Insulin secretion and insulin sensitivity at different stages of glucose tolerance: a cross-sectional study of Japanese type 2 diabetes

Efficacy and Safety of Linagliptin in 2681 Asian Patients Stratified by Age, Obesity, and Renal Function: A Pooled Analysis of Randomized Clinical Trials

Introduction

Asian patients with type 2 diabetes (T2D) are younger, leaner, and more likely to develop renal dysfunction than White populations. In this multiethnic analysis of data from phase 3 trials, we investigated the efficacy and safety of the dipeptidyl peptidase-4 inhibitor linagliptin in Asians stratified by these subphenotypes.

Methods

Data from randomized, double-blind, placebo-controlled trials evaluating linagliptin (as monotherapy, add-on therapy to metformin ± sulfonylurea, combined with pioglitazone or added to insulin) were pooled with efficacy data from 11 randomized trials of at least 24 weeks and safety data from 15 trials of various durations.

Results

In the efficacy set, 1404 Asian patients received linagliptin [mean (standard deviation) age 54.5 (10.1) years; body mass index (BMI) 26.0 (3.9) kg/m²] and 661 received placebo [age 55.0 (9.7) years; BMI 26.1 (3.9) kg/m²] with the same glycated hemoglobin (HbA1c): 8.2 (0.9)% in both groups. At 24 weeks, the placebo-corrected adjusted mean ± standard error change from baseline in HbA1c with linagliptin was −0.73 ± 0.04% (95% confidence interval −0.81, −0.65; P < 0.0001). Reductions in HbA1c were similar upon stratification by age [<65 years, −0.71 ± 0.05% (−0.80, −0.62; P < 0.0001); ≥65 years, −0.81 ± 0.10% (−1.01, −0.60; P < 0.0001)], BMI (<25 kg/m², −0.82 ± 0.06% [−0.94, −0.70; P < 0.0001]; ≥25 kg/m², −0.65 ± 0.06% [−0.76, −0.54; P < 0.0001]) and estimated glomerular filtration rate [<90 mL/min/1.73 m², −0.71 ± 0.06% (−0.82, −0.60; P < 0.0001); ≥90 mL/min/1.73 m², −0.75 ± 0.06% (−0.87, −0.64; P < 0.0001)]. In the safety set (linagliptin, n = 1842; placebo, n = 839), 52.2% and 54.6% of patients, respectively, experienced adverse events. The rates of drug-related adverse events were 10.9% in the linagliptin group and 10.4% in the placebo group. The respective rates of hypoglycemia were 8.3% and 9.5%, mainly among patients treated with sulfonylurea or insulin. Severe hypoglycemia was rare (<1.0% in either group).

Conclusion

Linagliptin effectively reduced hyperglycemia in Asian patients with uncontrolled T2D, irrespective of age, BMI, renal function, or ethnic subgroups, and was well tolerated.

Funding

Boehringer Ingelheim, Eli Lilly and Company, and the Diabetes Alliance.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-017-0595-7) contains supplementary material, which is available to authorized users.

Insulin lispro 25/75 and insulin lispro 50/50 as starter insulin in Japanese patients with type 2 diabetes: subanalysis of the CLASSIFY randomized trial

In Japan, premixed insulins are commonly used as starter insulin for type 2 diabetes. This subpopulation analysis assessed the efficacy and safety of twice-daily LM25 (25% insulin lispro/75% insulin lispro protamine) and LM50 (50% insulin lispro/50% insulin lispro protamine) as starter insulin in Japanese subjects, and compared these results with the whole-trial populations of East Asian subjects. In this subpopulation analysis of an open-label, phase 4, randomized trial (CLASSIFY), Japanese subjects received LM25 (n = 88) or LM50 (n = 84) twice-daily for 26 weeks. The primary outcome was change from baseline at Week 26 in glycated hemoglobin (HbA1c). Results for Japanese subjects were generally similar to those for the whole-trial population. Similar changes from baseline in HbA1c were observed for LM25 and LM50 groups (least squares [LS] mean difference [95% confidence interval] of LM25 - LM50 = 0.13 [-0.16, 0.41]%, 1.42 [-1.75, 4.48] mmol/mol, p = 0.388). More LM50-treated subjects than LM25-treated subjects achieved HbA1c targets of <7.0% (59.5% versus 43.2%; p = 0.034) or ≤6.5% (45.2% versus 28.4%; p = 0.027). The reduction in postprandial blood glucose concentrations after morning and evening meals was statistically significantly greater for LM50 than for LM25. The incidence of both hypoglycemia and treatment-emergent adverse events were similar between treatment groups. Both LM25 and LM50 twice daily appear to be effective and well tolerated as starter insulin, although LM50 might be more effective for Japanese type 2 diabetes patients.

Review of insulin-associated hypoglycemia and its impact on the management of diabetes in Southeast Asian countries

Although the incidence of diabetes is rising in Southeast Asia, there is limited information regarding the incidence and manifestation of insulin-associated hypoglycemia. The aim of the present review was to discuss what is currently known regarding insulin-associated hypoglycemia in Southeast Asia, including its known incidence and impact in the region, and how the Southeast Asian population with diabetes differs from other populations. We found a paucity of data regarding the incidence of hypoglycemia in Southeast Asia, which has contributed to the adoption of Western guidelines. This might not be appropriate, as Southeast Asians have a range of etiological, educational and cultural differences from Western populations with diabetes that might place them at greater risk of hypoglycemia if not managed optimally. For example, Southeast Asians with type 2 diabetes tend to be younger, with lower body mass indexes than their Western counterparts, and the management of type 2 diabetes with premixed insulin preparations is more common in Southeast Asia. Both of these factors might result in higher rates of hypoglycemia. In addition, Southeast Asians are often poorly educated about hypoglycemia and its management, including during Ramadan fasting. We conclude there is a need for more information about Southeast Asian populations with diabetes to assist with the construction of more appropriate national and regional guidelines for the management of hypoglycemia, more closely aligned to patient demographics, behaviors and treatment practices. Such bespoke guidelines might result in a greater degree of implementation and adherence within clinical practice in Southeast Asian nations.

Prediabetes Exhibits Decreased Disposition Index Correlated with Deterioration of Glycemic Parameters in Nonobese Japanese Subjects: A Cross-Sectional Study from Medical Examination

BACKGROUND

Prediabetes, defined as impaired fasting glucose (IFG) and impaired glucose tolerance (IGT), likely develops to type 2 diabetes mellitus (DM) and independently increases cardiovascular risk. We employed disposition index (DI), a new metabolic parameter indicating the pancreatic beta cell function adjusted for insulin resistance, and investigated whether it could be altered in Japanese population with prediabetes and associated with early glucose intolerance.

METHODS

A total of 102 adults who underwent an oral glucose tolerance test at the medical screening were designated to normal glucose tolerance (NGT), IFG, IGT, and DM. We calculated insulinogenic index (IGI) and homeostasis model assessment (HOMA) of β cell function (HOMA-β) as insulin secretory function, HOMA-insulin resistance (HOMA-IR), and quantitative insulin sensitivity check index (QUICKI) as insulin resistance and DI, and assessed correlations between these indices and glycemic parameters.

RESULTS

We observed graded increase of glycemic parameters in the order of NGT, IFG, IGT, and DM. HOMA-IR was significantly higher only in DM compared with NGT, although HOMA-β, IGI, and QUICKI showed no significant differences among the groups. In contrast, DI was significantly lower in IFG, IGT, and DM compared with NGT. In correlation analysis, glycemic parameters related positively to HOMA-IR, but inversely to DI. Only two parameters, IGI and particularly DI, were significantly decreased in the subjects with 1-hr postload glucose >8.6 mmol/L previously proposed as a predictor of type 2 diabetes.

CONCLUSIONS

Our results suggest that reduction of DI promptly reflects the alteration of early glucose intolerance in Japanese population presenting with prediabetes.

Prenatal Dexamethasone Exposure Programs the Development of the Pancreas and the Secretion of Insulin in Rats

BACKGROUND

There is increasing epidemiological evidence indicating that many chronic diseases originate during early life, even before birth, through what are termed fetal programming effects. Prenatal glucocorticoid is frequently used clinically to accelerate the maturation of the lung, but its long-term effects remain unclear.

METHODS

We gave pregnant Sprague-Dawley rats either intraperitoneal dexamethasone (0.1 mg/kg body weight) or vehicle at Gestational Days 14-20 and assessed the effects to pancreas at Postnatal Days 7 and 120.

RESULTS

We found fewer pancreatic β cell fractions (0.31±0.05 % vs. 0.49±0.05 %, p=0.013) and tissues (0.0017±0.0002 % vs. 0.0025±0.0002 %, p=0.042) and decreased secretion of insulin in response to a glucose challenge at Postnatal Day 105 (1.00±0.19 ng/mL vs. 1.57±0.17 ng/mL at the 15-minute time-point, p=0.046) in rats treated prenatally with dexamethasone. At Postnatal Day 7 in rats treated prenatally with dexamethasone, the expression of pancreatic duodenal homeobox gene-1 and V-maf avian musculoaponeurotic fibrosarcoma oncogene homolog A was lower than that in the rats in the Vehicle group (0.22±0.07 vs. 1.00±0.41 fold, p=0.01, 0.20±0.12 vs. 1.00±0.35 fold, p=0.01) while the histone deacetylases activity (54.2±3.7 ng/h/mL vs. 37.6±3.5 ng/h/mL, p=0.012) and 8-hydroxy-2-deoxyguanosine staining (1.34±0.01 vs. 1.00±0.02 fold, p<0.01) were higher.

CONCLUSION

Prenatal dexamethasone exposure affects early postnatal gene expression related to pancreas development and may exert an effect on β-cell development at 120 postnatal days.

Albiglutide, a weekly GLP-1 receptor agonist, improves glycemic parameters in Japanese patients with type 2 diabetes over 1 year when added to single oral antidiabetic drugs

OBJECTIVE

To evaluate the safety and efficacy of once weekly albiglutide added to a single oral antidiabetic drug (OAD) in Japanese patients with inadequately controlled type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

In this phase 3, 1 year study (NCT01777282), patients (N = 374) received albiglutide 30 mg plus a single OAD (sulfonylurea [n = 120], biguanide [n = 67)], glinide [n = 65], thiazolidinedione [n = 61], or α-glucosidase inhibitor [n = 61]). Albiglutide could be increased to 50 mg after Week 4, based on glycemic criteria. Primary endpoints were the incidence of adverse events (AEs) and hypoglycemia; secondary endpoints were changes from baseline at Week 52 in HbA_1c and fasting plasma glucose (FPG), proportion of patients achieving HbA_1c ≤7.0%, and withdrawals due to hyperglycemia.

RESULTS

On-therapy AEs occurred in 78.6% of patients and serious AEs in 2.1%. Common AEs were nasopharyngitis (32.6%), constipation (7.2%), and diabetic retinopathy (5.3%). No serious AEs occurred more than once or were reported in >1 patient. Hypoglycemia occurred in 6.4% of patients, mostly in the albiglutide + sulfonylurea (14.2%) and the albiglutide + glinide (6.2%) groups. Albiglutide was uptitrated in 53.2% of patients. Mean baseline HbA_1c was 8.1%. Mean decreases from baseline in HbA_1c were observed with the addition of albiglutide to thiazolidinediones (-1.42%), α-glucosidase inhibitors (-1.39%), sulfonylureas (-1.04%), glinides (-0.95%), and biguanides (-0.94%). HbA_1c of <7% in >50% of patients and mean reductions in FPG were achieved in all groups. Mean changes from baseline in body weight ranged from +0.52 kg (albiglutide + thiazolidinedione) to -0.33 kg (albiglutide + biguanide). Limitations of the study included open label treatment that was not randomized.

CONCLUSIONS

When combined with a single OAD in Japanese patients with inadequately controlled T2DM, albiglutide led to favorable changes in all glycemic parameters, with minor changes in body weight depending on the background OAD. No new safety concerns were noted.

Place of sodium-glucose cotransporter-2 inhibitors in East Asian subjects with type 2 diabetes mellitus: Insights into the management of Asian phenotype

The burden of type 2 diabetes (T2DM) in East Asia is alarming. Rapid modernization and urbanization have led to major lifestyle changes and a tremendous increase in the prevalence of obesity, metabolic syndrome, and diabetes mellitus. The development of T2DM at a younger age, with lower body mass index, higher visceral adiposity, and more significant pancreatic beta-cell dysfunction compared to Caucasians are factors responsible for the increased prevalence of T2DM in East Asians. Sodium-glucose Cotransporter-2 (SGLT2) inhibitors (canagliflozin, dapaglifozin, empagliflozin, etc.) reduce renal glucose reabsorption, leading to favorable effects on glycemic, blood pressure, and weight control. The insulin-independent mechanism enables their use as monotherapy or combination therapy with insulin and other oral antidiabetic agents. The role of SGLT2 inhibitors in the management of T2DM among East Asians is an interesting area of research, given that East Asians have been proven to be uniquely different from Caucasians. This review provides comprehensive coverage of the available literature not only on the efficacy and safety, but also on the recent cardiovascular and renal outcomes of SGLT2 inhibitors, focusing among East Asians.

The Glucose-lowering Efficacy of Sitagliptin in Obese Japanese Patients with Type 2 Diabetes

Objective Dipeptidyl peptidase-4 (DPP-4) inhibitors are the most frequently prescribed oral hypoglycemic agents in Japan. Although a relationship between the efficacy of DPP-4 inhibitors and the body mass index (BMI) has been reported, this relationship is controversial. We investigated whether the BMI value affects the glucose-lowering efficacy of sitagliptin in obese Japanese patients with type 2 diabetes. Methods One hundred sixty-two outpatients with inadequate glycemic control were divided into four groups based on their baseline BMI values. They were then treated with sitagliptin (a DPP-4 inhibitor) for 3 months and followed-up for 12 months. Results Sitagliptin significantly reduced the hemoglobin A1c level (HbA1c: -0.71±0.55%) after 3 months, and continued to reduce the HbA1c level until 12 months. There was no significant difference in the efficacy of sitagliptin among the four BMI groups. A multiple linear regression analysis indicated that the factors contributing to the change in the HbA1c level were the baseline level of HbA1c and the homeostasis model assessment of β-cell function (HOMA-β). In terms of the relationship between the baseline BMI value and the efficacy of sitagliptin treatment, the number of patients who responded to sitagliptin treatment after 3 months was lowest in the group of patients with the highest BMI values. A multiple logistic regression analysis revealed that the baseline HOMA-β function and HbA1c level and a baseline BMI value of ≥30 kg/m² significantly contributed to the response to sitagliptin treatment. Conclusion The results indicated that sitagliptin treatment was effective in controlling glucose metabolism disorder in obese Japanese patients with type 2 diabetes. However, the efficacy of sitagliptin treatment might be attenuated in severely obese patients, such as those with a BMI value of ≥30 kg/m².

Comparison of insulin lispro mix 25 with insulin lispro mix 50 as an insulin starter in Asian patients with type 2 diabetes: a phase 4, open-label, randomized trial (CLASSIFY study)

BACKGROUND

Lispro Mix 25% insulin lispro/75% insulin lispro protamine (LM25) and Lispro Mix 50% insulin lispro/50% insulin lispro protamine (LM50) were compared as starter insulins in East Asian patients with type 2 diabetes.

METHODS

Phase 4, open-label, randomized trial conducted in China, Japan, Korea, and Turkey. Subjects received twice-daily LM25 (n = 207) or LM50 (n = 196) for 26 weeks. The primary outcome was the HbA_1c change from baseline.

RESULTS

The least squares mean changes from baseline in HbA_1c are -1.52% and -1.69% for LM25 and LM50, respectively, and the least squares mean difference [95% CI] is 0.17% [-0.01, 0.35]. More subjects in the LM50 group than in the LM25 group achieved HbA_1c targets of <7.0% (59.7% versus 45.9%, respectively; p = 0.007). LM50 was more effective than LM25 in reducing postprandial glucose after the morning (mean difference in change from baseline, 0.56 mmol/L; p = 0.038) and evening (1.11 mmol/L; p < 0.001) meals. The reduction in fasting blood glucose was significantly greater (p = 0.046) in the LM25 group (LS mean [95% CI] change from baseline: -2.37 mmol/L [-2.68, -2.06]) than in the LM50 group (-1.99 mmol/L [-2.30, -1.68]). LM50 was more effective than LM25 in reducing HbA_1c in subjects with baseline HbA_1c , postprandial glucose, or carbohydrate intake levels greater than the median levels. Hypoglycemia rates and weight gain were similar between groups.

CONCLUSIONS

LM25 and LM50 were noninferior to each other in improving glycemic control in Asian patients with type 2 diabetes. In addition, LM50 was more efficacious than LM25 with respect to the percentage of subjects reaching target HbA_1c levels. Copyright © 2016 John Wiley & Sons, Ltd.

Impact of Perturbed Pancreatic β-Cell Cholesterol Homeostasis on Adipose Tissue and Skeletal Muscle Metabolism

Elevated pancreatic β-cell cholesterol levels impair insulin secretion and reduce plasma insulin levels. This study establishes that low plasma insulin levels have a detrimental effect on two major insulin target tissues: adipose tissue and skeletal muscle. Mice with increased β-cell cholesterol levels were generated by conditional deletion of the ATP-binding cassette transporters, ABCA1 and ABCG1, in β-cells (β-DKO mice). Insulin secretion was impaired in these mice under basal and high-glucose conditions, and glucose disposal was shifted from skeletal muscle to adipose tissue. The β-DKO mice also had increased body fat and adipose tissue macrophage content, elevated plasma interleukin-6 and MCP-1 levels, and decreased skeletal muscle mass. They were not, however, insulin resistant. The adipose tissue expansion and reduced skeletal muscle mass, but not the systemic inflammation or increased adipose tissue macrophage content, were reversed when plasma insulin levels were normalized by insulin supplementation. These studies identify a mechanism by which perturbation of β-cell cholesterol homeostasis and impaired insulin secretion increase adiposity, reduce skeletal muscle mass, and cause systemic inflammation. They further identify β-cell dysfunction as a potential therapeutic target in people at increased risk of developing type 2 diabetes.

Decreased β-Cell Function Is Associated with Reduced Skeletal Muscle Mass in Japanese Subjects without Diabetes

BACKGROUND

Decreased insulin secretion has a great impact on the incidence of type 2 diabetes in Japanese subjects. It is not clear whether β-cell function is related to muscle mass in subjects without diabetes. We investigated the relationship between β-cell function and skeletal muscle mass in Japanese subjects without diabetes.

METHODS

The study included 1098 subjects (538 men and 560 women) aged 40 to 79 years, without diabetes (fasting glucose lower than 126 mg/dL and glycosylated hemoglobin lower than 6.5%), who consulted Osaka Medical College Health Science Clinic for a medical examination. Appendicular muscle mass was measured by bioelectrical impedance analysis. Appendicular muscle mass index was calculated as appendicular muscle mass divided by height squared (kg/m2). The homeostatic model assessment of β-cell function was used to assess β-cell function. The homeostatic model assessment of insulin resistance was used as a measure of insulin resistance. The association between appendicular muscle mass index and clinical parameters of β-cell function and insulin resistance was examined.

RESULTS

Log-transformed homeostatic model assessment of β-cell function and Log-transformed homeostatic model assessment of insulin resistance showed a normal distribution. In both men and women, there was a significant positive correlation between appendicular muscle mass index and clinical parameters of β-cell function and insulin resistance. Tertile analysis, following stratification according to appendicular muscle mass index, found that low appendicular muscle mass index was significantly associated with the Log homeostatic model assessment of β-cell function and Log-transformed homeostatic model assessment of insulin resistance.

CONCLUSION

This study shows that decreased β cell function is associated with reduced skeletal muscle mass in Japanese subjects without diabetes.

Duration of diabetes and types of diabetes therapy in Japanese patients with type 2 diabetes: The Japan Diabetes Complication and its Prevention prospective study 3 (JDCP study 3)

Aims/Introduction

To analyze the association between the duration of diabetes and selection of diabetes therapy in a large database of Japanese patients with type 2 diabetes.

Materials and Methods

We used the data of 5,844 patients with type 2 diabetes to evaluate the association between the duration of diabetes and types of diabetes therapy. The logistic regression model was used to analyze the association between duration of diabetes and selection of diabetes therapy, and restricted cubic spline curves were used to represent the schematic association.

Results

Overall, clinical characteristics of the patients were women, 39.9%; mean age, 61.4 years; median duration of diabetes, 9 years; mean glycated hemoglobin, 7.4% (57.0 mmol/mol); and mean body mass index, 24.5 kg/m². Compared with the first quartile of diabetes duration, the multivariable‐adjusted odds of any antidiabetic therapy (oral hypoglycemic agents or insulin) for the second, third and fourth quartiles were 2.17 (95% confidence interval [CI] 1.68–2.80; 3.39, 95% CI 2.53–4.54; 4.99, 95% CI 3.64–6.84), respectively (P for trend <0.001), and these associations were attenuated after adjusting possible confounders. Furthermore, those of insulin therapy were 1.48 (95% CI 1.20–1.84; 2.16, 95% CI 1.77–2.64; 4.94, 95% CI 4.04–6.04), respectively (P for trend <0.001). Schematic representation of restricted cubic spline curves analysis showed that a longer duration of diabetes was linearly associated with the odds of insulin therapy.

Conclusions

Obtained data showed that a longer duration of diabetes required complex diabetes drug regimens to be introduced to patients with type 2 diabetes.

Identification of Impaired Second-Phase Insulin Secretion in Various Degrees of Glucose Tolerance in a Chinese Population

AIM

Impaired insulin sensitivity and insulin secretion (ISEC) are major pathophysiologies of type 2 diabetes (T2DM). ISEC has two phases: the first and second phases (second ISEC). In this study, we derived equations to identify patients with second ISEC deficiency (ISEC-D).

METHODS

Data from 96 patients, namely 19 with a normal fasting plasma glucose (FPG) level, 21 with prediabetes, and 56 with T2DM, were enrolled. They underwent a modified low-dose graded glucose infusion test, which was originally proposed by Polonsky et al. The test results were interpreted as the slopes of the changes of plasma insulin against the glucose levels, which were considered second ISEC. Patients with the lowest quartile of the slopes were defined as having ISEC-D. We built three models: Model 0: FPG, Model 1: FPG + waist circumference, and Model 2: Model 1 + fasting plasma insulin. The area under the receiver operating characteristic (aROC) curve was used to determine the predictive power of these models.

RESULTS

Among the metabolic syndrome components, FPG had the largest aROC curve (78.2%). Although aROC curves of Models 1 and 2 (85.2% and 91.5%, respectively) were higher than the aROC curve of FPG, no difference was observed between Models 1 and 0. By contrast, the aROC curve of Model 2 was higher compared with Model 1.

CONCLUSIONS

FPG showed the largest aROC curve. Model 2 had the highest predictive power, which could identify patients with ISEC-D with a sensitivity and specificity of 94.3% and 82.6%, respectively. These two models could be conveniently used in daily practice.

Comparison of Vildagliptin and Pioglitazone in Korean Patients with Type 2 Diabetes Inadequately Controlled with Metformin

BACKGROUND

We compared the efficacies of vildagliptin (50 mg twice daily) relative to pioglitazone (15 mg once daily) as an add-on treatment to metformin for reducing glycosylated hemoglobin (HbA1c) levels in Korean patients with type 2 diabetes.

METHODS

The present study was a multicenter, randomized, active-controlled investigation comparing the effects of vildagliptin and pioglitazone in Korean patients receiving a stable dose of metformin but exhibiting inadequate glycemic control. Each patient underwent a 16-week treatment period with either vildagliptin or pioglitazone as an add-on treatment to metformin.

RESULTS

The mean changes in HbA1c levels from baseline were -0.94% in the vildagliptin group and -0.6% in the pioglitazone group and the difference between the treatments was below the non-inferiority margin of 0.3%. The mean changes in postprandial plasma glucose (PPG) levels were -60.2 mg/dL in the vildagliptin group and -38.2 mg/dL in the pioglitazone group and these values significantly differed (P=0.040). There were significant decreases in the levels of total, low density lipoprotein, high density lipoprotein (HDL), and non-HDL cholesterol in the vildagliptin group but increases in the pioglitazone group. The mean change in body weight was -0.07 kg in the vildagliptin group and 0.69 kg in the pioglitazone group, which were also significantly different (P=0.002).

CONCLUSION

As an add-on to metformin, the efficacy of vildagliptin for the improvement of glycemic control is not inferior to that of pioglitazone in Korean patients with type 2 diabetes. In addition, add-on treatment with vildagliptin had beneficial effects on PPG levels, lipid profiles, and body weight compared to pioglitazone.

Predictive Value of Glucose Parameters Obtained From Oral Glucose Tolerance Tests in Identifying Individuals at High Risk for the Development of Diabetes in Korean Population

Previous studies suggest that the future risk for type 2 diabetes is not similar among subjects in the same glucose tolerance category. In this study, we aimed to evaluate simple intuitive indices to identify subjects at high risk for future diabetes development by using 0, 30, 120 minute glucose levels obtained during 75 g OGTTs from participants of a prospective community-based cohort in Korea.Among subjects enrolled at the Chungju Metabolic disease Cohort, those who performed an OGTT between 2007 and 2010 and repeated the test between 2011 and 2014 were recruited after excluding subjects with diabetes at baseline. Subjects were categorized according to their 30 minute glucose (G30) and the difference between 120 and 0 minute glucose (G(120-0)) levels with cutoffs of 9.75 and 2.50 mmol/L, respectively.Among 1126 subjects, 117 (10.39%) developed type 2 diabetes after 4 years. In diabetes nonconverters, increased insulin resistance was accompanied by compensatory insulin secretion, but this was not observed in converters during 4 years of follow-up. Subjects with G(120-0) ≥ 2.50 mmol/L or G30 ≥ 9.75 mmol/L demonstrated lower degrees of insulin secretion, higher degrees of insulin resistance, and ∼6-fold higher risk of developing future diabetes compared to their lower counterparts after adjustment for possible confounding factors. Moreover, subjects with high G(120-0) and high G30 demonstrated 22-fold higher risk for diabetes development compared to subjects with low G(120-0) and low G30.By using the G(120-0) and G30 values obtained during the OGTT, which are less complicated measurements than previously reported methods, we were able to select individuals at risk for future diabetes development. Further studies in different ethnicities are required to validate our results.

Molecular and cellular mechanisms linking inflammation to insulin resistance and β-cell dysfunction

Obesity is a major public health problem worldwide, and it is associated with an increased risk of developing type 2 diabetes. It is now commonly accepted that chronic inflammation associated with obesity induces insulin resistance and β-cell dysfunction in diabetic patients. Obesity-associated inflammation is characterized by increased abundance of macrophages and enhanced production of inflammatory cytokines in adipose tissue. Adipose tissue macrophages are suggested to be the major source of local and systemic inflammatory mediators such as tumor necrosis factor α, interleukin (IL)-1β, and IL-6. These cytokines induce insulin resistance in insulin target tissues by activating the suppressors of cytokine signaling proteins, several kinases such as c-Jun N-terminal kinase, IκB kinase β, and protein kinase C, inducible nitric oxide synthase, extracellular signal-regulated kinase, and protein tyrosine phosphatases such as protein tyrosine phosphatase 1B. These activated factors impair the insulin signaling at the insulin receptor and the insulin receptor substrates levels. The same process most likely occurs in the pancreas as it contains a pool of tissue-resident macrophages. High concentrations of glucose or palmitate via the chemokine production promote further immune cell migration and infiltration into the islets. These events ultimately induce inflammatory responses leading to the apoptosis of the pancreatic β cells. In this review, the cellular and molecular players that participate in the regulation of obesity-induced inflammation are discussed, with particular attention being placed on the roles of the molecular players linking inflammation to insulin resistance and β-cell dysfunction.

Insulin degludec versus insulin glargine, both once daily as add-on to existing orally administered antidiabetic drugs in insulin-naive Japanese patients with uncontrolled type 2 diabetes: subgroup analysis of a pan-Asian, treat-to-target phase 3 trial

Insulin degludec (IDeg) is a novel basal insulin analogue with an ultralong duration of action that provides flat and stable reductions in blood glucose. The BEGIN ONCE ASIA trial was a phase 3 pan-Asian study examining the efficacy and safety of IDeg once daily (OD) versus insulin glargine (IGlar) OD in insulin-naive patients with type 2 diabetes (T2D). In this multinational, 26-week, open-label, treat-to-target trial, participants were randomised (2:1) to IDeg OD or IGlar OD, administered with one or more antidiabetic drugs (OAD) per os. Here we report the results from a post hoc analysis of Japanese patients enrolled in the trial [n = 133; 63.2 % male; mean age 61.0 years; mean body mass index 24.1 kg/m²; mean glycosylated haemoglobin (HbA_1c) 8.5 %]. After 26 weeks, mean HbA_1c levels were similar between the two groups [estimated mean treatment difference 0.11 %; 95 % confidence interval (CI) -0.09, 0.31]. Confirmed hypoglycaemia was reported in 53.4 and 61.4 % of patients in the IDeg OD and IGlar OD groups [rate ratio (IDeg/IGlar) 0.87; 95 % CI 0.51, 1.48]. Confirmed nocturnal hypoglycaemia was reported in 17.0 and 22.7 % of patients in the IDeg OD and IGlar OD groups, respectively [rate ratio (IDeg/IGlar) 0.50; 95 % CI 0.19, 1.32]. Adverse event rates were similar between treatment groups. Initiating insulin treatment with IDeg OD in Japanese patients with T2D, inadequately maintained on OADs and requiring treatment intensification, provided effective glycaemic control with low rates of confirmed and nocturnal confirmed hypoglycaemia.

Neurogenic hyperadrenergic orthostatic hypotension: a newly recognized variant of orthostatic hypotension in older adults with elevated norepinephrine (noradrenaline)

Patients with neurogenic orthostatic hypotension (OH) typically have impaired sympathetic nervous system tone and therefore low levels of upright plasma norepinephrine (NE) (noradrenaline). We report a subset of patients who clinically have typical neurogenic OH but who paradoxically have elevated upright levels of plasma NE. We retrospectively studied 83 OH patients evaluated at the Vanderbilt Autonomic Dysfunction Center between August 2007 and May 2013. Based on standing NE, patients were dichotomized into a hyperadrenergic OH group [hyperOH: upright NE ≥ 3.55 nmol/l (600 pg/ml), n=19] or a non-hyperadrenergic OH group [nOH: upright NE < 3.55 nmol/l (600 pg/ml), n=64]. Medical history and data from autonomic testing, including the Valsalva manoeuvre (VM), were analysed. HyperOH patients had profound orthostatic falls in blood pressure (BP), but less severe than in nOH [change in SBP (systolic blood pressure): -53 ± 31 mmHg compared with -68 ± 33 mmHg, P=0.050; change in DBP (diastolic blood pressure): -18 ± 23 mmHg compared with -30 ± 17 mmHg, P=0.01]. The expected compensatory increase in standing heart rate (HR) was similarly blunted in both hyperOH and nOH groups [84 ± 15 beats per minute (bpm) compared with 82 ± 14 bpm; P=0.6]. HyperOH patients had less severe sympathetic failure as evidenced by smaller falls in DBP during phase 2 of VM and a shorter VM phase 4 BP recovery time (16.5 ± 8.9 s compared with 31.6 ± 16.6 s; P<0.001) than nOH patients. Neurogenic hyperOH patients have severe neurogenic OH, but have less severe adrenergic dysfunction than nOH patients. Further work is required to understand whether hyperOH patients will progress to nOH or whether this represents a different disorder.

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.

Association of decrease in carbohydrate intake with reduction in abdominal fat during 3-month moderate low-carbohydrate diet among non-obese Japanese patients with type 2 diabetes

OBJECTIVE

The effectiveness of a moderate low-carbohydrate diet (M-LCD) has been demonstrated in terms of glycemic control, body weight and serum lipid profiles. We investigated the effect of a 3-month M-LCD on visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), and examined an association between decrease in carbohydrate intake and reduction in abdominal fat among patients with Type 2 diabetes mellitus (T2DM).

METHODS

Seventy-six patients (45 men and 31 women; mean age ± SD: 59.5 ± 11.1 years) with T2DM were instructed to follow an M-LCD for 3 months. We assessed abdominal fat distribution using computed tomography and macronutrient intakes from 3-day dietary records at baseline and after 3 months.

RESULTS

The patients complied well with the M-LCD - %carbohydrate: %fat: %protein at baseline and after 3 months were 51:27:15 and 41:33:18 in men and 54:27:16 and 42:37:19 in women, respectively. VAT and SAT significantly decreased during the 3 months (P for time < 0.001 for both). Decrease in carbohydrate intake (g/day) and %carbohydrate were correlated with decrease (%) in VAT. The correlations were significant in men (Spearman correlation coefficient r = 0.469 for carbohydrate intake (g) and r = 0.402 for %carbohydrate) but not in women (r = 0.269 and 0.278, respectively). The correlations in men remained significant in multiple regression analysis adjusted for age and changes in energy intake.

CONCLUSIONS

In men, decrease in carbohydrate intake was significantly correlated with VAT loss during a 3-month M-LCD, independently of reduction in energy intake.

Correlation of circulating betatrophin concentrations with insulin secretion capacity, evaluated by glucagon stimulation tests

AIM

To investigate the relationship between plasma betatrophin concentrations and insulin secretion capacity in people with Type 2 diabetes.

METHODS

Glucagon stimulation tests (1 mg) were performed in 70 people with Type 2 diabetes after an overnight fast. Plasma betatrophin concentrations were measured using an enzyme-linked immunosorbent assay. Insulin secretion capacity was evaluated by measuring increments of C-peptide concentration in response to glucagon stimulation, and creatinine clearance was determined by comparing creatinine concentrations in serum and 24-h urine samples.

RESULTS

Plasma betatrophin concentrations were positively correlated with duration of Type 2 diabetes (r = 0.34, P = 0.003), and negatively correlated with increments of C-peptide concentration (r = 0.37, P = 0.001) and creatinine clearance (r = 0.37, P = 0.001). The correlation with increments of C-peptide concentration remained significant after adjustment for age and duration of Type 2 diabetes (r = 0.25, P = 0.037). Multivariate analysis identified age and increments of C-peptide concentration as independent factors associated with plasma betatrophin levels.

CONCLUSION

Plasma betatrophin levels inversely correlate with insulin secretion capacity, suggesting that betatrophin levels are regulated by insulin secretion capacity in humans.

Association of genetic variants of the α-kinase 1 gene with type 2 diabetes mellitus in a longitudinal population-based genetic epidemiological study

Previously, our studies identified nine genes and the chromosomal region 3q28 as susceptibility loci for myocardial infarction, ischemic stroke or chronic kidney disease in individuals by genome-wide or candidate gene association studies. The present study examined the possible association of 13 polymorphisms at these 10 loci with the prevalence of type 2 diabetes mellitus (DM) in community-dwelling individuals. Study subjects comprised 6,027 individuals (797 subjects with type 2 DM and 5,230 controls) who were recruited to the Inabe Health and Longevity Study, a longitudinal genetic epidemiological study of atherosclerotic, cardiovascular and metabolic diseases. The subjects were recruited from individuals who visited for an annual health checkup and they were followed up each year (mean follow-up, 5 years). Longitudinal analysis with a generalized estimating equation and with adjustment for age, gender and body mass index (BMI) revealed that rs2116519 (C→T) of FAM78B (P=0.0188), as well as rs2074379 (G→A, P=0.0121) and rs2074388 (A→G, P=0.0053) of ALPK1 were significantly (P<0.05) associated with the prevalence of type 2 DM. Longitudinal analysis with a generalized linear mixed-effect model and with adjustment for age, gender and BMI among all the individuals revealed that rs2116519, rs2074379 and rs2074388 were significantly associated with fasting plasma glucose level (P=0.0352, 0.0017 and 0.0010, respectively) and to blood glycosylated hemoglobin (hemoglobin A_1c) content (P=0.0065, 0.0090 and 0.0079, respectively). Similar analysis among individuals not taking antidiabetic medication revealed that rs2074379 and rs2074388 were associated with the fasting plasma glucose level (P=0.0073 and 0.0042, respectively) and blood hemoglobin A_1c content (P=0.0142 and 0.0126, respectively), whereas rs2116519 was associated with blood hemoglobin A_1c content only (P=0.0470). ALPK1 may thus be a susceptibility gene for type 2 DM.

Levels of the first-phase insulin secretion deficiency as a predictor for type 2 diabetes onset by using clinical-metabolic models

AIMS

Type 2 diabetes mellitus (T2DM) is characterized by both decreased insulin sensitivity and impaired insulin secretion. The 2 phases of insulin secretion are the first-phase insulin secretion (1st ISEC) and the second-phase insulin secretion. In this study, we tried to build clinical-metabolic models to predict the 1st ISEC deficiency (ISEC-D) in non-diabetic subjects so that early intervention could be started.

DESIGN AND SETTINGS

A cross-sectional study was conducted in the clinical research department of a hospital in Taiwan from 2010 to 2011.

METHODS

A total of 89 subjects without diabetes were enrolled in the study, including 49 with normal glucose tolerance and 40 pre-diabetes. A frequently sampled intravenous glucose tolerance test was done to determine insulin sensitivity and acute insulin response after the glucose load, which is regarded as the 1st ISEC. Subjects with the lowest tertile of the 1st ISEC were defined as ISEC-D. From the simplest to the most complex, 3 models were build: Model 0: fasting plasma glucose (FPG); Model 1: FPG + body mass index (BMI) + High-density lipoprotein cholesterol (HDL-C); Model 2: Model 1+ fasting plasma insulin (FPI). The area under the receiver-operating characteristic curve (aROC curve) was used to determine the predictive power among these models. An optimal cut-off value was also determined.

RESULTS

Among metabolic syndrome (MetS) components (FPG, BMI, and HDL-C), FPG had the greatest aROC curve (70.9%). Moreover, the aROC curves of Models 1 and 2 were all significantly greater than that of FPG (80.4% and 82.3%, respectively). Their aROC curves were also greater than that of the homeostasis model assessment b-cell (HOMA-b) function, which is the most commonly used method to evaluate b-cell function.

CONCLUSION

By using only MetS components, ISEC-D could be predicted with an acceptable sensitivity of 84.0% and a specificity of 74.0%. However, after adding FPI into the Model, the predictive power of Model 2 did not increase. These model-derived MetS components could be widely used in clinical settings and early detection of non-diabetic subjects with high risk for T2DM.

Efficacy and safety of a single-pill combination of vildagliptin and metformin in Japanese patients with type 2 diabetes mellitus: a randomized, double-blind, placebo-controlled trial

INTRODUCTION

The use of dipeptidyl peptidase-4 inhibitors in combination with metformin is increasing in Japanese patients with type 2 diabetes mellitus (T2DM), but no single-pill combination (SPC) is currently available in Japan. The objective of this study was to assess the efficacy and safety of vildagliptin/metformin SPC in Japanese patients with T2DM inadequately controlled with vildagliptin monotherapy.

METHODS

This was a 14-week, randomized, double-blind, parallel-group, placebo-controlled trial. 171 patients with T2DM inadequately controlled [HbA1c (glycosylated hemoglobin) 7.0-10.0%] with vildagliptin 50 mg twice daily (bid) were randomized (2:1) to receive either a vildagliptin/metformin SPC (n = 115) or matching vildagliptin/placebo SPC (n = 56).

RESULTS

Baseline demographics and background characteristics were generally comparable between the treatment groups. The change in HbA1c [mean ± standard error (SE)] was -0.8 ± 0.1% in the vildagliptin/metformin SPC (baseline HbA1c, 7.9 ± 0.1%) group and 0.1 ± 0.1% in the vildagliptin/placebo SPC (baseline HbA1c, 8.0 ± 0.1%) group, with a between-treatment difference of -1.0 ± 0.1% (P <0.001) in favor of the vildagliptin/metformin SPC group. The proportion of patients achieving target HbA1c <7.0% was significantly higher with vildagliptin/metformin SPC compared with vildagliptin/placebo SPC (45.8% vs. 13.5%, P <0.001). The overall incidences of adverse events (AEs) were 43.5% in the vildagliptin/metformin SPC and 67.9% in the vildagliptin/placebo SPC group. The incidences of serious AEs were low in both the treatment groups (0.9% vs. 3.6%, respectively). Body weight remained constant throughout the study in both the treatment groups. There were no deaths or hypoglycemic events during the study.

CONCLUSIONS

Switching Japanese patients with T2DM requiring treatment intensification, from vildagliptin monotherapy to a vildagliptin/metformin SPC (50/250 or 50/500 mg) was efficacious and safe, eliciting significant reduction in HbA1c without increased risk of hypoglycemia and weight gain.

Effect of body mass index on insulin secretion or sensitivity and diabetes

BACKGROUND

Although the association between obesity and diabetes is well known, the factors predisposing to diabetes in non-obese Asians are less clearly characterized.

PURPOSE

To investigate the effects of impaired insulin secretion (IIS) and insulin resistance (IR) according to BMI on the incidence of diabetes in the Saku Study.

METHODS

This 4-year cohort study involved 3,083 participants aged 30-69 years without diabetes at baseline (2006-2007). Participants were stratified by BMI (<23.0, 23.0-24.9, and ≥25). Based on insulinogenic index and homeostasis model of IR values, participants were classified into four categories: normal; isolated IIS (i-IIS); isolated IR (i-IR); and IIS plus IR. All data were collected in 2006-2011 and analyzed in 2013-2014.

RESULTS

For participants with BMI <23.0, the risk of developing diabetes was higher in the i-IIS (adjusted hazard ratio=6.6; 95% CI=3.7, 11.6) and IIS plus IR groups (9.4; 3.1, 28.4) than in the normal group. For participants with BMI 23.0-24.9, risk was higher in the i-IIS (9.9; 4.4, 22.1); i-IR (3.4; 1.2, 9.5); and IIS plus IR (23.4; 9.3, 58.9) groups. Among participants with BMI ≥25, risk was higher in the i-IIS (16.9; 6.0, 47.7); i-IR (7.9; 2.8, 22.6); and IIS plus IR (26.9; 9.0, 80.8) groups. BMI was negatively associated with incidence of IIS but positively associated with IR incidence.

CONCLUSIONS

Individuals with normal BMI may develop diabetes mainly through IIS, whereas individuals with high BMI may develop diabetes primarily through IR.

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.

Efficacy of adding once-daily insulin glulisine in Japanese type 2 diabetes patients treated with insulin glargine and sitagliptin

BACKGROUND

Glucose fluctuation often remains to be corrected under basal-supported oral therapy. We investigated the efficacy of adding once-daily rapid-acting insulin in Japanese diabetes patients treated with basal-supported oral therapy.

SUBJECTS AND METHODS

In this 8-week, parallel-group, randomized, open-label trial, 62 Japanese adults with type 2 diabetes treated with insulin glargine and 50 mg of sitagliptin were randomized into the following two arms: the single-bolus group, in which once-daily insulin glulisine was initiated at a main meal at a fifth (i.e., 20%) the dose of insulin glargine, and the control group, in which the dose of sitagliptin was maximized to 100 mg. The primary end point was the change of glycemic fluctuation assessed with the M-value.

RESULTS

Baseline hemoglobin A1c levels, mean blood glucose profiles, and M-value were 7.2 ± 0.6%, 9.3 ± 1.7 mmol/L, and 21 ± 13 units, respectively. At the end of the study, the single-bolus group had a greater reduction of M-value than the control group (P=0.02); the difference was 6.5 units (95% confidence interval, 1.1-11.9 units). The single-bolus group also had a greater reduction of mean blood glucose levels (P=0.01). There were no significant differences in the incidence of hypoglycemia or the weight change between the two groups (P>0.05).

CONCLUSIONS

Adding once-daily insulin glulisine was more effective in controlling the glycemic fluctuation in Japanese type 2 diabetes patients treated with insulin glargine together with sitagliptin.

Increase in homeostasis model assessment of insulin resistance (HOMA-IR) had a strong impact on the development of type 2 diabetes in Japanese individuals with impaired insulin secretion: the Saku study

Our aim was to assess the impact of increase in homeostasis model assessment of insulin resistance (HOMA-IR) on the development of type 2 diabetes in Japanese individuals with impaired insulin secretion (IIS). This study included 2,209 participants aged 30–69 without diabetes at baseline who underwent comprehensive medical check-ups between April 2006 and March 2007 at Saku Central Hospital. Participants were classified into eight groups according to the combination of baseline IIS status (non-IIS and IIS) and category of HOMA-IR change between the baseline and follow-up examinations (decrease, no change/small increase, moderate increase, and large increase). Type 2 diabetes was determined from fasting and 2 h post-load plasma glucose concentrations at the follow-up examination between April 2009 and March 2011. At baseline, 669 individuals (30.3%) were classified as having IIS. At follow-up, 74 individuals developed type 2 diabetes. After adjusting for confounding factors including baseline HOMA-IR values, the multivariable-adjusted odds ratios (95% confidence intervals) for type 2 diabetes in the non-IIS with a decrease (mean change in HOMA-IR: −0.47), non-IIS with a moderate increase (mean change in HOMA-IR: 0.28), non-IIS with a large increase (mean change in HOMA-IR: 0.83), IIS with a decrease (mean change in HOMA-IR: −0.36), IIS with no change/small increase (mean change in HOMA-IR: 0.08), IIS with a moderate increase (mean change in HOMA-IR: 0.27), and IIS with a large increase (mean change in HOMA-IR: 0.73) groups, relative to the non-IIS with no change/small increase (mean change in HOMA-IR: 0.08) group were 0.23 (0.04, 1.11), 1.22 (0.26, 5.72), 2.01 (0.70, 6.46), 1.37 (0.32, 4.28), 3.60 (0.83, 15.57), 5.24 (1.34, 20.52), and 7.01 (1.75, 24.18), respectively. Moderate and large increases in HOMA-IR had a strong impact on the development of type 2 diabetes among individuals with IIS in this Japanese population.

Saxagliptin improves glycemic control by modulating postprandial glucagon and C-peptide levels in Chinese patients with type 2 diabetes

AIMS

Saxagliptin reduced glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), and postprandial glucose (PPG) in Asian patients with type 2 diabetes mellitus (T2DM). To understand the physiology of this effect, indices of α- and β-cell function were measured in a subpopulation of Chinese patients following a noodle mixed-meal tolerance test.

METHODS

Data from Chinese patients were pooled from two phase 3, 24-week studies of saxagliptin 5mg/d as monotherapy in drug-naive patients and as add-on to metformin in patients inadequately controlled with metformin alone. The end points for β- and α-cell function were change from baseline in C-peptide, insulin, and glucagon areas under the curve from 0 to 180 min (AUC0-180), insulinogenic index, and insulin sensitivity from Matsuda index after a mixed meal. Also glycemic variables, HbA1c, FPG, and PPG (AUC0-180), and homeostasis model assessment (HOMA) 2β were measured.

RESULTS

At 24 weeks, greater improvements in adjusted mean change from baseline HbA1c (difference vs placebo [95% CI], -0.33% [-0.50%, -0.17%], [-4 (-5.5, -1.9) mmol/mol], P<0.0001), FPG (-0.41 [-0.78, -0.03] mmol/L, P=0.03), PPG AUC0-180 (-168 [-245, -91.8] mmol min/L, P<0.0001), C-peptide AUC0-180 (19.7 [5.2, 34.2] nmol min/L, P=0.008), insulinogenic index (0.06% [0.02%, 0.09%], P=0.002), and greater suppression of glucagon secretion (glucagon AUC0-180, -322 [-493.6, -150.7] pmol min/L, P=0.0003) were observed with saxagliptin versus placebo.

CONCLUSION

In Chinese patients with T2DM, saxagliptin as monotherapy or as add-on to metformin improved glycemic control by modulating α- and β-cell function.

Significantly increased risk of cancer in diabetes mellitus patients: A meta-analysis of epidemiological evidence in Asians and non-Asians

Aims/Introduction:  Emerging evidence from observational studies suggests that diabetes mellitus affects the cancer risk. However, whether there are differences in the magnitude of the influence of diabetes among ethnic groups is unknown.

Materials and Methods:  We searched MEDLINE and the Cochrane Library for pertinent articles that had been published as of 4 April 2011, and included them in a meta‐analysis of the risk of all‐cancer mortality and incidence in diabetic subjects.

Results:  A total of 33 studies were included in the meta‐analysis, and they provided 156,132 diabetic subjects for the mortality analysis and 993,884 for the incidence analysis. Cancer mortality was approximately 3%, and cancer incidence was approximately 8%. The pooled adjusted risk ratio (RR) of all‐cancer mortality was significantly higher than for non‐diabetic people (RR 1.32 [CI 1.20–1.45] for Asians; RR 1.16 [CI 1.01–1.34] for non‐Asians). Diabetes was also associated with an increased RR of incidence across all cancer types (RR 1.23 [CI 1.09–1.39] for Asians; RR 1.15 [CI 0.94–1.43] for non‐Asians). The RR of incident cancer for Asian men was significantly higher than for non‐Asian men (P = 0.021).

Conclusions:  Diabetes is associated with a higher risk for incident cancer in Asian men than in non‐Asian men. In light of the exploding global epidemic of diabetes, particularly in Asia, a modest increase in the cancer risk will translate into a substantial socioeconomic burden. Our current findings underscore the need for clinical attention and better‐designed studies of the complex interactions between diabetes and cancer. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00183.x, 2012)

A randomized dose-finding study demonstrating the efficacy and tolerability of albiglutide in Japanese patients with type 2 diabetes mellitus

OBJECTIVE

To investigate the optimal dosage/regimen and to evaluate the efficacy and safety of albiglutide in Japanese patients with type 2 diabetes mellitus.

RESEARCH DESIGN AND METHODS

This was a randomized, double-blind, placebo-controlled, multicenter, parallel-group, dose-ranging, superiority study in Japanese patients with type 2 diabetes mellitus. Patients (n = 215) who were treatment naive or washed out of one oral antidiabetic drug were randomized to placebo or albiglutide 15 mg weekly, 30 mg weekly, or 30 mg every other week (biweekly).

CLINICAL TRIAL REGISTRATION

NCT01098461.

MAIN OUTCOME MEASURES

The primary end point was the change from baseline in HbA1c at week 16, measured using the Japan Diabetes Society standardization scheme and presented here using the National Glycohemoglobin Standardization Program equivalents. Other measures of efficacy as well as safety and population pharmacokinetics and pharmacokinetics/pharmacodynamics of albiglutide were assessed.

RESULTS

Baseline HbA1c was 8.53%. There was a statistically significant difference between each albiglutide treatment group and placebo for change from baseline in HbA1c at week 16, with treatment effects of -0.89% for 15 mg weekly, -1.55% for 30 mg weekly, and -1.10% for 30 mg biweekly (P < 0.0001 for all groups vs placebo). By week 16, 63.0% and 33.3% of patients in the 30 mg weekly albiglutide group compared with 6.0% and 0% of patients in the placebo group achieved HbA1c <7.4% and <6.9%, respectively. No serious adverse events were related to study therapy; no deaths occurred. Nasopharyngitis was the most frequently reported adverse event in all treatment groups (n = 43 [20.3%]).

CONCLUSIONS

Albiglutide exhibited therapeutic hypoglycemic effects with good tolerability among Japanese patients with type 2 diabetes mellitus; the 30 mg weekly dose was the most efficacious in this study. The 16 week duration of the study prevents generalizing these conclusions to longer treatment periods.

Efficacy and Safety of Vildagliptin as Add-on to Metformin in Japanese Patients with Type 2 Diabetes Mellitus

INTRODUCTION

The objective of this study was to evaluate the efficacy and safety of vildagliptin, a potent dipeptidyl peptidase-4 inhibitor, as an add-on to metformin in Japanese patients with type 2 diabetes mellitus (T2DM).

METHODS

This multicenter, 12-week, randomized, double-blind, placebo-controlled, parallel-arm study compared vildagliptin 50 mg bid with placebo in T2DM patients who were inadequately controlled [glycosylated hemoglobin (HbA1c) 7.0-10.0%] on a stable daily dose of metformin monotherapy (250 mg bid or 500 mg bid).

RESULTS

A total of 139 patients were randomized to receive either vildagliptin (n = 69) or placebo (n = 70). Patient demographics were comparable between the groups at baseline. After 12 weeks of treatment, adjusted mean change in HbA1c was -1.1% in the vildagliptin group (baseline 8.0%) and -0.1% in the placebo group (baseline 8.0%), with a between-treatment difference of -1.0% (P < 0.001). Vildagliptin showed a similar reduction in HbA1c of -1.1% for both the subpopulations of patients receiving metformin 250 mg bid or 500 mg bid (P < 0.001 vs. baseline). Significantly more patients in the vildagliptin group achieved an HbA1c target of ≤6.5% (30.9%) and <7.0% (64.1%) compared with the placebo group (P < 0.001). The between-treatment difference in adjusted mean change in fasting plasma glucose was -1.6 mmol/L (P < 0.001) in favor of vildagliptin. Patients in the vildagliptin and placebo groups reported comparable incidences of adverse events (44.1% vs. 41.4%). No deaths or hypoglycemic events were reported in the study.

CONCLUSIONS

Vildagliptin 50 mg bid added to metformin improved glycemic control without any tolerability issues and hypoglycemia in Japanese patients with T2DM inadequately controlled on metformin monotherapy.

The once-daily human glucagon-like peptide-1 analog, liraglutide, improves β-cell function in Japanese patients with type 2 diabetes

Aims/Introduction:  β‐cell function was evaluated by homeostasis model assessment of β‐cell function (HOMA‐B) index, proinsulin:insulin and proinsulin:C‐peptide ratios in adult, Japanese type 2 diabetes patients receiving liraglutide.

Materials and Methods:  Data from two randomized, controlled clinical trials (A and B) including 664 Japanese type 2 diabetes patients (mean values: glycated hemoglobin [HbA_1c] 8.61–9.32%; body mass index [BMI] 24.4–25.3 kg/m²) were analyzed. In two 24‐week trials, patients received liraglutide 0.9 mg (n = 268) or glibenclamide 2.5 mg (n = 132; trial A), or liraglutide 0.6, 0.9 mg (n = 176) or placebo (n = 88) added to previous sulfonylurea therapy (trial B).

Results:  Liraglutide was associated with improved glycemic control vs sulfonylurea monotherapy or placebo. In liraglutide‐treated groups in trials A and B, area under the curve (AUC) _{insulin 0–3 h} was improved (P < 0.001 for all) and the AUC_{insulin 0–3 h}:AUC_{glucose 0–3 h} ratio was increased (estimated treatment difference [liraglutide–comparator] 0.058 [0.036, 0.079]). HOMA‐B significantly increased with liraglutide relative to comparator in trial B (P < 0.05), but not in trial A. The reduction in fasting proinsulin:insulin ratio was 50% greater than in comparator groups.

Conclusions:  In Japanese type 2 diabetes patients, liraglutide was associated with effective glycemic control, restoration of prandial insulin response and indications of improved β‐cell function. This trial was registered with Clinicaltrials.gov (trial A: no. NCT00393718/JapicCTI‐060328 and trial B: no. NCT00395746/JapicCTI‐060324). (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2012.00193.x, 2012)

Liraglutide is effective in type 2 diabetic patients with sustained endogenous insulin-secreting capacity

Aims/Introduction:  Recently, glucagon-like peptide-1 (GLP-1) receptor agonists of liraglutide have become available in Japan. It has not yet been clarified what clinical parameters could discriminate liraglutide-effective patients from liraglutide-ineffective patients.

MATERIALS AND METHODS

  We reviewed 23 consecutive patients with type 2 diabetes admitted to Osaka University Hospital for glycemic control. All of the patients were treated with diet plus insulin (or plus oral antidiabetic drugs) to improve fasting plasma glucose (FPG) and postprandial glucose below 150 and 200 mg/dL, respectively. After insulin secretion and insulin resistance were evaluated, insulin was replaced by liraglutide. The efficacy of liraglutide was determined according to whether glycemic control was maintained at the target levels.

RESULTS

  Liraglutide was effective in 13 of 23 patients. There were significant differences in the parameters of insulin secretion, including fasting C-peptide (F-CPR), C-peptide index (CPI), insulinogenic index (I.I.) and urine C-peptide (U-CPR), between liraglutide-effective and -ineffective patients. The duration of diabetes was significantly shorter in liraglutide-effective patients than in liraglutide-ineffective patients. In receiver operating characteristic analyses, the cut-off value for predicting the efficacy of liraglutide was 0.14 for I.I., 1.1 for CPI, 1.5 ng/mL for F-CPR, 33.3 μg/day for U-CPR and 19.5 years for duration of type 2 diabetes.

CONCLUSIONS

  Insulin secretion evaluated by F-CPR, CPI, I.I., U-CPR and the duration of type 2 diabetes were useful parameters for predicting the efficacy of liraglutide in patients with type 2 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00168.x, 2011).

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)

Efficacy and safety of sitagliptin monotherapy and combination therapy in Japanese type 2 diabetes patients

(J Diabetes Invest, doi: 10.1111/j.2040-1124.2012.00221.x, 2012) Aims/Introduction:  To determine the efficacy and safety of sitagliptin monotherapy and combination therapy in Japanese type 2 diabetes patients after 3 months' therapy.

MATERIALS AND METHODS

  A retrospective, observational study of 741 type 2 diabetes patients was carried out; 110 received sitagliptin monotherapy, and 631 received combination therapy with sitagliptin when other oral medications were insufficient. The primary outcome measure was glycated hemoglobin (HbA1c) measured at 0, 4 and 12 weeks of sitagliptin therapy.

RESULTS

  In the monotherapy and combination therapy groups, HbA1c decreased significantly after 12 weeks. Target HbA1c (<7%) was achieved in 39.1% overall. On logistic regression analysis, baseline HbA1c was the strongest contributing factor for achieving target HbA1c; baseline body mass index and duration of diabetes were also significant factors. A total of 82 patients (11%) were unresponsive to sitagliptin. These patients' baseline body mass index was significantly higher and their baseline HbA1c was significantly lower than those of patients who responded to sitagliptin. The most commonly co-administered drugs were sulfonylureas (508 patients). In these patients, the dose of sulfonylurea decreased with time. In 66 patients whose sulfonylurea dosage was reduced when sitagliptin was started, HbA1c and bodyweight decreased significantly after 12 weeks. A total of 24 patients receiving sulfonylureas had mild hypoglycemia, but none discontinued sitagliptin.

CONCLUSIONS

  Sitagliptin was effective and safe as both monotherapy and combination therapy in Japanese type 2 diabetes patients. When sulfonylureas were ineffective, sitagliptin improved glycemic control. In patients whose sulfonylurea dose was reduced at the start of sitagliptin, blood glucose improved and bodyweight decreased after 12 weeks.

Insulin secretion and computed tomography values of the pancreas in the early stage of the development of diabetes

Aims/Introduction:  The computed tomography (CT) value of the pancreas was examined across the range of glucose tolerance, and the relationships between pancreatic CT values and factors responsible for glucose intolerance were analyzed.

Materials and Methods:  A total of 167 health‐check examinees were classified into normal glucose tolerance (NGT), impaired glucose tolerance (IGT) and diabetes mellitus (DM) according to 75 g oral glucose tolerance test (OGTT). Pancreatic and hepatic CT values were estimated at decreasing stages of glucose tolerance. The association of CT values of the pancreas and the indices of glucose tolerance were analyzed.

Results:  Insulinogenic index (II) was decreased from NGT through IGT to DM. Mean pancreatic CT value was decreased significantly from NGT through IGT to DM. Mean area under the curves of glucose (AUC‐G) was significantly associated with II and insulin sensitivity index (ISI) composite in univariate analysis. In multiple regression analysis, II was most strongly inversely correlated with mean AUC‐G, suggesting that II is the strongest determinant of glucose tolerance in Japanese. In addition, II was significantly associated with mean pancreatic CT value in univariate analysis. In multiple regression analysis, mean pancreatic CT value was strongly correlated with II.

Conclusions:  Pancreatic CT values were significantly decreased from NGT through IGT to DM. II was the strongest determinant of glucose tolerance, and was significantly influenced by pancreatic CT values. Thus, pancreatic fat deposition might impair insulin secretion in the early stage of development of type 2 diabetes, before overt deterioration of glucose tolerance. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2012.00212.x, 2012)

Maternal high-fat diet induces insulin resistance and deterioration of pancreatic β-cell function in adult offspring with sex differences in mice

Intrauterine environment may influence the health of postnatal offspring. There have been many studies on the effects of maternal high-fat diet (HFD) on diabetes and glucose metabolism in offspring. Here, we investigated the effects in male and female offspring. C57/BL6J mice were bred and fed either control diet (CD) or HFD from conception to weaning, and offspring were fed CD or HFD from 6 to 20 wk. At 20 wk, maternal HFD induced glucose intolerance and insulin resistance in offspring. Additionally, liver triacylglycerol content, adipose tissue mass, and inflammation increased in maternal HFD. In contrast, extending previous observations, insulin secretion at glucose tolerance test, islet area, insulin content, and PDX-1 mRNA levels in isolated islets were lower in maternal HFD in males, whereas they were higher in females. Oxidative stress in islets increased in maternal HFD in males, whereas there were no differences in females. Plasma estradiol levels were lower in males than in females and decreased in offspring fed HFD and also decreased by maternal HFD, suggesting that females may be protected from insulin deficiency by inhibiting oxidative stress. In conclusion, maternal HFD induced insulin resistance and deterioration of pancreatic β-cell function, with marked sex differences in adult offspring accompanied by adipose tissue inflammation and liver steatosis. Additionally, our results demonstrate that potential mechanisms underlying sex differences in pancreatic β-cell function may be related partially to increases in oxidative stress in male islets and decreased plasma estradiol levels in males.

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.

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

Aims/Introduction

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

Materials and Methods

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

Results

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

Conclusion

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

Factors influencing the durability of the glucose-lowering effect of sitagliptin combined with a sulfonylurea

We analyzed the changes of glycemic control over 12 months and the factors influencing blood glucose in 162 Japanese patients with type 2 diabetes having inadequate glycemic control despite sulfonylurea-based therapy who received add-on sitagliptin. Hemoglobin A1c (HbA1c) decreased significantly after 4 weeks of treatment, and this improvement was maintained for 1 year, although HbA1c was slightly higher in week 52 than in week 24. Comparison of the patients showing a ≥0.4% increase of HbA1c between weeks 24 and 52 (n = 57) with the others (n = 105) showed a significant difference in the change of bodyweight, as well as the dose of glibenclamide (both P < 0.01). Although combined therapy with sitagliptin and a sulfonylurea seems to be effective for at least 1 year, blood glucose levels are more likely to increase again in patients who show greater weight gain after 24 weeks of treatment and those receiving a higher dose of glibenclamide.

Effect of insulin glargine on endogenous insulin secretion and beta-cell function in Japanese type 2 diabetic patients using oral antidiabetic drugs

The aim of the present study was to evaluate the effect of insulin glargine (Gla) (as part of basal-supported oral therapy) on endogenous insulin secretion and beta-cell function in type 2 diabetic patients. In 33 insulin-naive patients showing poor glycemic control on treatment with sulfonylurea (SU)-based OADs without DPP4 inhibitors, once-daily injection of Gla was added without changing OADs, and the dose of Gla was titrated to attain a fasting plasma glucose (FPG) <110 mg/dL over 24 weeks. Morning meal tests were done at baseline, 12 weeks and 24 weeks. FPG and 2-hour plasma glucose (2HPG) and serum C-peptide (FCPR and 2HCPR) were measured 3 times, while serum intact proinsulin (FPI and 2HPI) was measured at baseline and 24 weeks. Levels of FPG, FCPR, 2HPG, and HbA1c were significantly reduced from baseline at 24 weeks (176±52 to 117±27 mg/dL, p<0.01; 2.0±0.9 to 1.6±1.0 ng/mL, p<0.01; 257±53 to 202±27 mg/dL, p<0.01; and 8.4±0.9 to 7.3±0.6%, p<0.01, Mean±SD), but 2HCPR was unchanged. The patients were divided into two groups depending on whether FPG at 24 weeks was <110 mg/dL or not: attained group (n=15) and not attained group (n=18). The dose of Gla did not differ between the two groups, but the 2HPI/2HCPR ratio at 24 weeks showed a significant decrease from baseline in the attained group. Supplementation with Gla improved glycemic control and maintained intrinsic basal insulin secretion, without changing 2-hour postprandial secretion. Achieving good glycemic control with an FPG<110 mg/dL by adding Gla decreased the 2HPI/2HCPR ratio at 24 weeks.

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.