Abstract

Aims:

It is necessary to evaluate glucose variability and postprandial hyperglycemia in patients with well-controlled type 2 diabetes mellitus because of the limitations associated with hemoglobin A1c (HbA1c) measurements. We evaluated parameters reflecting postprandial hyperglycemia and glycemic variability in patients with optimal HbA1c. Patients and

Methods:

Thirty-nine patients with HbA1c levels below 7% were recruited to the study. A continuous glucose monitoring system (CGMS) was applied for two 72-h periods. 1,5-Anhydroglucitol (1,5-AG) and fructosamine (FA) were measured as parameters for postprandial hyperglycemia and glucose variability. Using CGMS data, the following postprandial hyperglycemia parameters were calculated: mean postprandial maximum glucose (MPMG) and area under the curve for glucose above 180 mg/dL (AUC-180). To measure glycemic variability, we calculated mean amplitude of glucose excursion (MAGE) using a classical (MAGEc) and new method (MAGE group of sign [MAGEgos]).

Results:

The baseline HbA1c level was 6.3±0.3%. The mean MPMG was 10.34±1.84 mmol/L, and the mean AUC-180 was 0.17±0.23 mmol/L/day. The mean MAGEgos was 3.27±1.29 mmol/L, and MAGEc was 4.30±1.43 mmol/L, indicating glycemic variability in our patients. The mean levels of 1,5-AG and FA were 16.7±7.4 μg/mL and 273.0±22.5 μmol/L, respectively. In a correlation analysis, FA was significantly correlated with MPMG, AUC-180, MAGEgos, and MAGEc. In contrast, 1,5-AG was only correlated with AUC-180.

Conclusions:

This study demonstrated postprandial hyperglycemia and glycemic variability in subjects with well-controlled diabetes. FA may reflect postprandial hyperglycemia and glycemic variability, but 1,5-AG may be of limited value for assessing glucose variability in patients with well-controlled type 2 diabetes mellitus.

To assess the effects of sitagliptin and nateglinide on lipid metabolism.In a parallel group comparative open trial, patients with type 2 diabetes mellitus under treatment at the Japanese Red Cross Medical Center were randomly assigned to receive either sitagliptin (50 mg once daily) or nateglinide (90 mg three times daily before meals). Eligible patients met the following criteria: age ≥ 20 years; hemoglobin A1c (HbA1c) > 6.5% despite diet and exercise; HbA1c between 6.5% and 8.0%; fasting glucose < 7.77 mmol/L; diet and exercise therapy for more than 3 mo; and ability to read and understand the information for written informed consent. Exclusion criteria were contraindications to sitagliptin, contraindications to nateglinide, pregnancy or possible pregnancy, and severe liver/renal failure. Patients who were considered to be unsuitable by the attending physician for other reasons were also excluded. Blood samples were collected at one and three hours after intake of a test meal. The primary outcome measure was the area under the curve (AUC) of apolipoprotein (Apo) B48 at three hours postprandially.Twenty patients were randomly assigned to the sitagliptin group and sixteen patients were randomized to the nateglinide group. All 36 patients took the medication as directed by the physician in both groups, and they all were analyzed. Apart from antidiabetic drugs, there was no difference between the two groups with respect to the frequency of combined use of lipid-lowering, antihypertensive, and/or antiplatelet drugs. The doses of these medications were maintained during 12 wk of treatment. Detailed dietary advice, together with adequate exercise therapy, was given to the patients so that other factors apart from the two test drugs were similar in the two groups. There were no significant differences of the baseline characteristics between the two groups, except for body mass index (the sitagliptin group: 25.14 ± 3.05 kg/m(2); the nateglinide group: 21.39 ± 2.24 kg/m(2)). Fasting levels of HbA1c, glycated albumin, 1.5-anhydroglucitol, and blood glucose, as well as the blood glucose levels at one and three hours postprandially, improved in both groups after 12 wk of treatment, and there were no significant differences between the two groups. However, the glucagon level at one hour postprandially (P = 0.040) and the diastolic blood pressure (P < 0.01) only showed a significant decrease in the sitagliptin group. In the nateglinide group, there was no significant change in the AUC of Apo B48, the glucagon level at one hour postprandially, the fasting triglyceride level, or the diastolic blood pressure. Body weight was unchanged in both groups. However, the AUC of Apo B48 at three hours postprandially showed a significant decrease in the sitagliptin group from 2.48 ± 0.11 at baseline to 1.94 ± 0.78 g/L per hour after 12 wk (P = 0.019). The fasting triglyceride level also decreased significantly in the sitagliptin group (P = 0.035). With regard to lipid-related markers other than Apo B48 and fasting triglycerides, no significant changes were observed with respect to Apo A1, Apo B, or Apo C3 in either group. No adverse events occurred in either group.Sitagliptin significantly improves some lipid parameters while having a comparable effect on blood glucose to nateglinide. A large-scale prospective study of sitagliptin therapy is warranted.

The aim of this study was to evaluate the relationship between postprandial glucose level and atherosclerosis in patients without diabetes and cardiovascular disease by determining carotid ultrasonographic variables and serum levels of 1,5-anhydroglucitol (1,5-AG).The subjects were 72 patients without diabetes and cardiovascular disease being treated for hypertension or dyslipidemia. The clinical characteristics of all subjects, including the serum level of 1,5-AG, which appears to be well suited for monitoring postprandial hyperglycemia, were evaluated after an overnight fast. The average intima-media thickness (IMT) and the average pulsatility index (PI) of the right and left common carotid arteries were determined with high-resolution ultrasonography and used as ultrasonographic variables. The subjects were divided into a Lower 1,5-AG group (n = 36) and a Higher 1,5-AG group (n = 36). We evaluated the relationship between clinical characteristics and ultrasonographic variables of the carotid artery in both groups.The average PI in the Lower 1,5-AG group was significantly higher than that in the Higher 1,5-AG group, but the average IMT did not differ between the groups. Linear regression analysis, with the ultrasonographic variables as the dependent variables, with 1,5-AG as the independent variable, and adjusted for other clinical characteristics, showed significant correlation between 1,5-AG and the PI but not between 1,5-AG and IMT.Our results suggest that postprandial hyperglycemia increases carotid artery stiffness, but not morphological change, in patients without diabetes or cardiovascular disease.

Obesity-related inflammation-induced insulin resistance and metabolic dysregulation were investigated in retrospective analysis of placebo hematologic and metabolic laboratory data from trials associated with increasing chronic low-grade inflammation and body mass index. Studies included healthy subjects and those with progressive stages of metabolic dysregulation, including type 2 diabetes mellitus with uncontrolled hemoglobin A1c. Intrasubject variances in erythroid and metabolic values increased with metabolic dysregulation. Random effects were demonstrated in treatment-naïve diabetes for erythroid, glucose, and HbA1c fluctuations. The anti-inflammatory insulin sensitizer, HE3286, was tested for its ability to decrease obesity-related inflammation-induced insulin resistance and metabolic dysregulation in diabetes. HE3286 significantly decreased erythroid and metabolic variances and improved 1,5-anhydroglucitol (a surrogate of postprandial glucose) compared to the placebo group. HE3286 HbA1c decrease correlated with weight loss and inversely with baseline monocyte chemoattractant protein-1 (MCP-1) in metformin-treated diabetics. Normalization of HbA1c to the 84-day average hemoglobin revealed that HE3286 HbA1c decrease correlated with high baseline MCP-1 and MCP-1 decrease in treatment-naïve diabetics. HE3286 decreased insulin resistance, increased the frequency of decreased day 84 HbA1c in metformin-treated subjects, and decreased day 112 HbA1c in treatment-naïve diabetics. HE3286 may be useful to restore metabolic homeostasis in type 2 diabetes.

Most pregnant women with type 1 diabetes mellitus achieve HbA1c targets; however, macrosomia remains prevalent and better pregnancy glycaemic markers are therefore needed. 1,5-Anhydroglucitol (1,5-AG) is a short-term marker of glycaemia, reflecting a period of 1 to 2 weeks. Its excretion rate depends on the renal glucose threshold and thus it is unclear whether it may be used in pregnant type 1 diabetes women. We evaluated 1,5-AG as a glycaemic marker and birthweight predictor in pregnant women with type 1 diabetes, and compared its performance with HbA1c.1,5-AG and HbA1c were measured in 82 pregnant women with type 1 diabetes. In addition, 58 continuous glucose monitoring system (CGMS) records were available. Macrosomia was defined as birthweight >90th centile. The data were analysed with Pearson's correlations, and linear and logistic regression models. Receiver operating characteristic (ROC) analysis was used to evaluate third trimester 1,5-AG as a predictor of macrosomia.Unlike HbA1c, 1,5-AG strongly correlated with CGMS indices: the AUC above 7.8 mmol/l (r = -0.66; p < 0.001), average maximum glucose (r = -0.58; p < 0.001) and mean glucose (r = -0.54; p < 0.001). In the third trimester, 1,5-AG was the strongest predictor of macrosomia, with ROC AUC 0.81 (95% CI 0.70, 0.89). In contrast, HbA1c in the third trimester had a ROC AUC of 0.69 (95% CI 0.58, 0.81). The best discrimination was achieved when both markers were used jointly, yielding a ROC AUC of 0.84 (95% CI 0.76, 0.93).In pregnant women with type 1 diabetes, 1,5-AG is a better glycaemic marker than HbA1c, as assessed by CGMS. A decreased third trimester 1,5-AG level, either singly or with HbA1c, is a strong predictor of macrosomia.

This study aimed to determine the efficacy and safety of pioglitazone/glimepiride as a fixed-dose combination (FDC) in Japanese patients with type 2 diabetes.In this multicenter, phase III, open-label evaluation, eligible patients had to have a glycosylated hemoglobin (HbA(1c)) level of ≥7.4% and <10.4% halfway through a 4-week run-in period while being treated with glimepiride 1 or 3 mg once daily plus diet and exercise. At baseline, patients were assigned to 8 weeks of treatment with pioglitazone/glimepiride (15 mg/1 mg) FDC once daily (group A; n=31) or pioglitazone/glimepiride (30 mg/3 mg) FDC once daily (group B; n=31) according to their glimepiride dose during run-in.Pioglitazone/glimepiride significantly reduced the mean HbA(1c) level from baseline (primary end point) by 0.59±0.556% in group A (P<0.0001) and by 0.55±0.637% in group B (P<0.0001). Corresponding reductions in the mean fasting blood glucose level were 12.5±21.67 mg/dL (P=0.0032) and 29.1±35.38 mg/dL (P<0.0001). Significant alterations from baseline to week 8 in either one or both treatment groups were also noted for the following parameters: 1,5-anhydroglucitol, glycoalbumin, triglycerides, high-density lipoprotein cholesterol, and free fatty acid levels. Five patients in group A (16.1%) had five treatment-related adverse events, and 10 patients in group B (32.3%) had 13 such events; all events were mild.Pioglitazone/glimepiride as a FDC (30 mg/3 mg and 15 mg/1 mg once daily) significantly improved glycemic control and lipid profiles and was well tolerated in Japanese patients with type 2 diabetes.

BACKGROUND:

A growing body of evidence suggests that caffeinated beverages may impair chronic glucose control in type 2 diabetes. This pilot study tested the chronic effects of caffeine abstinence on glucose control in type 2 diabetic patients who were daily coffee drinkers.

METHODS:

Twelve coffee drinkers (six males) with established type 2 diabetes participated. Seven (five males) completed 3 months of total caffeine abstinence. Measures of chronic glucose control, long-term (hemoglobin A1c [HbA1c]) and short-term (1,5-anhydroglucitol [1,5-AG]), were collected at baseline and during follow-up. Abstinence was established by diaries confirmed by saliva caffeine assays.

RESULTS:

Abstinence produced significant decreases in HbA1c and increases in 1,5-AG, both indicating improvements in chronic glucose control. Fasting glucose and insulin did not change, nor were changes in body weight observed.

CONCLUSIONS:

Although preliminary, these results suggest that caffeine abstinence may be beneficial for patients with type 2 diabetes. This hypothesis should be confirmed in larger controlled clinical trials.

1,5-Anhydroglucitol (1,5-AG), fructosamine, and glycated albumin are of increasing interest as alternative measures of hyperglycemia. We characterize the associations of these nontraditional glycemic markers with hemoglobin A(1c) (Hb A(1c)) and fasting glucose and assess their ability to identify people with diabetes.We conducted a cross-sectional comparison of 1,5-AG, fructosamine, and glycated albumin with Hb A(1c) and fasting glucose measurements in 1719 participants from the Atherosclerosis Risk in Communities Study. We evaluated nonlinear relationships using R(2) and F-statistics. Performance for identification of cases of diabetes was determined using the area under the curve (AUC). Diabetes was defined by Hb A(1c) ≥6.5%, fasting glucose ≥126 mg/dL (≥6.99 mmol/L), and/or a self-reported history of diagnosed diabetes.Median values of Hb A(1c) and fasting glucose were 5.8% and 109 mg/dL (6.05 mmol/L), respectively; 17.3% of the study population had diagnosed diabetes. Glycated albumin, fructosamine, and 1,5-AG were more strongly correlated with Hb A(1c) compared with fasting glucose (all P values <0.05). Nonlinear models provided the best fit for describing the relationships of the alternative markers to Hb A(1c). When diabetes was defined by an Hb A(1c) ≥6.5%, fructosamine (AUC 0.83; 95% CI, 0.79-0.87) and glycated albumin (AUC 0.87; 95% CI, 0.83-0.90) performed comparably to fasting glucose (AUC 0.83; 95% CI, 0.79-0.87), while 1,5-AG performed worse (AUC 0.74; 95% CI, 0.69-0.78) for identifying cases of undiagnosed diabetes.Fructosamine and glycated albumin may be useful adjuncts to Hb A(1c) and fasting glucose. Future studies should examine these markers in situations in which fasting glucose or Hb A(1c) measurements are invalid or not available.

Fructosamine, glycated albumin, and 1,5-anhydroglucitol (1,5-AG) are of interest for monitoring short-term glycemic control in patients with diabetes; however, their associations with diabetes risk are uncharacterized.We used Cox proportional hazards models to examine the associations of fructosamine, glycated albumin, and 1,5-AG with incident diabetes in 1,299 participants, from the Atherosclerosis Risk in Communities (ARIC) Study (2005-2006), who had no history of diagnosed diabetes at baseline. Incident diabetes was self-reported during annual telephone calls.There were 119 new cases of diabetes during a median follow-up of 3.3 years. When compared with the lowest quartile, the fourth quartiles of fructosamine and glycated albumin were significantly associated with diabetes risk (hazard ratio [HR] 3.99 [95% CI 1.93-8.28] and 5.22 [2.49-10.94], respectively). The fourth quartile of 1,5-AG was associated with a significantly lower diabetes risk (0.27 [0.14-0.55]). Associations were attenuated but still significant after adjustment for hemoglobin A(1c) (A1C) or fasting glucose.Fructosamine, glycated albumin, and 1,5-AG were associated with the subsequent development of diabetes independently of baseline A1C and fasting glucose. Our results suggest these alternative biomarkers may be useful in identifying persons at risk for diabetes.