Based on recent CV outcome trials, sodium glucose cotransporter-2 inhibitors and glucagon like peptide-1 receptor agonists are recommended who have established ASCVD, indicators of high risk, or HF because of their demonstrated benefits for CVD. These circumstances have led to an increasing emphasis on ASCVD and HF in T2DM patients. In this review, we examine the literature published within the last 5 years on the risk assessment of CVD in asymptomatic T2DM patients. In particular, we review recent guidelines regarding screening for CVD and research focusing on the role of coronary artery calcium, coronary computed tomography angiography, and carotid intima-media thickness in asymptomatic T2DM patients.

The efficacy of glycemic control with continuous glucose monitoring on atheroma progression: rationale and design of the Observation of Coronary Atheroma Progression under Continuous Glucose Monitoring Guidance in Patients with Type 2 Diabetes Mellitus (OPTIMAL)

Background

Patients with type 2 diabetes mellitus (T2DM) are high-risk subjects who more frequently have micro- and macrovascular diseases including coronary artery disease (CAD). Since impaired glycemic homeostasis directly influences the formation and propagation of atherosclerotic plaques, optimal management of glycemic status is required for the prevention of diabetic atherosclerosis. Continuous glucose monitoring (CGM) provides not only average glucose level but also the degree of glucose fluctuation and hypoglycemia. Given the association of glycemic variability with diabetic macrovascular diseases, CGM-based glycemic management could favorably modulate glycemic fluctuation, thereby potentially modifying atheroma burden in T2DM subjects. To test this hypothesis, the Observation of Coronary Atheroma Progression under Continuous Glucose Monitoring Guidance in Patients with Type 2 Diabetes Mellitus (OPTIMAL) study has been designed (Japan Registry of Clinical Trials: jRCT1052180152, University Hospital Medical Information Network Clinical Trial Registry UMIN000036721).

Methods

The OPTIMAL is a single-center, randomized trial to evaluate the efficacy of CGM-based glycemic control on atheroma progression in T2DM patients with CAD by using serial intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) imaging. A total of 90 eligible subjects will be randomized 1:1 into two groups to receive either CGM-based glycemic control or HbA1c-baded glycemic management. Coronary angiography and NIRS/IVUS imaging is repeated at the end of the assigned treatment period.

Results

The primary endpoint is the normalized absolute change in total atheroma volume (TAV) from baseline to 12 months. The secondary endpoints include (I) the absolute change in percent atheroma volume, (II) the percent change in lipid core burden index, (III) the change in coefficient variance measured by CGM, (IV) the change in atherogenic markers (high-density lipoprotein functionality, proprotein convertase subxilisin/kexin type 9 and fatty-acid binding proteins), and (V) the frequency of hypoglycemia. Safety will also be evaluated.

Conclusions

The collaboration of CGM use with serial NIRS/IVUS imaging will enable to compare atheroma progression rate under CGM-based glycemic management and HbA1c-based approach.

Asymptomatic coronary artery disease in a Norwegian cohort with type 2 diabetes: a prospective angiographic study with intravascular ultrasound evaluation

Aims

The prevalence of asymptomatic coronary artery disease (CAD) in type 2 diabetes (T2D) is unclear. We investigated the extent and prevalence of asymptomatic CAD in T2D patients by utilizing invasive coronary angiography (ICA) and intravascular ultrasound (IVUS), and whether CAD progression, evaluated by ICA, could be modulated with a multi-intervention to reduce cardiovascular (CV) risk.

Methods

Fifty-six T2D patients with ≥ 1 additional CV risk factor participated in a 2 year randomized controlled study comparing hospital-based multi-intervention (multi, n = 30) versus standard care (stand, n = 26), with a pre-planned follow-up at year seven. They underwent ICA at baseline and both ICA and IVUS at year seven. ICA was described by conventional CAD severity and extent scores. IVUS was described by maximal intimal thickness (MIT), percent and total atheroma volume and compared with individuals without T2D and CAD (heart transplant donors who had IVUS performed 7–11 weeks post-transplant, n = 147).

Results

Despite CV risk reduction in multi after 2 years intervention, there was no between-group difference in the progression of CAD at year seven. Overall, the prevalence of CAD defined by MIT ≥ 0.5 mm in the T2DM subjects was 84%, and as compared to the non-T2DM controls there was a significantly higher atheroma burden (mean MIT, PAV and TAV in the T2D population were 0.75 ± 0.27 mm, 33.8 ± 9.8% and 277.0 ± 137.3 mm³ as compared to 0.41 ± 0.19 mm, 17.8 ± 7.3% and 134.9 ± 100.6 mm³ in the reference population).

Conclusion

We demonstrated that a 2 year multi-intervention, despite improvement in CV risk factors, did not influence angiographic progression of CAD. Further, IVUS revealed that the prevalence of asymptomatic CAD in T2D patients is high, suggesting a need for a broader residual CV risk management using alternative approaches.

Trial registration Clinical trials.gov id: NCT00133718 (https://clinicaltrials.gov/ct2/show/NCT00133718)

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0832-2) contains supplementary material, which is available to authorized users.

Alpha-glucosidase inhibitors for prevention or delay of type 2 diabetes mellitus and its associated complications in people at increased risk of developing type 2 diabetes mellitus

BACKGROUND

Alpha-glucosidase inhibitors (AGI) reduce blood glucose levels and may thus prevent or delay type 2 diabetes mellitus (T2DM) and its associated complications in people at risk of developing of T2DM.

OBJECTIVES

To assess the effects of AGI in people with impaired glucose tolerance (IGT), impaired fasting blood glucose (IFG), moderately elevated glycosylated haemoglobin A1c (HbA1c) or any combination of these.

SEARCH METHODS

We searched CENTRAL, MEDLINE, 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. The date of the last search of all databases was December 2017.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), with a duration of one year or more, comparing AGI with any pharmacological glucose-lowering intervention, behaviour-changing intervention, placebo or no intervention in people with IFG, IGT, moderately elevated HbA1c or combinations of these.

DATA COLLECTION AND ANALYSIS

Two review authors read all abstracts and full-text articles or 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 involvement of a third review author. For meta-analyses we used a random-effects model with assessment of risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, using 95% confidence intervals (CIs) for effect estimates. We assessed the overall quality of the evidence by using the GRADE instrument.

MAIN RESULTS

For this update of the Cochrane Review (first published 2006, Issue 4) we included 10 RCTs (11,814 participants), eight investigating acarbose and two investigating voglibose, that included people with IGT or people "at increased risk for diabetes". The trial duration ranged from one to six years. Most trials compared AGI with placebo (N = 4) or no intervention (N = 4).Acarbose reduced the incidence of T2DM compared to placebo: 670 out of 4014 people (16.7%) in the acarbose groups developed T2DM, compared to 812 out of 3994 people (20.3%) in the placebo groups (RR 0.82, 95% CI 0.75 to 0.89; P < 0.0001; 3 trials; 8008 participants; moderate-certainty evidence). One trial including participants with coronary heart disease and IGT contributed 64% of cases for this outcome. Acarbose reduced the risk of T2DM compared to no intervention: 7 out 75 people (9.3%) in the acarbose groups developed T2DM, compared to 18 out of 65 people (27.7%) in the no-intervention groups (RR 0.31, 95% CI 0.14 to 0.69; P = 0.004; 2 trials; 140 participants; very low-certainty evidence).Acarbose compared to placebo did not reduce or increase the risk of all-cause mortality (RR 0.98, 95% CI 0.82 to 1.18; P = 0.86; 3 trials; 8069 participants; very low-certainty evidence), cardiovascular mortality (RR 0.88; 95% CI 0.71 to 1.10; P = 0.26; 3 trials; 8069 participants; very low-certainty evidence), serious adverse events (RR 1.12, 95% CI 0.97 to 1.29; P = 0.13; 2 trials; 6625 participants; low-certainty evidence), non-fatal stroke (RR 0.50, 95% CI 0.09 to 2.74; P = 0.43; 1 trial; 1368 participants; very low-certainty evidence) or congestive heart failure (RR of 0.87; 95% CI 0.63 to 1.12; P = 0.40; 2 trials; 7890 participants; low-certainty evidence). Acarbose compared to placebo reduced non-fatal myocardial infarction: one out of 742 participants (0.1%) in the acarbose groups had a non-fatal myocardial infarction compared to 15 out of 744 participants (2%) in the placebo groups (RR 0.10, 95% CI 0.02 to 0.53; P = 0.007; 2 trials; 1486 participants; very low-certainty evidence). Acarbose treatment showed an increased risk of non-serious adverse events (mainly gastro-intestinal events), compared to placebo: 751 of 775 people (96.9%) in the acarbose groups experienced an event, compared to 723 of 775 people (93.3%) in the placebo groups (RR 1.04; 95% CI 1.01 to 1.06; P = 0.0008; 2 trials; 1550 participants). Acarbose compared to no intervention showed no advantage or disadvantage for any of these outcome measures (very low-certainty evidence).One trial each compared voglibose with placebo (1780 participants) or diet and exercise (870 participants). Voglibose compared to placebo reduced the incidence of T2DM: 50 out of 897 participants (5.6%) developed T2DM, compared to 106 out of 881 participants (12%) in the placebo group (RR 0.46, 95% CI 0.34 to 0.64; P < 0.0001; 1 trial; 1778 participants; low-certainty evidence). For all other reported outcome measures there were no clear differences between voglibose and comparator groups. One trial with 90 participants compared acarbose with diet and exercise and another trial with 98 participants reported data on acarbose versus metformin. There were no clear differences for any outcome measure between these two acarbose interventions and the associated comparator groups.None of the trials reported amputation of lower extremity, blindness or severe vision loss, end-stage renal disease, health-related quality of life, time to progression to T2DM, or socioeconomic effects.

AUTHORS' CONCLUSIONS

AGI may prevent or delay the development of T2DM in people with IGT. There is no firm evidence that AGI have a beneficial effect on cardiovascular mortality or cardiovascular events.

Application of causal inference methods in the analyses of randomised controlled trials: a systematic review

BACKGROUND

Applications of causal inference methods to randomised controlled trial (RCT) data have usually focused on adjusting for compliance with the randomised intervention rather than on using RCT data to address other, non-randomised questions. In this paper we review use of causal inference methods to assess the impact of aspects of patient management other than the randomised intervention in RCTs.

METHODS

We identified papers that used causal inference methodology in RCT data from Medline, Premedline, Embase, Cochrane Library, and Web of Science from 1986 to September 2014, using a forward citation search of five seminal papers, and a keyword search. We did not include studies where inverse probability weighting was used solely to balance baseline characteristics, adjust for loss to follow-up or adjust for non-compliance to randomised treatment. Studies where the exposure could not be assigned were also excluded.

RESULTS

There were 25 papers identified. Nearly half the papers (11/25) estimated the causal effect of concomitant medication on outcome. The remainder were concerned with post-randomisation treatment regimens (sequential treatments, n =5 ), effects of treatment timing (n = 2) and treatment dosing or duration (n = 7). Examples were found in cardiovascular disease (n = 5), HIV (n = 7), cancer (n = 6), mental health (n = 4), paediatrics (n = 2) and transfusion medicine (n = 1). The most common method implemented was a marginal structural model with inverse probability of treatment weighting.

CONCLUSIONS

Examples of studies which exploit RCT data to address non-randomised questions using causal inference methodology remain relatively limited, despite the growth in methodological development and increasing utilisation in observational studies. Further efforts may be needed to promote use of causal methods to address additional clinical questions within RCTs to maximise their value.

Long-term Sustainability of Diabetes Prevention Approaches: A Systematic Review and Meta-analysis of Randomized Clinical Trials

Importance

Diabetes prevention is imperative to slow worldwide growth of diabetes-related morbidity and mortality. Yet the long-term efficacy of prevention strategies remains unknown.

Objective

To estimate aggregate long-term effects of different diabetes prevention strategies on diabetes incidence.

Data Sources

Systematic searches of MEDLINE, EMBASE, Cochrane Library, and Web of Science databases. The initial search was conducted on January 14, 2014, and was updated on February 20, 2015. Search terms included prediabetes, primary prevention, and risk reduction.

Study Selection

Eligible randomized clinical trials evaluated lifestyle modification (LSM) and medication interventions (>6 months) for diabetes prevention in adults (age ≥18 years) at risk for diabetes, reporting between-group differences in diabetes incidence, published between January 1, 1990, and January 1, 2015. Studies testing alternative therapies and bariatric surgery, as well as those involving participants with gestational diabetes, type 1 or 2 diabetes, and metabolic syndrome, were excluded.

Data Extraction and Synthesis

Reviewers extracted the number of diabetes cases at the end of active intervention in treatment and control groups. Random-effects meta-analyses were used to obtain pooled relative risks (RRs), and reported incidence rates were used to compute pooled risk differences (RDs).

Main Outcomes and Measures

The main outcome was aggregate RRs of diabetes in treatment vs control participants. Treatment subtypes (ie, LSM components, medication classes) were stratified. To estimate sustainability, post-washout and follow-up RRs for medications and LSM interventions, respectively, were examined.

Results

Forty-three studies were included and pooled in meta-analysis (49 029 participants; mean [SD] age, 57.3 [8.7] years; 48.0% [n = 23 549] men): 19 tested medications; 19 evaluated LSM, and 5 tested combined medications and LSM. At the end of the active intervention (range, 0.5-6.3 years), LSM was associated with an RR reduction of 39% (RR, 0.61; 95% CI, 0.54-0.68), and medications were associated with an RR reduction of 36% (RR, 0.64; 95% CI, 0.54-0.76). The observed RD for LSM and medication studies was 4.0 (95% CI, 1.8-6.3) cases per 100 person-years or a number-needed-to-treat of 25. At the end of the washout or follow-up periods, LSM studies (mean follow-up, 7.2 years; range, 5.7-9.4 years) achieved an RR reduction of 28% (RR, 0.72; 95% CI, 0.60-0.86); medication studies (mean follow-up, 17 weeks; range, 2-52 weeks) showed no sustained RR reduction (RR, 0.95; 95% CI, 0.79-1.14).

Conclusions and Relevance

In adults at risk for diabetes, LSM and medications (weight loss and insulin-sensitizing agents) successfully reduced diabetes incidence. Medication effects were short lived. The LSM interventions were sustained for several years; however, their effects declined with time, suggesting that interventions to preserve effects are needed.

High burden of coronary atherosclerosis in patients with a new diagnosis of type 2 diabetes

PURPOSE

The purposes of this study were to compare the presence, extent and composition of coronary plaques in asymptomatic patients with newly diagnosed type 2 diabetes to age- and sex-matched controls.

METHODS

Patients with newly diagnosed (<1 year) type 2 diabetes ( n = 44) and controls ( n = 44) underwent contrast-enhanced coronary computed tomography angiography. Advanced plaque analysis including total plaque volume and volumes of plaque components (calcified plaque and non-calcified plaque, including low-attenuation [low-density non-calcified plaque]) was performed using validated semi-automated software.

RESULTS

Coronary artery calcification was more often seen in patients with type 2 diabetes (66%) versus controls (48%), p < 0.05. Both the absolute volume (median; interquartile range) of low-density non-calcified plaque (7.9 mm³; 0-50.5 mm³ vs 0; 0-34.3 mm³, p < 0.05) and the increase in low-density non-calcified plaque ratio in relation to total plaque volume ( τ = 0.5, p < 0.001) were significantly higher in patients with type 2 diabetes. More patients with type 2 diabetes had spotty calcification (31% vs 0%, p < 0.05). By multivariate analysis, the presence of any low-density non-calcified plaque was higher in males (odds ratio: 4.06, p < 0.05), who also demonstrated a larger low-density non-calcified plaque volume ( p < 0.001). The presence and extent of low-density non-calcified plaque increased with age, smoking, hypertension and hyperglycaemia, all p < 0.05.

CONCLUSION

Asymptomatic patients with newly diagnosed type 2 diabetes had plaque features associated with increased vulnerability as compared with age- and sex-matched controls.

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.

Atheroma Progression in Obese Early-stage Diabetic Japanese Patients in Response to Glycemic Control: Sub-analysis from the DIANA Study

AIM

Diabetes is accompanied by abdominal obesity, which produces various metabolic abnormalities. While metabolic factors have been considered to promote the development of coronary atherosclerosis in the early-stage of diabetes, it remains unknown whether the presence of obesity in early-stage diabetics affects the natural history of coronary atherosclerosis. We herein investigated the characteristics of the disease substrate in obese early-stage diabetics.

METHODS

The DIANA (DIAbetes and diffuse coronary NArrowing) study was a serial evaluation of angiographic disease progression in early-stage diabetics with coronary artery disease. A total of 252 study subjects were stratified into non-obese (n=168) and obese groups (n=84). Obesity in Japanese subjects was defined as a body mass index ≥25 kg/m(2) according to the statement about Japanese obesity from the Japan Society for the Study of Obesity. Coronary atherosclerotic changes were evaluated by a quantitative computed analysis. The total lesion length (TLL=total length of all atherosclerotic lesions) was compared between the groups.

RESULTS

The obese patients were younger (p=0.0002) and had higher levels of fasting (p=0.002) and postprandial insulin (p=0.01), and higher triglyceride levels (p=0.02). On serial angiographic evaluations, obese patients had greater disease progression, reflected by a larger percent change in the TLL (24.7±13.7 vs. 7.4±10.0%, p=0.04). However, the improvement of abnormal glucose tolerance was associated with a slowing of disease progression in both non-obese (-0.9±10.7 vs. ＋15.0±11.2%, p=0.04) and obese (＋4.2±22.8 vs. ＋55.5±26.5%, p=0.005) patients.

CONCLUSIONS

Obese patients with early-stage diabetes exhibit profound disease progression. Glycemic control attenuated the progression of their coronary atherosclerosis. Our findings indicate progressive but modifiable disease in obese early-stage diabetics under optimal glycemic management.

Efficacy of voglibose in type 2 diabetes

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is currently at epidemic proportions and the forecast is for a continued sharp increase in global prevalence. An even larger proportion of the population has prediabetes (impaired glucose tolerance [IGT]) underscoring the urgent need for preventive strategies. Even in the presence of adequate glycosylated hemoglobin (HbA1c) levels, postprandial hyperglycemia can occur and is known to have a stronger association with cardiovascular morbidity than fasting glucose. The α-glucosidase inhibitor voglibose is widely used in Japan to improve postprandial hyperglycemia.

AREAS COVERED

This review examines the literature for the pharmacology, pharmacokinetics, clinical efficacy and safety of voglibose in patients with T2DM. Particular focus is on its efficacy in preventing T2DM in individuals with IGT and its efficacy as add-on therapy or in combination with other oral antidiabetic agents in patients with T2DM.

EXPERT OPINION

As the relationship between glucose levels and cardiovascular risk extends below the diabetic threshold, postprandial hyperglycemia is recognized as a key therapeutic target in the treatment of T2DM. Strategies to prevent the progression of IGT to overt T2DM have enormous potential to reduce the individual and societal burden of disease. Voglibose is the first oral antidiabetic agent to gain approval in Japan for this indication.

Voglibose: an alpha glucosidase inhibitor

Diabetes Mellitus (DM) is a morbid disease worldwide, with increasing incidence as time passes. It has macro-vascular and micro-vascular complications. The main cause of these complications is poorly controlled postprandial hyperglycaemia. Alpha glucosidase inhibitors, namely acarbose, voglibose and miglitol, are available for therapy. Voglibose is well tolerated and effective in comparable doses among these drugs. This article highlights the important features of voglibose.

Comparison of effects of α-Glucosidase inhibitors and glinide drugs on endothelial dysfunction in diabetic patients with coronary artery disease

BACKGROUND

Studies have shown that repeated post-prandial hyperglycemia may play an important role in the development of atherosclerosis by suppressing endothelial function. α-Glucosidase inhibitors (α-GIs), which reduce post-prandial hyperglycemia without stimulating insulin secretion, significantly reduce the risk of coronary artery disease (CAD), whereas glinides, which improve post-prandial hyperglycemia through post-prandial insulin secretion, do not appear to affect CAD.

METHODS AND RESULTS

A total of 104 diabetic patients with CAD were randomly divided into 2 groups: those treated with miglitol (M-group; n=52) and those treated with nateglinide (N-group; n=52). After 4 months' treatment, although hemoglobin A1c and 1,5-anhydroglucitol were significantly improved in both groups, only the M-group had significant reductions in insulin resistance index and triglyceride/high-density lipoprotein cholesterol (TG/HDL-C; a beneficial index for assessing the presence of small dense low-density lipoprotein, and a marker of atherogenic dyslipidemia). Furthermore, only the M-group had improvement in percentage flow-mediated dilatation (%FMD) and reactive oxygen metabolites. In the M-group, multiple regression analysis showed that improvement in TG/HDL-C, in addition to 1,5-anhydroglucitol, was an independent predictor of improvement in %FMD.

CONCLUSIONS

The ameliorating effect of α-GI on post-prandial hyperglycemia without stimulating insulin secretion may improve atherogenic dyslipidemia by reducing insulin resistance. These effects are associated with its beneficial impact on oxidative stress, consequently leading to an improvement in endothelial dysfunction.

Comparison of the hypoglycemic effect of sitagliptin versus the combination of mitiglinide and voglibose in drug-naïve Japanese patients with type 2 diabetes

OBJECTIVE

The postprandial glucose (PPG) level is reduced by α-GIs, glinides and DPP4Is through different pharmacological actions. The aim of this study was to compare the effect of sitagliptin (S) versus that of the combination of mitiglinide and voglibose (M+V) on markers of glycemic control.

RESEARCH DESIGN AND METHODS

A randomized cross-over trial was performed in 20 patients with drug-naïve type 2 diabetes. The patients were randomized to receive S (50 mg/day) or M+V (1 tablet 3 times daily). Treatment was continued for 8 weeks, after which they were switched to the other regimen and treated for another 8 weeks. At baseline, after the first regimen, and after the second regimen, a meal test was performed.

MAIN OUTCOME MEASURES

The markers of glycemic control were examined.

RESULTS

Reduction of glucose excursion was significantly greater with M+V than with S. HbA1c did not change with either regimen. However, 1,5-anhydroglucitol showed a significant increase from baseline with both regimens (7.9 ± 4.3 μg/ml at baseline vs. 10.6 ± 5.5 with S, p < 0.05 and 15.1 ± 6.2 with M+V, p < 0.01). Compared with baseline, glycoalbumin was significantly reduced by M+V, but not S (19.6 ± 2.9% at baseline vs. 17.3 ± 3.8% with M+V, p < 0.05).

CONCLUSION

M+V achieved better control of PPG excursion than S.

Impact of post-challenge hyperglycemia on clinical outcomes in Japanese patients with stable angina undergoing percutaneous coronary intervention

BACKGROUND

Post-challenge hyperglycemia (PH) is well-established as one of risk factors for coronary artery disease. However, it remains unclear whether PH affects clinical outcomes in patients with stable angina undergoing percutaneous coronary intervention (PCI).

METHODS

A total of 828 patients with stable angina undergoing PCI were retrospectively analyzed. Of these, 452 patients with previously diagnosed diabetes mellitus (DM) or fasting plasma glucose (PG) ≥126 mg/dl and HbA1c ≥6.5% were defined as known DM. The remaining 376 patients were divided into the two groups according to 2-h PG: PH (2-h PG ≥140 mg/dl, n=236) and normal glucose tolerance (NGT, 2-h PG <140 mg/dl, n=140). We assessed the rate of major adverse cardiovascular events (MACE), defined as a composite of cardiovascular death, myocardial infarction, stroke, and clinically-driven revascularization.

RESULTS

During the median follow-up of 4.3 years, the MACE rate was significantly higher in the DM and PH groups than the NGT group (39.3% vs. 20.7%, P <0.001; 31.4% vs. 20.7%, P=0.044, respectively). Compared with the NGT group, the cumulative incidence of revascularization was significantly higher in the DM group (35.1% vs. 18.5%, P <0.001) and tended to be higher in the PH group (27.1% vs. 18.5%, P=0.067). In the multivariate analysis, known DM (Hazard ratio [HR]: 2.16, 95% confidence interval (CI): 1.49-3.27, P < 0.001), PH (HR: 1.62, 95% CI: 1.07-2.53, P = 0.023), LDL-C >100 mg/dl (HR: 1.62, 95% CI: 1.26 to 2.10, P < 0.001), and previous stroke (HR: 1.47, 95% CI: 1.03-2.04, P = 0.034) were predictors of MACE.

CONCLUSION

PH is associated with future cardiovascular events in patients with stable angina undergoing PCI.

α-Glucosidase inhibitors and their use in clinical practice

Post-prandial hyperglycemia still remains a problem in the management of type 2 diabetes mellitus. Of all available anti-diabetic drugs, α-glucosidase inhibitors seem to be the most effective in reducing post-prandial hyperglycemia. We conducted a review analyzing the clinical efficacy and safety of α-glucosidase inhibitors, both alone and in combination with other anti-diabetic drugs, with respect to glycemic control, inflammation and atherosclerosis. α-Glucosidase inhibitors proved to be effective and safe both in monotherapy and as an add-on to other anti-diabetic drugs. Compared to miglitol and voglibose, acarbose seems to have some additive effects such as stabling carotid plaques, and reducing inflammation. Acarbose also proved to reverse impaired glucose tolerance to normal glucose tolerance.

Postprandial hyperglycemia and endothelial function in type 2 diabetes: focus on mitiglinide

The risk of cardiovascular complication in a diabetes patient is similar to that in a nondiabetic patient with a history of myocardial infarction. Although intensive control of glycemia achieved by conventional antidiabetic agents decreases microvascular complications such as retinopathy and nephropathy, no marked effect has been reported on macrovascular complications or all-cause mortality. Evidence from VADT, ACCORD, and ADVANCE would suggest that glycemic control has little effect on macrovascular outcomes. Moreover, in the case of ACCORD, intensive glycemic control may be associated with an increased risk of mortality. There is sufficient evidence that suggests that postprandial hyperglycemia may be an independent risk factor for cardiovascular disease in diabetes patients. However, there are no prospective clinical trials supporting the recommendation that lowering postprandial blood glucose leads to lower risk of cardiovascular outcomes. Mitiglinide is a short-acting insulinotropic agent used in type 2 diabetes treatment. It has a rapid stimulatory effect on insulin secretion and reduces postprandial plasma glucose level in patients with type 2 diabetes. Because of its short action time, it is unlikely to exert adverse effects related to hypoglycemia early in the morning and between meals. Mitiglinide reduces excess oxidative stress and inflammation, plays a cardioprotective role, and improves postprandial metabolic disorders. Moreover, mitiglinide add-on therapy with pioglitazone favorably affects the vascular endothelial function in type 2 diabetes patients. These data suggest that mitiglinide plays a potentially beneficial role in the improvement of postprandial hyperglycemia in type 2 diabetes patients and can be used to prevent cardiovascular diseases. Although the results of long-term, randomized, placebo-controlled trials for determining the cardiovascular effects of mitiglinide on clinical outcomes are awaited, this review is aimed at summarizing substantial insights into this topic.