Characteristics of Japanese subjects who progress from normal to impaired glucose tolerance. Longitudinal study excluding changes in body weight

Glucose levels during oral glucose tolerance tests and gamma-glutamyl transpeptidase are predictors of change from normal to impaired glucose tolerance in healthy middle-aged Japanese men

We evaluated the predictors of the development from normal to impaired glucose tolerance (IGT) in healthy middle-aged Japanese men. Forty male subjects who showed normal glucose tolerance (NGT) levels based on WHO criteria and who had undergone 75-g OGTT annually for 10 years were selected in the database of medical checkups retrospectively, and divided into two groups: those retaining NGT and those that developed IGT. Gamma-glutamyl transpeptidase (GGT) and the glucose levels at 30 and 60 min were significantly associated with the development of IGT in the Cox proportional hazard model. However, other clinical characteristics and the glucose levels at pre-load and at 120 min were not significantly associated with the development of IGT. GGT and the glucose levels at 30 and 60 min after the 75-g glucose load were predictors of development from NGT to IGT in healthy middle-aged Japanese men.

Beta-cell function is a major contributor to oral glucose disposition in obese Japanese students

Determinants of glucose intolerance were studied in 163 obese Japanese young adults, 18 to 21 years old (43 females,120 males), who underwent 75-g oral glucose tolerance testing. Type 2 diabetes was newly diagnosed in 2.9% (n = 4); impaired fasting glucose (IFG) in 5.1% (n = 7); and impaired glucose tolerance (IGT) in 10.9% (n = 15). A homeostasis model assessment of insulin resistance (HOMA-IR) was used to estimate insulin sensitivity; beta-cell function during the first 30 min of the test was measured and defined as the insulinogenic index. This index was adjusted for insulin sensitivity, since this affects both beta-cell function and glucose disposition (disposition index). The relationship between insulinogenic index and 1/HOMA-IR was not hyperbolic. However, the disposition index (DI) was useful for the estimation of beta-cell function with the correct confirmation about it validity using beta-cell function index (BI). The association between insulin sensitivity and beta-cell function to glucose disposal, as measured by the area under the glucose curve (AUCg), was examined in all subjects. Insulin sensitivity was significantly related to AUCg (log HOMA-IR; R (2) = 0.142, p<0.0001). On the other hand, an inverse curvilinear relationship was observed between beta-cell function and AUCg (log(Delta I/Delta G)/HOMA-IR, R (2) = 0.411, p<0.0001). Thus, impaired beta-cell function, when estimated as DI, was strongly associated with impaired glucose disposal. In conclusion, our study showed that both insulin sensitivity and impaired beta-cell function are associated with impaired glucose metabolism, and that beta-cell function may be more important in determining glucose disposal.

Clinical characteristics influencing the effectiveness of metformin on Japanese type 2 diabetes receiving sulfonylureas

In this study, we described the effectiveness of metformin on Japanese type 2 diabetes patients receiving sulfonylureas and the clinical characteristics of the patients whose glycemic control were significantly improved with metformin administration. Our results showed that the reduction of glycohemoglobin (HbA1C), serum concentration of total cholesterol, and diastolic blood pressure was statistically significant through the administration of metformin. The clinical characteristics of the patients who responded to metformin therapy exhibited lower systolic blood pressure in addition to higher HbA1C value just before administration of metformin when compared with DeltaHbA1C (HbA1C 6 months after administration of metformin--HbA1C before administration of metformin). Moreover, effectiveness of metformin was weakened, in comparison with non-hypertensive patients, even though the blood pressure of hypertensive patients was reduced to normal range by medication with antihypertensive drugs. But average reduction of HbA1C level of hypertensive patients without antihypertensive medications was smaller than those of patients with high blood pressure with such medication. These results suggested that high blood pressure and hypertension phenotype itself were suppressive factors of metformin but antihypertensive therapy itself enhanced the effectiveness of metformin regardless of the improvement of blood pressure.

Soluble CD40 ligand levels in otherwise healthy subjects with impaired fasting glucose

Unlike diabetes mellitus and impaired glucose tolerance, it is not clear whether the subjects with impaired fasting glucose (IFG) are at increased risk of atherosclerosis and cardiovascular diseases. The CD40-CD40 ligand interaction is involved in the mechanism of atherosclerosis. We investigated whether soluble CD40L (sCD40L) as well as high sensitive C-reactive protein (hsCRP) levels are increased in subjects with IFG having no confounding factors for inflammation or atherosclerosis. Twenty four IFG subjects with no additional disorders and 40 appropriate healthy controls were studied. sCD40L and hsCRP levels in the IFG and control groups were similar. Blood pressures, total and LDL-cholesterol, and triglyceride levels were also similar, whereas HDL-cholesterol was lower and HOMA-IR indexes were higher in the IFG group. Though the sample size was small, the present data show that sCD40L seems not to alter in subjects with IFG suggesting that it might not be an independent risk factor for atherosclerosis.

Long-term effect of combination therapy with mitiglinide and once daily insulin glargine in patients who were successfully switched from intensive insulin therapy in short-term study

We have previously reported the therapeutic efficacy of mitiglinide combined with once daily insulin glargine (mitiglinide regimen) after switching from multiple daily insulin regimen of aspart insulin and glargine (intensive insulin regimen) in inpatients with type 2 diabetes mellitus in two consecutive days. In the present study, we followed up 9 of the 15 responsive patients with these novel regimens for 6 months after discharge. The data collected from these patients were compared to those of 15 randomly chosen patients who had well matched background and received intensive insulin regimen during hospitalization which was continued after discharge. The average HbA1c level of these 9 patients with mitiglinide regimen at 6 months was 6.7 +/- 0.8% and was comparable to that of the patients with intensive insulin regimen (HbA1c = 7.0 +/- 1.0%). In conclusion, mitiglinide and insulin glargine combination therapy maintained fair glycemic control for as long as 6 months in subpopulation of Japanese patients with type 2 diabetes.

Efficacy and adverse effects of nateglinide in early type 2 diabetes. Comparison with voglibose in a cross-over study

An open-label prospective cross-over trial was performed to compare the efficacy and adverse effects of nateglinide with those of voglibose on Japanese early type 2 diabetes (who were oral hypoglycemic agent naïve and whose HbA(1C) levels were between 7.0 and 7.9% before treatment). Fourteen patients received 270 mg/day of nateglinide and 15 patients received 0.6 mg/day of voglibose. After 12 weeks of either therapy, the drugs were switched and treatment was continued for another 12 weeks. After 3-month treatment with each drug, HbA(1C) value decreased significantly (baseline HbA(1C) 7.24 +/- 0.42%, 6.70 +/- 0.47% with nateglinide: p<0.01, 6.93 +/- 0.62% with voglibose: p<0.05) but the difference in the effect between nateglinide and voglibose was not significant (p = 0.121). Symptoms related to hypoglycemia (e.g., increased appetite, palpitation, sweating, tremor) were scarcely observed with either voglibose or nateglinide treatments. Abdominal fullness/borborygmi was frequently reported, with variable severity, by patients on voglibose but this was absent or mild in those on nateglinide. After completion of both arms of the study, more patients favored nateglinide than voglibose. Our results suggest that nateglinide is an effective and safe drug in the treatment of early type 2 diabetes, similar to voglibose.

Therapeutic efficacy of mitiglinide combined with once daily insulin glargine after switching from multiple daily insulin regimen of aspart insulin and glargine in patients with type 2 diabetes mellitus

Mitiglinide is novel class of rapid-acting insulin secretagogues, which have been widely used alone or in combination with other oral hypoglycemic drugs to improve postprandial hyperglycemia in early type 2 diabetes. While mitiglinide enhances postprandial requirement of insulin, the efficacy of mitiglinide combined with insulin has yet to be established. We investigated the efficacy of mitiglinide combined with insulin glargine, the first soluble insulin analog that has a flat and prolonged effect. After control with the intensive regimen (daily aspart insulin and glargine), 30 inpatients with type 2 diabetes were switched to premeal mitiglinide combined with once daily insulin glargine (mitiglinide regimen), and daily profiles of blood glucose level were compared under each regimen. Fifteen patients showed similar control of hyperglycemia with mitiglinide regimen and intensive insulin regimen, assessed by M value (<32), while the remaining 15 showed worsening under the mitiglinide regimen. The patients who were well controlled with mitiglinide regimen were significantly younger (51.9 +/- 16.0 years, p<0.005) and heavier (body mass index: 25.7 +/- 3.3 kg/m(2), p<0.05) than those who were not (67.9 +/- 8.7 and 23.0 +/- 3.1, respectively). Moreover, insulin doses of aspart per body weight were significantly fewer in effective group than in ineffective group. Duration of diabetes was shorter in the effective group, albeit insignificantly. Previous treatment before starting intensive insulin regimen, such as insulin and sulfonylurea, was not different between the two groups. Our results suggest that mitiglinide plus insulin glargine combination therapy is useful for lowering both fasting and postprandial hyperglycemia in a subpopulation of type 2 diabetes. The long-term effects of such treatment need to be established in future studies.