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

Smoking Cessation without Educational Instruction could Promote the Development of Metabolic Syndrome

AIM

Smoking cessation is particularly important for maintaining health; however, the subsequent risk of an increased body weight is of major concern. The present study investigated the influence of smoking cessation on the incidence of metabolic syndrome and its components in the Japanese general population.

METHODS

This study enrolled individuals without metabolic syndrome or a history of smoking via our annual health checkup program (n=5,702, 55.2±11.5 years). Participants were divided into three groups mentioned below and followed up with the endpoint being the development of metabolic syndrome: (1) subjects who had never smoked and did not smoke during the observation period (non-smoker); (2) those who continued smoking during the observation period (continuous smoker); and (3) those who ceased smoking during the observation period (smoking cessation).

RESULTS

During the observation period (median 1,089 days), 520 subjects developed metabolic syndrome, and Kaplan-Meier analysis showed a higher incidence of metabolic syndrome in the smoking cessation group than in the other groups. Smoking cessation was confirmed as an independent predictor of the new onset of metabolic syndrome by multivariate Cox proportional hazard analysis after adjustment. Subjects only from the smoking cessation group showed a significant deterioration in metabolic factors during the study in correlation with an increased waist circumference after smoking cessation.

CONCLUSIONS

Smoking cessation without instruction could be followed by the development of metabolic syndrome, and the incidence of metabolic syndrome might reduce the benefit obtained from smoking cessation. Therefore, further educational outreach is needed to prevent the progression of metabolic syndrome during the course of smoking cessation.

Four Plasma Glucose and Insulin Responses to a 75 g OGTT in Healthy Young Japanese Women

The incidence of diabetes has been gradually increasing, not only in middle-aged individuals but also in young individuals. However, insulin and glucose patterns have not been investigated in apparently healthy young individuals, as they are typically grouped as controls. In this study, we investigated and classified glucose and insulin patterns in healthy young women. Sixty-two nonobese women without metabolic disease were recruited. The subjects underwent a 75 g oral glucose tolerance test (OGTT), physical measurements, and a biochemical examination. Two subjects displayed impaired glucose tolerance. The 62 subjects were categorized into four patterns by plasma glucose and insulin peak time during OGTT: normal type (n = 39), insulin-late type (n = 11), insulin- and glucose-late type (n = 7), and insulin-very late type (n = 5). OGTT glucose and insulin levels at all time points, insulinogenic index, HOMA-IR, and glucose area under the curve (AUC) significantly differed among the four groups. However, insulin AUC did not significantly differ. We did not detect significant differences in body condition or biochemical measurements. Our study demonstrated that some healthy young individuals might have delayed insulin secretion by OGTT. Early detection of altered glucose metabolism might be helpful to improve lifestyle choices and prevent progression to diabetes.

Effect of antihyperglycemic drug monotherapy to prevent the progression of mild hyperglycemia in early type 2 diabetic patients: the Japan Early Diabetes Intervention Study (JEDIS)

To effectively prevent the worsening of hyperglycemia in type 2 diabetes mellitus, it is of interest to see the clinical efficacy of early introduction of pharmacotherapy in addition to lifestyle intervention which is not always easy to continue throughout life. This is a randomized unblinded comparative clinical study on suppressive effects of lifestyle intervention alone and additional monotherapies for mild hyperglycemia at an early stage of treatment-naïve type 2 diabetic patients, whose fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1c) are less than 140 mg/dl and 7.4%, respectively. The control group (group N = arm N) received conventional lifestyle intervention assisted by routine facilities, while the pharmacological intervention group (group D composed of 4 arms) was additionally treated by monotherapy with one of four kinds of oral antihyperglycemic agents i.e., sulfonylurea (SU), α-glucosidase inhibitor, biguanide and dipeptidyl peptidase-4 inhibitor. The participants were scheduled to follow up for 3 years to maintain glycemic control below primary endpoint which was defined as the first occurrence of FPG ≥140 mg/dl and HbA1c ≥7.4% simultaneously even by increasing doses of oral drug in group D, if necessary. The outcomes of occurrences of primary endpoint were not different between group N and group D composed of 4 arms during 3 years by Kaplan-Meyer plots (p = 0.405). On the other hand, ΔFPG (Δ: incremental change from baseline) and ΔHbA1c in group D significantly decreased when compared to those of group N during 3 years (p < 0.05 and p < 0.01 respectively). Significant reductions of ΔBMI were seen similarly in both groups throughout the study (p < 0.05), but did not differ between two groups. Among these 5 arms, significant decreases of ΔHbA1c were observed in three monotherapy arms of group D compared to arm N for 3 years (p < 0.05 or p < 0.01), except for arm SU in which ΔBMI and ΔHbA1c tended to increase at the latter half of the study. The final achievement rates of target HbA1c less than 7.4, 7.0 and 6.5% in all the participants tended to be higher in group D than in group N (p < 0.047 for 7.4%, but not significant for others). In conclusion, the early introduction of pharmacological monotherapy in addition to lifestyle intervention seem to suppress mild hyperglycemia with small doses of antihyperglycemic agents for 3 years, except for the use of SU drug. Although a larger scale of trial will be necessary to conclude, the early treatment with suitable monotherapy could be effective to bring and keep "safe level of glycemia".

S-Equol Activates cAMP Signaling at the Plasma Membrane of INS-1 Pancreatic β-Cells and Protects against Streptozotocin-Induced Hyperglycemia by Increasing β-Cell Function in Male Mice

Background:S-equol, which is enantioselectively produced from daidzein by gut microbiota, has been suggested as a chemopreventive agent against type 2 diabetes mellitus (T2DM), but the underlying mechanisms remain unclear.Objective: We investigated the effects of S-equol on pancreatic β-cell function.Methods: β-Cell growth and insulin secretion were evaluated with male Institute of Cancer Research mice and isolated pancreatic islets from the mice, respectively. The mechanisms by which S-equol stimulated β-cell response were examined in INS-1 β-cells. The effect of S-equol treatment on β-cell function was assessed in low-dose streptozotocin-treated mice. S-equol was used at 10 μmol/L for in vitro and ex vivo studies and was administered by oral gavage (20 mg/kg, 2 times/d throughout the experimental period) for in vivo studies.Results:S-equol administration for 7 d increased Ki67-positive β-cells by 27% (P < 0.01) in mice. S-equol enantioselectively enhanced glucose-stimulated insulin secretion in mouse pancreatic islets by 41% (P < 0.001). In INS-1 cells, S-equol exerted stronger effects than daidzein on cell growth, insulin secretion, and cAMP-response element (CRE)-mediated transcription. These S-equol effects were diminished by inhibiting protein kinase A. The effective concentration of S-equol for stimulating cAMP production at the plasma membrane was lower than that for phosphodiesterase inhibition. S-equol-stimulated CRE activation was negatively controlled by the knockdown of G-protein α subunit group S (stimulatory) and positively controlled by that of G-protein-coupled receptor kinase-3 and -6. Compared with vehicle-treated controls, S-equol gavage treatment resulted in an increase in β-cell mass of 104% (P < 0.05), a trend toward high plasma insulin concentrations (by 118%; P = 0.06), and resistance to hyperglycemia after streptozotocin treatment (78% of AUC after glucose challenge; P < 0.01). S-equol administration significantly increased the number of Ki67-positive proliferating β-cells by 62% (P < 0.01) and decreased that of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive apoptotic β-cells by 75% (P < 0.05).Conclusions: Our results show that S-equol boosts β-cell function and prevents hypoglycemia in mice, suggesting its potential for T2DM prevention.

Efficacy and safety of dapagliflozin in Asian patients: A pooled analysis

BACKGROUND

The efficacy and safety of dapagliflozin, a sodium-glucose cotransporter 2 inhibitor, has been demonstrated predominantly in Western populations. This study examined the efficacy and safety of dapagliflozin in Asian patients with type 2 diabetes mellitus (T2DM) from eight Phase IIb/III double-blind trials of up to 24 weeks, treated with placebo (n = 497) or dapagliflozin 5 mg (n = 491) or 10 mg (n = 465).

METHODS

Efficacy was assessed in the pooled population receiving dapagliflozin 5, 10 mg or placebo over 24 weeks. Safety and tolerability were assessed by collating data for overall adverse events (AEs) and AEs of special interest over the 24-week period.

RESULTS

Demographic and baseline characteristics were comparable across treatment groups. Placebo-corrected adjusted mean changes from baseline at 24 weeks in the dapagliflozin 5 and 10 mg groups, respectively, were -0.52% and -0.58% for HbA1c and -1.34 and -1.80 kg for body weight. Modest reductions in blood pressure were also noted with dapagliflozin. Overall, 56.5%, 53.6%, and 58.7% of patients in the placebo and dapagliflozin 5 and 10 mg groups, respectively, experienced AEs, compared with 2.8%, 4.1%, and 2.4% experiencing serious AEs. Genital infections were more frequent with dapagliflozin 10 mg than placebo, whereas the pattern for urinary tract infections was less clear. A transient reduction in mean estimated glomerular filtration rate was noted with dapagliflozin, but was not associated with an increased frequency of serious renal AEs. In contrast, placebo-corrected reductions in urinary albumin : creatinine ratio in patients with albuminuria at baseline suggest a potential renoprotective effect of dapagliflozin.

CONCLUSION

Dapagliflozin was efficacious and well tolerated in Asian patients with T2DM.

The association between insulin resistance, metabolic syndrome, and ischemic heart disease among Rumoi residents

Background

It has widely been proven that metabolic syndrome (MetS) increases the risk of ischemic heart disease (IHD). MetS is confirmed based upon insulin resistance (IR). Our aim of this study is to evaluate the role of MetS and IR in the prediction of IHD incidence.

Methods

A total of 404 non‐diabetic participants who underwent 75 g oral glucose tolerance test (75 g OGTT) were enrolled from 2001 to 2009. Risk factors for IHD were measured as well. The homeostatic index of IR (HOMA‐IR) and the homeostatic model assessment beta cell function (HOMA‐β) were calculated according to the homeostasis model assessment. Cox proportional‐hazard regression model was used to estimate hazard ratio (HR). All data were analyzed using SPSS 21 software (IBM, Armonk, NY, USA).

Results

In our study, the average follow‐up period was 6.7 years. Eighteen subjects of IHD incidence were recorded. After adjusting for age and sex, subjects with IR or hyperinsulinemia had a high risk of IHD, the hazard ratio (95% confidence intervals) for IHD were 4.58 (1.59‐13.15), 4.25 (1.64‐11.91), respectively. The highest hazard ratio was 7.56 (2.27‐25.18) which was found among the subjects with both IR and hyperinsulinemia. In addition, the hazard ratio (95% confidence intervals) of subjects with MetS was 2.80(1.10‐7.09).

Conclusions

IR and hyperinsulinemia are related to the risk of IHD. IR combined with hyperinsulinemia may be superior to MetS for predicting the IHD incidence.

Efficacy and safety of canagliflozin as add-on therapy to teneligliptin in Japanese patients with type 2 diabetes mellitus: Results of a 24-week, randomized, double-blind, placebo-controlled trial

AIMS

To investigate efficacy and safety of the sodium-glucose co-transporter 2 (SGLT2) inhibitor canagliflozin administered as add-on therapy to the dipeptidyl peptidase-4 (DPP-4) inhibitor teneligliptin in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

We conducted a multicentre, randomized, double-blind, placebo-controlled, phase 3 clinical trial in Japanese patients with T2DM who had inadequate glycaemic control with teneligliptin. Patients were randomized to receive teneligliptin 20 mg plus either canagliflozin 100 mg (T + C, n = 70) or placebo (T + P, n = 68) once daily. The primary endpoint was the change in glycated haemoglobin (HbA1c) from baseline to week 24. Other endpoints included changes in fasting plasma glucose, body weight, proinsulin/C-peptide ratio, homeostatic model assessment 2-%B and adverse events. Patients also underwent mixed-meal tolerance tests.

RESULTS

The difference between the T + C and T + P groups for HbA1c change from baseline to week 24 was -0.88% (least-squares mean, P < .001). Fasting plasma glucose, body weight and the proinsulin/C-peptide ratio were significantly lower in the T + C group than in the T + P group. Homeostatic model assessment 2-%B improved with T + C compared with T + P. The T + C group exhibited a decrease in the 2-hour postprandial plasma glucose and plasma glucose area under the curve (AUC)_0-2h in a mixed-meal tolerance test. No significant between-group differences were observed for C-peptide AUC_0-2h or glucagon AUC_0-2h after meals. Incidences of adverse events were 60.0% and 47.1% in the T + C and T + P groups, respectively. No hypoglycaemia was observed.

CONCLUSIONS

Canagliflozin administered as add-on therapy to teneligliptin was effective and well tolerated in Japanese T2DM patients.

Adenovirus vector-mediated macrophage erythroblast attacher (MAEA) overexpression in primary mouse hepatocytes attenuates hepatic gluconeogenesis

Japanese patients with type 2 diabetes mellitus present a different responsiveness in terms of insulin secretion to glucose and body mass index (BMI) from other populations. The genetic background that predisposes Japanese individuals to type 2 diabetes mellitus is under study. Recent genetic studies demonstrated that the locus mapped in macrophage erythroblast attacher (MAEA) increases the susceptibility to type 2 diabetes mellitus in East Asians, including Japanese individuals. MAEA encodes a protein that plays a role in erythroblast enucleation and in the normal differentiation of erythroid cells and macrophages. However, the contribution of MAEA to type 2 diabetes mellitus remains unknown. In this study, to overexpress MAEA in the mouse liver and primary mouse hepatocytes, we generated a MAEA-expressing adenovirus (Ad) vector using a novel Ad vector exhibiting significantly lower hepatotoxicity (Ad-MAEA). Blood glucose and insulin levels in Ad-MAEA-treated mice were comparable to those in control Ad-treated mice. Primary mouse hepatocytes transduced with Ad-MAEA showed lower levels of expression of gluconeogenesis genes than those transduced with the control Ad vector. Hepatocyte nuclear factor-4α (HNF-4α) mRNA expression in primary mouse hepatocytes was also suppressed by MAEA overexpression. These results suggest that MAEA overexpression attenuates hepatic gluconeogenesis, which could potentially lead to improvement of type 2 diabetes mellitus.

Efficacy and safety of alogliptin in patients with type 2 diabetes mellitus: A multicentre randomized double-blind placebo-controlled Phase 3 study in mainland China, Taiwan, and Hong Kong

BACKGROUND

This study determined the efficacy and safety of once-daily oral alogliptin in patients from mainland China, Taiwan, and Hong Kong with type 2 diabetes mellitus.

METHODS

In this Phase 3 multicenter double-blind placebo-controlled 16-week trial, 506 patients were randomized to receive once-daily alogliptin 25 mg or placebo: 185 in the monotherapy group, 197 in the add-on to metformin group, and 124 in the add-on to pioglitazone group. The primary efficacy variable was the change from baseline (CFB) in HbA1c at Week 16; other efficacy measures included CFB to Week 16 in fasting plasma glucose (FPG), incidence of marked hyperglycemia (FPG ≥11.1 mmol/L), and the incidence of clinical HbA1c ≤6.5 % (48 mmol/mol) and ≤7.0 % (53 mmol/mol) at Week 16. Safety was assessed throughout the trial.

RESULTS

Alogliptin monotherapy provided a significantly greater decrease in HbA1c from baseline to Week 16 compared with placebo (-0.58 %; 95 % confidence interval [CI] -0.78 %, -0.37 %; P < 0.001). As an add-on to metformin or pioglitazone, alogliptin also significantly decreased HbA1c compared with placebo (-0.69 % [95 % CI -0.87 %, -0.51 %; P < 0.001] and -0.52 % [95 % CI -0.75 %, -0.28 %; P < 0.001], respectively). In any treatment group versus placebo, alogliptin led to greater decreases in FPG (P ≤ 0.004) and a higher percentage of patients who achieved an HbA1c target of ≤6.5 % and ≤7.0 % (P ≤ 0.003). No weight gain was observed in any treatment group. A similar percentage of patients experienced drug-related, treatment-emergent adverse events in the alogliptin and placebo arms. Four and two patients in the alogliptin and placebo arms, respectively, experienced mild or moderate hypoglycemia.

CONCLUSIONS

Alogliptin 25 mg once daily reduced HbA1c and FPG and enhanced clinical response compared with placebo when used as monotherapy or as an add-on to metformin or pioglitazone. Therapy with alogliptin was well tolerated.

Efficacy and Safety of the Dipeptidyl Peptidase-4 Inhibitor Sitagliptin on Atherosclerosis, β-Cell Function, and Glycemic Control in Japanese Patients with Type 2 Diabetes Mellitus Who are Treatment Naïve or Poorly Responsive to Antidiabetes Agents: A Multicenter, Prospective Observational, Uncontrolled Study

BACKGROUND

Sitagliptin, a dipeptidyl peptidase-4 inhibitor, is widely used in patients with type 2 diabetes. However, the pleiotropic effects of sitagliptin is not well understood.

OBJECTIVE

To assess the clinical efficacy and safety of sitagliptin on atherosclerosis, β-cell function, and glycemic control in Japanese patients with type 2 diabetes.

METHODS

A prospective observational study of 270 patients with type 2 diabetes mellitus was carried out. Patients (aged 64.3 [12.4] years, body mas index 25.2 [4.3]) with glycated hemoglobin >6.9% (52 mmol/mol) or fasting plasma glucose >130 mg/dL were treated with sitagliptin for 12 months. The primary end point was glycated hemoglobin level changes from baseline to 3 months. The secondary end points included changes in several biomarkers related to inflammation and β-cell function from baseline to 3 months, as well as changes in glycated hemoglobin level from baseline to 12 months.

RESULTS

Glycated hemoglobin levels were significantly lower in patients treated with sitagliptin for 3 months than at baseline (8.1% [1.4%]-7.3% [1.2%]) (65 [16.9]-56 [13.1] mmol/mol]) (P < 0.0001), which continued after 12 months (7.4% [1.3%]) (56 [15.2] mmol/mol) (P < 0.0001). In addition, a marker of vascular-specific inflammation, pentraxin-3, and a marker of β-cell function (proinsulin/insulin ratio), respectively, were lower after treatment with sitagliptin for 3 months than at baseline (1.88 [0.78]-1.65 [0.63] ng/mL [P = 0.0038] and 0.20 [0.14]-0.17 [0.11] [P = 0.01], respectively). On the other hand, a biomarker reflecting whole body inflammation; that is, high-sensitivity C-reactive protein level, was unchanged. Adverse events occurred in 14 patients (5.18%).

CONCLUSIONS

Sitagliptin may have beneficial effects on vascular inflammation and β-cell function in Japanese patients with type 2 diabetes. Pentraxin-3 may be an early predictive marker for detecting the antiatherosclerotic effects of dipeptidyl peptidase-4.

Impact of metabolic syndrome on the incidence of type 2 diabetes in middle-aged Japanese individuals with impaired insulin secretion: the Saku study

AIMS

To assess the impact of metabolic syndrome (MetS) on the incidence of type 2 diabetes in middle-aged Japanese individuals with impaired insulin secretion (IIS).

METHODS

This cohort study included 1,702 individuals aged 40-59 without diabetes at baseline who underwent a comprehensive medical check-up between April 2008 and March 2009 at Saku Central Hospital. Participants were classified according to their IIS and insulin resistance (IR) status [normal, isolated IR (i-IR), or isolated IIS (i-IIS)] and MetS (presence or absence). They were followed up until March 2014. Type 2 diabetes was defined based on fasting and 2-h post-load plasma glucose concentrations and by the receipt of medical treatment for diabetes.

RESULTS

During 7,572 person-years of follow-up, 92 individuals developed type 2 diabetes. The incidence rates (/1,000 person-years) for type 2 diabetes in the normal without MetS, normal with MetS, i-IR without MetS, i-IR with MetS, i-IIS without MetS, and i-IIS with MetS groups were 5.3, 3.7, 11.3, 24.7, 16.7, and 59.5, respectively. The multivariable-adjusted hazard ratios (HRs) and 95 % confidence intervals (CIs) for type 2 diabetes in the normal with MetS, i-IR with MetS, and i-IIS with MetS groups, relative to the normal without MetS group, were 0.52 (0.12-2.25), 3.78 (1.93-7.42), and 7.94 (3.96-15.91), respectively. Additionally, a positive association of MetS with type 2 diabetes was observed in the i-IIS group [HR (95 % CI) 3.56 (1.88-6.73)] but not in the normal and i-IR groups.

CONCLUSIONS

The prevention of MetS is important, particularly in individuals with low insulin secretion.

Effect of race and ethnicity on vildagliptin efficacy: A pooled analysis of phase II and III studies

AIMS

To determine the impact of race and ethnicity on the efficacy, body weight and hypoglycaemia incidence with vildagliptin treatment in patients with type 2 diabetes mellitus using patient-level data from the vildagliptin clinical trial programme.

METHODS

Data from 22 randomized, placebo-controlled global and local (Japan, China) registration studies of vildagliptin (50 mg once-daily or twice-daily) of ≥12-week duration were analysed by race (Caucasian [n = 2764] and Asian [n = 2232]) and by ethnicity (Japanese, Chinese, and Indian). The placebo-subtracted differences in the change in glycated haemoglobin (HbA1c) and body weight from baseline to week 12 or week 24 were evaluated by race or ethnicity using repeated measure analysis of unstructured covariance. Hypoglycaemia incidences were summarized using descriptive statistics.

RESULTS

The HbA1c reduction from baseline with vildagliptin was similar across the racial/ethnic subgroups (-0.83% ± 0.02% to -1.01% ± 0.05%). Placebo-corrected HbA1c reduction was similar between Caucasian (-0.68% ± 0.03%) and Asian (-0.80% ± 0.03%) patients ( P value for interaction = .56); analysis by race and ethnicity showed better efficacy ( P < .02) in Japanese patients. Japanese patients were drug-naïve and treated with a single oral anti-diabetes drug only; they showed no response to placebo. Weight neutrality of vildagliptin was demonstrated in all groups (0.47 ± 0.11 kg to -0.29 ± 0.08 kg). Hypoglycaemic events (≥1) were infrequent in all ethnic subgroups.

CONCLUSIONS

The glycaemic efficacy of vildagliptin was similar in Caucasian and Asian patients. The slightly better efficacy observed in Japanese patients was driven by the absence of placebo effect and might be explained by their earlier stage of diabetes compared to other subgroups.

Comparative analysis of the effects of alogliptin and vildagliptin on glucose metabolism in type 2 diabetes mellitus

The aim of this 24-week, prospective randomized open-label study was to compare the effects of alogliptin and vildagliptin on glucose control, renal function, and lipid metabolism. In Study 1, DPP-4 inhibitor-naive type 2 diabetes (T2DM) were randomly assigned to alogliptin 25 mg/day or vildagliptin 50 mg twice daily. In Study 2, T2DM on treatment with 50 mg/day sitagliptin were switched to either 25 mg/day alogliptin or 50 mg twice daily vildagliptin. The primary endpoint was change in glycosylated hemoglobin (HbA1c) level at 24 weeks, while the secondary endpoints were changes in urinary albumin excretion and low-density lipoprotein cholesterol (LDL-C) levels at 24 weeks. In Study 1, HbA1c levels changed at 24-week by -0.5±0.7% in the alogliptin group (p=0.002, relative to baseline) and -0.7±0.9% in the vildagliptin group (p=0.001, relative to baseline), and the extent of these changes were comparable between the two groups (p=0.219). The decrease in log urinary albumin excretion was more significant in the vildagliptin group (p=0.008). In Study 2, HbA1c levels at 24-week changed by 0.2±0.7% in the switch-to-alogliptin group (p=0.007) and 0.0±0.6% in the switch-to-vildagliptin group (p=0.188), indicating a significant difference between the groups (p=0.003). In both studies, the changes in LDL-C levels were comparable between the two groups. The two drugs had comparable glucose-lowering effects in DPP-4 inhibitor-naive patients but the effect was more pronounced for vildagliptin in patients switched from sitagliptin. The results may point to subtle yet important differences between the two DPP-4 inhibitors. This trial was registered with UMIN (no. #000019022).

Joint impact of modifiable lifestyle behaviors on glycemic control and insulin resistance in patients with type 2 diabetes: the Fukuoka Diabetes Registry

Aims

Little is known about the combined effects of unhealthy lifestyle behaviors on glycemia. The objective of this study was to examine the association between combined modifiable lifestyle and glycemic control, as well as markers of insulin resistance and secretion.

Patients and methods

In total, 4,870 patients with type 2 diabetes were sorted by lifestyle scores. Scores were determined by summing the number of unhealthy lifestyle factors that showed a significant association with hemoglobin A_1c (HbA_1c) (current smoking, decreased dietary fiber intake, eating quickly, inadequate sleep duration, and obesity). The associations between lifestyle score and hemoglobin A_1c (HbA_1c), homeostasis model assessment of insulin resistance (HOMA2-IR), and β-cell function (HOMA2-%B) were cross-sectionally analyzed.

Results

HbA_1c increased progressively with increases in lifestyle score (p for trend <0.001). Mean HbA_1c was 0.48% (95% confidence intervals 0.34-0.63) higher in patients with scores of four to five than in those with zero scores. HOMA2-IR and high-sensitivity C-reactive protein also revealed a similar tendency, but adiponectin showed an inverse association. However, these graded tendencies were not observed for HOMA2-%B. Additionally, lower HOMA2-%B levels enhanced the effects of lifestyle score on glycemia. Increases in HbA_1c per point in the lifestyle score in patients with the lowest and highest quartiles of HOMA2-%B were 0.25% (0.18-0.32) and 0.10% (0.06-0.15), respectively (p for interaction <0.001).

Conclusions

Accumulation of unhealthy lifestyle factors was dose-dependently associated with poor glycemic control, which may be modified by insulin secretory capacity.

Basal insulin treatment intensification in patients with type 2 diabetes mellitus: A comprehensive systematic review of current options

AIM

As type 2 diabetes mellitus progresses, most patients require treatment with basal insulin in combination with another agent to achieve recommended glycaemic targets. The purpose of this systematic review was to examine the evidence supporting the use of the available add-on treatments [rapid-acting insulin (RAI), glucagon-like peptide-1 receptor agonists (GLP-1 RAs), dipeptidyl peptidase (DPP)-4 inhibitors and sodium-glucose cotransporter-2 (SGLT-2) inhibitors] to basal insulin.

METHODS

MEDLINE, EMBASE and EBSCOhost were searched for English-language articles, and all those captured were original articles (case studies and narrative reviews were omitted). Data on study design, population demographics, interventions and outcomes were tabulated. The extracted outcome data included changes in glycated haemoglobin (HbA_1c), fasting plasma glucose (FPG) and postprandial plasma glucose (PPG), as well as body weight and safety data.

RESULTS

A total of 88 publications were deemed relevant. All treatments reduced HbA_1c and FPG. The most pronounced reductions in PPG, an unmet need in patients not controlled by basal insulin, were seen following administration of RAIs and short-acting GLP-1 RAs, although data for this outcome are generally lacking. Body weight benefits were observed with GLP-1 RAs and SGLT-2 inhibitors. However, as only articles in English were included, the result was a possible publication bias, while the diversity of study designs and drug combinations limited comparisons between studies.

CONCLUSION

The evidence supports effectiveness of the available add-on treatments to basal insulin. However, other factors, such as potential body-weight increases, convenience/compliance and adverse events, particularly hypoglycaemia, should be considered on a patient-by-patient basis to optimalize treatment outcomes.

Comparison of baseline characteristics and clinical course in Japanese patients with type 2 diabetes among whom different types of oral hypoglycemic agents were chosen by diabetes specialists as initial monotherapy (JDDM 42)

Little is known about the relationships between patient factors and the antihyperglycemic agents that have been prescribed as initial therapy by diabetes specialists for patients with type 2 diabetes. Moreover, there has been little clarification of the subsequent usage patterns and related factors that influenced the continuation or discontinuation of the drug or the addition of another drug. To provide information on these issues, we evaluated the clinical characteristics of Japanese patients with type 2 diabetes for whom different types of oral hypoglycemic agents (i.e., either sulfonylureas, biguanides, or DPP-4 inhibitors (DPP-4Is)) were chosen as initial monotherapy by diabetes specialists and evaluated subsequent usage patterns.Prescription data on 3 different antidiabetic agents from December 2009 to March 2015 from diabetes specialists' patient registries were used to identify variables at baseline related to initial prescriptions; also, the addition of another hypoglycemic drug or discontinuation of the initial therapy was evaluated 1 year after the initial prescription. Analyzed were data on 2666 patients who received initial monotherapy with either a sulfonylurea (305 patients), biguanide (951 patients), or DPP-4I (1410 patients). Patients administered sulfonylureas were older, had a lower body mass index (BMI), longer duration of diabetes, and worse glycemic control than recipients of biguanides. Use of biguanides was related to younger age, short duration of diabetes, and obesity but was negatively associated with poor glycemic control. Older age but neither obesity nor poor glycemic control was associated with DPP-4Is. In all 3 groups a high HbA1c value was related to adding another hypoglycemic agent to the initial therapy. Moreover, adding another drug to a DPP-4I was related to a younger age and higher BMI.Patients' age, duration of diabetes, obesity, and glycemic control at baseline influenced the choice of hypoglycemic agents. Selection of a biguanide differs greatly from that of a sulfonylurea or DPP-4I with regard to age and obesity.

Predictive Factors for the Therapeutic Response to Concomitant Treatment with DPP-4 Inhibitors in Type 2 Diabetes with Short-Term Follow-Up

Objectives To evaluate the efficacy and predictive factors of Dipeptidyl peptidase-4 (DPP-4) inhibitors in type 2 diabetes mellitus (T2DM) patients who were not well controlled with other oral antidiabetic drugs or insulin in real clinical practice. Methods From December 2012 to January 2014, retrospective longitudinal observation study was conducted for patients with T2DM who were not reached a glycemic target (glycated hemoglobin [HbA1c] &gt; 6.5%) with other oral antidiabetic drugs or insulins. Type 1 diabetes or other types of diabetes were excluded. Responders were eligible with decreased HbA1c from baseline for more than 5% during follow up period. Results Of total 135 T2DM patients having an average 9.0 months follow-up period, 84 (62.2%) of patients were responder to DPP-4 inhibitors. After concomitant treatment with DPP-4 inhibitors, patients had a mean decrease in HbA1c of 0.69 ± 1.3%, fasting plasma glucose of 13 ± 52 ㎎/㎗, and postprandial plasma glucose of 29 ± 85 ㎎/㎗ from baseline (all P&lt; 0.05). Independent predictive factor for an improvement of glycemic control with DPP-4 inhibitors was higher baseline HbA1c (odds ratio 2.07 with 95% confidence interval 1.15–3.72) compared with non-responders. Conclusions A clinical meaningful improvement in glycemic control was seen when DPP-4 inhibitors were added to other anti-diabetic medications in patients with T2DM regardless of age, duration of T2DM, type of combination treatment regimen. Patients who had higher HbA1c were more easily respond to DPP-4 inhibitors treatment in short-term follow-up period.

Delayed insulin secretion response during an OGTT is associated with an increased risk for incidence of diabetes in NGT subjects

AIMS

This study aimed to assess whether insulin secretion patterns during oral glucose tolerance tests (OGTTs) could predict future type 2 diabetes (T2D) in Chinese normal glucose tolerance (NGT) subjects.

METHODS

A total of 558 NGT, 419 newly diagnosed impaired glucose tolerance, and 694 newly diagnosed T2D patients were assessed. NGT subjects were grouped based on the time of peak insulin secretion during a 3h- OGTT; at 30min (InsP30), 60min (InsP60), 120min (InsP120), or 180min (InsP180), respectively. NGT subjects were followed up for an average duration of 5.58±1.08years. Beta-cell function was estimated by Stumvoll insulin secretion.

RESULTS

The InsP120 and InsP180 groups had lower Stumvoll first-phase insulin secretion levels compared with InsP30. At 5.58±1.08years, 25 (5.39%) NGT subjects had developed T2D. The cumulative incidence rate of diabetes was higher in the InsP120 and InsP180 groups (8.94%), compared with InsP30 (1.48%) (P<0.05). The adjusted relative risk for incident diabetes was 7.30 (95% CI: 1.53-34.72) times higher in the InsP120 and InsP180 groups.

CONCLUSIONS

NGT subjects with late insulin responses had defective early insulin secretion and were at higher risk of developing diabetes. Insulin secretion patterns could be a useful T2D predictor in the Chinese population.

Alogliptin for the treatment of type 2 diabetes: a drug safety evaluation

INTRODUCTION

Dipeptidyl peptidase-4 (DPP-4) inhibitors such as alogliptin are becoming more widely established as treatment options for patients with type 2 diabetes (T2DM) because of their ability to improve glycemic control without increasing the risk of hypoglycemia or weight gain. New therapies with improved safety profiles are needed, especially because of the chronic and progressive nature of T2DM.

AREAS COVERED

In this article, the overall safety and tolerability of alogliptin are evaluated based upon a review of the literature. In particular, adverse events (AEs) that have been of interest for the DPP-4 class of drugs, such as the risk of major cardiovascular (CV) events and acute pancreatitis, will be investigated in detail.

EXPERT OPINION

Alogliptin is generally well-tolerated in a broad range of patient populations including different ethnic groups and the elderly. In the pivotal EXAMINE clinical trial, alogliptin was found not to be associated with an increased risk of major CV events or acute pancreatitis/pancreatic cancer.

Efficacy of lixisenatide in patients with type 2 diabetes: A post hoc analysis of patients with diverse β-cell function in the GetGoal-M and GetGoal-S trials

AIMS

To evaluate the impact of β-cell function on the efficacy of lixisenatide, a once-daily prandial glucagon-like peptide-1 receptor agonist, in patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

In this post hoc analysis, patients from the Phase 3 GetGoal-M and GetGoal-S clinical trials randomized to lixisenatide 20μg once daily were stratified into quartiles by baseline β-cell function, as measured by the secretory units of islet in transplantation (SUIT) index.

RESULTS

Patients (N=437) were distributed evenly among SUIT index quartiles 1 to 4 (lowest to highest β-cell function). Clinical outcomes improved from baseline across all SUIT quartiles; mean changes at week 24 were: glycated hemoglobin (HbA1c; % [mmol/mol]), -0.99 (-10.8), -0.87 (-9.5), -0.86 (-9.4), -0.83 (-9.1); and postprandial plasma glucose (PPG; mmol/L), -7.9, -5.6, -5.5, -4.3 (overall effect P<0.0001). Furthermore, postprandial glucagon was reduced in all SUIT quartiles, while insulinogenic index improved only in patients with higher baseline SUIT (overall effect P=0.0286). No severe symptomatic hypoglycemic events were reported.

CONCLUSIONS

Lixisenatide treatment resulted in reductions in HbA1c and PPG levels across all SUIT quartiles. This suggests that non-insulin-related actions of lixisenatide contribute to improved glycemic control in T2D.

Delayed heart rate recovery after exercise as a risk factor of incident type 2 diabetes mellitus after adjusting for glycometabolic parameters in men

BACKGROUND

Some studies have reported that delayed heart rate recovery (HRR) after exercise is associated with incident type 2 diabetes mellitus (T2DM). This study aimed to investigate the longitudinal association of delayed HRR following a graded exercise treadmill test (GTX) with the development of T2DM including glucose-associated parameters as an adjusting factor in healthy Korean men.

MATERIAL AND METHODS

Analyses including fasting plasma glucose, HOMA-IR, HOMA-β, and HbA1c as confounding factors and known confounders were performed. HRR was calculated as peak heart rate minus heart rate after a 1-min rest (HRR 1). Cox proportional hazards model was used to quantify the independent association between HRR and incident T2DM.

RESULTS

During 9082 person-years of follow-up between 2006 and 2012, there were 180 (10.1%) incident cases of T2DM. After adjustment for age, BMI, systolic BP, diastolic BP, smoking status, peak heart rate, peak oxygen uptake, TG, LDL-C, HDL-C, fasting plasma glucose, HOMA-IR, HOMA-β, and HbA1c, the hazard ratios (HRs) [95% confidence interval (CI)] of incident T2DM comparing the second and third tertiles to the first tertile of HRR 1 were 0.867 (0.609-1.235) and 0.624 (0.426-0.915), respectively (p for trend=0.017). As a continuous variable, in the fully-adjusted model, the HR (95% CI) of incident T2DM associated with each 1 beat increase in HRR 1 was 0.980 (0.960-1.000) (p=0.048).

CONCLUSIONS

This study demonstrated that delayed HRR after exercise predicts incident T2DM in men, even after adjusting for fasting glucose, HOMA-IR, HOMA-β, and HbA1c. However, only HRR 1 had clinical significance.

Predictors of Abnormal Glucose Tolerance in the Early Postpartum Period in Patients with Gestational Diabetes

This study was designed to investigate the clinical predictors of abnormal glucose tolerance 5-7 weeks after delivery. Subjects were 155 women diagnosed with gestational diabetes mellitus (GDM) between October 2005 and September 2013 whose pregnancy and delivery were managed at our center. Subjects were divided into a normal glucose tolerance group (NGT; n = 113), or abnormal glucose tolerance group (AGT; n = 42) with borderline or overt diabetes mellitus, based on 75-g oral glucose tolerance test (75 gOGTT) results 5-7 weeks after delivery. We extracted profiles by which abnormal glucose tolerance levels 5-7 weeks after delivery were predicted using a classification and regression tree (CART) from parameters measured at the time of GDM diagnosis. Logistic regression analysis was used to determine prediction accuracy. Subjects with fasting plasma glucose (FPG) ≥92 mg/dL and immuno-reactive insulin level <100 μU/mL 60 min after load (IRI60min) at time of diagnosis showed a significantly higher risk of developing abnormal glucose tolerance 5-7 weeks after delivery than subjects with FPG <92 mg/dL (p < 0.0001). Subjects with FPG ≥92 mg/dL and IRI60min ≥ 100 μU/mL had the same risk as those with FPG of <92 mg/dL. Patients with gestational diabetes who met the criteria specified above at diagnosis were at a higher risk of developing diabetes mellitus in the future. By explaining this issue to patients, we expect to improve the rate of postpartum follow-up. This should facilitate early detection of diabetes, and help prevent associated complications.

Effect of Switching from Sulphonylurea to Repaglinide Twice or Three Times Daily for 4 Months on Glycemic Control in Japanese Patients with Type 2 Diabetes

Objective Switching from sulfonylureas to repaglinide in patients with type 2 diabetes improves glycemic control; however, the optimal dosage has not been fully evaluated. We designed to show that repaglinide was equivalent to sulfonylurea in Japanese patients with type 2 diabetes. We herein evaluated whether we could switch from sulfonylureas to repaglinide twice or thrice daily in Japanese adult patients who had been treated with anti-diabetic drugs, including sulfonylureas, and whose conditions were moderately well-controlled. Methods A total of 78 patients taking less than half the Japanese maximum dose of sulfonylurea were randomized into three groups: 26 in group A (switching from sulfonylureas to taking 0.25 or 0.5 mg of repaglinide just before breakfast and dinner twice daily), 27 in group B (switching from sulfonylureas to taking 0.25 or 0.5 mg of repaglinide just before meals thrice daily), and 25 in group C (continuing to take sulfonylurea). Blood samples were collected at 0, 1, 2, 3, and 4 months following the initiation of the maintenance period. Results The HbA1c and glycoalbumin levels did not significantly differ among the three groups after 4 months of treatment. Conclusion With the assumption that 1 mg of glimepiride is equivalent to 1.25 mg of glibenclamide or 40 mg of gliclazide, the administration of repaglinide (0.44 mg/meal) twice and thrice daily is similar to the efficacy of sulfonylurea (glimepiride 1.63-1.98 mg/day) after four months of treatment in Japanese patients with moderately well-controlled type 2 diabetes (HbA1c, 7-7.5%).

Comparison of efficacy and safety of two starting insulin regimens in non-Asian, Asian Indian, and East Asian patients with type 2 diabetes: a post hoc analysis of the PARADIGM study

OBJECTIVE

The objective of this study was to explore the efficacy and safety of insulin lispro mix 25 (25% insulin lispro and 75% insulin lispro protamine suspension [LM25]) or insulin glargine plus insulin lispro (G+L) in insulin-naïve patients with type 2 diabetes from different racial/ethnic groups.

METHODS

Three subgroups from the PARADIGM study were analyzed post hoc: non-Asian (n=130), Asian Indian (n=106), and East Asian (n=89).

RESULTS

All subgroups recorded glycated hemoglobin (HbA1c) reductions: non-Asian (LM25, -2.07%; G+L, -2.05%), Asian Indian (LM25, -1.75%; G+L, -1.60%), and East Asian (LM25, -2.03%; G+L, -1.76%); end point HbA1c values were higher in Asian Indians and East Asians than in non-Asians. Fewer Asian Indians (LM25, 43.2%; G+L, 29.2%) and East Asians (LM25, 37.5%; G+L, 36.1%) reached HbA1c <7% versus non-Asians (LM25, 51.7%; G+L, 48.1%); differences were not significant (P=0.12 and P=0.06, respectively). The mean total daily insulin dose (U/kg) for non-Asians was 0.67 (LM25) and 0.61 (G+L), for Asian Indians was 0.91 (LM25) and 0.90 (G+L), and for East Asians was 0.53 (LM25) and 0.59 (G+L). The ratio of mealtime to total insulin dose in the G+L arm for non-Asians was 0.19±0.23, for Asian Indians was 0.33±0.25, and for East Asians was 0.34±0.27. Overall incidence (%) of hypoglycemia in non-Asians was 94.1 (LM25) and 91.8 (G+L), in Asian Indians was 90.4 (LM25) and 88.5 (G+L), and in East Asians was 69.8 (LM25) and 77.3 (G+L).

CONCLUSION

Asian Indians showed least improvement in glycemic HbA1c reduction despite greater insulin use. East Asians and non-Asians achieved similar HbA1c reduction in the LM25 arm with a lower rate of hypoglycemia. Asians required more mealtime insulin coverage than non-Asians. This study added important insight into the effect of ethnicity on insulin treatment outcomes in patients with type 2 diabetes.

Incretin secretion in obese Korean children and adolescents with newly diagnosed type 2 diabetes

OBJECTIVE

The role of incretins in type 2 diabetes is controversial. This study investigated the association between incretin levels in obese Korean children and adolescents newly diagnosed with type 2 diabetes.

DESIGN

We performed a 2-hr oral glucose tolerance test (OGTT) in obese children and adolescents with type 2 diabetes and with normal glucose tolerance.

PATIENTS

Twelve obese children and adolescents with newly diagnosed type 2 diabetes (DM group) and 12 obese age-matched subjects without type 2 diabetes (NDM group) were included.

MEASUREMENTS

An OGTT was conducted and insulin, C-peptide, glucagon, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) were measured during the OGTT.

RESULTS

The mean age of the patients was 13·8 ± 2·0 years, and the mean body mass index (BMI) Z-score was 2·1 ± 0·5. The groups were comparable in age, sex, BMI Z-score and waist:hip ratio. The DM group had significantly lower homeostasis model assessment of β and insulinogenic index values (P < 0·001). The homeostasis model assessment of insulin resistance index was not different between the two groups. Insulin and C-peptide secretions were significantly lower in the DM group than in the NDM group (P < 0·001). Total GLP-1 secretion was significantly higher in the DM group while intact GLP-1 and GIP secretion values were not significantly different between the two groups.

CONCLUSION

Impaired insulin secretion might be important in the pathogenesis of type 2 diabetes in obese Korean children and adolescents, however, which may not be attributed to incretin secretion.

Lixisenatide improves glycemic outcomes of Japanese patients with type 2 diabetes: a meta-analysis

BACKGROUND

The GetGoal-L-Asia and -S trials were multi-center trials conducted in 4 and 16 countries, respectively including Japan that evaluated the efficacy and safety of lixisenatide add-on treatment vs. placebo among patients with type 2 diabetes. The aims of this study were to determine the efficacy and safety of lixisenatide add-on treatment among Japanese patient groups.

METHODS

All Japanese intent-to-treat patients with baseline and endpoint HbA1c measurements were included in the meta-analyses. Subgroup analyses were carried out for patients with low (<8 %) and high (≥8 %) baseline HbA1c levels, low (<25 kg/m(2)) and high (≥25 kg/m(2)) baseline body mass index (BMI), short (<10 years) and long (≥10 years) durations of diabetes, and for those <65 and ≥65 years of age.

RESULTS

The overall study population of Japanese type 2 diabetes patients included 143 patients (mean age: 59.0 years; 35 % female) treated with lixisenatide and 136 patients treated with placebo (mean age: 57.8 years; 32 % female). Among the subgroups, lixisenatide treatment vs. placebo was associated with greater change in HbA1c (Low HbA1c -0.80 %, p < 0.0001; High HbA1c -1.19 %, p < 0.0001; low BMI -0.88 %, p < 0.0001; high BMI -1.28 %, p < 0.0001; short diabetes duration -1.28 %, p < 0.0001; long diabetes duration -0.93 %, p < 0.0001; <65 years: -1.00 %, p < 0.0001; ≥65 years -1.24 %, p < 0.0001). Additionally, among the subgroups, lixisenatide treatment vs. placebo was associated with greater change in post-prandial glucose.

CONCLUSIONS

For Japanese type 2 diabetes patients lixisenatide may be an efficacious and safe add-on therapy leading to improved glycemic outcomes. GetGoal-L-Asia NCT01169779 GetGoal-S NCT00713830.

Sitagliptin monotherapy has better effect on insulinogenic index than glimepiride monotherapy in Japanese patients with type 2 diabetes mellitus: a 52-week, multicenter, parallel-group randomized controlled trial

BACKGROUND

The 52-week monotherapy with the dipeptidyl peptidase-4 inhibitor sitagliptin and the sulphonylurea glimepiride on early-phase insulin secretion in Japanese patients with type 2 diabetes mellitus (T2DM) is not known.

METHODS

A randomized, parallel-group, open-label trial was conducted at 18 centers between February, 2011 and March, 2013. 171 outpatients with T2DM were recruited and randomly assigned to glimepiride or sitagliptin by minimization. Doses of glimepiride (0.25-1.0 mg/day) and sitagliptin (25-100 mg/day) were adjusted for hemoglobin A1c (HbA1c) > 6.9 %. Analyses were performed on full analysis set (FAS) of randomized subjects taking medications as allocated, and underwent 75 g oral glucose tolerance test (OGTTs) before and after treatment. The primary outcome was insulinogenic index to quantify early-phase insulin secretion after treatment, which was evaluated by analysis of covariance (ANCOVA).

RESULTS

Of 171 enrolled subjects, 68 in the sitagliptin group and 65 in the glimepiride group were included in the FAS (mean age, 64 years; baseline (HbA1c), 7.4 %). The primary outcome revealed a significantly higher insulinogenic index in the sitagliptin group than that in the glimepiride group (p = 0.036). Sitagliptin also reduced plasma glucose levels at 60 and 120 min during OGTT compared with glimepiride, while achieving a similar improvement in HbA1c during treatment. Body weight did not change in either of the two groups, and one case of hypoglycemia was observed in the glimepiride group.

CONCLUSIONS

Sitagliptin shows better effects on insulinogenic index after 52-week treatment compared with glimepiride in Japanese patients with T2DM. Trial registration University hospital Medical Information Network (UMIN) Clinical Trials Registry, No.00004791.

Dietary magnesium intake and the risk of diabetes in the Japanese community: results from the Takayama study

PURPOSE

Several experimental studies showed that magnesium intake improved insulin resistance and glucose uptake in diabetes patients. However, epidemiological studies on the association between magnesium intake and diabetes risk have yielded inconsistent results. We investigated whether magnesium intake is related to the risk of developing diabetes in a population-based cohort study in Japan.

METHODS

Study subjects were participants in the Takayama study. A total of 13,525 residents in Takayama City, Japan, responded to a self-administered questionnaire in 1992 and to a follow-up questionnaire seeking information about diabetes in 2002. Magnesium and other nutrient intakes were estimated from a validated food frequency questionnaire administered at the baseline.

RESULTS

During a follow-up of 10 years, 438 subjects reported diabetes newly diagnosed by physician. Compared with women in the low quartile of magnesium intake, women in the high quartile were at a significantly reduced risk of diabetes (HR 0.50; 95 % CI 0.30-0.84; P-trend 0.005) after adjustments for covariates. In men, there was no association between magnesium intake and the risk of diabetes.

CONCLUSION

These results suggest that diets with a high intake of magnesium may decrease the risk of diabetes in women.

Changing Clinical Characteristics according to Insulin Resistance and Insulin Secretion in Newly Diagnosed Type 2 Diabetic Patients in Korea

BACKGROUND

The role of increased insulin resistance in the pathogenesis of type 2 diabetes has been emphasized in Asian populations. Thus, we evaluated the proportion of insulin resistance and the insulin secretory capacity in patients with early phase type 2 diabetes in Korea.

METHODS

We performed a cross-sectional analysis of 1,314 drug-naive patients with newly diagnosed diabetes from primary care clinics nationwide. The homeostasis model assessment of insulin resistance (HOMA-IR) was used as an index to measure insulin resistance, which was defined as a HOMA-IR ≥2.5. Insulin secretory defects were classified based on fasting plasma C-peptide levels: severe (<1.1 ng/mL), moderate (1.1 to 1.7 ng/mL) and mild to non-insulin secretory defect (≥1.7 ng/mL).

RESULTS

The mean body mass index (BMI) was 25.2 kg/m(2); 77% of patients had BMIs >23.0 kg/m(2). Up to 50% of patients had central obesity based on their waist circumference (≥90 cm in men and 85 cm in women), and 70.6% had metabolic syndrome. Overall, 59.5% of subjects had insulin resistance, and 20.2% demonstrated a moderate to severe insulin secretory defect. Among those with insulin resistance, a high proportion of subjects (79.0%) had a mild or no insulin secretory defect. Only 2.6% of the men and 1.9% of the women had both insulin resistance and a moderate to severe insulin secretory defect.

CONCLUSION

In this study, patients with early phase type 2 diabetes demonstrated increased insulin resistance, but preserved insulin secretion, with a high prevalence of obesity and metabolic syndrome.

Diabetes in Asians

The prevalence of diabetes is increasing globally, particularly in Asia. According to the 2013 Diabetes Atlas, an estimated 366 million people are affected by diabetes worldwide; 36% of those affected live in the Western Pacific region, with a significant proportion in East Asia. The reasons for this marked increase in the prevalence of diabetes can be extrapolated from several distinct features of the Asian region. First, the two most populated countries, China and India, are located in Asia. Second, Asians have experienced extremely rapid economic growth, including rapid changes in dietary patterns, during the past decades. As a result, Asians tend to have more visceral fat within the same body mass index range compared with Westerners. In addition, increased insulin resistance relative to reduced insulin secretory function is another important feature of Asian individuals with diabetes. Young age of disease onset is also a distinctive characteristic of these patients. Moreover, changing dietary patterns, such as increased consumption of white rice and processed red meat, contributes to the deteriorated lifestyle of this region. Recent studies suggest a distinctive responsiveness to novel anti-diabetic agents in Asia; however, further research and efforts to reverse the increasing prevalence of diabetes are needed worldwide.

Safety and efficacy of addition of sitagliptin to rapid-acting insulin secretagogues for glycemic control, including post-prandial hyperglycemia, among Japanese with type 2 diabetes mellitus

The safety and efficacy of sitagliptin as add-on therapy to glinides, rapid-acting insulin secretagogues, were evaluated for Japanese patients with type 2 diabetes mellitus. This 52-week study consisted of a 12-week double-blind period, followed by a 40-week open-label period. During the double-blind period, patients were randomized to sitagliptin 50 mg q.d. (S/S group) or placebo (P/S group) as add-on therapy to glinide monotherapy. During the open-label period, all patients in both groups were administered sitagliptin 50 mg q.d. (or 100 mg q.d. after up-titration). During the double-blind period, the overall occurrence of adverse experiences (AE) was similar in both treatment groups. The frequency of reported AE of hypoglycemia in both groups was low and not notably different. The nature of clinical AE during the open-label period for both groups was not notably different from that of clinical AE in the sitagliptin group during the double-blind period. The between-group difference in HbA1c least squares (LS) mean of change from baseline (95 % CI) at Week 12 was -1.1 % (-1.3, -0.8) in favor of sitagliptin (P < 0.001). LS mean of reductions from baseline of fasting plasma glucose and 2-h postmeal glucose were significantly greater in the sitagliptin group than in the placebo group: -23.1 mg/dL (-32.2, -13.9) and -51.2 mg/dL (-67.4, -35.0), respectively (both P < 0.001). The changes from baseline in glycemic data in the S/S group remained generally stable throughout the 52-week treatment period.

Effects of 6-Month Sitagliptin Treatment on Insulin and Glucagon Responses in Korean Patients with Type 2 Diabetes Mellitus

BACKGROUND

This study aimed to evaluate the effect of sitagliptin, an oral dipeptidyl peptidase-4 inhibitor, on insulin secretion and glucagon suppression in Korean subjects with type 2 diabetes mellitus.

METHODS

Twenty-four subjects underwent a 75-g oral glucose tolerance test (OGTT) before and after 6 months of sitagliptin treatment. Sitagliptin, insulin, and sulfonylurea were withdrawn for 3 days before OGTT to eliminate any acute effects on β-cell insulin or α-cell glucagon secretion. Venous samples were drawn five times during each OGTT to measure plasma glucose, insulin, and glucagon. Indices on insulin secretion and resistance were calculated.

RESULTS

Early phase insulin secretion, measured by the insulinogenic index significantly increased after 6 months of sitagliptin treatment, especially in the higher baseline body mass index group and higher baseline glycosylated hemoglobin (HbA1c) group. There were no significant differences in the insulin resistance indices before and after sitagliptin treatment. Although no significant differences were observed in the absolute levels of glucagon and the glucagon-to-insulin ratio, there was a significant reduction in the percentile change of glucagon-to-insulin ratio at 30- and 120-minute during the OGTT.

CONCLUSION

Although the HbA1c level did not decrease significantly after 6 months of sitagliptin treatment, an increase in insulin secretion and reduction in early phase postprandial plasma glucagon-to-insulin ratio excursion was confirmed in Korean subjects with type 2 diabetes.

Comparison of clinical characteristics in patients with type 2 diabetes among whom different antihyperglycemic agents were prescribed as monotherapy or combination therapy by diabetes specialists

AIMS/INTRODUCTION

We compared clinical characteristics in patients with type 2 diabetes for whom different antihyperglycemic agents were prescribed as monotherapy or combination therapy by diabetes specialists in Japan.

MATERIALS AND METHODS

Prescription data for 2005, 2008 and 2011 from diabetes specialists' patient registries identified variables related to prescription of different antihyperglycemic agents.

RESULTS

A total of 33,251 prescriptions in 2005, 25,119 in 2008 and 20,631 in 2011 were analyzed. Prescribing insulin was related to younger age, long duration of diabetes and glycated hemoglobin (HbA1c) ≥8.0%, but was negatively associated with obesity. Prescribing sulfonylureas was related to older age and long duration of diabetes, but not to obesity. Use of biguanides was related to younger age, short duration of diabetes and obesity, but was negatively associated with HbA1c ≥8.0%. A short duration of diabetes and HbA1c ≥8.0% were associated with use of a DPP-4 inhibitor, but not with obesity. Prescribing GLP-1 receptor agonists was related to younger age, obesity and HbA1c ≥8.0%. Odds ratios for each antihyperglycemic combination therapy were determined based on the characteristics of each included antihyperglycemic agent.

CONCLUSIONS

These results could be expected to reflect in part the consensus of diabetes specialists, and might provide guidance regarding pharmacotherapy in the clinical setting.

Ethnic differences in insulin sensitivity and beta-cell function among Asian men

BACKGROUND AND OBJECTIVES

Lean Asian Indians are less insulin sensitive compared with Chinese and Malays, but the pancreatic beta-cell function among these ethnic groups has yet to be studied in depth. We aimed to study beta-cell function in relation to insulin sensitivity among individuals of Chinese, Malay and Asian-Indian ethnicity living in Singapore.

SUBJECTS AND METHODS

This is a sub-group analysis of 59 normoglycemic lean (body mass index (BMI) <23 kg m(-)(2)) adult males (14 Chinese, 21 Malays and 24 Asian Indians) from the Singapore Adults Metabolism Study. Insulin sensitivity was determined using fasting state indices (homeostatic model assessment-insulin resistance), the euglycemic-hyperinsulinemic clamp (ISI-clamp) and a liquid mixed-meal tolerance test (LMMTT) (Matsuda insulin sensitivity index (ISI-Mat)). Beta-cell function was assessed using fasting state indices (homeostatic model assessment-beta-cell function) and from the LMMTT (insulinogenic index and insulin secretion index). The oral disposition index (DI), a measure of beta-cell function relative to insulin sensitivity during the LMMTT, was calculated as a product of ISI-Mat and insulin secretion index.

RESULTS

Asian Indians had higher waist circumference and percent body fat than Chinese and Malays despite similar BMI. Overall, Asian Indians were the least insulin sensitive whereas the Chinese were most insulin sensitive. Asian Indians had higher beta-cell function compared with Chinese or Malays but these were not statistically different. Malays had the highest incremental area under the curve for glucose during LMMTT compared with Asian Indians and Chinese. However, there were no significant ethnic differences in the incremental insulin area under the curve. The oral DI was the lowest in Malays, followed by Asian Indians and Chinese.

CONCLUSION

Among lean Asians, Chinese are the most insulin sensitive whereas Asian Indians are the least insulin sensitive. However, Malays demonstrate higher postprandial glucose excursion with lower beta-cell response compare with Chinese or Asian Indians. The paths leading to type 2 diabetes mellitus might differ between these Asian ethnic groups.

Complementary glucagonostatic and insulinotropic effects of DPP-4 inhibitors in the glucose-lowering action in Japanese patients with type 2 diabetes

The dipeptidyl peptidase-4 (DPP-4) inhibitors have a low risk of causing hypoglycemia as monotherapy. However, insulin administration is frequently required, particularly in patients with type 2 diabetes and with reduced insulin secretory capacity. The effects of adding DPP-4 inhibitors were evaluated using continuous glucose monitoring (CGM) in Japanese patients with type 2 diabetes who were insufficiently controlled by basal insulin with biguanide. The effects of adding DPP-4 inhibitors on blood glucose and plasma insulin and glucagon levels were evaluated. Δ glucagon showed a significant association with post-prandial glucose increase in the group with diminished insulin secretory capacity, C-peptide index (CPI) <0.8 (p = 0.016), while Δ C-peptide reached significant association in the group with relatively intact insulin secretory capacity, CPI ≥0.8 (p = 0.017). The mean plasma glucose levels and M values were similarly improved in patients treated with the three DPP-4 inhibitors. Hypoglycemia did not occur in any of the DPP-4 inhibitor groups. In conclusion, complementary glucagonostatic and insulinotropic effects of adding DPP-4 inhibitors are involved in the glucose-lowering action of Japanese patients with type 2 diabetes according to their insulin secretory capacity. Such combination therapy may well be a superior therapeutic option for the treatment of diabetes in Japanese patients who often exhibit reduced insulin secretory capacity.

Expression of pancreatic and duodenal homeobox1 (PDX1) protein in the interior and exterior regions of the intestine, revealed by development and analysis of Pdx1 knockout mice

We developed pancreatic and duodenal homeobox1 (Pdx1) knockout mice to improve a compensatory hyperinsulinemia, which was induced by hyperplasia in the β cells or Langerhans' islands, as the diabetic model mice. For targeting of Pdx1 gene by homologous recombination, ES cells derived from a 129^+Ter/SvJcl×C57BL/6JJcl hybrid mouse were electroporated and subjected to positive-negative selection with hygromycin B and ganciclovir. As these results, one of the three chimeric mice succeeded to produce the next or F1 generation. Then, the mouse fetuses were extracted from the mother's uterus and analyzed immunohistologically for the existence of a pancreas. The fetuses were analyzed at embryonic day 14.5 (E14.5) because Pdx1 knockout could not alive after birth in this study. Immunohistochemical staining revealed that 10 fetuses out of 26 did not have any PDX1 positive primordium of the pancreas and that the PDX1 expresses in both the interior and exterior regions of intestine. In particular, one the exterior of the intestine PDX1 was expressed in glands that would be expected to form the pancreas. The result of PCR genotyping with extracted DNA from the paraffin sections showed existence of 10 Pdx1-knockout mice and corresponded to results of immunostaining. Thus, we succeeded to establish a Pdx1-knockout (Pdx1^-/-) mice.

C-peptide immunoreactivity index is associated with improvement of HbA1c: 2-Year follow-up of sitagliptin use in patients with type 2 diabetes

AIMS

This retrospective study aimed to determine the hypoglycaemic effect of 2 years of sitagliptin administration in terms of changes in HbA1c and C-peptide immunoreactivity (CPR) index (plasma CPR [ng/mL]/glucose [mg/dL]×100).

METHODS

The inclusion criteria for DPP-4 inhibitor-naive outpatients with type 2 diabetes (n=285) were: continuation of sitagliptin for ≥700 days from initial administration and measurement of HbA1c, serum CPR, and plasma glucose levels at 0, 3, 6, 12, 18, and 24 months after sitagliptin initiation. Logistic regression analyses determined the factors contributing to the response to sitagliptin, based on responder (ΔHbA1c ≤-0.4% [≤-4 mmol/mol]) and non-responder (ΔHbA1c >-0.4% [>-4 mmol/mol]) groups.

RESULTS

The HbA1c level decreased and CPR index increased from baseline to 3, 6, 12, 18, and 24 months after the start of sitagliptin administration (HbA1c: 7.4 ± 0.8% [57 ± 9 mmol/mol], 7.3 ± 0.9% [57 ± 9 mmol/mol], 7.4 ± 0.9% [58 ± 10 mmol/mol], 7.1 ± 0.8% [55 ± 9 mmol/mol], and 7.3 ± 0.9% [57 ± 10 mmol/mol], respectively, all P<0.001 vs. baseline [8.0 ± 1.0%, 64 ± 11 mmol/mol] and CPR index: 1.69 ± 0.96, 1.71 ± 1.10, 1.62 ± 0.96, 1.64 ± 0.92, and 1.66 ± 0.96, respectively, all P<0.05 vs. baseline [1.47 ± 0.81]). Higher baseline HbA1c level, shorter diabetes duration, and greater CPR index increase after sitagliptin administration were associated with the response to sitagliptin.

CONCLUSIONS

Our results suggest that sitagliptin improves glycaemic control via an improved intrinsic insulin response.

β cell dysfunction versus insulin resistance in the pathogenesis of type 2 diabetes in East Asians

Type 2 diabetes (T2DM) is one of the most serious global health problems and is mainly a result of the drastic increase in East Asia, which includes over a fourth of the global diabetes population. Lifestyle factors and ethnicity are two determinants in the etiology of T2DM, and lifestyle changes such as higher fat intake and less physical activity link readily to T2DM in East Asians. It is widely recognized that T2DM in East Asians is characterized primarily by β cell dysfunction, which is evident immediately after ingestion of glucose or meal, and less adiposity compared to the disease in Caucasians. These pathophysiological differences have an important impact on therapeutic approaches. Here, we revisit the pathogenesis of T2DM in light of β cell dysfunction versus insulin resistance in East Asians and discuss ethnic differences in the contributions of insulin secretion and insulin resistance, together with incretin secretin and action, to glucose intolerance.

Lack of predictive power of plasma lipids or lipoproteins for gestational diabetes mellitus in Japanese women

Aims/Introduction

To determine the diagnostic potential of plasma lipids and apolipoproteins in gestational diabetes mellitus (GDM), we carried out a retrospective cohort study of 1,161 Japanese women at 20–28 weeks of gestation who underwent a glucose challenge test (GCT).

Materials and Methods

A total of 1,161 Japanese women at 20–28 weeks of gestation underwent a GCT. Participants with a positive test (GCT[+]) underwent a subsequent oral glucose tolerance test. Clinical and biochemical parameters were determined and quantification of apolipoproteins (Apo), including ApoB, ApoB48, ApoA-I and ApoC-III, was carried out.

Results

The prevalence of GCT(+; with a 130 mg/dL glucose cut-off) and GDM was 20% and 4%, respectively. There was a trend for increased triglycerides and ApoC-III in GDM(+) participants. However, the difference in plasma triglycerides, ApoC-III or ApoB48 did not reach statistical significance between GDM(+) and GDM(−) women. Values of 1-h glucose (P < 0.001) and fasting glucose (P = 0.002) were significant risk factors for GDM.

Conclusions

Prediction of GDM using only the ApoC-III value is not easy, although triglycerides and ApoC-III were higher in the GDM(+) group. The present findings show no significant difference in plasma lipid levels between women diagnosed with GDM and those with normal glucose tolerance.

Early phase glucagon and insulin secretory abnormalities, but not incretin secretion, are similarly responsible for hyperglycemia after ingestion of nutrients

AIMS

Hypersecretion of glucagon and reduced insulin secretion both contribute to hyperglycemia in type 2 diabetes (T2DM). However, the relative contributions of impaired glucagon and insulin secretions in glucose excursions at the various stages of T2DM development remain to be determined.

METHODS

The responses of glucagon and insulin as well as those of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) were examined before and after ingestion of glucose or mixed meal in Japanese subjects with normal or impaired glucose tolerance (NGT and IGT) and in non-obese, untreated T2DM of short duration.

RESULTS

In OGTT, T2DM showed a rise in glucagon at 0-30 min, unlike NGT and IGT, along with reduced insulin. In MTT, all three groups showed a rise in glucagon at 0-30 min, with that in T2DM being highest, while T2DM showed a significant reduction in insulin. Linear regression analyses revealed that glucose area under the curve (AUC)0-120 min was associated with glucagon-AUC0-30 min and insulin-AUC0-30 min in both OGTT and MTT. Total and biologically intact GIP and GLP-1 levels were similar among the three groups.

CONCLUSIONS

Disordered early phase insulin and glucagon secretions but not incretin secretion are involved in hyperglycemia after ingestion of nutrients in T2DM of even a short duration.

The Insulin Resistance but Not the Insulin Secretion Parameters Have Changed in the Korean Population during the Last Decade

BACKGROUND

This study aimed to compare the patterns of insulin secretion and resistance between Korean subjects in the 1990s and 2000s.

METHODS

Insulin secretion and resistance indices were calculated from subjects who underwent 75-g oral glucose tolerance tests in the year 1997 to 1999 and 2007 to 2011 at the Seoul St. Mary's Hospital, Korea.

RESULTS

A total of 578 subjects from the 1990s (mean age, 48.5 years) and 504 subjects from the 2000s (mean age, 50.2 years) were enrolled. Compared with the subjects from the 1990s, those from the 2000s exhibited increased insulin resistance (increased homeostatic model assessment for insulin resistance), and reduced insulin sensitivity (reduced Matsuda index and quantitative insulin sensitivity check index), regardless of their glucose tolerance status. However, insulinogenic index did not reveal significant differences between the 2 decades in subjects with or without diabetes. A distinct relationship was confirmed between Matsuda index and total area under the curve (insulin/glucose) in each glucose tolerance group. The mean product of the Matsuda index and the total area under the curve (insulin/glucose) as well as the oral disposition index, was lower in subjects with normal glucose tolerance from the 2000s than in those from the 1990s.

CONCLUSION

After rapid economic growth and changes in lifestyle patterns, insulin resistance has worsened across the glucose tolerance status; however, the insulin secretory function remained unchanged, which resulted in an increase in the susceptibility to the development of type 2 diabetes mellitus among Korean subjects without diabetes. We could not rule out the potential selection bias and therefore, further studies in general Korean population are needed.

Use of the Japanese health insurance claims database to assess the risk of acute pancreatitis in patients with diabetes: comparison of DPP-4 inhibitors with other oral antidiabetic drugs

This study was initiated to evaluate the association of acute pancreatitis (AP) with the use of dipeptidyl peptidase-4 (DPP-4) inhibitors among patients with diabetes in Japan. A retrospective cohort study of a large medical and pharmacy claims database was performed to compare the incidence of AP among those receiving DPP-4 inhibitors and those receiving other oral antidiabetic drugs. The incidence of all AP and hospitalizations for AP was similar between the two groups. Previous exposure to DPP-4 inhibitors did not affect occurrence of AP in patients on other oral antidiabetic drugs. The Kaplan-Meier curve for time to AP was similar between the two groups, and was not affected by previous exposure to DPP-4 inhibitors. The Cox proportional hazard models showed the incidence of AP was not significantly higher in those receiving DPP-4 inhibitors. Despite numerous, important limitations related to claims database-based analyses, our results indicate that there is no increased risk of AP with use of DPP-4 inhibitors among patients with diabetes in Japan.

Dose- and time-dependent association of smoking and its cessation with glycemic control and insulin resistance in male patients with type 2 diabetes mellitus: the Fukuoka Diabetes Registry

Objective

Cigarette smoking is an important modifiable risk factor for cardiovascular diseases. However, the effect of smoking and its cessation on glycemic control in diabetic patients has not been fully examined yet. The aim of the present study was to examine the association of smoking status with glycemic level and markers of insulin resistance and secretion in patients with type 2 diabetes mellitus.

Research Design and Methods

A total of 2,490 Japanese male patients with type 2 diabetes mellitus aged ≥20 years were divided according to smoking status, amount of cigarettes smoked and years since quitting. The associations with glycemic level and markers of insulin resistance and secretion were examined cross-sectionally.

Results

HbA_1c levels increased progressively with increases in both number of cigarettes per day and pack-years of cigarette smoking compared with never smokers (P for trend = 0.001 and <0.001, respectively), whereas fasting plasma glucose did not. On the other hand, HbA_1c, but not fasting plasma glucose, decreased linearly with increase in years after smoking cessation (P for trend <0.001). These graded relationships persisted significantly after controlling for the confounders, including total energy intake, current drinking, regular exercise, depressive symptoms, and BMI. In addition, a homeostasis model assessment of insulin resistance and high-sensitivity C-reactive protein also showed similar trends.

Conclusions

Smoking and its cessation showed dose- and time-dependent relationship with glycemic control and insulin resistance in patients with type 2 diabetes mellitus. These findings may highlight the importance of smoking cessation in the clinical management of diabetes mellitus.

Combined use of basal insulin analog and acarbose reduces postprandial glucose in patients with uncontrolled type 2 diabetes

Aims/Introduction

Early initiation of basal insulin therapy is recommended for normalizing fasting blood glucose in type 2 diabetes mellitus. However, basal insulin treatment might not adequately control postprandial glucose levels. The present study evaluated whether the combination of the α-glucosidase inhibitor, acarbose, and basal insulin improved blood glucose control under daily-life treatment conditions in a large sample of Korean patients.

Materials and Methods

The present study was a multicenter, prospective, observational study under daily-life treatment conditions. A total of 539 patients with type 2 diabetes who were treated with basal insulin and additional acarbose were enrolled and followed up for 20 weeks. Changes in hemoglobin A1c, fasting and postprandial blood glucose were evaluated at baseline and at the end of the observation period. The physician and patient satisfaction of the combination treatment and safety were assessed.

Results

Hemoglobin A1c decreased by 0.55 ± 1.05% from baseline (P < 0.0001). Fasting and postprandial blood glucose levels were reduced by 0.89 ± 3.79 and 2.59 ± 4.77 mmol/L (both P < 0.0001). The most frequently reported adverse drug reactions were flatulence (0.37%) and abnormal gastrointestinal sounds (0.37%), and all were mild in intensity and transient. In the satisfaction evaluation, 79.0% of physicians and 77.3% of patients were ‘very satisfied’ or ‘satisfied’ with the combined basal insulin and acarbose therapy.

Conclusions

Combination therapy of basal insulin and acarbose in patients with type 2 diabetes improved glucose control, and had no drug-specific safety concerns, suggesting that the treatment might benefit individuals who cannot control blood glucose with basal insulin alone.

Effects of combined therapy with glipizide and Aralia root bark extract on glycemic control and lipid profiles in patients with type 2 diabetes mellitus

BACKGROUND

The root bark of Aralia is a rich source of bioactive components that may improve glycemic control and lipid status. In this study, 148 patients with type 2 diabetes mellitus (T2DM) were assigned randomly to receive either glipizide alone or glipizide plus Aralia root bark extract (ARBE) for 8 weeks to test the effects of ARBE plus glipizide therapy on glycemic control and lipid profiles in these patients.

RESULTS

Levels of HbA1c, fasting plasma glucose (FPG) and 2 h postprandial plasma glucose (2-h PPG) in both groups significantly decreased from baseline. Glycated hemoglobin (HbA1c) decreased marginally significantly in participants taking glipizide plus ARBE compared with the glipizide group (P = 0.06). Participants in the combination group had significant decreases in total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), and the between-group difference achieved statistical significance for LDL-C (P = 0.04). Reduction in HbA1c in the combination group was significantly associated with changes in TC (r = 0.32; P = 0.006) and LDL-C (r = 0.34; P = 0.005), and the change in FPG was inversely correlated with LDL-C reduction (r = 0.34; P = 0.004).

CONCLUSIONS

In patients with T2DM, combination therapy with glipizide and ARBE resulted in moderately lowering HbA1c and LDL-C levels compared with glipizide alone.