Insulin secretion capacity in the development from normal glucose tolerance to type 2 diabetes

Efficacy of acarbose in different geographical regions of the world: analysis of a real-life database

BACKGROUND

Alpha-glucosidase inhibitors are recommended in some international guidelines as first-line, second-line and third-line treatment options but are not used worldwide due to perceived greater effectiveness in Asians than Caucasians.

METHODS

Data from ten post-marketing non-interventional studies using acarbose, the most widely used alpha-glucosidase inhibitor, from 21 countries, provinces and country groups were pooled. Effects on glycated hemoglobin (HbA1c ) were analysed for four major ethnicity/region groups (European Caucasians and Asians from East, Southeast and South Asia) to identify differences in the response to acarbose.

RESULTS

The safety and efficacy populations included 67 682 and 62 905 patients, respectively. Mean HbA1c in the total population decreased by 1.12 ± 1.31% at the 3-month visit from 8.4% at baseline (p < 0.0001). Reductions in HbA1c , fasting plasma glucose and post-prandial plasma glucose were greater in patients with higher baseline values. Acarbose was well tolerated, with few episodes of hypoglycemia (0.03%) and gastrointestinal adverse events (2.76%). Data from 30 730 Caucasians from Europe and Asians from three major regions of Asia with non-missing gender/age information and baseline/3-month HbA1c data were analysed by multivariable analyses of covariance. After adjustment for relevant baseline confounding factors, Southeast and East Asians had slightly better responses to acarbose than South Asians and European Caucasians; however, the differences were small.

CONCLUSIONS

Acarbose was effective in both European Caucasians and Asians; however, after adjustment for baseline confounding factors, significant small differences in response favoured Southeast and East Asians.

Positive association of free triiodothyronine with pancreatic β-cell function in people with prediabetes

AIM

To analyse the effects of thyroid hormones on β-cell function and glucose metabolism in people with prediabetes who are euthyroid.

METHODS

A total of 111 people who were euthyroid underwent 75-g oral glucose tolerance tests, of whom 52 were assigned to the normal glucose tolerance and 59 to the prediabetes groups. Homeostatic model assessment of β-cell function, insulinogenic index and areas under the curve for insulin and glucose were evaluated as indices of pancreatic β-cell function.

RESULTS

In both groups, BMI, fasting insulin, homeostasis model assessment ratio and HDL cholesterol correlated significantly with all indices of pancreatic β-cell function. Free triiodothyronine correlated positively with all insulin secretion indices in the prediabetes group. Multiple linear regression analysis showed that free triiodothyronine was an independent variable that had a positive correlation with all indices of β-cell function in the prediabetes group. By contrast, no such correlation was found in the normal glucose tolerance group.

CONCLUSIONS

Free triiodothyronine is associated with both basal and glucose-stimulated insulin secretion in people with prediabetes who are euthyroid; therefore, the regulation of insulin secretion by thyroid hormones is a potentially novel therapeutic target for the treatment of diabetes.

Insulin requirement profiles in Japanese hospitalized subjects with type 2 diabetes treated with basal-bolus insulin therapy

To assess the total daily inulin dose (TDD) and contribution of basal insulin to TDD and to identify the predictive factors for insulin requirement profiles in subjects with type 2 diabetes, we retrospectively examined insulin requirement profiles of 275 hospitalized subjects treated with basal-bolus insulin therapy (BBT) (mean age, 60.1 ± 12.9 years; HbA1c, 10.2 ± 4.5%). Target plasma glucose level was set between 80 and 129 mg/dL before breakfast and between 80 and 179 mg/dL at 2-hour after each meal without causing hypoglycemia. We also analyzed the relationship between the insulin requirement profiles (TDD and basal/total daily insulin ratio [B/TD ratio]) and insulin-associated clinical parameters. The mean TDD was 0.463 ± 0.190 unit/kg/day (range, 0.16-1.13 unit/kg/day). The mean B/TD ratio was 0.300 ± 0.099 (range, 0.091-0.667). A positive correlation of TDD with B/TD ratio was revealed by linear regression analysis (r=0.129, p=0.03). Stepwise multiple regression analysis identified post-breakfast glucose levels before titrating insulin as an independent determinant of the insulin requirement profile [Std β (standard regression coefficient) = 0.228, p<0.01 for TDD, Std β = -0.189, p<0.01 for B/TD ratio]. The TDD was <0.6 unit/kg/day and the B/TD ratio was <0.4 in the majority (70.2%) of subjects in the present study. These findings may have relevance in improving glycemic control and decreasing the risk of hypoglycemia and weight gain in subjects with type 2 diabetes treated with BBT.

An inverse U-shaped association of late and peak insulin levels during an oral glucose load with glucose intolerance in a Japanese population: a cross-sectional study

The current study investigated the association of post-load insulin levels with glucose tolerance in a Japanese population. A total of 1450 Japanese employees who underwent a 75-g oral glucose tolerance test (OGTT) were included. Glucose tolerance was assessed by 120-min glucose levels during a 75-g OGTT. A penalized cubic regression spline model analysis revealed that the 60- and 120-min insulin levels, but not 0- or 30-min insulin levels, had an inverse U-shaped relationship to the 120-min glucose level. Furthermore, peak insulin level followed an inverse U shape in relation to the 120-min glucose level, whereas the peak of insulin appeared at a later point in time as the 120-min glucose level increased. These associations were similarly observed in both obese and non-obese subgroups, although obesity was associated with higher insulin levels. Peak insulin levels also demonstrated an inverse U shape in association with 0-min glucose levels and indices of β cell function, assessed by the disposition index and the β-cell function index. In conclusion, peak insulin levels followed an inverse U shape in relation to glucose intolerance in a Japanese population, whereas the impairment of glucose tolerance was associated with a delay in the time to reach peak insulin levels.

Utility of 75-g oral glucose tolerance test results and hemoglobin a1c values for predicting the incidence of diabetes mellitus among middle-aged Japanese men -a large-scale retrospective cohort study performed at a single hospital

OBJECTIVE

The aim of this study was to investigate the associations between the incidence of diabetes and the accumulation of markers of impaired glucose metabolism; i.e., pre-diabetes.

METHODS

This retrospective cohort study recruited 1,631 men without diabetes at baseline who attended more than two routine health check-ups at our institution between 2006 and 2012. The participants were divided into four groups based on the number of markers of impaired glucose metabolism exhibited at the initial examination. The following markers of impaired glucose metabolism were defined as risk factors for diabetes: a fasting plasma glucose level of ≥110 mg/dL, 2-hour plasma glucose level of ≥140 mg/dL and glycated hemoglobin (HbA1c) value of ≥6.0% (42 mmol/moL). The risk of developing diabetes was assessed using a multivariate analysis.

RESULTS

The median examination interval was 1,092 days. The incidence of diabetes rose in association with the number of markers. The subjects with two markers displayed a multivariate-adjusted odds ratio (OR) for diabetes of 19.43 [95% confidence interval (CI): 9.70-38.97] and the subjects with three markers displayed an OR of 48.30 (95% CI: 20.39-115.85) compared with the subjects with one or no markers.

CONCLUSION

The present results demonstrate the impact of accumulating markers of impaired glucose metabolism on the risk of developing diabetes. Anti-diabetes intervention strategies should aim to comprehensively assess an individual's risk of developing diabetes at the pre-diabetes stage.

Incretin response in Asian type 2 diabetes: Are Indians different?

Incretin-based therapy has clearly emerged as one of the most sought out strategy in managing type 2 diabetes, primarily because they generally do not causes hypoglycemia and possess weight-neutral or weight losing properties. Efficacy-wise too, these agents, are more or less similar to commonly used drugs metformin and sulfonylureas. Interestingly, some studies recently suggested that glycemic response to these incretin-based therapies could also differ ethnicity-wise. Subsequently, meta-analysis from these studies also suggested that Asians may have better response to these incretin-based therapies. This review will be an attempt to critically analyze those studies available in literature and to address as to why East-Asians and South-Asians may have different incretin response compared to non-Asians.

Identification of putative biomarkers for prediabetes by metabolome analysis of rat models of type 2 diabetes

Biomarkers for the development of type 2 diabetes (T2D) are useful for prediction and intervention of the disease at earlier stages. In this study, we performed a longitudinal study of changes in metabolites using an animal model of T2D, the spontaneously diabetic Torii (SDT) rat. Fasting plasma samples of SDT and control Sprague-Dawley (SD) rats were collected from 6 to 24 weeks of age, and subjected to gas chromatography-mass spectrometry-based metabolome analysis. Fifty-nine hydrophilic metabolites were detected in plasma samples, including amino acids, carbohydrates, sugars and organic acids. At 12 weeks of age, just before the onset of diabetes in SDT rats, the amounts of nine of these metabolites (asparagine, glutamine, glycerol, kynurenine, mannose, n-alpha-acetyllysine, taurine, threonine, and tryptophan) in SDT rats were significantly different from those in SD rats. In particular, metabolites in the tryptophan metabolism pathway (tryptophan and kynurenine) were decreased in SDT rats at 12 weeks of age and later. The lower tryptophan and kynurenine levels in the prediabetic state and later were further confirmed by a replication study on SDT rats and by a longitudinal study on another animal model of T2D, the Otsuka Long-Evans Tokushima Fatty rat. Our data indicate that tryptophan and its metabolites are potential biomarkers for prediabetes and that tryptophan metabolism may be a potential target of intervention for treatment of the disease.

Fat intake and the development of type 2 diabetes

The increase in the number of patients with diabetes has become a worldwide healthcare issue, with numbers predicted to reach approximately 600 million by 2035. In Asia-Pacific region, the prevalence of type 2 diabetes has increased dramatically in recent decades, of which the major causes are believed to be modern lifestyle changes, e.g., Western dietary pattern and reduced physical activity, on their genetic basis of lower insulin secretory capacity. Particularly, in East Asian countries, the amount of fat intake has increased nearly three-fold over this half of century; dietary fat appears to be the major culprit of type 2 diabetes pandemic in East Asia. However, convincing evidence has not yet been provided as to whether high-fat diet causes type 2 diabetes in epidemiological cohort studies. Here, we summarize clinical studies regarding fat intake and type 2 diabetes, and animal studies on high-fat diet-induced diabetes including our recent works on the novel mouse lines (selectively bred diet-induced glucose intolerance-prone [SDG-P] and -resistant [SDG-R]) to address the etiology of high-fat diet-induced diabetes. These epidemiological and experimental findings would provide further insight into the etiology of type 2 diabetes under the modern nutritional environment, namely in the context of increased fat intake.

Excess body weight affects HbA1c progression irrespective of baseline HbA1c levels in Japanese individuals: a longitudinal retrospective study

PURPOSE/AIM

Obese individuals with normal HbA1c levels and low-body-weight individuals with high-normal HbA1c levels are frequently encountered in clinical settings, but the effects of these phenotypes on the onset of diabetes are poorly understood. Therefore, we addressed this issue in a longitudinal study.

MATERIALS AND METHODS

We analyzed clinical parameters, including body mass index (BMI) and HbA1c levels, in 5325 non-diabetic Japanese people aged 20-75 years who underwent four medical checkups between 1999 (baseline) and 2007. The subjects were then classified into six baseline BMI categories, each of which was divided into two HbA1c groups, resulting in a total of 12 groups.

RESULTS

In 405 obese subjects with a normal baseline HbA1c (BMI ≥ 27.0 kg/m(2), HbA1c 5.2-5.6%), the mean HbA1c level increased during the study period, and 50.9% developed prediabetes/diabetes. In contrast, in 77 low-body-weight subjects with a high-normal baseline HbA1c (BMI ≤ 18.9 kg/m(2), HbA1c 5.7-6.4%), the mean HbA1c level remained constant. Similar changes occurred in the other groups during the study, resulting in a linear increase in HbA1c levels with increasing BMI.

CONCLUSION

Our results suggest that approximately half of the obese individuals with HbA1c in the normal range develop prediabetes or diabetes within 8 years, whereas low-body-weight individuals with high-normal HbA1c are less likely to exhibit worsening in glycemia. Thus, excess body weight may be the primary therapeutic target to prevent the early onset of diabetes, regardless of the individual's HbA1c.

Incretin physiology and pathophysiology from an Asian perspective

Incretin hormones, such as glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1, are secreted on oral nutrient ingestion and regulate postprandial glucose homeostasis by conveying the signal of intestinal glucose flux. In East Asians, the secretion of glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 is not reduced in type 2 diabetes relative to normal glucose tolerance. Although the incretin effect is blunted in European patients with type 2 diabetes, a few East Asian studies showed no difference in the incretin effect between type 2 diabetes and normal glucose tolerance. Interestingly, the glucose-lowering efficacy of dipeptidyl peptidase-4 inhibitors or glucagon-like peptide-1 receptor agonists was reported to be greater in Asians than in non-Asians. The difference in the treatment responses could be ascribed to a different pathophysiology of type 2 diabetes (lower insulin secretory function and less insulin resistance), lower body mass index, different genetic makeups, preserved incretin effect and different food compositions in East Asians compared with other ethnic groups. Based on the currently available data, incretin-based therapies appear to be safe and well tolerated in East Asians. Nevertheless, continuous pharmacovigilance is required. The characteristics of incretin biology and treatment responses to incretin-based therapies should be considered in developing ethnicity-specific treatment guidelines and making patient-centered decisions for patients with type 2 diabetes.

The effects of pitavastatin on glucose metabolism in patients with type 2 diabetes with hypercholesterolemia

BACKGROUND

Although there have been several reports that statins cause insulin resistance that leads to the occurrence of type 2 diabetes in Caucasians, there has been no Japanese prospective studies investigating the effects of statins on the glucose metabolism system.

MATERIALS AND METHODS

Our subjects were 86 Japanese patients with type 2 diabetes with hypercholesterolemia. Pitavastatin 2mg/day was administered for 12 months and the lipid-related values, glucose metabolism values, and the presence/absence of side effects were investigated.

RESULTS

None of these factors was found to differ between before and after administration of pitavastatin in overall analysis of all subjects. In subgroup analysis, fasting blood glucose showed a decrease in the BMI ≥ 25 group and there was a significant difference between the BMI<25 and BMI ≥2 5 groups (P-values: 0.021 and 0.0036). Although HbA1c showed an increase both in the group switched to pitavastatin and the BMI<25 group (P-values: 0.035 and 0.033) and HOMA-β showed a decrease in the BMI<25 group (P-values: 0.044), there were no significant differences in changes between each divided group and their counterparts.

CONCLUSION

In the Japanese obese group with BMI ≥ 25, pitavastatin elicited a significant decrease in fasting blood glucose. It is not clear whether or not this is due to improved insulin resistance as a direct effect of pitavastatin, but in contrast to findings in Caucasians pitavastatin does not worsen insulin resistance in Japanese patients with type 2 diabetes complicated by hypercholesterolemia.

Efficacy of a 3-month lifestyle intervention program using a Japanese-style healthy plate on body weight in overweight and obese diabetic Japanese subjects: a randomized controlled trial

Background and objectives

The portion size of food is a determinant of energy intake, linking with obese traits. A healthy plate for portion control has recently been made in a Japanese style. The aim of the current study was to assess the efficacy of a lifestyle intervention program using the Japanese-style healthy plate on weight reduction in overweight and obese diabetic Japanese subjects.

Methods

We randomized overweight and obese diabetic subjects (n = 19, 10 women) into an intervention group including educational classes on lifestyle modification incorporating the healthy plate (n = 10) or a waiting-list control group (n = 9). The intervention period was three months, and the educational classes using the healthy plate were conducted monthly in a group session for the intervention group. The body weight, blood glycemic and metabolic measures, and psychosocial variables were measured at the baseline and after the 3-month intervention in both groups. The impression of the intervention was interviewed using a structured questionnaire.

Results

There was one drop-out in the control group. No adverse events were reported in the groups. Subjects in the intervention group had a greater weight change from baseline to the end of the 3-month intervention period (-3.7 +/- 2.5 [SD] kg in the intervention group vs. -0.1 +/- 1.4 kg in the control group, P = 0.002). Most subjects recorded that the use of a healthy plate could be recommended to other people.

Conclusions

The lifestyle intervention program using the Japanese-style healthy plate, which was developed for portion control, may effectively reduce body weight in overweight and obese diabetic subjects in Japan. Further studies are needed to establish the efficacy of this methodology on weight management.

Alogliptin benzoate for the treatment of type 2 diabetes

INTRODUCTION

Type 2 diabetes mellitus continues to be a global problem, placing an enormous burden on healthcare systems and resources. Effective treatment options to minimize the effects of hyperglycemia are essential. Most patients eventually need to take multiple drugs to maintain glycemic control, and many antidiabetic drugs are associated with adverse effects, such as hypoglycemia, weight gain or gastrointestinal effects. Dipeptidyl peptidase (DPP)-4 inhibitor is one of the newer classes of oral antidiabetic drug, and alogliptin is the most recently approved drug in this class.

AREAS COVERED

This paper reviews the pharmacodynamic and pharmacokinetic properties of alogliptin and the results of clinical trials evaluating its efficacy at improving glycemic control in patients with type 2 diabetes both as monotherapy and in combination with other antidiabetic drugs. The drug's tolerability and safety profiles are also considered.

EXPERT OPINION

Alogliptin is a DPP-4 inhibitor that can help in improving glycemic control in patients with type 2 diabetes, including the elderly. It is generally well tolerated and does not increase the risk of hypoglycemia or weight gain.

Defining the role of GLP-1 receptor agonists for individualized treatment of Type 2 diabetes

With the advent of dipeptidyl peptidase (DPP)-4 inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) over the past decade, incretin therapy has become established as an important treatment strategy for Type 2 diabetes mellitus (T2DM), with an efficacy and safety profile distinct from that of other anti-hyperglycemic agents. However, our understanding of the optimal clinical use of incretins remains incomplete. This review focuses on the use of GLP-1 RAs in the treatment of T2DM, with reference to the differing dominant mechanisms of action between short- and long-acting GLP-1 RAs and the clinical implications of this difference. The role of GLP-1 and the effects of GLP-1 RAs in various organs other than the pancreas will also be discussed.

Effects of a sitagliptin safety alert on prescription behaviour for oral antihyperglycaemic drugs: a propensity score-matched cohort study of prescription receipt data in Japan

BACKGROUND

Sitagliptin, the first of a new class of dipeptidyl peptidase-4 (DPP-4)-inhibitory oral antihyperglycaemic drugs (OHDs), was introduced in Japan in December 2009. In April 2010 a safety alert was issued regarding the risk of serious hypoglycaemic events, and prescribers were recommended to reduce the dose of sulfonylurea (i.e. glimepiride, glibenclamide [glyburide] or gliclazide) in patients receiving a combination of sulfonylurea and sitagliptin.

OBJECTIVE

A propensity score-matched cohort study was performed using Japanese pharmacy prescription receipt data for OHDs in order to confirm reported changes in OHD prescription behaviour for patients receiving sitagliptin before and after the safety alert.

METHODS

Prescription data from about 6,500 medical institutions throughout Japan during December 2009 to 31 December 2010 were randomly collected from 300 pharmacies, covering 82,064 patients with 629,955 prescriptions for OHDs. Patients who had received a sulfonylurea and sitagliptin (1,788 patients/3,576 prescriptions) before the safety alert were designated as the DPP-4 group. Patients who had received a sulfonylurea but not sitagliptin (30,963 patients/61,926 prescriptions) before the alert were designated as the non-DPP-4 group. Propensity score matching was employed to match baseline characteristics, such as age, sex, type of OHD, metformin use, type of prescribers period for measuring baseline period and type of prescribers' institutions, for 1,783 patients from each group. In the matched cohort, logistic regression analysis was conducted to compare prescription trends before and after the alert. The primary outcome measure of this study was dose of glimepiride, glibenclamide or gliclazide prescribed for DPP-4 and non-DPP-4 patients.

RESULTS

In the propensity score-matched cohort, the proportion of glimepiride dose >2 mg of DPP-4 patients was reduced from 45.8 % in Period 1 (before the alert) to 37.5 % in Period 2 (after the alert) (odds ratio [OR] 0.71; 95 % CI 0.579-0.870), whereas in the case of non-DPP-4 patients the proportion was changed from 28.9 % to 29.5 % in the matched cohort (OR 1.03; 95 % CI 0.868-1.215). The mean prescribed glimepiride dose in DPP-4 patients was also reduced from 2.79 ± 1.81 mg in Period 1 (before the alert) to 2.38 ± 1.71 mg in Period 2 (after the alert) [p < 0.0001], whereas the corresponding change in the case of non-DPP-4 patients was from 2.01 ± 1.56 mg to 2.01 ± 1.54 mg (p = 0.94). The difference between the mean prescribed doses in the two groups was statistically significant in both periods. Similar trends of prescription pattern changes were seen for glibenclamide and gliclazide. The reduction of prescribed sulfonylurea dose in DPP-4 patients following the safety alert coincided with a decrease of adverse event reports.

CONCLUSION

Our results indicate that propensity score matching to control for baseline characteristics of individual patients and prescribers is a useful approach to avoid selection bias and confounding effects in evaluating the influence of an event on prescription behaviour. This case-matched study indicated that sulfonylurea prescription behaviour changed significantly after the sitagliptin safety alert. There was a significant reduction in sulfonylurea dose after the alert in DPP-4 patients, but not in non-DPP-4 patients. Our findings should be helpful for assessing and improving the effectiveness of other regulatory safety alerts.

Active and passive exposure to tobacco smoke in relation to insulin sensitivity and pancreatic β-cell function in Japanese subjects

AIM

Several studies have suggested that cigarette-smoking affects insulin sensitivity in Western populations. The present study evaluated glucose tolerance, pancreatic β-cell function and insulin sensitivity in relation to active and passive smoking among the Japanese.

METHODS

A total of 411 men and 586 women were recruited into a community-based cross-sectional study in Gifu, Japan. Diabetes, impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) were screened for by a 75g oral glucose tolerance test. HOMA and insulinogenic (ΔI0-30/ΔG0-30) indexes were used to estimate insulin secretion and sensitivity. To assess the possible association of self-reported smoking status and parameters of glucose metabolism, logistic regression was applied after adjusting for potential confounders.

RESULTS

Currently smoking women were more likely to have diabetes, IGT or IFG compared with never-smoking women (OR: 2.26, 95% CI: 1.05-4.84). Heavy-smoking men (≥25 cigarettes/day) were likely to be in the lowest tertile group of ΔI0-30/ΔG0-30 compared with never-smoking men (OR: 2.64, 95% CI: 1.05-6.68, Ptrend=0.04). The number of cigarettes/day was borderline significantly associated with diabetes in men. Also with borderline significance, never-smoking women with smoking husbands were more likely to have diabetes, IGT or IFG (OR: 1.62, 95% CI: 1.00-2.62) and significantly more likely to have lower HOMA-β (OR: 2.17, 95% CI: 1.36-3.48) than those without smoking husbands.

CONCLUSION

The greater the number of cigarettes smoked per day appears to be associated with diabetes among men whereas, among women, both active and passive smoking appear to be associated with diabetic states, including IGT and IFG. An association between smoking status and insulin secretion is also suggested, whereas no significant association was observed with HOMA-IR in this Japanese subjects, suggesting that the influence of smoking on glucose metabolism may differ among races.

Comparing postprandial efficacy in type 2 diabetic patients receiving mitiglinide and sitagliptin by using continuous glucose monitoring: a pilot study

OBJECTIVE

To compare postprandial efficacy in type 2 diabetic patients given mitiglinide and sitagliptin, both of which are known to improve postprandial hyperglycemia, by using continuous glucose monitoring (CGM).

METHODS

Eleven patients with type 2 diabetes were given mitiglinide 10 mg three times a daily or sitagliptin 50 mg once a day for 1 month and were hospitalized for 4 days and evaluated by CGM. On discharge, they were crossed over to the other regimen for 1 month of treatment/4 days of evaluation. The CGM data were used to compare each parameter for glycemic variability.

RESULTS

The patients were 60 ± 10 (mean ± SD) years old, and had HbA1c value 7.3 ± 0.9%. The pre-meal glucose levels before lunch were significantly lower with mitiglinide than with sitagliptin (116 ± 26/131 ± 34 mg/dl, p = 0.022). The AUC measuring over 140 mg/dl 3 h after breakfast (mitiglinide 4812 ± 4219/sitagliptin 7807 ± 6391 mg/dl·min, p = 0.042) and lunch (mitiglinide 5658 ± 5856/sitagliptin 8492 ± 7161, p = 0.050) was significantly lower with mitiglinide than with sitagliptin.

CONCLUSIONS

A CGM-based comparison showed that mitiglinide and sitagliptin were different in their glucose-lowering effects, where mitiglinide significantly improved hyperglycemia after breakfast and lunch, and significantly lowered pre-meal glucose levels before lunch, compared to sitagliptin.

Comparison of the administration of teneligliptin every day versus every other day in Japanese patients with type 2 diabetes: a randomized non-inferior test

The half life (t1/2 ) of teneligliptin is 24.2 hours. Accordingly, we hypothesized that the administration of teneligliptin every other day might improve glycemic control. In this study, we evaluated the effectiveness of the administration of teneligliptin every other day in Japanese patients with type 2 diabetes. Fifty-one patients were randomly assigned to receive treatment with 20 mg of teneligliptin every day (Group A) or 20 mg of teneligliptin every other day (Group B) for 12 weeks. HbA1c, glycoalbumin (GA), 1,5-anhydroglucitol (1,5-AG), lipid, blood pressure, body weight, urine albumin-to-creatinine ratio, overall treatment satisfaction level, adverse events and drug adherence were all measured. Forty-seven patients completed this study, and the HbA1c, GA, and 1,5-AG levels in group B were found to be decreased to the same extent as those in group A. No distinct differences in the overall treatment satisfaction level, adverse events, or drug adherence were seen between the two groups at 12 weeks. The administration of teneligliptin every other day had a similar efficacy, patient satisfaction level, and safety compared with its administration every day. This information will be useful for reducing the economic load without changing the patients' satisfaction and glycemic control.

Association of genetic variants of the incretin-related genes with quantitative traits and occurrence of type 2 diabetes in Japanese

Background

None of the high frequency variants of the incretin-related genes has been found by genome-wide association study (GWAS) for association with occurrence of type 2 diabetes in Japanese. However, low frequency and rare and/or high frequency variants affecting glucose metabolic traits remain to be investigated.

Method

We screened all exons of the incretin-related genes (GCG, GLP1R, DPP4, PCSK1, GIP, and GIPR) in 96 patients with type 2 diabetes and investigated for association of genetic variants of these genes with quantitative metabolic traits upon test meal with 38 young healthy volunteers and with the occurrence of type 2 diabetes in Japanese subjects comprising 1303 patients with type 2 diabetes and 1014 controls.

Result

Two mutations of GIPR, p.Thr3Alafsx21 and Arg183Gln, were found only in patients with type 2 diabetes, and both of them were treated with insulin. Of ten tagSNPs, we found that risk allele C of SNP393 (rs6235) of PCSK1 was nominally associated with higher fasting insulin and HOMA-R (P = 0.034 and P = 0.030), but not with proinsulin level, incretin level or BMI. The variant showed significant association with occurrence of type 2 diabetes after adjustment for age, sex, and BMI (P = 0.0043).

Conclusion

Rare variants of GIPR may contribute to the development of type 2 diabetes, possibly through insulin secretory defects. Furthermore, the genetic variant of PCSK1 might influence glucose homeostasis by altered insulin resistance independently of BMI, incretin level or proinsulin conversion, and may be associated with the occurrence of type 2 diabetes in Japanese.

Pharmacodynamics of the glucagon-like peptide-1 receptor agonist lixisenatide in Japanese and Caucasian patients with type 2 diabetes mellitus poorly controlled on sulphonylureas with/without metformin

AIMS

The PDY6797 study evaluated efficacy, safety and pharmacodynamics of lixisenatide in Japanese and Caucasian patients with type 2 diabetes mellitus (T2DM) insufficiently controlled with sulphonylureas with/without metformin.

METHODS

This randomized, double-blind, placebo-controlled trial comprised a single-dose assessment of lixisenatide 5 and 10 µg, and a 5- to 6-week repeated dose-escalation assessment of lixisenatide 5 to 30 µg once (QD) or twice daily (BID). The primary endpoint was change in postprandial plasma glucose (PPG) area under the curve (AUC)[0:29-4:30 h] after a standardized breakfast at the highest tolerated lixisenatide dose. Change from baseline in glycated haemoglobin (HbA1c), 2-h PPG and fasting plasma glucose (FPG) were assessed, as were adverse events.

RESULTS

Change from baseline in PPG AUC[0:29-4:30 h] with lixisenatide QD and BID was significantly greater than placebo (p < 0.0001 for all study populations), with particularly prominent effects in Japanese patients. Greater reductions in PPG AUC[0:29-4:30 h] were seen with lixisenatide QD versus BID, while the totality of evidence suggested that the lixisenatide 20 µg dose was optimal. In the overall population, changes from baseline for 2-h PPG, HbA1c and FPG were significant with lixisenatide QD and BID versus placebo (p < 0.01 for all). Lixisenatide was well tolerated.

CONCLUSIONS

Lixisenatide significantly reduced PPG AUC[0:29-4:30 h] versus placebo at the highest well-tolerated dose in patients with T2DM treated with sulphonylureas with/without metformin and had a good safety and tolerability profile. Japanese patients experienced particular benefits with lixisenatide in terms of reductions in PPG excursions.

Effect of repaglinide, administered two or three times daily for 3 months, on glycaemic control in Japanese patients with type 2 diabetes mellitus

OBJECTIVES

To compare the efficacy, safety and compliance of repaglinide, administered either two or three times daily, regarding glycaemic control in patients with type 2 diabetes mellitus.

METHODS

Japanese adults with type 2 diabetes mellitus, who had been treated without sulphonylureas or glinides for >3 months, were randomly assigned to two groups to receive either 0.25 mg repaglinide, oral, twice daily (group A) or 0.25 mg repaglinide, oral, three times daily (group B). Glycosylated haemoglobin (HbA1c), glycoalbumin (GA) and 1,5-anhydroglucitol (1,5-AG) levels were measured at 0, 1, 2 and 3 months after treatment commenced.

RESULTS

Out of 43 patients who enrolled (group A, n = 22; group B, n = 21), 33 patients completed the trial (group A, n = 16; group B, n = 17). No significant between-group differences in HbA1c, GA, or 1,5-AG levels were seen at 1-3 months. No severe hypoglycaemic episodes or other adverse events were observed.

CONCLUSIONS

Minimal-dose repaglinide administered twice daily was similar in efficacy and safety to three-times-daily administration, in Japanese patients with type 2 diabetes mellitus. Administration of repaglinide twice daily could be an alternative regimen for patients who cannot take repaglinide three times daily.

Profile of saxagliptin in the treatment of type 2 diabetes: focus on Japanese patients

Saxagliptin is a selective and potent dipeptidyl peptidase (DPP)-4 inhibitor, approved as an adjunct to diet and exercise to improve glycemic control in type 2 diabetes mellitus (T2DM) in the USA on July 2009, and had been launched globally in over 86 countries by September 2013. In patients with T2DM, once-daily administration of saxagliptin before breakfast achieves sustained inhibition of plasma DPP-4 activity and reduction of postprandial hyperglycemia, including after dinner, associated with an increase in plasma glucagon-like peptide-1 levels. This paper reviews the safety and efficacy of saxagliptin in Japanese patients with T2DM. The clinical development study in Japan supported its usefulness for the disease. Saxagliptin 1, 2.5, and 5 mg led to significant improvements in glycated hemoglobin (HbA_1c), and was generally well tolerated. Treatment with saxagliptin 5 mg induced a sustained reduction in HbA_1c over 52 weeks. Long-term combination therapy with saxagliptin and other oral hypoglycemic agents also provided sustained glycemic control and was well tolerated for up to 52 weeks. Saxagliptin as add-on to sulfonylureas or glinides has a tendency to increase hypoglycemia, but not with other oral antidiabetic agents, such as α-glucosidase inhibitors, metformin, or thiazolidinediones. The results of clinical trials have confirmed the long-term efficacy and safety of saxagliptin monotherapy as well as its use as add-on combination therapy, and support its usefulness as a therapeutic agent for T2DM. Saxagliptin has less concern for hypoglycemia and weight gain, which often becomes problematic in routine care of T2DM. Meta-analysis of clinical trials in the USA showed no evidence of increased risk of cardiovascular events associated with saxagliptin, suggesting the superior of saxagliptin in terms of safety. Recently, investigators in the SAVOR-TIMI (Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus-Thrombolysis in Myocardial Infarction) 53 study suggested that DPP-4 inhibition with saxagliptin did not increase or decrease the rate of ischemic events, although the rate of hospitalization for heart failure was increased. Although saxagliptin improves glycemic control, other approaches are necessary to reduce cardiovascular risk in patients with diabetes. Saxagliptin is applicable for various pathological conditions, and is considered to be clinically significant as a new therapeutic option for Japanese patients with T2DM.

GIP and GLP-1, the two incretin hormones: Similarities and differences

Gastric inhibitory polypeptide (GIP) and glucagon‐like peptide‐1 (GLP‐1) are the two primary incretin hormones secreted from the intestine on ingestion of glucose or nutrients to stimulate insulin secretion from pancreatic β cells. GIP and GLP‐1 exert their effects by binding to their specific receptors, the GIP receptor (GIPR) and the GLP‐1 receptor (GLP‐1R), which belong to the G‐protein coupled receptor family. Receptor binding activates and increases the level of intracellular cyclic adenosine monophosphate in pancreatic β cells, thereby stimulating insulin secretion glucose‐dependently. In addition to their insulinotropic effects, GIP and GLP‐1 play critical roles in various biological processes in different tissues and organs that express GIPR and GLP‐1R, including the pancreas, fat, bone and the brain. Within the pancreas, GIP and GLP‐1 together promote β cell proliferation and inhibit apoptosis, thereby expanding pancreatic β cell mass, while GIP enhances postprandial glucagon response and GLP‐1 suppresses it. In adipose tissues, GIP but not GLP‐1 facilitates fat deposition. In bone, GIP promotes bone formation while GLP‐1 inhibits bone absorption. In the brain, both GIP and GLP‐1 are thought to be involved in memory formation as well as the control of appetite. In addition to these differences, secretion of GIP and GLP‐1 and their insulinotropic effects on β cells have been shown to differ in patients with type 2 diabetes compared to healthy subjects. We summarize here the similarities and differences of these two incretin hormones in secretion and metabolism, their insulinotropic action on pancreatic β cells, and their non‐insulinotropic effects, and discuss their potential in treatment of type 2 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00022.x, 2010)

Glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1: Incretin actions beyond the pancreas

Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the two primary incretin hormones secreted from the intestine on ingestion of various nutrients to stimulate insulin secretion from pancreatic β-cells glucose-dependently. GIP and GLP-1 undergo degradation by dipeptidyl peptidase-4 (DPP-4), and rapidly lose their biological activities. The actions of GIP and GLP-1 are mediated by their specific receptors, the GIP receptor (GIPR) and the GLP-1 receptor (GLP-1R), which are expressed in pancreatic β-cells, as well as in various tissues and organs. A series of investigations using mice lacking GIPR and/or GLP-1R, as well as mice lacking DPP-4, showed involvement of GIP and GLP-1 in divergent biological activities, some of which could have implications for preventing diabetes-related microvascular complications (e.g., retinopathy, nephropathy and neuropathy) and macrovascular complications (e.g., coronary artery disease, peripheral artery disease and cerebrovascular disease), as well as diabetes-related comorbidity (e.g., obesity, non-alcoholic fatty liver disease, bone fracture and cognitive dysfunction). Furthermore, recent studies using incretin-based drugs, such as GLP-1 receptor agonists, which stably activate GLP-1R signaling, and DPP-4 inhibitors, which enhance both GLP-1R and GIPR signaling, showed that GLP-1 and GIP exert effects possibly linked to prevention or treatment of diabetes-related complications and comorbidities independently of hyperglycemia. We review recent findings on the extrapancreatic effects of GIP and GLP-1 on the heart, brain, kidney, eye and nerves, as well as in the liver, fat and several organs from the perspective of diabetes-related complications and comorbidities.

Glycemic variability in normal glucose regulation subjects with elevated 1-h postload plasma glucose levels

Subjects with normal glucose regulation (NGR), whose 1-h postload plasma glucose is ≥8.6 mmol/L (155 mg/dL, NGR 1 h ≥ 8.6) during 75-g oral glucose tolerance test (OGTT), have an increased risk of type 2 diabetes and subclinical organ damage. And, the deficiency in islet β cell function is responsible for glycemic disorders. The purpose of this study is to investigate glycemic variability in NGR subjects with elevated 1-h postload plasma glucose levels and its association with islet β cell function. The 29 NGR subjects with 1-h postload plasma glucose ≥8.6 mmol/L (NGR 1 h ≥ 8.6) and 29 age- and sex-matched NGR subjects with 1-h postload plasma glucose <8.6 mmol/L (NGR 1 h < 8.6) were recruited in the study. Insulin sensitivity (Matsuda index, ISI), insulin secretion (insulinogenic index ΔI30/ΔG30), and integrated β cell function measured by the oral disposition index (ΔI30/ΔG30 multiplied by the ISI) were derived from OGTT. All subjects were monitored using the continuous glucose monitoring system for consecutive 72 h. The multiple parameters of glycemic variability included the standard deviation of blood glucose (SDBG), mean blood glucose (MBG), mean of daily differences (MODD), and mean amplitude of glycemic excursions (MAGE). MAGE is considered as a gold standard of glycemic variability. Glycemic variability parameters SDBG, MBG, MODD, and MAGE in NGR 1 h ≥ 8.6 group were higher than those in NGR 1 h < 8.6 group (p < 0.05), and oral disposition index in NGR 1 h ≥ 8.6 group was lower than that in NGR 1 h < 8.6 group (p < 0.05). SDBG, MBG, MODD, MAGE, and 1-h postload plasma glucose all negatively associated with oral disposition index in the separate group (p < 0.05) and in the whole subjects (p < 0.05). After multivariate regression analysis, oral disposition index was the strongest independent contributor to MAGE and 1-h postload plasma glucose in the separate group (p < 0.05) and in the whole subjects (p < 0.05). It is concluded that NGR 1 h ≥ 8.6 group had higher glycemic variability and lower oral disposition index, compared with NGR 1 h < 8.6 group. Increased glycemic variability parameters and elevated 1-h postload plasma glucose consistently associated with declined oral disposition index in subjects from NGR 1 h < 8.6 to NGR 1 h ≥ 8.6 group.

Insulin secretory capacity and insulin sensitivity in impaired fasting glucose in Japanese

Aims/Introduction:  Impaired fasting glucose (IFG) increases the risk of developing diabetes mellitus (DM). This study was carried out to characterize Japanese patients who have fasting glucose levels (FPG) between 100 and 109 mg/dL (IFG_100–109).

Materials and Methods:  A total of 1383 Japanese participants were examined by oral glucose tolerance test. We compared insulin secretory capacity (insulinogenic index) and insulin sensitivity (ISI composite) of IFG_100–109/normal glucose tolerance (NGT; 100 ≤ FPG < 110 mg/dL and 2‐h postchallenge glucose level (2‐hPG) < 140 mg/dL) with NGT (100 mg/dL < FPG and 2‐hPG < 140 mg/dL) and IFG_110–125/NGT (110 ≤ FPG < 126 mg/dL and 2‐hPG < 140 mg/dL). In addition, IFG_100–109 patients were analyzed in three subgroups according to glucose intolerance by 2‐hPG.

Results:  Of the three categories of IFG_100–109, IFG_100–109/DM had the lowest insulinogenic index despite an ISI composite showing only a small decline from IFG_100–109/NGT through IFG_100–109/IGT (100 ≤ FPG < 110 mg/dL and 140 ≤ 2‐hPG < 200 mg/dL) to IFG_100–109/DM (100 ≤ FPG < 110 mg/dL and 200 mg/dL < 2‐hPG). By multiple regression analysis, the insulinogenic index showed a significant relationship with 2‐h PG levels. Both insulinogenic index and ISI composite were decreased significantly from NGT through IFG_100–109/NGT to IFG_110–125/NGT.

Conclusions:  Although impaired early‐phase insulin secretion plays the more important role in the elevation of postchallenge glucose in IFG_100–109 patients, both impaired early‐phase insulin secretion and decreased insulin sensitivity are involved in the deterioration of FPG in Japanese. In addition, insulin secretory defect and decreased insulin sensitivity already have begun in patients with IFG_100–109.(J Diabetes Invest, doi: 10.1111/j.2040‐1124.2012.00201.x, 2012)

Relationship and factors responsible for regulating fasting and post-challenge plasma glucose levels in the early stage development of type 2 diabetes mellitus

AIMS/INTRODUCTION

Elevation of 2-h plasma glucose (2-h PG) levels keeps step with fasting plasma glucose (FPG) levels elevation, but some individuals show dominant elevation of 2-h PG and others FPG. We analyzed dependent and independent relationships between 2-h PG and FPG, and investigated the factors regulating 2-h PG and FPG.

MATERIALS AND METHODS

In 1,657 Japanese participants who underwent a 75-g oral glucose tolerance test at the initial examination for a medical check-up, we carried out simple linear regression analysis between 2-h PG and FPG levels on the three patterns of independent variables. We divided the participants into two subgroups: the 2-h PG-side group and the FPG-side from the regression line, and examined the relationships between 2-h PG-FPG and factors responsible for elevation of plasma glucose levels.

RESULTS

There was a significant positive correlation between 2-h PG and FPG levels. The regression line of both 2-h PG and FPG as independent variables was in accordance with the regression line of 2-h PG as an independent variable and FPG as a dependent variable. In 2-h PG-side group, age was the independent factor affecting 2-h PG in addition to insulinogenic index and insulin sensitivity index (ISI composite). In the FPG-side group, triglyceride was the independent factor affecting FPG in addition to insulinogenic index and ISI composite.

CONCLUSIONS

Two-hour PG was an independent predictor of FPG. In addition to the importance of decreased insulin secretion and insulin sensitivity, age was the strong factor to elevate 2-h PG levels in the 2-h PG-side group and triglyceride was the strong factor to elevate FPG levels in the FPG-side group in the early stage of development of type 2 diabetes.

Renal sodium glucose cotransporter 2 inhibitors as a novel therapeutic approach to treatment of type 2 diabetes: Clinical data and mechanism of action

Type 2 diabetes is characterized by impaired insulin secretion from pancreatic β-cells and/or reduced response of target tissues to insulin. Good glycemic control delays the development and slows the progression of micro- and macrovascular complications. Although there are numerous glucose-lowering agents in clinical use, only approximately half of type 2 diabetic patients achieve glycemic control, and undesirable side-effects often hamper treatment in those treated with the medications. There is a need for novel treatment options that can help overcome these difficulties. Sodium glucose cotransporter 2 (SGLT2) inhibitors have recently been developed as a novel potential therapeutic option for the treatment of type 2 diabetes. These drugs lower the plasma glucose concentration through inhibition of glucose reuptake in the kidney, independent of insulin secretion and insulin action, with a consequent lower risk of hypoglycemia. The data of clinical trials with monotherapy as well as combination therapy show that SGLT2 inhibitors have a blood glucose-lowering effect and also reduce bodyweight. A follow-up study shows long-term efficacy and the durability of these effects. SGLT2 inhibitors have the potential to reverse glucose toxicity, and to improve insulin resistance, blood pressure and lipid profile. The available data suggest a good tolerability profile. However, clinicians should carefully prescribe these drugs in light of already reported and/or unexpected side-effects. Further studies in larger numbers and longer-term clinical use data are required to place these agents in standard treatment of type 2 diabetes.

Insulin supersensitivity and normoinsulinaemic hypoglycaemia in uncontrolled type 2 diabetes mellitus: clinical usefulness of 3 h assessment in the 75 g oral glucose tolerance test

A 60-year-old man with uncontrolled type 2 diabetes mellitus (DM) (glycated haemoglobin 11%) had the unusual symptoms of palpitations and sweating after drinking an excessive amount of soft drinks. Three-hour data in the 75-g oral glucose tolerance test (75g-OGTT) repeatedly showed normoinsulinaemic hypoglycaemia. His diabetic disorder was based on a delayed insulin secretory response to hyperglycaemia and daily excessive intake of glucose from a high caloric diet and soft drinks. However, we paradoxically observed increased insulin sensitivity evaluated by a hyperinsulinaemic-euglycaemic clamp (glucose infusion rate: 64.83 μmol/kg/min). We considered that insulin supersensitivity might be involved in the pathogenic mechanisms of his clinical normoinsulinaemic hypoglycaemia. He was successfully treated by diet and exercise therapy without any hypoglycaemic medications or insulin. Assessment after the 75g-OGTT is useful for investigating the pathogenesis of DM. Insulin supersensitivity and normoinsulinaemic hypoglycaemia might play a role in clinical manifestation and pathogenesis of type 2 DM.

Comparison of global versus Asian clinical trial strategies supportive of registration of drugs in Japan

The number of worldwide and Asian multiregional clinical trials (MRCTs) submitted for Japanese New Drug Applications increased markedly between 2009 and 2013, with an increasing number performed for simultaneously submission in the USA, EU, and Japan. Asian studies accounted for 32% of MRCTs (14/44 studies) and had comparatively small sample sizes (<500 subjects). Moreover, the number of Japanese subjects in Asian studies was 2.1- to 13.4-fold larger than the sample size estimated using the method described in Japanese MRCT guidelines, whereas the ratio for worldwide studies was 0.05- to 4.9-fold. Before the introduction of this guidelines, bridging or domestic clinical development strategies were used as the regional development strategy in accordance with ICH E5 guidelines. The results presented herein suggest that Asian studies were conducted when the drug had already been approved in the US/EU, when phase 3 clinical trials were not be planned in the USA/EU, when there was insufficient knowledge of ethnic differences in drug efficacy and safety, or when Caucasian data could not be extrapolated to the Japanese population. New strategies with Asian studies including the Japanese population could be conducted instead of Japanese domestic development strategy.

The incretin effect in Korean subjects with normal glucose tolerance or type 2 diabetes

BACKGROUND

The incretin effect is known to be decreased in type 2 diabetes. However, there are limited data on the incretin effect in non-Caucasian subjects. Because Asian patients with type 2 diabetes are characterized by decreased insulin secretion, this study set out to examine the incretin effect in Korean subjects with normal glucose tolerance (NGT) or type 2 diabetes.

METHODS

We performed 75-g oral glucose tolerance tests (OGTTs) and corresponding isoglycaemic intravenous glucose infusion (IIGI) studies in Korean subjects with NGT (n = 14) or type 2 diabetes (n = 16). The incretin effect was calculated based on the incremental area under the curves (iAUCs) of the plasma levels of insulin, C-peptide or insulin secretion rate (ISR). The plasma levels of total glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) were measured by ELISA.

RESULTS

The incretin effect was not different between the subjects with NGT and type 2 diabetes (43 ± 6% vs 47 ± 4%, P = 0·575 by insulin; 29 ± 7% vs 38 ± 4%, P = 0·253 by C-peptide; 28 ± 7% vs 35 ± 5%, P = 0·372 by ISR, respectively). However, the gastrointestinally mediated glucose disposal (GIGD) was markedly decreased in type 2 diabetes (28·5 ± 4·2% vs 59·0 ± 4·3%, P < 0·001). The plasma levels of the total GLP-1 and GIP during the OGTTs were comparable between the two groups.

CONCLUSION

In Koreans, the secretion of GLP-1 or GIP during OGTTs and the incretin effect were comparable between subjects with NGT and type 2 diabetes, whereas the GIGD was significantly decreased in patients with type 2 diabetes.

Flushing response modifies the association of alcohol consumption with markers of glucose metabolism in Japanese men and women

BACKGROUND

Influences of alcohol use on glucose metabolism may depend on alcohol flushing response. We investigated the effect of alcohol flushing response on the associations between alcohol consumption and markers of glucose metabolism in Japanese men and women.

METHODS

The subjects were 979 employees (885 men and 94 women), aged 18 to 69 years, of a manufacturing company in Japan. Flushing response and alcohol consumption were determined using a self-administered questionnaire. Homeostasis model assessment-insulin resistance (HOMA-IR) and homeostasis model assessment for β-cell function (HOMA-β) were computed using fasting plasma glucose and insulin. For each group of flushers and nonflushers, multiple regression analysis was used to estimate means of fasting plasma glucose, hemoglobin A1c (HbA1c), and HOMAs for each category of alcohol consumption, with adjustments for potential confounders.

RESULTS

In flushers, alcohol consumption was associated with HbA1c levels in a U-shaped manner, with the lowest HbA1c levels being observed at an alcohol consumption level of 23.0 to <34.5 g ethanol/d (p for quadratic trend = 0.002). In nonflushers, alcohol consumption was linearly and inversely associated with HbA1c levels (p for linear trend = 0.001). Decreases in HbA1c were more evident among flushers compared with nonflushers at moderate alcohol consumption levels (p for interaction = 0.049). An increase of fasting glucose associated with highest alcohol consumption was observed in both flushers and nonflushers. A statistically significant decrease in HOMA-IR with increasing alcohol consumption was observed in flushers (p for trend = 0.007), whereas HOMA-IR levels slightly decreased at higher alcohol consumption in nonflushers. HOMA-β similarly decreased with increasing alcohol consumption in both flushers and nonflushers (both p for trend < 0.001).

CONCLUSIONS

The results suggest that the alcohol flushing response may improve glucose metabolism and insulin resistance at moderate alcohol use levels in apparently healthy Japanese adults.

Post-meal β-cell function predicts the efficacy of glycemic control in patients with type 2 diabetes inadequately controlled by metformin monotherapy after addition of glibenclamide or acarbose

BACKGROUND

This study aimed to explore parameters which will predict good control of HbA1c after adding a second anti-diabetic drug in patients with type 2 diabetes mellitus (T2DM) inadequately controlled with metformin monotherapy.

METHODS

Fifty-one patients (M/F: 25/26, mean age: 53.7 ± 8.2 years, mean glycated hemoglobin [HbA1c] 8.4 ± 1.2%) with T2DM inadequately controlled with metformin were randomized to add-on glibenclamide or acarbose for 16 weeks. Before and after combination therapy, the subjects underwent a 2-hour liquid mixed meal tolerance test to determine insulin secretion (HOMA-β, insulinogenic index, and disposition index [DI]) and insulin sensitivity (HOMA-IR and Matsuda insulin sensitivity index).

RESULTS

At baseline, there was a significant inverse relationship between DI120 and HbA1c (p = 0.001) in all subjects. The addition of glibenclamide and acarbose improved HbA1c significantly from 8.6 ± 1.6% to 7.4 ± 1.2% (p < 0.001), and from 8.2 ± 0.8% to 7.5 ± 0.8% (p < 0.001), respectively. In the glibenclamide group, DI120 significantly increased from 51.2 ± 24.2 to 74.9 ± 41.9 (p < 0.05), and in the acarbose group, from 62.5 ± 31.4 to 91.7 ± 36.2 (p < 0.05), respectively. Multiple regression analyses showed that both baseline HbA1c and DI120 independently predicted reduction of HbA1c as well as final HbA1c after combination therapy.

CONCLUSIONS

In patients with T2DM inadequately controlled with metformin, add-on oral anti-diabetic agent with glibenclamide or acarbose resulted in the significant HbA1c reduction and improvement of β-cell function. Subjects with greater baseline β-cell function reserve displayed better glycemic response in the combination therapy of metformin with glibenclamide or acarbose.

TRIAL REGISTRATION

This study was registered in the ClinicalTrials.gov with registration number of NCT00417729.

Body composition is the main determinant for the difference in type 2 diabetes pathophysiology between Japanese and Caucasians

OBJECTIVE This cross-sectional clinical study compared the pathophysiology of type 2 diabetes in Japanese and Caucasians and investigated the role of demographic, genetic, and lifestyle-related risk factors for insulin resistance and β-cell response. RESEARCH DESIGN AND METHODS A total of 120 Japanese and 150 Caucasians were enrolled to obtain comparable distributions of high/low BMI values across glucose tolerance states (normal glucose tolerance, impaired glucose tolerance, and type 2 diabetes), which were assessed by oral glucose tolerance tests. BMI in the two cohorts was distributed around the two regional cutoff values for obesity. RESULTS Insulin sensitivity was higher in Japanese compared with Caucasians, as indicated by the homeostatic model assessment of insulin resistance and Matsuda indices, whereas β-cell response was higher in Caucasians, as measured by homeostatic model assessment of β-cell function, the insulinogenic indices, and insulin secretion ratios. Disposition indices were similar for Japanese and Caucasians at all glucose tolerance states, indicating similar β-cell response relative to the degree of insulin resistance. The main determinants for differences in metabolic indices were measures of body composition, such as BMI and distribution of adipose tissue. Differences in β-cell response between Japanese and Caucasians were not statistically significant following adjustment by differences in BMI. CONCLUSIONS Our study showed similar disposition indices in Japanese and Caucasians and that the major part of the differences in insulin sensitivity and β-cell response between Japanese and Caucasians can be explained by differences in body composition.

Relative contribution of insulin secretion and sensitivity at different stages of glucose tolerance: non-obese versus obese Japanese subjects

OBJECTIVE

We examined the relative contribution of insulin secretion and insulin sensitivity at different stages of glucose tolerance in non-obese and obese Japanese subjects.

METHODS

A total of 641 subjects who underwent 75-g glucose tolerance testing were divided into two groups: 436 non-obese subjects (body mass index: BMI <25) and 205 obese subjects (BMI ≥25). The subjects were further divided into four groups: those with normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and diabetes. We compared insulin secretion and sensitivity indices, such as the insulinogenic index (IGI), homeostatic model insulin resistance (HOMA-IR), homeostatic model assessment of β-cell (HOMA-β) and insulin sensitivity index (ISI).

RESULTS

In a univariate analysis, the obese subjects had higher levels of HOMA-IR, HOMA-β and IGI associated with lower ISI values in comparison with that observed in the non-obese subjects at different stages of glucose tolerance. A multiple logistic regression analysis showed that the HOMA-IR was a significant independent factor between the non-obese and obese subjects; the odds ratio (OR) (95% confidential interval: CI) was 3.78 (2.04-7.01; p<0.01) in the NGT group, 4.91 (2.06-11.72; p<0.01) in the IGT group and 2.02 (1.22-3.34; p<0.01) in the diabetes group. Although a similar trend was also observed in the IFG group (OR=15.83), the difference did not reach a level of statistical significance (p=0.066).

CONCLUSION

These data suggest that obese subjects are characterized by increased insulin resistance rather than reduced insulin secretion at all stages of glucose tolerance. Therefore, non-obese subjects and obese subjects are distinct entities at all stages of glucose tolerance.

Effects of valsartan versus amlodipine in diabetic hypertensive patients with or without previous cardiovascular disease

Recently, we reported that angiotensin II receptor blocker (ARB), valsartan, and calcium channel blocker (CCB), amlodipine, had similar effects on the prevention of cardiovascular disease (CVD) events in diabetic hypertensive patients. We assessed the difference of cardiovascular protective effects between ARB and CCB in patients with and without previous CVD, respectively. A total of 1,150 Japanese diabetic hypertensive patients were randomized to either valsartan or amlodipine treatment arms, which were additionally divided into 2 groups according to the presence of previous CVD at baseline (without CVD, n = 818; with CVD, n = 332). The primary composite outcomes were sudden cardiac death, acute myocardial infarction, stroke, coronary revascularization, or hospitalization for heart failure. The incidence of primary end point events in patients with previous CVD was 3.5-times greater than that in patients without previous CVD (64.1 vs 17.9/1,000 person-years). The ARB- and the CCB-based treatment arms showed similar incidence of composite CVD events in both patients without previous CVD (hazard ratio [HR] 1.35, 95% confidence interval [CI] 0.76 to 2.40) and those with previous CVD (HR 0.79, 95% CI 0.48 to 1.31). The ARB-treatment arm showed less incidence of stroke compared with the CCB-based treatment arm in patients with previous CVD (HR 0.24, 95% CI 0.05 to 1.11, p = 0.068), whereas the 2 treatment arms showed similar incidence of stroke in patients without previous CVD (HR 1.52, 95% CI 0.59 to 3.91). In conclusion, the ARB- and the CCB-based treatments exerted similar protective effects of CVD events regardless of the presence of previous CVD. For stroke events, the ARB may have more protective effects than the CCB in diabetic hypertensive patients with previous CVD.

Effects of a single bout of aerobic exercise on short-term low-carbohydrate/high-fat intake-induced postprandial glucose metabolism during an oral glucose tolerance test

OBJECTIVE

A single bout of exercise can improve acute postprandial glucose metabolism aggravated by short-term low-carbohydrate/high-fat diet (HFD). The purpose of this study was to investigate the effect of a single bout of aerobic exercise on short-term HFD-induced postprandial glucose and incretin metabolism during an oral glucose tolerance test (OGTT).

MATERIALS/METHODS

Eleven healthy young men (age [mean±SE] 27±1 years; body mass index, 22±1 kg/m(2)) performed three, 3-day interventions in randomized order: (1) a normal diet (ND: ~22% fat), (2) an HFD (~69% fat) and (3) an HFD with a single bout of aerobic exercise (HFDEx). The exercise (50% peak oxygen consumption; ~200 kcal) was performed on the third day in HFDEx. An OGTT was performed after each 3-day dietary intervention.

RESULTS

The incremental area under the curve (iAUC) of plasma glucose levels during the OGTT was significantly higher in the HFD and HFDEx trials than in the ND trial (P=0.001). In addition, the iAUC of glucagon-like peptide-1 (GLP-1) level was significantly higher in the HFD trial than in the ND and HFDEx trials (P=0.04). The first-phase insulin secretion indexes were significantly lower in the HFD (P=0.01 and 0.002) and HFDEx trials (P=0.05 and 0.008) than in the ND trial.

CONCLUSION

A single bout of aerobic exercise did not improve the short-term HFD-induced aggravation of postprandial glucose and insulin metabolism during the OGTT. However, it did normalize the increased postprandial GLP-1 level induced by HFD.

A hospital-based cross-sectional study to develop an estimation formula for 2-h post-challenge plasma glucose for screening impaired glucose tolerance

AIMS

To create and validate an estimation formula for 2-h post-challenge plasma glucose (2-hPG) as an alternative to oral glucose tolerance test (OGTT) for impaired glucose tolerance (IGT) screening.

METHODS

380 Japanese subjects (57.6% males, aged 58.5 (14.0); mean (SD) years) undergoing OGTT were included in this hospital-based cross-sectional study mainly at Kyoto University Hospital between 2000 and 2011. We determined the main predictive variables of 2-hPG from clinical variables and separated the subjects randomly into two groups: a derivation group to construct an estimation formula of 2-hPG on the basis of predictive variables and a validation group to evaluate the accuracy of the formula.

RESULTS

Fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) were highly correlated with 2-hPG measured by OGTT. Multiple linear regression analysis showed that estimated 2-hPG (e2-hPG) was calculated by the formula: e2-hPG = 1.66 × FPG (mmol/l) + 1.63 × HbA1c (%)-10.11 (R(2), coefficient of determination=60.2%). When the cut-off value was set to the diagnostic criteria of IGT, 7.8 mmol/l of e2-hPG, sensitivity, specificity, and negative predictive value (NPV) were 83.3%, 44.1%, and 74.3%, respectively. When the cut-off value was set lower (7.2 mmol/l), these values were 94.4%, 30.5%, and 85.7%, respectively. The area under the receiver operating characteristic (ROC) curve was 0.68.

CONCLUSIONS

This high-sensitive estimation formula may be a useful alternative to OGTT for IGT screening. For the levels ≤ 7.2 mmol/l, this formula may also be useful in cross-sectional study to identify people whose glucose tolerance is normal.

Insulin degludec compared with insulin glargine in insulin-naïve patients with type 2 diabetes: A 26-week, randomized, controlled, Pan-Asian, treat-to-target trial

Introduction

Insulin degludec (IDeg) is an ultra‐long‐acting basal insulin with a consistent action profile of >42 h. This trial compared the efficacy and safety of IDeg with insulin glargine (IGlar) in insulin‐naïve Asian patients with type 2 diabetes.

Materials and Methods

In this multinational, 26‐week, open‐label, treat‐to‐target trial, 435 participants (202 females, 233 males; mean age 58.6 years; mean body mass index 25 kg/m²; mean glycated hemoglobin [HbA_1c] 8.5%) were randomized (2:1) to IDeg or IGlar, each administered once daily with ≥1 oral antidiabetic drug(s) (OAD).

Results

After 26 weeks, HbA_1c had decreased by 1.24 and 1.35% in the IDeg and IGlar groups, respectively (treatment difference [IDeg – IGlar] 0.11%, 95% confidence interval [CI] −0.03 to 0.24), confirming non‐inferiority. Rates of overall confirmed hypoglycemia were similar for IDeg and IGlar during the full trial period (3.0 vs 3.7 episodes/patient‐year of exposure [PYE]; rate ratio [RR] 0.82, 95% CI 0.60 to 1.11, P = 0.20), but significantly lower (by 37%) for IDeg during the maintenance period (from week 16 onward; RR 0.63, 95% CI 0.42 to 0.94, P = 0.02). No significant difference in the rate of nocturnal confirmed hypoglycemia was found between IDeg and IGlar in the full trial period (0.8 vs 1.2 episodes/PYE; RR 0.62, 95% CI 0.38 to 1.04, P = 0.07) or maintenance period (RR 0.52, 95% CI 0.27 to 1.00, P = 0.05). Adverse event rates were similar between treatments.

Conclusions

Initiating insulin therapy with IDeg in Asian patients with type 2 diabetes, inadequately controlled with OADs, provides similar improvements in long‐term glycemic control to IGlar, but at a significantly lower rate of overall confirmed hypoglycemia once stable glycemic control and insulin dosing are achieved. This trial was registered with www.clinicaltrials.gov (no. NCT01059799).

Plant oils were associated with low prevalence of impaired glucose metabolism in Japanese workers

Fatty acid has been suggested to be involved in development of diabetes. However, its association is unclear among Japanese populations, which consume large amounts of fish rich in n-3 polyunsaturated fatty acids. The present cross-sectional study examined the association of individual dietary fatty acids and dietary fatty acid patterns with abnormal glucose metabolism among 1065 Japanese employees, aged 18-69 years. Impaired glucose metabolism is defined if a person has a history of diabetes, current use of anti-diabetic drug, fasting plasma glucose of 110 mg/dl (≥6.1 mmol/L) or greater, or hemoglobin A1C of 6.0% (≥42 mmol/mol) or greater. Dietary intake was assessed with a self-administered diet history questionnaire. Dietary fatty acid patterns were extracted by principal component analysis. Odds ratios of impaired glucose metabolism according to tertile categories of each fatty acids and dietary fatty acid patterns were estimated using logistic regression with adjustment for potential confounding variables. A higher intake of polyunsaturated fatty acid, n-6 fatty acid, linoleic acid, and oleic acid were significantly associated with a decreased prevalence of impaired glucose metabolism (P for trend = 0.03, 0.01, 0.02, and 0.04, respectively). Alpha-linolenic acid was marginally significantly associated with a decreased prevalence of impaired glucose metabolism (P for trend = 0.12). Of three fatty acid patterns identified, a higher plant oil pattern score, which characterized by high intake of alpha-linolenic acid, linoleic acid, and oleic acid, was associated with a decreased prevalence of impaired glucose metabolism (P for trend = 0.03). No association was observed for other patterns. In conclusion, plant source fatty acids might be protectively associated with development of diabetes in Japanese adults.

Twenty-year trend of increasing obesity in young patients with poorly controlled type 2 diabetes at first diagnosis in urban Japan

Aims/Introduction

To investigate trends over the past 20 years for the prevalence of obesity and glycemic control in association with a patient's first hospital visit for type 2 diabetes mellitus.

Materials and Methods

This was a historical, cross‐sectional, time‐series, single‐center study carried out at Marunouchi Hospital. Data from type 2 diabetic patients who were never treated until their first hospital visit were analyzed for the following periods: 1986–1987 (group A, n = 453), 1996–1997 (group B, n = 547) and 2006–2008 (group C, n = 443). Data on each patient's body mass index (BMI), age, untreated duration and glycated hemoglobin levels were also collected.

Results

Obesity in younger patients (below age 40 years and ages 40–49 years in group C) with poor glycemic control increased over time. Patients with a BMI of <21.0 kg/m² or ≥23.0 kg/m² showed worse glycemic control than those with a BMI of 21.0–23.0 kg/m² in group C. Younger patients had worse glycemic control and shorter untreated durations in group C. A BMI ≥23.0 kg/m² was an independent risk factor for glycated hemoglobin levels ≥8.4% in group C, even after correction for sex, age, untreated duration and symptoms.

Conclusions

In recent years, glycemic control has worsened in young, obese patients in urban Japan. Obesity is rapidly increasing in younger patients, and patients with a BMI ≥23.0 kg/m² might be candidates for diabetes screening. This trial was registered with the University Medical Information Network Clinical Trials Registry (no. UMIN000005725).

Effects of insulin changes on quality of life and glycemic control in Japanese patients with type 2 diabetes mellitus: The insulin-changing study intending to gain patients' insights into insulin treatment with patient-reported health outcomes in actual clinical treatments (INSIGHTs) study

Aims/Introduction

Our primary objective was to assess changes in quality of life (QOL) associated with changes in insulin regimen in patients with type 2 diabetes mellitus. Secondary objectives were to assess the reasons for and patterns of changes in insulin regimen, and the effects on glycemic control.

Materials and Methods

This 12‐week, observational study included patients with type 2 diabetes mellitus (n = 625) who planned to change insulin regimen (type of insulin, injection device and/or number of injections). The primary outcome measure was a change from baseline in QOL assessed by the Insulin Therapy‐Related (ITR) QOL questionnaire. The secondary outcome measures included change from baseline in plasma glycated hemoglobin (HbA_1c) level, the reasons for and pattern of insulin regimen change, and change from baseline in QOL assessed by Diabetes Treatment Satisfaction Questionnaire (DTSQ).

Results

QOL did not worsen during the study. Improvements were seen in the ITR‐QOL ‘daily activities’ subscale score (baseline: 12.7 ± 2.3; week 12: 12.9 ± 2.3; P = 0.038, n = 568) and the DTSQ ‘perceived frequency of hyperglycemia’ subscale score (baseline: 3.4 ± 1.6; week 12: 3.0 ± 1.7; P < 0.001, n = 573). Glycemic control improved, as evidenced by decreased plasma HbA_1c levels (baseline: 8.21 ± 1.47%; week 12: 7.85 ± 1.31%; P < 0.001, n = 606).

Conclusions

It was suggested that insulin regimen changes might improve glycemic control in Japanese patients with type 2 diabetes mellitus without worsening QOL. This trial was registered with ClinicalTrials.gov (no. NCT01055808).

Differences in the glucose-lowering efficacy of dipeptidyl peptidase-4 inhibitors between Asians and non-Asians: a systematic review and meta-analysis

AIMS/HYPOTHESIS

The aim of this work was to compare the glucose-lowering efficacy of dipeptidyl peptidase-4 (DPP-4) inhibitors between Asian and non-Asian patients with type 2 diabetes.

METHODS

We searched MEDLINE, EMBASE, LILACS, CENTRAL, ClinicalTrials.gov and conference proceedings. Studies were eligible if they were randomised controlled trials with a treatment duration of at least 12 weeks, compared a DPP-4 inhibitor with a placebo as either monotherapy or oral combination therapy, had information on ethnicity and HbA1c values and were published or described in English. A systematic review and meta-analysis with a meta-regression analysis was conducted.

RESULTS

Among 809 potentially relevant studies, 55 trials were included. A meta-analysis revealed that DPP-4 inhibitors lowered HbA1c to a greater extent in studies with ≥50% Asian participants (weighted mean difference [WMD] -0.92%; 95% CI -1.03, -0.82) than in studies with <50% Asian participants (WMD -0.65%; 95% CI -0.69, -0.60). The between-group difference was -0.26% (95% CI -0.36, -0.17, p < 0.001). The baseline BMI significantly correlated with the HbA1c-lowering efficacy of DPP-4 inhibitors. The RR of achieving the goal of HbA1c <7.0% (53.0 mmol/mol) was higher in studies with ≥50% Asian participants (3.4 [95% CI 2.6, 4.7] vs 1.9 [95% CI 1.8, 2.0]). The fasting plasma glucose-lowering efficacy was higher with monotherapy in the Asian-dominant studies, but the postprandial glucose-lowering efficacy and changes in body weight were comparable between the two groups.

CONCLUSIONS/INTERPRETATION

DPP-4 inhibitors exhibit a better glucose-lowering efficacy in Asians than in other ethnic groups; this requires further investigation to understand the underlying mechanism, particularly in relation to BMI.

Family history of diabetes, lifestyle factors, and the 7-year incident risk of type 2 diabetes mellitus in middle-aged Japanese men and women

Aims/Introduction

This cohort study of middle‐aged Japanese participants investigated the relationship between family history of diabetes, the incident risk of type 2 diabetes and the interaction of these variables with other factors.

Materials and Methods

Study participants were 3,517 employees (2,037 men and 1,480 women) of a metal products factory in Japan. Baseline health examinations included questions about medical history, physical examination, anthropometric measurements, questions about lifestyle factors, such as smoking, alcohol consumption and habitual exercise, and a self‐administered diet history questionnaire. Family history of diabetes was defined as having at least one‐first‐degree relative with diabetes. The incidence of diabetes was determined in annual medical examinations over a 7‐year period. Hazard ratios (HRs) for type 2 diabetes were estimated by Cox proportional hazards analysis.

Results

Of the 3,517 participants, 630 (18%) had a family history of diabetes mellitus. During the study, 228 participants developed diabetes. The age and sex‐adjusted HR for type 2 diabetes in participants with a family history of diabetes was 1.82 (95% confidence interval 1.36–2.43) as compared with those without a family history of diabetes. HRs did not change after adjustment for body mass index and lifestyle factors. We found no interactions with body mass index, insulin resistance, pancreatic β‐cell function or lifestyle factors.

Conclusions

Family history of diabetes was associated with the incident risk of diabetes, and these associations were independent of other risk factors, such as obesity, insulin resistance, and lifestyle factors in Japanese men and women.

Effects of liraglutide, a human glucagon-like peptide-1 analogue, on body weight, body fat area and body fat-related markers in patients with type 2 diabetes mellitus

OBJECTIVE

To evaluate the effects of six-month liraglutide treatment on body weight, visceral and subcutaneous fat and related markers in Japanese type 2 diabetic patients.

METHODS

A total of 59 patients with type 2 diabetes were treated with liraglutide (0.3 mg/day for ≥1 week and then 0.6 mg/day for ≥1 week, gradually increasing the dose to 0.9 mg/day) for six months. Changes in body weight, body mass index (BMI), HbA1c, the fasting blood glucose level, visceral and subcutaneous fat areas, hepatic and renal CT values and the associated markers proinsulin, adiponectin and pentraxin (PTX) 3 were measured.

RESULTS

The study included one treatment-naïve patient, 10 patients who were switched from oral antidiabetic drugs and 35 patients who were switched from insulin therapy. At six months after treatment, the preprandial blood glucose levels were higher (148.8±40.5 mg/dL) than the baseline values (130.8±36.7, p<0.05); however, body weight, BMI and abdominal circumference were lower, and the liver/kidney CT ratio improved significantly from 1.64±0.44 at baseline to 1.78±0.42. An analysis of the patients who were not pretreated with insulin resistance ameliorators showed that six months of liraglutide treatment significantly decreased the subcutaneous but not visceral fat areas, significantly decreased the serum adiponectin levels and significantly increased the serum PTX3 levels.

CONCLUSION

In addition to its glucose-lowering effects, liraglutide exhibits weight loss promotion actions, reducing subcutaneous fat areas in particular. The weight and total fat area reduction properties of liraglutide are likely to be beneficial when this medication is used in combination with other oral antidiabetic drugs and insulin.