Relationship between fluctuations in glucose levels measured by continuous glucose monitoring and vascular endothelial dysfunction in type 2 diabetes mellitus

Association between blood glucose variability and coronary plaque instability in patients with acute coronary syndromes

Background

Blood glucose variability is receiving considerable attention as a new risk factor for coronary artery disease. This study aimed to investigate the association between blood glucose variability and coronary plaque tissue characteristics.

Methods

In 57 patients with acute coronary syndrome, integrated backscatter intravascular ultrasound (IB-IVUS) and gray-scale IVUS were performed before balloon dilatation or stent implantation in the culprit vessels. Standard IVUS indices were evaluated for volume index (volume/length), and plaque components were measured by IB-IVUS for percent tissue volume. In addition to conventional glucose indicators, blood glucose variability in a stable state was determined by calculating the mean amplitude of glycemic excursions (MAGE) using a continuous glucose monitoring system.

Results

Higher MAGE values were significantly correlated with larger percent plaque volumes (r = 0.32, p = 0.015), and increased lipid (r = 0.44, p = 0.0006) and decreased fibrous (r = −0.45, p = 0.0005) plaque components. In contrast, HbA1c or fasting plasma glucose values were not significantly correlated with plaque volumes and percent plaque components. Homeostasis model assessment of insulin resistance values were positively correlated with vessel (r = 0.35, p = 0.007) and plaque (r = 0.27, p = 0.046) volumes, but not with percent plaque components. In multiple regression analysis, higher MAGE values were independently associated with increased lipid (β = 0.80, p = 0.0035) and decreased fibrous (β = -0.79, p = 0.0034) contents in coronary plaques.

Conclusions

Among all glucose indicators studied, only higher blood glucose variability was an independent determinant of increased lipid and decreased fibrous contents with larger plaque burden, suggesting blood glucose variability as one of the important factors related to coronary plaque vulnerability.

Lack of correlation between the optimal glycaemic control and coronary micro vascular dysfunction in patients with diabetes mellitus: a cross sectional study

Background

Coronary microvascular dysfunction (CMD) is associated with cardiovascular events in type 2 diabetes mellitus (T2DM). Optimal glycaemic control does not always preclude future events. We sought to assess the effect of the current target of HBA1c level on the coronary microcirculatory function and identify predictive factors for CMD in T2DM patients.

Methods

We studied 100 patients with T2DM and 214 patients without T2DM. All of them with a history of chest pain, non-obstructive angiograms and a direct assessment of coronary blood flow increase in response to adenosine and acetylcholine coronary infusion, for evaluation of endothelial independent and dependent CMD. Patients with T2DM were categorized as having optimal (HbA1c < 7 %) vs. suboptimal (HbA1c ≥ 7 %) glycaemic control at the time of catheterization.

Results

Baseline characteristics and coronary endothelial function parameters differed significantly between T2DM patients and control group. The prevalence of endothelial independent CMD (29.8 vs. 39.6 %, p = 0.40) and dependent CMD (61.7 vs. 62.2 %, p = 1.00) were similar in patients with optimal vs. suboptimal glycaemic control. Age (OR 1.10; CI 95 % 1.04–1.18; p < 0.001) and female gender (OR 3.87; CI 95 % 1.45–11.4; p < 0.01) were significantly associated with endothelial independent CMD whereas glomerular filtrate (OR 0.97; CI 95 % 0.95–0.99; p < 0.05) was significantly associated with endothelial dependent CMD. The optimal glycaemic control was not associated with endothelial independent (OR 0.60, CI 95 % 0.23–1.46; p 0.26) or dependent CMD (OR 0.99, CI 95 % 0.43–2.24; p = 0.98).

Conclusions

The current target of HBA1c level does not predict a better coronary microcirculatory function in T2DM patients. The appropriate strategy for prevention of CMD in T2DM patients remains to be addressed.

Cardioprotective effect of pioglitazone in diabetic and non-diabetic rats subjected to acute myocardial infarction involves suppression of AGE-RAGE axis and inhibition of apoptosis

Insulin resistance increases risk of cardiovascular diseases. This work investigated the protective effect of pioglitazone on myocardial infarction (MI) in non-diabetic and diabetic rats, focusing on its role on advanced glycated endproducts (AGEs) and cardiac apoptotic machinery. Male rats were divided into 2 experiments: experiment I and II (non-diabetic and diabetic rats) were assigned as saline, MI (isoproterenol, 85 mg/kg, daily), and MI+pioglitazone (5, 10, and 20 mg/kg). Injection of isoproterenol in diabetic rats produced greater ECG disturbances compared to non-diabetic rats. Treatment with pioglitazone (5 mg/kg) reduced the infarct size and improved some ECG findings. Pioglitazone (10 mg/kg) enhanced ECG findings, improved the histopathological picture and downregulated apoptosis in cardiac tissues. Whereas the higher dose of pioglitazone (20 mg/kg) did not improve most of the measured parameters but rather worsened some of them, such as proapoptotic markers. Importantly, a positive correlation was found between serum AGEs and cardiac AGE receptors (RAGEs) versus caspase 3 expression in the two experiments. Therefore, the current effect of pioglitazone was, at least in part, mediated through downregulation of AGE-RAGE axis and inhibition of apoptosis. Consequently, these data suggest that pioglitazone, at optimized doses, may have utility in protection from acute MI.

Improving the Quality of Outpatient Diabetes Care Using an Information Management System: Results From the Observational VISION Study

BACKGROUND

This study aimed to evaluate the effects of information management system (IMS) use with individuals with type 1 and type 2 diabetes who were treated in outpatient settings.

METHODS

In this 7-month, prospective, observational study, 965 adults with diabetes, mean (SD) baseline HbA1c 8.61(1.2)% (70.6[13.1] mmol/mol), were recruited from 132 outpatient care centers in Germany and Denmark. HbA1c was measured at baseline, month 4, and month 7. IMS reports were generated from uploaded self-monitored blood glucose data and therapy adjustments were documented at months 1 and 4. Hypoglycemic events were documented.

RESULTS

Mean (SD) HbA1c decreased from baseline in type 1 and type 2 diabetes patients at month 4 (-0.61[1.03]% (-6.7[11.3] mmol/mol), n = 213; -0.88[1.22]% (-9.6[13.3] mmol/mol), n = 589, respectively) and month 7 (-0.64[1.02]% (-7.0[11.1] mmol/mol), n = 219; -0.93[1.27]% (-10.2[13.9] mmol/mol), n = 594, respectively), all P < .0001, with no increase in hypoglycemic events. Therapy was adjusted in 106(42.7)% type 1 and 349(52.4)% type 2 diabetes patients at months 1 and 105(42.3)% type 1 and 282(42.3)% type 2 diabetes patients at month 4. Physicians used IMS reports to make therapy adjustments in 90% of patients at month 1 and 86% of patients at month 4.

CONCLUSIONS

Integration of the IMS into outpatient care facilitates significant improvements in glycemic control.

Genistein ameliorates cardiac inflammation and oxidative stress in streptozotocin-induced diabetic cardiomyopathy in rats

The present study was undertaken to evaluate the protective effects of genistein against cardiac inflammation and oxidative stress in streptozotocin (STZ) (45 mg/kg body weight)-induced diabetic rats. genistein (300 mg/kg/day) was administered orally for 24 weeks to STZ-induced diabetic rats. The effects of genistein on blood glucose, % glycosylated hemoglobin (HbA1c), C-reactive protein, tumor necrosis factor (TNF- α), transforming growth factor (TGF-β1), and total antioxidant were studied. Ultrastructural and histopathological assessment of injury were also undertaken using transmission electron microscope. STZ-induced diabetes resulted in significant increase in the levels of blood glucose, HbA1c, C-reactive protein, TNF- α and TGF-β1, and a decline in total antioxidant reserve of the myocardium. Administration of genistein to diabetic rats resulted in a decrease in blood glucose (p < 0.001), % HbA1c (p < 0.0001), C-reactive protein (p < 0.001), and expression of TNF- α (p < 0.001) and TGF-β1 (p < 0.0001) proteins. In addition, genistein treatment results in augmentation of total antioxidant (p < 0.01) reserve of the hearts. The above findings were supported by histological as well as immunohistochemical localization of NF-κB (p65) in the heart. Genistein treatment ameliorated the ultrastructural degenerative changes in the cardiac tissues as compared to the diabetic control. The result demonstrates that genistein restored the integrity of the diabetic myocardium by virtue of its anti-inflammatory and antioxidant effects.

Association between daily glucose fluctuation and coronary plaque properties in patients receiving adequate lipid-lowering therapy assessed by continuous glucose monitoring and optical coherence tomography

Background

Glucose fluctuation has been recognized as a residual risk apart from dyslipidemia for the development of coronary artery disease (CAD). This study aimed to investigate the association between glucose fluctuation and coronary plaque morphology in CAD patients.

Methods

This prospective study enrolled 72 consecutive CAD patients receiving adequate lipid-lowering therapy. They were divided into 3 tertiles according to the mean amplitude of glycemic excursions (MAGE), which represents glucose fluctuation, measured by continuous glucose monitoring (tertile 1; <49.1, tertile 2; 49.1 ~ 85.3, tertile 3; >85.3). Morphological feature of plaques were evaluated by optical coherence tomography. Lipid index (LI) (mean lipid arc × length), fibrous cap thickness (FCT), and the prevalence of thin-cap fibroatheroma (TCFA) were assessed in both culprit and non-culprit lesions.

Results

In total, 166 lesions were evaluated. LI was stepwisely increased according to the tertile of MAGE (1958 ± 974 [tertile 1] vs. 2653 ± 1400 [tertile 2] vs. 4362 ± 1858 [tertile 3], p <0.001), whereas FCT was the thinnest in the tertile 3 (157.3 ± 73.0 μm vs. 104.0 ± 64.1 μm vs. 83.1 ± 34.7 μm, p <0.001, respectively). The tertile 3 had the highest prevalence of TCFA. Multiple linear regression analysis showed that MAGE had the strongest effect on LI and FCT (standardized coefficient β = 0.527 and −0.392, respectively, both P <0.001). Multiple logistic analysis identified MAGE as the only independent predictor of the presence of TCFA (odds ratio 1.034; P <0.001).

Conclusions

Glucose fluctuation and hypoglycemia may impact the formation of lipid-rich plaques and thinning of fibrous cap in CAD patients with lipid-lowering therapy.

Intermittent high glucose implements stress-induced senescence in human vascular endothelial cells: role of superoxide production by NADPH oxidase

Impaired glucose tolerance characterized by postprandial hyperglycemia, which occurs frequently in elderly persons and represents an important preliminary step in diabetes mellitus, poses an independent risk factor for the development of atherosclerosis. Endothelial cellular senescence is reported to precede atherosclerosis. We reported that continuous high glucose stimulus causes endothelial senescence more markedly than hypertension or dyslipidemia stimulus. In the present study, we evaluated the effect of fluctuating glucose levels on human endothelial senescence. Constant high glucose increased senescence-associated-β-galactosidase(SA-β-gal) activity, a widely used marker for cellular senescence. Interestingly, in intermittent high glucose, this effect was more pronounced as well as increase of p21 and p16^INK4a , senescence related proteins with DNA damage. However, telomerase was not activated and telomere length was not shortened, thus stress-induced senescence was shown. However, constant high glucose activated telomerase and shortened telomere length, which suggested replicative senescence. Intermittent but not constant high glucose strikingly up-regulated the expression of p22^phox, an NADPH oxidase component, increasing superoxide. The small interfering RNA of p22^phox undermined the increase in SA-β-gal activity induced by intermittent high glucose. Conclusively, intermittent high glucose can promote vascular endothelial senescence more than constant high glucose, which is in partially dependent on superoxide overproduction.

Treating coronary disease and the impact of endothelial dysfunction

Ischemic heart disease is the leading cause of morbidity and mortality throughout the world. Many clinical trials have suggested that lifestyle and pharmacologic interventions are effective in attenuating atherosclerotic disease progression and events development. However, an individualized approach with careful consideration to comprehensive vascular health is necessary to perform successful intervention strategies. Endothelial dysfunction plays a pivotal role in the early stage of atherosclerosis and is also associated with plaque progression and occurrence of atherosclerotic complications. The assessment of endothelial function provides us with important information about individual patient risk, progress and vulnerability of disease, and guidance of therapy. Thus, the application of endothelial function assessment might enable clinicians to innovate ideal individualized medicine. In this review, we summarize the current knowledge on the impact of pharmacological therapies for atherosclerotic cardiovascular disease on endothelial dysfunction, and argue for the utility of non-invasive assessment of endothelial function aiming at individualized medicine.

Glycemic variability and oxidative stress: a link between diabetes and cardiovascular disease?

Diabetes is associated with a two to three-fold increase in risk of cardiovascular disease. However, intensive glucose-lowering therapy aiming at reducing HbA1c to a near-normal level failed to suppress cardiovascular events in recent randomized controlled trials. HbA1c reflects average glucose level rather than glycemic variability. In in vivo and in vitro studies, glycemic variability has been shown to be associated with greater reactive oxygen species production and vascular damage, compared to chronic hyperglycemia. These findings suggest that management of glycemic variability may reduce cardiovascular disease in patients with diabetes; however, clinical studies have shown conflicting results. This review summarizes the current knowledge on glycemic variability and oxidative stress, and discusses the clinical implications.

Evaluation of endothelial function by peripheral arterial tonometry and relation with the nitric oxide pathway

Endothelial dysfunction is an important component in the development of cardiovascular diseases. Endothelial function may be evaluated by peripheral arterial tonometry (PAT) which measures the vasodilator function in the microvasculature of the fingertip during reactive hyperaemia. The reactive hyperaemia index (RHI) is decreased in the presence of cardiovascular risk factors and thus far several studies have shown that PAT-RHI may provide reliable prediction of outcome. The technique is operator independent and easy to perform. Abnormalities measured by PAT follow the same trend as those measured by flow-mediated dilation in the brachial artery, but the two methods are not interchangeable. We have reviewed the recent literature in an effort to evaluate peripheral arterial tonometry as a method to assess the function of the endothelium and additionally suggest directions for future research. Special attention will be directed to the nitric oxide dependency of the reactive hyperaemia index obtained by peripheral arterial tonometry.

Low levels of 1,5-anhydro-D-glucitol are associated with vascular endothelial dysfunction in type 2 diabetes

Background

Vascular endothelial dysfunction is involved in macrovascular disease progression in type 2 diabetes mellitus (T2DM). We reported previously that blood glucose fluctuations, as evaluated by continuous glucose monitoring (CGM), correlate with vascular endothelial function, serving as a marker of vascular endothelial function. However, the use of CGM is limited, suggesting the need for another marker of vascular endothelial function. Here, we investigated the relationship between vascular endothelial dysfunction and blood levels of 1,5-anhydro-D-glucitol (1,5-AG), a marker of both postprandial hyperglycemia and fluctuations in blood glucose.

Methods

In 32 inpatients with T2DM and HbA1c less than 8.0%, the reactive hyperemia index (RHI), an index of vascular endothelial function, was determined by peripheral arterial tonometry. The relationships between RHI and 1,5-AG, blood glucose, lipid metabolism markers, and blood pressure, were examined.

Results

There was a strong correlation between 1,5-AG and natural logarithmic-scaled RHI (L_RHI) (r = 0.55; P = 0.001). However, there was no correlation between L_RHI and HbA1c, fasting blood glucose, IRI, LDL-C, HDL-C, TG, systolic blood pressure, or diastolic blood pressure. Multivariate analysis identified blood 1,5-AG levels to be the only significant and independent determinant of L_RHI.

Conclusions

In T2DM with HbA1c <8.0%, low 1,5-AG levels were associated with vascular endothelial dysfunction, suggesting it is a potentially useful marker for vascular endothelial dysfunction.

Trial registration

UMIN000015317

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

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

Association of reduced levels of serum 1,5-Anhydro-d-glucitol with carotid atherosclerosis in patients with type 2 diabetes

BACKGROUND

HbA1c level represents mean blood glycemic control. 1,5-Anhydro-d-glucitol (1,5-AG) level reflects glycemic fluctuations, a strong risk factor for the development of macroangiopathy. The present study investigated the relationship between serum 1,5-AG levels and macroangiopathy in patients with type 2 diabetes.

METHODS

A total of 115 consecutive patients with type 2 diabetes, aged 45-79 years, were included. HbA1c, 1,5-AG, and lipid profile were measured. Carotid maximum intima-media thickness (IMT) and plaque score (PS) were determined by carotid sonography. An 1,5-AG level < 14.2 μg/mL was used as a predictor of a post-challenge 2-h blood glucose level > 200 mg/dL. Patients were divided into four groups: A (n=32), HbA1c ≥ 6.5% and 1,5-AG<14.2 μg/mL; B (n=23), HbA1c ≥ 6.5% and 1,5-AG ≥ 14.2 μg/mL; C (n=24), HbA1c < 6.5% and 1,5-AG <14.2 μg/mL; and D (n=36), HbA1c < 6.5% and 1,5-AG ≥ 14.2 μg/mL.

RESULTS

HbA1c level had significant positive correlation with IMT and PS. 1,5-AG level had a significant negative correlation with PS. PS was significantly higher in group C than in group D, but similar to that in group B. In multivariate analysis, HbA1c (β=0.27, p=0.03) and 1,5-AG (β=-0.24, P=0.04) were independent determinants of PS.

CONCLUSIONS

1,5-AG level might provide additional information to identify macroangiopathy of patients with type 2 diabetes, especially in those with excellent HbA1c levels.

The relationship between glycemic variability and diabetic peripheral neuropathy in type 2 diabetes with well-controlled HbA1c

BACKGROUND

Diabetic peripheral neuropathy (DPN) is one of the most common microvascular complications of diabetes. Glycemic variability could be an independent risk factor for diabetes complications in addition to average glucose. Type 2 diabetes with well-controlled glycosylated hemoglobin A1c (HbA1c) may have different terms of glycemic variability and vascular complication consequences. The aim of the study is to investigate the relationship between glycemic variability and DPN in type 2 diabetes with well-controlled HbA1c (HbA1c < 7.0%).

METHODS

45 type 2 diabetes with well-controlled HbA1c(HbA1c < 7.0%) and with DPN (DM/DPN group) were recruited in the study, and 45 type 2 diabetes with well-controlled HbA1c and without DPN (DM/-DPN group) were set as controls. The two groups were also matched for age and diabetic duration. Blood pressure, body mass index(BMI), insulin sensitivity index (Matsuda index, ISI), total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDLC), and low density lipoprotein cholesterol (LDLC) were tested in the two groups. And all patients were monitored using the continuous glucose monitoring (CGM) system for consecutive 72 hours. The multiple parameters of glycemic variability included the standard deviation of blood glucose (SDBG), mean of daily differences (MODD) and mean amplitude of glycemic excursions (MAGE).

RESULTS

The DM/DPN group had a greater SDBG, MODD and MAGE, when compared to the DM/-DPN group (p < 0.05). BMI, TC, and LDLC of DM/DPN group were lower than those of DM/-DPN group (p < 0.05). The patients with hypoglycemia were comparable between the two groups (p > 0.05). Univariate analysis showed DPN was closely associated with BMI (OR 0.82, CI 0.72-0.94, p = 0.005), TC (OR 0.63, CI 0.42-0.93, p = 0.02), LDLC (OR 0.4, CI 0.20-0.80, p = 0.009), SDBG (OR 2.95, CI 1.55-5.61, p = 0.001), MODD (OR 4.38, CI 1.48-12.93, p = 0.008), MAGE (OR 2.18, CI 1.47-3.24, p < 0.001). Multivariate logistic regression analysis showed that MAGE (OR 2.05, CI 1.36-3.09, p = 0.001) and BMI (OR 0.85, CI 0.73-0.99, p = 0.033) were significantly correlating with DPN. Glycemic variability, evaluated by MAGE, was the most significantly independent risk factor for DPN.

CONCLUSIONS

There was a close relationship between glycemic variability evaluated by MAGE and DPN in type 2 diabetes with well-controlled HbA1c.

The effects of glucose fluctuation on the severity of coronary artery disease in type 2 diabetes mellitus

OBJECTIVES

To explore the difference of glucose fluctuations between the normal subjects and diabetes mellitus (DM) patients and explore their impact on the development of CAD in type 2 DM patients.

METHODS

The subjects were divided into 3 groups: normal control (group A, n = 40), type 2 DM patients without cardiovascular complications (group B, n = 56), and type 2 DM patients with cardiovascular complications (group C, n = 92). The SYNTAX scores were collected in group C. CGMS for 72 h was applied on all the subjects. The indexes such as MBG and the LAGE were calculated. Glycemic excursions were compared between groups A, B, and C, respectively.

RESULTS

The tested indexes had significant differences among the three groups. SYNTAX scores are related to systolic blood pressure, CRP, MAGE, and HbA1c and are significantly correlated at 6:00-8:00 and 11:00-13:00 time points in group C.

CONCLUSIONS

Compared with normal subjects, T2DM patients have greater blood glucose fluctuations; T2DM patients with CAD have larger glucose fluctuations than T2DM patients without CAD. Blood glucose fluctuations are positively correlated with carotid artery intima-media thickness in T2DM patients and have a significant influence on the development of coronary artery.

Glycemic variability in relation to oral disposition index in the subjects with different stages of glucose tolerance

BACKGROUND

Glucose variability could be an independent risk factor for diabetes complications in addition to average glucose. The deficiency in islet β cell secretion and insulin sensitivity, the two important pathophysiological mechanisms of diabetes, are responsible for glycemic disorders. The oral disposition index evaluated by product of insulin secretion and sensitivity is a useful marker of islet β cell function. The aim of the study is to investigate glycemic variability in relation to oral disposition index in the subjects across a range of glucose tolerance from the normal to overt type 2 diabetes.

METHODS

75-g oral glucose tolerance test (OGTT) was performed in total 220 subjects: 47 with normal glucose regulation (NGR), 52 with impaired glucose metabolism (IGM, 8 with isolated impaired fasting glucose [IFG], 18 with isolated impaired glucose tolerance [IGT] and 26 with combined IFG and IGT), 61 screen-diagnosed diabetes by isolated 2-h glucose (DM2h) and 60 newly diagnosed diabetes by both fasting and 2-h glucose (DM). Insulin sensitivity index (Matsuda index, ISI), insulin secretion index (ΔI30/ΔG30), and integrated β cell function measured by the oral disposition index (ΔI30/ΔG30 multiplied by the ISI) were derived from OGTT. All subjects were monitored using the continuous glucose monitoring system for consecutive 72 hours. The multiple parameters of glycemic variability included the standard deviation of blood glucose (SD), mean of blood glucose (MBG), high blood glucose index (HBGI), continuous overlapping net glycemic action calculated every 1 h (CONGA1), mean of daily differences (MODD) and mean amplitude of glycemic excursions (MAGE).

RESULTS

From the NGR to IGM to DM2h to DM group, the respective values of SD (mean ± SD) (0.9 ± 0.3, 1.5 ± 0.5, 1.9 ± 0.6 and 2.2 ± 0.6 mmol/), MBG (5.9 ± 0.5, 6.7 ± 0.7, 7.7 ± 1.0 and 8.7 ± 1.5 mmol/L), HGBI [median(Q1-Q3)][0.8(0.2-1.2), 2.0(1.2-3.7), 3.8(2.4-5.6) and 6.4(3.2-9.5)], CONGA1 (1.0 ± 0.2, 1.3 ± 0.2, 1.5 ± 0.3 and 1.8 ± 0.4 mmol/L), MODD (0.9 ± 0.3, 1.4 ± 0.4, 1.8 ± 0.7 and 2.1 ± 0.7 mmol/L) and MAGE (2.1 ± 0.6, 3.3 ± 1.0, 4.3 ± 1.4 and 4.8 ± 1.6 mmol/L) were all increased progressively (all p < 0.05), while their oral disposition indices [745(546-947), 362(271-475), 203(134-274) and 91(70-139)] were decreased progressively (p < 0.05). In addition, SD, MBG, HGBI, CONGA1, MODD and MAGE were all negatively associated with the oral disposition index in each group (all p < 0.05) and in the entire data set (r = -0.66, -0.66, -0.72, -0.59, -0.61 and -0.65, respectively, p < 0.05).

CONCLUSIONS

Increased glycemic variability parameters are consistently associated with decreased oral disposition index in subjects across the range of glucose tolerance from the NGR to IGM to DM2h to DM group.