Glycaemic variability using continuous glucose monitoring and endothelial function in the metabolic syndrome and in Type 2 diabetes

Glycemic variability assessed using continuous glucose monitoring in individuals without diabetes and associations with cardiometabolic risk markers: A systematic review and meta-analysis

BACKGROUND & AIMS

Continuous glucose monitoring (CGM) provides data on short-term glycemic variability (GV). GV is associated with adverse outcomes in individuals with diabetes. Whether GV is associated with cardiometabolic risk in individuals without diabetes is unclear. We systematically reviewed the literature to assess whether GV is associated with cardiometabolic risk markers or outcomes in individuals without diabetes.

METHODS

Searches were performed in PubMed/Medline, Embase and Cochrane from inception through April 2022. Two researchers were involved in study selection, data extraction and quality assessment. Studies evaluating GV using CGM for ≥24 h were included. Studies in populations with acute and/or critical illness were excluded. Both narrative synthesis and meta-analyzes were performed, depending on outcome.

RESULTS

Seventy-one studies were included; the majority were cross-sectional. Multiple measures of GV are higher in individuals with compared to without prediabetes and GV appears to be inversely associated with beta cell function. In contrast, GV is not clearly associated with insulin sensitivity, fatty liver disease, adiposity, blood lipids, blood pressure or oxidative stress. However, GV may be positively associated with the degree of atherosclerosis and cardiovascular events in individuals with coronary disease.

CONCLUSION

GV is elevated in prediabetes, potentially related to beta cell dysfunction, but less clearly associated with obesity or traditional risk factors. GV is associated with coronary atherosclerosis development and may predict cardiovascular events and type 2 diabetes. Prospective studies are warranted, investigating the predictive power of GV in relation to incident disease. GV may be an important risk measure also in individuals without diabetes.

Comparative effects of fixed-dose mitiglinide/voglibose combination and glimepiride on vascular endothelial function and glycemic variability in patients with type 2 diabetes: A randomized controlled trial

INTRODUCTION

The aim of this study was to compare the effects of mitiglinide/voglibose with those of glimepiride on glycemic variability and vascular endothelial function in patients with type 2 diabetes.

MATERIALS AND METHODS

It was a multicenter, open-label, randomized, crossover study. Hospitalized patients received either mitiglinide/voglibose (three times daily administration of 10 mg mitiglinide and 0.2 mg voglibose) or glimepiride (once-daily 2 mg) in random order, each for 5 days. The reactive hyperemia index (RHI) and the mean amplitude of glycemic excursions (MAGE) were measured as co-primary endpoints using reactive hyperemia peripheral arterial tonometry and continuous glucose monitoring.

RESULTS

The analysis included 30 patients (15 in each group). The RHI was 1.670 ± 0.369 during treatment with mitiglinide/voglibose and 1.716 ± 0.492 during treatment with glimepiride, with no significant difference between the two. MAGE was significantly lower in the mitiglinide/voglibose group (47.6 ± 18.5 mg/dL) than in the glimepiride group (100.6 ± 32.2 mg/dL). Although the mean blood glucose levels over the entire 24 h period were comparable between the two groups, the use of mitiglinide/voglibose was associated with a lower standard deviation of mean glucose, coefficient of variation, and mean postprandial glucose excursion compared with glimepiride. The time below range (<70 mg/dL) and the time above range (>180, >200, and 250 mg/dL) were lower in the mitiglinide/voglibose group, while the time in range (70-180 mg/dL) was higher.

CONCLUSIONS

In our short-duration randomized crossover study, although not impacting vascular endothelial function, mitiglinide/voglibose demonstrated potential benefits in reducing glycemic variability, postprandial hyperglycemia, and hypoglycemia in patients with type 2 diabetes.

Glycemic variability: Measurement, target, impact on complications of diabetes and does it really matter?

Over the past two decades, there has been continuous advancement in the accuracy and complexity of continuous glucose monitoring devices. Continuous glucose monitoring provides valuable insights into blood glucose dynamics, and can record glucose fluctuations accurately and completely. Glycemic variability (GV) is a straightforward measure of the extent to which a patient's blood glucose levels fluctuate between high peaks and low nadirs. Many studies have investigated the relationship between GV and complications, primarily in the context of type 2 diabetes. Nevertheless, the exact contribution of GV to the development of diabetes complications remains unclear. In this literature review, we aimed to summarize the existing evidence regarding the measurement, target level, pathophysiological mechanisms relating GV and tissue damage, and population-based studies of GV and diabetes complications. Additionally, we introduce novel methods for measuring GV, and discuss several unresolved issues of GV. In the future, more longitudinal studies and trials are required to confirm the exact role of GV in the development of diabetes complications.

Impact of early postoperative blood glucose variability on serum endocan level in cardiac surgery patients: a sub study of the ENDOLUNG observational study

BACKGROUND

Early postoperative glycemic variability is associated with worse outcome after cardiac surgery, but the underlying mechanisms remain unknown. This study aimed to describe the relationship between postoperative glycemic variability and endothelial function, as assessed by serum endocan level in cardiac surgery patients.

METHODS

We performed a post hoc analysis of patients included in the single-center observational ENDOLUNG study. Adult patients who underwent planned isolated coronary artery bypass graft surgery were eligible. Postoperative glycemic variability was assessed by calculating the coefficient of variability (CV) of blood glucose measured within 24 (CV24) and 48 (CV48) hours after surgery. Serum endocan level was measured at 24 (Endocan24) and 48 (Endocan48) hours after surgery. Pearson's correlation coefficient with 95% confidence interval (95% CI) was calculated between CV24 and Endocan24, and between CV48 and Endocan48.

RESULTS

Data from 177 patients were analyzed. Median CV24 and CV48 were 18% (range 7 to 39%) and 20% (range 7 to 35%) respectively. Neither CV48 nor CV24 were significantly correlated to Endocan48 and Endocan24 respectively (r (95% CI) = 0.150 (0.001 to 0.290; and r (95% CI) = 0.080 (-0.070 to 0.220), respectively).

CONCLUSIONS

Early postoperative glycemic variability within 48 h after planned cardiac surgery does not appear to be correlated with postoperative serum endocan level.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02542423.

Higher metabolic variability increases the risk of depressive disorder in type 2 diabetes mellitus: a longitudinal nationwide cohort study

BACKGROUND AND OBJECTIVES

While variabilities in metabolic parameters (METv) have been linked to adverse health outcomes in type 2 DM, their association with depression is yet to be studied. This research aimed to investigate the association between METv and depressive disorder in patients with type 2 DM.

METHODS

The study involved a nationwide cohort of 1,119,631 type 2 DM patients who had undergone three or more serial health examinations between 2005 and 2012. At each visit, body mass index (BMI), fasting glucose (FG), systolic blood pressure (BP), and total cholesterol (TC) were measured and stratified into quartiles, with Q4 being the highest and Q1 the lowest. The risk of depressive disorder was evaluated using Cox proportional hazard regression models, which accounted for METs in the indexes, after adjusting for sex, income status, lifestyle habits, medical comorbidities, DM severity, and baseline levels of BMI, FG, BP, and TC.

RESULTS

During a mean follow-up period of 6.00 ± 2.42 years, 239,477 (21.4%) cases of type 2 DM patients developed depressive disorder. The risk of developing depressive disorder was gradually increased as the number of METv increased (HR 1.18; 95% CI 1.13, 1.23 for the group with the highest METv in all parameters compared to those with the lowest METv in all parameters). In the subgroup analysis, the risk of developing depressive disorder was 43% higher in men (HR 1.43; 95% CI 1.34, 1.51), and 31% higher in those younger than 65 years of age (HR 1.31; 95% CI 1.23, 1.39) in the group with the highest number of METv compared to the group with the lowest number of METv.

CONCLUSION

In type 2 DM, higher METv was an independent risk factor for depressive disorder. This risk is notably elevated in men and individuals under the age of 65 years.

Early glycaemic variability increases 28-day mortality and prolongs intensive care unit stay in critically ill patients with pneumonia

OBJECTIVE

This study aimed to evaluate the effect of early glycaemic variability (GV) on 28-day mortality in critically ill patients with pneumonia.

PATIENTS AND METHODS

This single-centre retrospective study included patients admitted to the intensive care unit (ICU) due to pneumonia between 2018 and 2019. A total of 282 patients (mean age, 68.6 years) with blood sugar test (BST) results measured more than three times within 48 h after hospitalization and haemoglobin A1c (HbA1c) levels recorded within 2 months were enrolled. Coefficient of variation (CV) was calculated using the BST values. The effects of GV on 28-day mortality and prolonged ICU stay (>14 days) were also assessed.

RESULTS

The mean age was 60.6 years (male to female ratio, 2.5:1). The 28-day mortality rate was 31.6% (n = 89) and was not different according to the presence of diabetes (DM vs. non-DM) or HbA1c levels (≥7.5 vs. <7.5%; both p > .05). However, the mortality rate was significantly higher in patients with high GV (CV ≥ 36%) than in those with low GV (CV < 36%; 37.5 vs. 25.4%, p = .028). The risk of mortality in patients with high GV was prominent in the subgroups with DM or low HbA1c levels. Among the surviving patients (n = 193), 44 remained in the ICU for more than 14 days. Compared to low GV, high GV was associated with a higher rate of prolonged ICU stay, although not statistically significant (27.8 vs. 18.5%, p = .171). After adjusting for the severity of illness and treatment strategy, CV was an independent risk factor for 28-day mortality (hazard ratio [HR], 1.01, p = .04) and prolonged ICU stay (odds ratio, 1.02; p = .04).

CONCLUSIONS

High GV within 48 h of ICU admission was associated with an increased 28-day mortality risk and prolonged ICU stay. Early phase GV should be carefully managed in critically ill patients with pneumonia.KEY MESSAGESThe presence of diabetes or HbA1c alone is insufficient to predict 28-day mortality and prolonged ICU stay in critically ill patients with pneumonia.High glycaemic variability (GV) within 48 h of ICU admission increases 28-day mortality and prolongs ICU stay, which is consistent after adjusting for severity of illness and treatment strategy.Patients with high GV, especially those with DM or low HbA1c levels (<7.5%) should be more carefully treated to reduce mortality.

Perioperative blood glucose variability and autonomic nervous system activity in on-pump cardiac surgery patients: Study protocol of a single-center observational study

INTRODUCTION

On-pump coronary artery bypass graft (CABG) and surgical valve replacement (SVR) are high-risk procedures. Several studies reported that perioperative blood glucose (BG) variability was independently associated with impaired postoperative outcome. However, the underlying mechanisms contributing to increased perioperative BG variability and to its deleterious impact remain unknown. The hypothesis of the study is that perioperative BG variability could be related to perioperative alteration of the autonomic nervous system (ANS) activity and to preoperative BG variability.

METHODS AND ANALYSIS

We designed a prospective observational single-center study. Four groups of 30 patients will be studied: group 1, including insulin-requiring type 2 diabetic patients undergoing on-pump CABG; group 2, including non-insulin-requiring type 2 diabetic patients undergoing on-pump CABG; group 3, including non-diabetic patients undergoing aortic SVR; and group 4, including non-diabetic patient undergoing on-pump CABG. Preoperative (baseline) and postoperative BG variability will be quantified using the Abbott's Freestyle Libre Pro sensor allowing for continuous subcutaneous BG monitoring. Preoperative (baseline) and postoperative ANS activity will be measured using noninvasive continuous heart rate monitoring (Mooky HR memory®). Blood level and urinary concentration of inflammatory and endothelial dysfunction biomarkers will be measured from blood and urinary samples at the end of the surgery and on postoperative day 1 and 2. The primary objective is to describe the relationship between baseline BG variability and postoperative BG variability. The secondary objectives are to describe the relationship: between baseline and postoperative BG variability according to the diabetes phenotype and to the type of surgery; between the ANS activity and the BG variability; and between postoperative BG variability and, urinary and blood biomarkers.

Continuous glucose monitoring metrics for earlier identification of pre-diabetes: protocol for a systematic review and meta-analysis

INTRODUCTION

Glycaemic variability and other metrics are not well characterised in subjects without diabetes. More comprehensive sampling as obtained with continuous glucose monitoring (CGM) may improve diagnostic accuracy of the transition from health to pre-diabetes. Our goal is to investigate the glycaemic system as it shifts from health to pre-disease in adult patients without diabetes using CGM metrics. New insights may offer therapeutic promise for reversing dysglycaemia more successfully with dietary, nutritional and lifestyle change before progression occurs to pre-diabetes and diabetes.

METHODS AND ANALYSIS

This systematic review will include comprehensive searches of the PubMed, Scopus, Cochrane Library and ClinicalTrials.gov databases, with restrictions set to studies published in the last 10 years in English and planned search date 10 March 2022. Reference lists of studies that meet eligibility criteria in the screening process will subsequently be screened for the potential inclusion of additional studies. We will include studies that examine CGM use and report diagnostic criteria such as fasting glucose and/or haemoglobin A1c such that we can assess correlation between CGM metrics and established diagnostic criteria and describe how CGM metrics are altered in the transition from health to pre-diabetes. The screening and data extraction will be conducted by two independent reviewers using Covidence. All included papers will also be evaluated for quality and publication bias using Cochrane Collaboration risk of bias tools. If there are two or more studies with quantitative estimates that can be combined, we will conduct a meta-analysis after assessing heterogeneity.

ETHICS AND DISSEMINATION

The systematic review methodology does not require formal ethical review due to the nature of the study design. Study findings will be publicly available and published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022308222.

Glycemic Variability Assessment with a 14-Day Continuous Glucose Monitoring System: When and How Long to Measure MAGE (Mean Amplitude of Glucose Excursion) for Optimal Reliability?

Mean amplitude of glucose excursion (MAGE) is considered as the "gold standard" for assessing the short-term within-day glycemic variability (GV), which is an important component of overall glycemic control. A 14-day continuous glucose monitoring system is now widely used and allows easier assessment of GV. However, it is still unknown whether MAGE, usually calculated on a 48-hour period is identical whatever the time during the 14-day lifespan of the sensor and whether a longer time period might give additional information. We evaluated in 68 patients with type 1 diabetes, MAGE during three 2-day periods (day1-day3; day6-day8; day11-day13) and during periods of 3 days and 4 days. MAGE calculated at the three 2-day periods were identical and not different from MAGE of the 3-day or 4-day periods.

Blood Glucose Fluctuation in Older Adults with Diabetes Mellitus and End-Stage Renal Disease on Maintenance Hemodialysis: An Observational Study

INTRODUCTION

Patients with diabetes mellitus and end-stage renal disease are at a high risk of developing coronary, cerebrovascular, and peripheral vascular diseases. This study aimed to characterize hypoglycemia and blood glucose fluctuations associated with maintenance hemodialysis in older adult patients with diabetes mellitus and end-stage renal disease using a continuous glucose monitoring system.

METHODS

Seven patients were enrolled in this study, and 13 pairs of continuous glucose monitoring system data were collected. Each pair included data of 1 dialysis-on day and 1 dialysis-off day. Information on basic patient characteristics, including age, diabetes mellitus duration, hemodialysis duration, and proportions of hemoglobin A1c and glycated albumin, were collected. Differences in blood glucose fluctuation were compared between dialysis-on days and dialysis-off days.

RESULTS

The mean blood glucose on dialysis-on days (6.96 ± 2.57 mmol/L) was significantly lower than that on dialysis-off days (7.68 ± 2.31 mmol/L; P < 0.05). In contrast, the following parameters had significantly higher values (all P < 0.05) on dialysis-on days compared to dialysis-off days: large amplitude of glycemic excursion level (5.82 ± 2.86 mmol/L versus 4.21 ± 1.71 mmol/L), large amplitude of glycemic excursion level from 8 a.m. to 2 p.m. (3.6 ± 1.74 mmol/L versus 2.8 ± 1.33 mmol/L), mean amplitude of glycemic excursion level (4.78 ± 1.68 mmol/L versus 3.89 ± 1.67 mmol/L), mean amplitude of glycemic excursion level from 8 a.m. to 2 p.m. (4.01 ± 1.03 mmol/L versus 3.12. ± 0.97 mmol/L), standard deviation of blood glucose (1.55 ± 0.89 mmol/L versus 1.03 ± 0.4 mmol/L), and time below a target glucose range of less than 3.9 mmol/L (8.27% versus 4.25%).

CONCLUSION

Fluctuations in blood glucose levels were larger on dialysis-on days, particularly from the start of hemodialysis to 2 h post-hemodialysis, than on dialysis-off days. Hypoglycemia, as indicated by the time below a target glucose range of less than 3.9 mmol/L, occurred more frequently on dialysis-on days than on dialysis-off days.

Glycaemia dynamics in gestational diabetes mellitus

Pregnant women may develop gestational diabetes mellitus (GDM), a disease of pregnancy characterised by maternal and fetal hyperglycaemia with hazardous consequences to the mother, the fetus, and the newborn. Maternal hyperglycaemia in GDM results in fetoplacental endothelial dysfunction. GDM-harmful effects result from chronic and short periods of hyperglycaemia. Thus, it is determinant to keep glycaemia within physiological ranges avoiding short but repetitive periods of hyper or hypoglycaemia. The variation of glycaemia over time is defined as 'glycaemia dynamics'. The latter concept regards with a variety of mechanisms and environmental conditions leading to blood glucose handling. In this review we summarized the different metrics for glycaemia dynamics derived from quantitative, plane distribution, amplitude, score values, variability estimation, and time series analysis. The potential application of the derived metrics from self-monitoring of blood glucose (SMBG) and continuous glucose monitoring (CGM) in the potential alterations of pregnancy outcome in GDM are discussed.

Metabolic syndrome associated with higher glycemic variability in type 1 diabetes: A multicenter cross-sectional study in china

AIMS

The comorbidity of metabolic syndrome (MetS) and type 1 diabetes mellitus (T1DM) is an obstacle to glucose control in patients with T1DM. We compared glycemic profiles using continuous glucose monitoring (CGM) systems in patients with T1DM with or without MetS.

METHODS

This was a multicenter cross-sectional study of patients with T1DM (N = 207) with or without MetS. CGM data were collected from study enrollment until discharge during a 1-week study session. We analyzed baseline HbA1c, average glucose, estimated HbA1c, time in range (TIR), time above range (TAR), time below range (TBR), coefficient of variation (CV), postprandial glucose excursions (PPGE) and other glycemic variability (GV) metrics. Logistic regression was developed to investigate the association between MetS and CGM metrics.

RESULTS

The results showed higher average baseline HbA1c levels, and a higher percentage of patients with baseline HbA1c levels ≥7.5%, in the T1DM with MetS group. Furthermore, MetS was associated with GV, which indicated a higher CV in patients with T1DM with MetS. However, our results showed that TAR, TIR, TBR and other GV metrics were comparable between the two groups. The T1DM with MetS group also had a higher proportion of patients with high CV (≥ 36%) than the group without MetS. In multivariable logistic regression analysis, the presence of MetS was a risk factor for high CV (≥ 36%) in our study participants.

CONCLUSIONS

T1DM patients with MetS in our study had better β-cell function. However, MetS was associated with worse glycemic control characterized by higher GV and HbA1c levels. Efforts should be expanded to improve treatment of MetS in patients with T1DM to achieve better glycemic control.

Metabolic and sympathovagal effects of bolus insulin glulisine versus basal insulin glargine therapy in people with type 2 diabetes: A randomized controlled study

AIMS/INTRODUCTION

This study compares the effects of two different insulin regimens - basal versus bolus insulin - on metabolic and cardiovascular autonomic function in Japanese participants with type 2 diabetes.

MATERIALS AND METHODS

Participants were randomly assigned to groups for therapy with insulin glulisine (IGlu) or insulin glargine (IGla). The primary efficacy end-point was glycemic variability, including M-values, mean of glucose levels, and a blood glucose profile of seven time points before and after the intervention. The secondary end-points included pleiotropic effects, including endothelial and cardiac autonomic nerve functions.

RESULTS

Blood glucose levels at all time points significantly decreased in both groups. Post-lunch, post-dinner, and bedtime blood glucose levels were significantly lower in the IGlu group than in the IGla group. Nadir fasting blood glucose levels at the end-point were significantly lower in the IGla group than in the IGlu group. The M-value and mean blood glucose levels were significantly decreased from baseline in both groups, although the former was significantly lower in the IGlu group than in the IGla group. IGla, but not IGlu, was found to elevate 24-h parasympathetic tone, especially during night-time, and it decreased 24-h sympathetic nerve activity, especially at dawn.

CONCLUSIONS

Both IGlu and IGla regimens reduced glucose variability, with IGlu bringing a greater reduction in M-value. IGla, but not IGlu, increased parasympathetic tone during night-time and decreased sympathetic nerve activity at dawn. These findings shed light on the previously unrecognized role of night-time basal insulin supplementation on sympathovagal activity in type 2 diabetes patients.

The effects of breaking sedentary time with different intensity exercise bouts on energy metabolism: A randomized cross-over controlled trial

BACKGROUND AND AIMS

Breaking up sedentary periods, particularly with light activity, increases total energy expenditure (EE), and helps provide better glycemic control. However, the effects of activities of various intensities to interrupt prolonged sedentary time are unclear. The purpose of the present study was to examine potential differences in glycemic control and EE from breaking up sedentary time with short exercise bouts of different intensities.

METHODS AND RESULTS

Nine overweight/obesity young men underwent whole body indirect calorimetry at 19:00 on day 1 and stayed overnight. After awakening on day 2, they performed short duration jogging every 30 min over 8 h (16-time bouts in total) under 3 different conditions with the same running distance: (1) lactate threshold (LT) for 2 min, (2) 60% LT for 200 s, and (3) onset of blood lactate accumulation (OBLA) for 75 s. The 24-h EE and interstitial glucose concentration (from 8:00 to 19:00 on day 2) was continuously measured throughout the trials. The standard deviation during intervention and indexes of postprandial of the interstitial glucose concentration was significantly lower at LT and OBLA than at 60% LT (p < 0.05). The 24-h EE was not significantly different among conditions, but EE at OBLA during intervention was slightly but significantly higher than at 60% LT and LT.

CONCLUSION

Breaking up sedentary time with short-duration jogging at LT and with OBLA intensities may have better glycemic control and increased use of carbohydrate as a fuel, while short-duration a jogging at OBLA intensity may increase EE.

TRIAL REGISTRATION

UMIN000041361.

Associations of continuous glucose monitoring-assessed glucose variability with intima-media thickness and ultrasonic tissue characteristics of the carotid arteries: a cross-sectional analysis in patients with type 2 diabetes

BACKGROUND

The association between glucose variability and the progression of atherosclerosis is not completely understood. We aimed to evaluate the associations of glucose variability with the progression of atherosclerosis in the early stages.

METHODS

We conducted a cross-sectional analysis to investigate the associations of glucose variability, assessed by continuous glucose monitoring, with intima-media thickness (IMT) and gray-scale median (GSM) of the carotid arteries, which are different indicators for the progression of atherosclerosis. We used baseline data from a hospital-based multicenter prospective observational cohort study among Japanese patients with type 2 diabetes without a history of cardiovascular diseases aged between 30 and 80 years. Continuous glucose monitoring was performed by Freestyle Libre Pro, and glucose levels obtained every 15 min for a maximum of eight days were used to calculate the metrics of glucose variability. IMT and GSM were evaluated by ultrasonography, and the former indicates thickening of intima-media complex in the carotid artery wall, while the latter indicates tissue characteristics.

RESULTS

Among 600 study participants (age: 64.9 ± 9.2 (mean ± SD) years; 63.2%: men; HbA1c: 7.0 ± 0.8%), participants with a larger intra- and inter-day glucose variability had a lower GSM and most of these associations were statistically significant. No trend based on glucose variability was shown regarding IMT. Standard deviation of glucose (regression coefficient, β = - 5.822; 95% CI - 8.875 to - 2.768, P < 0.001), glucose coefficient of variation (β = - 0.418; - 0.685 to - 0.151, P = 0.002), mean amplitude of glycemic excursion (β = - 1.689; - 2.567 to - 0.811, P < 0.001), mean of daily differences (β = - 6.500; - 9.758 to - 3.241, P < 0.001), and interquartile range (β = - 4.289; - 6.964 to - 1.614, P = 0.002) had a statistically significant association with mean-GSM after adjustment for conventional cardiovascular risk factors, including HbA1c. No metrics of glucose variability had a statistically significant association with IMT.

CONCLUSIONS

Continuous glucose monitoring-assessed glucose variability was associated with the tissue characteristics of the carotid artery wall in type 2 diabetes patients without cardiovascular diseases.

Acute Effects of Cocoa Flavanols on Blood Pressure and Peripheral Vascular Reactivity in Type 2 Diabetes Mellitus and Essential Hypertension: A Protocol for an Acute, Randomized, Double-Blinded, Placebo-Controlled Cross-Over Trial

Introduction: Patients with type 2 diabetes mellitus are at high risk to develop vascular complications resulting in high morbidity and mortality. Cocoa flavanols are promising nutraceuticals with possible beneficial vascular effects in humans. However, limited research is currently available on the vascular effects in a diabetic population with inconsistent results. Possible reasons for this inconsistency might be heterogeneity in the given intervention (dose per time and day, single dose vs. split-dose, placebo formula) and the studied population (blood pressure at baseline, duration of diabetes, use of vasoactive antihypertensive and antidiabetic drugs, sex). Therefore, we aimed to develop a randomized, double-blinded, placebo-controlled cross-over trial to investigate whether cocoa flavanols have an acute impact on blood pressure and vascular reactivity in patients with type 2 diabetes with and without arterial hypertension.

Methods and Analysis: We will include participants in four groups: (i) patients with type 2 diabetes without arterial hypertension, (ii) patients with type 2 diabetes with arterial hypertension and 1 antihypertensive drug, (iii) non-diabetic participants with essential hypertension and 1 antihypertensive drug, and (iv) healthy controls. All participants will complete the same protocol on both testing days, consuming high-flavanol cocoa extract (790 mg flavanols) or placebo. Macrovascular endothelial function (flow-mediated dilation) and blood pressure will be measured before and after capsule ingestion. Forearm muscle vasoreactivity (near-infrared spectroscopy) and brachial artery blood flow (echo-doppler) will be assessed in response to a dynamic handgrip exercise test after capsule ingestion. Data will be analyzed with a random intercept model in mixed models.

Clinical Trial Registration:www.Clinicaltrials.gov, identifier: NCT03722199.

Repetitive Intermittent Hyperglycemia Drives the M1 Polarization and Inflammatory Responses in THP-1 Macrophages Through the Mechanism Involving the TLR4-IRF5 Pathway

Repetitive intermittent hyperglycemia (RIH) is an independent risk factor for complications associated with type-2 diabetes (T2D). Glucose fluctuations commonly occur in T2D patients with poor glycemic control or following intensive therapy. Reducing blood glucose as well as glucose fluctuations is critical to the control of T2D and its macro-/microvascular complications. The interferon regulatory factor (IRF)-5 located downstream of the nutrient sensor toll-like receptor (TLR)-4, is emerging as a key metabolic regulator. It remains unclear how glucose fluctuations may alter the IRF5/TLR4 expression and inflammatory responses in monocytes/macrophages. To investigate this, first, we determined IRF5 gene expression by real-time qRT-PCR in the white adipose tissue samples from 39 T2D and 48 nondiabetic individuals. Next, we cultured THP-1 macrophages in hypo- and hyperglycemic conditions and compared, at the protein and transcription levels, the expressions of IRF5, TLR4, and M1/M2 polarization profile and inflammatory markers against control (normoglycemia). Protein expression was assessed using flow cytometry, ELISA, Western blotting, and/or confocal microscopy. IRF5 silencing was achieved by small interfering RNA (siRNA) transfection. The data show that adipose IRF5 gene expression was higher in T2D than nondiabetic counterparts (p = 0.006), which correlated with glycated hemoglobin (HbA1c) (r = 0.47/p < 0.001), homeostatic model assessment of insulin resistance (HOMA-IR) (r = 0.23/p = 0.03), tumor necrosis factor (TNF)-α (r = 0.56/p < 0.0001), interleukin (IL)-1β (r = 0.40/p = 0.0009), and C-C motif chemokine receptor (CCR)-2 (r = 0.49/p < 0.001) expression. IRF5 expression in macrophages was induced/upregulated (p < 0.05) by hypoglycemia (3 mM/L), persistent hyperglycemia (15 mM/L–25 mM/L), and RIH/glucose fluctuations (3–15 mM/L) as compared to normoglycemia (5 mM/L). RIH/glucose fluctuations also induced M1 polarization and an inflammatory profile (CD11c, IL-1β, TNF-α, IL-6, and monocyte chemoattractant protein (MCP)-1) in macrophages. RIH/glucose fluctuations also drove the expression of matrix metalloproteinase (MMP)-9 (p < 0.001), which is a known marker for cardiovascular complication in T2D patients. Notably, all these changes were counteracted by IRF5 silencing in macrophages. In conclusion, RIH/glucose fluctuations promote the M1 polarization and inflammatory responses in macrophages via the mechanism involving TLR4-IRF5 pathway, which may have significance for metabolic inflammation.

Longitudinal Average Glucose Levels and Variance and Risk of Stroke: A Chinese Cohort Study

BACKGROUND

Diabetes is a known independent risk factor for stroke. However, whether higher glucose levels (126-139.9 mg/dl) can increase the risk of stroke in people without diabetes is still unknown. Moreover, as a fluctuating parameter, long-term glucose levels may also be related to the risk of stroke outcome. It is important to explore the correlation between long-term average blood glucose, as well as its variability, and stroke.

METHODS

We used 40,975 clinical measurements of glucose levels and 367 measurements of glycated hemoglobin A1c levels from 12,321 participants without stroke to examine the relationship between glucose levels and the risk of stroke. Participants were from the Weitang Geriatric Diseases study, including 5,707 men and 6,614 women whose mean age at baseline was 60.8 years; 1,011 participants had diabetes, and 11,310 did not. We estimated the long-term average blood glucose level based on the multilevel Bayesian model and fit in Cox regression models, stratified according to diabetes status.

RESULTS

Over a median follow-up period of 5 years, stroke developed in 279 of the 12,321 participants (244 without diabetes and 35 with). For people with an average glucose level of 126-139.9 mg per deciliter, compared with 90-99.9 mg per deciliter, the adjusted hazard ratio (HR) for total stroke was 1.78 (95% confidence interval (CI), 1.16-2.75), and the HR for levels higher than 140 mg per deciliter was 1.89 (95% CI, 1.09-3.29). Among those without diabetes whose glucose level was higher than 140 mg per deciliter, compared with 90-99.9 mg per deciliter, the adjusted HRs for total stroke and fatal stroke were 3.66 (95% CI, 1.47-9.08) and 5 (95% CI, 1.77-14.15), respectively. For a glucose standard deviation level higher than 13.83 mg per deciliter, compared with that lower than 5.91 mg per deciliter, the adjusted HR for total stroke was 2.31 (95% CI, 1.19-4.48).

CONCLUSIONS

Our results suggest that higher average glucose levels (126-139.9 mg/dl) and variance may be risk factors for stroke, even among people without diabetes diagnosis.

Reducing Type 1 Diabetes Mortality: Role for Adjunctive Therapies?

Individuals with type 1 diabetes (T1D) frequently fail to achieve glycemic goals and have excess cardiovascular risk and premature death. Adjunctive agents may play a role in reducing morbidity, mortality, and the adverse sequelae of insulin treatment. A surge in type 2 diabetes drug development has revealed agents with benefits beyond glucose lowering, including cardiovascular risk reduction. Could these benefits translate to T1D? Specific trials for T1D demonstrate substantial hemoglobin (Hb)A1c reductions with sodium glucose cotransporter inhibitors (SGLTis) and glucagon-like peptide (GLP)1 agonists, and modest improvements with metformin, dipeptidyl peptidase-4 inhibitor (DPP4i), and pramlintide. Studies exploring cardiovascular risk reduction are warranted. This review synthesizes the emerging literature for researchers and clinicians treating people with T1D. Challenges in T1D research are discussed.

Metabolic and Cardiovascular Effects of Switching Thiazides to Amlodipine in Hypertensive Patients With and Without Type 2 Diabetes (the Diuretics and Diabetes Control Study)

Background: Different studies have indicated that thiazide diuretics can increase the risk of developing type 2 diabetes (T2D). Therefore, in this study, we investigated whether switching from hydrochlorothiazide (HCTZ) to amlodipine resulted in ameliorating different cardiovascular and metabolic measures in hypertensive patients with or without T2D. Methods: This study [Diuretics and Diabetes Control (DiaDiC)] was a 6-week, single-blind, single-center randomized controlled trial. The first 20 normal glucose-tolerant, 20 prediabetic, and 20 T2D consecutive patients were randomized to continue the previous antihypertensive treatment with HCTZ (12.5-25 mg/day) or to switch from HCTZ to amlodipine (2.5-10 mg/day). The primary endpoints were the absolute change in 7-day continuous subcutaneous glucose monitoring (CSGM) glycemia, serum uric acid concentrations, and endothelial function [measured as flow-mediated dilation (FMD)]. Other secondary endpoints were investigated, including changes in glycated hemoglobin (HbA₁c), glycemic variability from 7-day CSGM, and the estimated glomerular filtration rate (eGFR). Results: Amlodipine treatment was associated with a significant reduction in HbA₁c (P = 0.03) for both 7-day CSGM glycemia (P = 0.01) and glycemic variability (coefficient of variability %: HCTZ +3%, amlodipine -2.8%), and a reduction in uric acid concentrations (P < 0.001), especially in participants with T2D or prediabetes. Following amlodipine treatment, a significant increase in both eGFR (P = 0.01) and FMD (P = 0.02) was also observed. Conclusions: This study demonstrates that the replacement of HCTZ with amlodipine has several metabolic and cardiovascular beneficial effects. However, further intervention studies are necessary to confirm the clinical effects of thiazides, especially in diabetic people and in those at risk of diabetes.

The efficacy of glycemic control with continuous glucose monitoring on atheroma progression: rationale and design of the Observation of Coronary Atheroma Progression under Continuous Glucose Monitoring Guidance in Patients with Type 2 Diabetes Mellitus (OPTIMAL)

Background

Patients with type 2 diabetes mellitus (T2DM) are high-risk subjects who more frequently have micro- and macrovascular diseases including coronary artery disease (CAD). Since impaired glycemic homeostasis directly influences the formation and propagation of atherosclerotic plaques, optimal management of glycemic status is required for the prevention of diabetic atherosclerosis. Continuous glucose monitoring (CGM) provides not only average glucose level but also the degree of glucose fluctuation and hypoglycemia. Given the association of glycemic variability with diabetic macrovascular diseases, CGM-based glycemic management could favorably modulate glycemic fluctuation, thereby potentially modifying atheroma burden in T2DM subjects. To test this hypothesis, the Observation of Coronary Atheroma Progression under Continuous Glucose Monitoring Guidance in Patients with Type 2 Diabetes Mellitus (OPTIMAL) study has been designed (Japan Registry of Clinical Trials: jRCT1052180152, University Hospital Medical Information Network Clinical Trial Registry UMIN000036721).

Methods

The OPTIMAL is a single-center, randomized trial to evaluate the efficacy of CGM-based glycemic control on atheroma progression in T2DM patients with CAD by using serial intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) imaging. A total of 90 eligible subjects will be randomized 1:1 into two groups to receive either CGM-based glycemic control or HbA1c-baded glycemic management. Coronary angiography and NIRS/IVUS imaging is repeated at the end of the assigned treatment period.

Results

The primary endpoint is the normalized absolute change in total atheroma volume (TAV) from baseline to 12 months. The secondary endpoints include (I) the absolute change in percent atheroma volume, (II) the percent change in lipid core burden index, (III) the change in coefficient variance measured by CGM, (IV) the change in atherogenic markers (high-density lipoprotein functionality, proprotein convertase subxilisin/kexin type 9 and fatty-acid binding proteins), and (V) the frequency of hypoglycemia. Safety will also be evaluated.

Conclusions

The collaboration of CGM use with serial NIRS/IVUS imaging will enable to compare atheroma progression rate under CGM-based glycemic management and HbA1c-based approach.

The continuums of impairment in vascular reactivity across the spectrum of cardiometabolic health: A systematic review and network meta-analysis

This study aimed to assess, for the first time, the change in vascular reactivity across the full spectrum of cardiometabolic health. Systematic searches were conducted in MEDLINE and EMBASE databases from their inception to March 13, 2017, including studies that assessed basal vascular reactivity in two or more of the following health groups (aged ≥18 years old): healthy, overweight, obesity, impaired glucose tolerance, metabolic syndrome, or type 2 diabetes with or without complications. Direct and indirect comparisons of vascular reactivity were combined using a network meta-analysis. Comparing data from 193 articles (7226 healthy subjects and 19344 patients), the network meta-analyses revealed a progressive impairment in vascular reactivity (flow-mediated dilation data) from the clinical onset of an overweight status (-0.41%, 95% CI, -0.98 to 0.15) through to the development of vascular complications in those with type 2 diabetes (-4.26%, 95% CI, -4.97 to -3.54). Meta-regressions revealed that for every 1 mmol/l increase in fasting blood glucose concentration, flow-mediated dilation decreased by 0.52%. Acknowledging that the time course of disease may vary between patients, this study demonstrates multiple continuums of vascular dysfunction where the severity of impairment in vascular reactivity progressively increases throughout the pathogenesis of obesity and/or insulin resistance, providing information that is important to enhancing the timing and effectiveness of strategies that aim to improve cardiovascular outcomes.

Glycemic variability in the development of cardiovascular complications in diabetes

Diabetes mellitus represents a major risk factor for the development of coronary artery disease and other vascular complications. Glycated haemoglobin, fructosamine, and fasting blood glucose levels are partial parameters to exhaustively describe patient dysglycemic status. Thus, recently the new concept of glycemic variability has emerged, including information about two major aspects: the magnitude of blood glucose excursions (from nadir to peak, thus lower and higher spikes) and the time intervals in which these fluctuations occur. Despite the lack of consensus regarding the most appropriate definition and tools for its assessment, glycemic variability seems to have more deleterious effects than sustained hyperglycemia in the pathogenesis of diabetic cardiovascular complications. This manuscript aimed to review the most recent evidence on glycemic variability and its potential use in everyday clinical practice to identify diabetic patients at higher risk of cardiovascular complications and thus needing stricter monitoring and treatment.

Mealtime dosing of a rapid-acting insulin analog reduces glucose variability and suppresses daytime cardiac sympathetic activity: a randomized controlled study in hospitalized patients with type 2 diabetes

OBJECTIVE

Glucose variability induces endothelial dysfunction and cardiac autonomic nerve abnormality. Here we compared the effects of mealtime insulin aspart and bedtime insulin detemir on glucose variability, endothelial function, and cardiac autonomic nerve activity among Japanese patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Forty hospitalized patients received either mealtime insulin aspart or bedtime insulin detemir treatment for 2 weeks. We assessed glucose variability indices, including M-value, SD of blood glucose level, and mean blood glucose (MBG) level. Flow-mediated dilation (FMD) of the brachial artery was measured as an index of endothelial function. Low-frequency power, high-frequency power, and the low-frequency to high-frequency power ratio (LF:HF ratio) derived via heart rate variability analysis using a Holter ECG were employed as indices of cardiac autonomic nerve function.

RESULTS

M-values and MBG levels showed a considerably greater decrease in the insulin aspart group than in the insulin detemir group (p=0.006  vs p=0.001); no change in FMD was observed in either group. Daytime LF:HF ratio significantly decreased in the insulin aspart group but not in the insulin detemir group. Total insulin dose at endpoint in the insulin aspart group was significantly higher than that in the insulin detemir group (p<0.001).

CONCLUSIONS

Mealtime insulin aspart reduced glucose variability to a greater extent than bedtime insulin detemir in patients with type 2 diabetes. Despite the need for higher insulin doses, insulin aspart decreased daytime cardiac sympathetic nerve activity. These properties may subsequently help reduce cardiovascular risks.

TRIAL REGISTRATION NUMBER

UMIN000008369.

Continuous glucose monitoring is more sensitive than HbA1c and fasting glucose in detecting dysglycaemia in a Spanish population without diabetes

AIMS

To investigate whether continuous glucose monitoring (CGM) reveals patterns of glycaemic behaviour, the detection of which might improve early diagnosis of dysglycaemia.

METHODS

A total 1521 complete days of valid CGM data were recorded under real-life conditions from a healthy sample of a Spanish community, as were matching FPG and HbA1_C data. No participant was pregnant, had a history of kidney or liver disease, or was taking drugs known to affect glycaemia.

RESULTS

CGM and fingerstick measurements showed a mean relative absolute difference of 6.9 ± 2.2%. All subjects were normoglycaemic according to FPG and HbA_1C except 21% who were prediabetic. The normoglycaemic subjects had a 24-hour mean blood glucose concentration (MBG) of 5.7 ± 0.4 mmol/L, spending a median of 97% of their time within the target range (3.9-7.8 mmol/L). 73% of them experienced episodes with blood glucose levels above the threshold for impaired glucose tolerance, and 5% levels above the threshold for diabetes. These normoglycaemic participants with episodes of high glycaemia had glycaemic variabilities similar to those of prediabetic subjects with episodes of similar intensity or combined duration.

CONCLUSIONS

CGM is a better indicator of possible early dysglycaemia than either FPG or HbA1c.

Effect of the GSTM1 gene deletion on glycemic variability, sympatho-vagal balance and arterial stiffness in patients with metabolic syndrome, but without diabetes

AIMS

An increased rate of cerebrovascular complications in patients with metabolic syndrome (MetS) has been reported. Previous studies demonstrated an association between glycemic variability (GV) and cerebrovascular reactivity (CRV) in MetS, thus suggesting a putative role of GV on cerebrovascular events. Although the pathophysiological mechanism linking GV to damage is still to be elucidated, evidence suggests oxidative stress plays a crucial role. Since functional variants in glutathione S-transferases (GST) genes modulate the cellular detoxification processes, the aim of this study was to elucidate the involvement of GSTs in MetS and investigating the correlation with GV, arterial stiffness, and sympatho-vagal (SV) balance.

METHODS

A hundred metabolic syndrome patients without diabetes underwent GST gene polymorphism analysis and a sub-sample 36 patients were randomly selected to investigate the correlation between GST gene polymorphisms and GV, and sympatho-vagal (SV) balance and arterial stiffness.

RESULTS

GSTM1 showed a significant association with several GV, arterial stiffness, and SV balance indexes. In particular, the GSTM1 deletion positively correlates with lower values of these indexes when compared to the presence of the gene.

CONCLUSIONS

Therefore, we suggested a global influence of GSTM1 deletion on the GV, arterial stiffness, and SV balance pathways in MetS patients, probably also interacting with AMP-activated protein kinase (AMPK) regulation. Our novel findings indicate GSTM1 could be a risk locus in MetS development and shed light novel scenarios on the role of glucose fluctuations in neurological impairments.

Analysis of Postprandial Glycemia in Relation to Metabolic Compensation and Other Observed Parameters of Outpatients with Type 2 Diabetes Mellitus in the Czech Republic

INTRODUCTION

The goal of the study was to determine the level of metabolic compensation expressed by glycosylated hemoglobin, fasting plasma glucose, and postprandial glucose as determined after a standardized breakfast; further, to evaluate interrelationships between the studied parameters and postprandial glucose levels.

METHODS

The study included 1055 patients with type 2 diabetes mellitus. Their fasting plasma glucose and postprandial glucose were measured before and after a standardized breakfast. Attending diabetologists completed a uniform questionnaire that included demographic data, type of antidiabetic treatment, duration of diabetes, latest glycosylated hemoglobin value, presence of dyslipidemia, and organic complications.

RESULTS

Glycosylated hemoglobin < 53 mmol/mol was achieved in 363 (34.2%), postprandial glucose < 7.5 mmol/l in 211 (19.9%), and fasting plasma glucose < 6 mmol/l in 251 (23.7%) patients. Excellent metabolic compensation, indicated by all the above mentioned glycosylated hemoglobin, fasting plasma glucose, and postprandial glucose values simultaneously, was achieved in only 71 (6.7%) patients. Comparable to fasting plasma glucose and postprandial glucose values, correlation with glycosylated hemoglobin levels is statistically significant; however, there is no difference at different glycosylated hemoglobin levels. There was a significant correlation between dyslipidemia and postprandial glycemia (p = 0.013).

CONCLUSION

The objective of care for patients with diabetes mellitus is to improve their long-term metabolic compensation; to that end, both fasting plasma glucose and postprandial glucose deserve equal attention.

Targeting postprandial glycaemia in children with diabetes: Opportunities and challenges

Postprandial glycaemia makes a substantial contribution to overall glycaemic control in diabetes, particularly in patients whose preprandial glycaemia is relatively well controlled and glycated haemoglobin (HbA1c) only modestly elevated. Our review addresses the determinants of postprandial glycaemia and how it may be targeted therapeutically in children with diabetes. Postprandial glycaemia is influenced by preprandial glycaemia, macronutrients and their absorption, insulin delivery and sensitivity, the action of the enteroendocrine system, and the rate of gastric emptying. Contemporary continuous glucose monitoring systems reveal patterns of post prandial glycaemia and allow management to be guided more precisely. Delays in blood glucose determination, insulin delivery and its absorption remain challenges in the rapidly evolving closed loop continuous subcutaneous insulin and glucagon delivery systems developed for children with type 1 diabetes. Augmentation of the incretin system through nutritional preloads or incretin mimetics targets postprandial glycaemia by slowing gastric emptying as well as insulinotropic and glucagonostatic effects. These treatments are of particular relevance to children with type 2 diabetes. Following the development of targeted therapies in adults, postprandial blood glucose control will now be increasingly targeted in the treatment of diabetes in children.

The Relationship Between Glycemic Variability and Inflammatory Markers in Obese Children with Insulin Resistance and Metabolic Syndrome

OBJECTIVE

Increased glycemic variability (GV) is associated with increased oxidative stress, vascular complications, and mortality in metabolic syndrome (MS) and diabetes mellitus patients. To investigate the relationship between GV and inflammatory parameters in obese children with insulin resistance (IR) and to elucidate their effects on the development of MS.

METHODS

Fifty obese adolescents with IR were included in the study. All patients underwent anthropometric measurements, body fat analysis, and continuous glucose monitoring system (CGMS) for 24 hours. Serum lipids, adiponectin, and interleukin-6 (IL-6) levels were measured. GV coefficient (GVC) was calculated using the standard deviation and the average glucose value obtained by CGMS. IR was diagnosed according to the results of oral glucose tolerance test (OGTT). MS was diagnosed according to the modified World Health Organization and the International Diabetes Federation criteria.

RESULTS

Twenty-seven of the patients had MS and the remaining had only IR. Body fat mass, HbA1c, IL-6 levels, and peak insulin levels in the OGTT were significantly higher in the group with MS, but there was no difference in adiponectin levels. GVC was not different between the groups, but GVC significantly positively correlated with homeostasis model of assessment for IR, as well as with fasting, peak, and total insulin levels when all the patients were analyzed, while no significant relation was detected with adiponectin and IL-6 levels.

CONCLUSION

This study suggests that GV is not different among obese adolescents with IR and MS. There seems to be a significant association between GV and IR parameters. However, other diagnostic criteria of MS (hypertension and/or dyslipidemia) or elevated IL-6 levels does not cause further increase in GV.

Visit-to-visit glycemic variability is a strong predictor of chronic obstructive pulmonary disease in patients with type 2 diabetes mellitus: Competing risk analysis using a national cohort from the Taiwan diabetes study

Background

This study aims to examine the association between visit-to-visit glucose variability, which was measured by coefficient of variation (CV) of fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c), and risk of chronic obstructive pulmonary disease (COPD) in a large number of patients with type 2 diabetes with an average follow-up of 7.58 years.

Methods

We conducted a retrospective cohort study on 27,257 patients with type 2 diabetes who participated in the National Diabetes Case Management Program in Taiwan. Visit-to-visit variability in HbA1c and FPG at baseline and the incidence of COPD were analyzed using a modified Cox proportional hazards model considering competing risks.

Results

A total of 2,346 incident cases of COPD. Patients were grouped into tertiles of FPG-CV and HbA1c-CV. The incidence rates in the first, second, and third tertiles were 9.87, 11.06, and 13.19, respectively, for FPG-CV and 10.2, 11.81, and 12.07, for HbA1c-CV per 1000 person-years. After adjusting for age, gender, diabetes duration, treatment type, smoking, hypertension, hyperlipidemia, baseline FPG and HbA1c levels, and complications, both FPG-CV and HbA1c-CV were independently associated with COPD. The hazard ratios of COPD for the third terile compared with the first tertile of FPG-CV were 1.26 (95% confidence interval [CI]: 1.13–1.40). Moreover, the hazard ratios of COPD for the third and second tertiles compared with the first tertile of HbA1c-CV were 1.13 (1.02–1.25) and 1.13 (1.02–1.26), respectively.

Conclusions

Patients with FPG-CV higher than 34.6% or HbA1c-CV higher than 8.4% exhibited an increased risk of COPD. This finding confirmed the linear relationship of FPG-CV and HbA1c-CV to COPD. Visit-to-visit variability in FPG and HbA1c levels are strong predictors of COPD in patients with type 2 diabetes. Future studies should focus on lung dysfunction in diabetes, and adequate glucose control strategy in regular clinical practices must be established for COPD prevention.

Influence of initial insulin dosage on blood glucose dynamics of children and adolescents with newly diagnosed type 1 diabetes mellitus

OBJECTIVE

To investigate the effect of initial insulin dosage on blood glucose (BG) dynamics, β-cell protection, and oxidative stress in type 1 diabetes mellitus.

METHODS

Sixty newly diagnosed type 1 diabetes mellitus patients were randomly assigned to continuous subcutaneous insulin infusions of 0.6 ± 0.2 IU/kg/d (group 1), 1.0 ± 0.2 IU/kg/d (group 2), or 1.4 ± 0.2 IU/kg/d (group 3) for 3 wk. BG was monitored continuously for the first 10 d and the last 2 d of wk 2 and 3. A total of 24-hour urinary 8-iso-PGF2α was assayed on days 8, 9, and 10. The occurrence and duration of the honeymoon period were recorded. Fasting C-peptide and glycosylated hemoglobin (HbA1c) were assayed after 1, 6, and 12 months of insulin treatment.

RESULTS

BG decreased to the target range by the end of wk 3 (group 1), wk 2 (group 2), or wk 1 (group 3). The actual insulin dosage over the 3 wk, frequency of hypoglycemia on wk 1 and 2, and median BG at the end of wk 1 differed significantly, but not 8-iso-PGF2α and the honeymoon period in the three groups. No severe hypoglycemia event was observed in any patient, but there was significant difference in the first occurrence of hypoglycemia.

CONCLUSIONS

Differences in initial insulin dosage produced different BG dynamics in wk 1, equivalent BG dynamics on wk 2 and 3, but had no influence on short- and long-term BG control and honeymoon phase. The wide range of initial insulin dosage could be chosen if guided by BG monitoring.

Excessive visit-to-visit glycemic variability independently deteriorates the progression of endothelial and renal dysfunction in patients with type 2 diabetes mellitus

Background

Glycemic variability (GV) creates challenges to glycemic control and may be an independent marker for unfavorable outcome in management of patients with diabetes. This study was designed to investigate the effect of excessive visit-to-visit GV on the progression of endothelial and renal dysfunction in patients with type 2 diabetes mellitus (T2DM).

Methods

Two hundred and thirty nine patients with T2DM, who were recruited from outpatient, completed 48-month follow-up visit. Visit-to-visit GV was calculated by the standard deviation (SD) and coefficient of variation (CV) of serially measured HbA1c and fasting plasma glucose (FPG). Endothelial and renal function was assessed at baseline and end of follow-up.

Results

At end of follow-up, brachial flow-mediated dilation (FMD), nitric oxide (NO), creatinine-based estimated glomeruar filtration rate (eGFR-Cr), and cystatin C-based estimated glomeruar filtration rate (eGFR-Cys C) increased, and endothelin-1 and urine albumin/creatinine ratio (ACR) declined as compared with baseline in overall (P < 0.05). The increment of FMD, NO, eGFR-Cr, and eGFR-Cys C and the decrement of endothelin-1 and ACR in first tertile group were significantly greater than those in third tertile group classified by tertile of either SD of HbA1c or SD of FPG. Change percentage of FMD, NO, eGFR-Cr, and eGFR-Cys C were positively, and change percentage of endothelin-1 and ACR were negatively correlated with SDs of HbA1c and FPG, and CVs of HbA1c FPG (P < 0.01, respectively). After adjusted for mean HbA1c, mean FPG, baseline demographic, and clinical characteristics, SD of HbA1c and SD of FPG were always statistically correlated with change percentage of FMD, NO, endothelin-1, ACR, eGFR-Cr, and eGFR-Cys C.

Conclusion

Excessive visit-to-visit GV independently deteriorates the progression of endothelial and renal dysfunction in patients with T2DM.

Arterial stiffness in metabolic syndrome

Arterial stiffness is increasingly recognized as an important determinant of cardiovascular risk and may be directly involved in the process of atherosclerosis. As atherosclerosis leads to increased arterial resistance and decrease the flow propagation speed within the arterial lumen, a similar decrease in aortic flow propagation with increased downstream resistance is detected, so aortic flow propagation velocity AVP was evaluated in many studies as a new parameter of aortic stiffness.

Aim

To measure arterial stiffness using the new parameter AVP and compare it to flow mediated dilatation FMD as a parameter of endothelial dysfunction in patients with metabolic syndrome MS.

Methods

AVP (assessed by transthoracic echocardiography) and FMD (assessed by brachial artery reactivity test) were measured in 100 patients with MS (Group 1) and were compared to 14 normal subjects (Group 2).

Results

Patients with MS had significantly lower values of AVP as compared to the normal subjects; 36 ± 5 cm/s vs 57 ± 5, p < 0.05, and lower FMD; 6% ± 1 vs 17 ± 3 p < 0.05 as well, there was significant correlations between AVP and FMD (r = 0.89, p < 0.001).

Conclusion

Transthoracic echocardiographic determination of AVP is a simple practical method and correlates well with FMD in patients with MS.

Impact of Real-Time Continuous Glucose Monitoring Use on Glucose Variability and Endothelial Function in Adolescents with Type 1 Diabetes: New Technology--New Possibility to Decrease Cardiovascular Risk?

Children with type 1 diabetes (T1DM) are the high-risk group of accelerated atherosclerosis. Real-time continuous glucose monitoring (RT-CGM) provides possibilities for the detection of glycaemic variability, newly recognized cardiovascular risk factor. The aim of the study was to assess the usefulness of RT-CGM as an educational tool to find and reduce glycaemic variability in order to improve endothelial function in T1DM adolescents. Forty patients aged 14.6 years were recruited. The study was based on one-month CGM sensors use. Parameters of glycaemic variability were analyzed during first and last sensor use, together with brachial artery flow-mediated dilatation (FMD) to assess endothelial function. In the whole group, FMD improvement was found (10.9% to 16.6%, p < 0.005), together with decrease in all studied glycaemic variability parameters. In patients with HbA1c improvement compared to the group without HbA1c improvement, we found greater increase of FMD (12% to 19%, p < 0.005 versus 8.2% to 11.3%, p = 0.080) and greater improvement of glucose variability. RT-CGM can be considered as an additional tool that offers T1DM adolescents the quick reaction to decrease glycaemic variability in short time observation. Whether such approach might influence improvement in endothelial function and reduction of the risk of future cardiovascular disease remains to be elucidated.

Comparison of low- and high-carbohydrate diets for type 2 diabetes management: a randomized trial

BACKGROUND

Few well-controlled studies have comprehensively examined the effects of very-low-carbohydrate diets on type 2 diabetes (T2D).

OBJECTIVE

We compared the effects of a very-low-carbohydrate, high-unsaturated fat, low-saturated fat (LC) diet with a high-carbohydrate, low-fat (HC) diet on glycemic control and cardiovascular disease risk factors in T2D after 52 wk.

DESIGN

In this randomized controlled trial that was conducted in an outpatient research clinic, 115 obese adults with T2D [mean ± SD age: 58 ± 7 y; body mass index (in kg/m(2)): 34.6 ± 4.3; glycated hemoglobin (HbA1c): 7.3 ± 1.1%; duration of diabetes: 8 ± 6 y] were randomly assigned to consume either a hypocaloric LC diet [14% of energy as carbohydrate (carbohydrate <50 g/d), 28% of energy as protein, and 58% of energy as fat (<10% saturated fat)] or an energy-matched HC diet [53% of energy as carbohydrate, 17% of energy as protein, and 30% of energy as fat (<10% saturated fat)] combined with supervised aerobic and resistance exercise (60 min; 3 d/wk). Outcomes were glycemic control assessed with use of measurements of HbA1c, fasting blood glucose, glycemic variability assessed with use of 48-h continuous glucose monitoring, diabetes medication, weight, blood pressure, and lipids assessed at baseline, 24, and 52 wk.

RESULTS

Both groups achieved similar completion rates (LC diet: 71%; HC diet: 65%) and mean (95% CI) reductions in weight [LC diet: -9.8 kg (-11.7, -7.9 kg); HC diet: -10.1 kg (-12.0, -8.2 kg)], blood pressure [LC diet: -7.1 (-10.6, -3.7)/-6.2 (-8.2, -4.1) mm Hg; HC diet: -5.8 (-9.4, -2.2)/-6.4 (-8.4, -4.3) mm Hg], HbA1c [LC diet: -1.0% (-1.2%, -0.7%); HC diet: -1.0% (-1.3%, -0.8%)], fasting glucose [LC diet: -0.7 mmol/L (-1.3, -0.1 mmol/L); HC diet: -1.5 mmol/L (-2.1, -0.8 mmol/L)], and LDL cholesterol [LC diet: -0.1 mmol/L (-0.3, 0.1 mmol/L); HC diet: -0.2 mmol/L (-0.4, 0.03 mmol/L)] (P-diet effect ≥ 0.10). Compared with the HC-diet group, the LC-diet group achieved greater mean (95% CI) reductions in the diabetes medication score [LC diet: -0.5 arbitrary units (-0.7, -0.4 arbitrary units); HC diet: -0.2 arbitrary units (-0.4, -0.06 arbitrary units); P = 0.02], glycemic variability assessed by measuring the continuous overall net glycemic action-1 [LC diet: -0.5 mmol/L (-0.6, -0.3 mmol/L); HC diet: -0.05 mmol/L (-0.2, -0.1 mmol/L); P = 0.003], and triglycerides [LC diet: -0.4 mmol/L (-0.5, -0.2 mmol/L); HC diet: -0.01 mmol/L (-0.2, 0.2 mmol/L); P = 0.001] and greater mean (95% CI) increases in HDL cholesterol [LC diet: 0.1 mmol/L (0.1, 0.2 mmol/L); HC diet: 0.06 mmol/L (-0.01, 0.1 mmol/L); P = 0.002].

CONCLUSIONS

Both diets achieved substantial weight loss and reduced HbA1c and fasting glucose. The LC diet, which was high in unsaturated fat and low in saturated fat, achieved greater improvements in the lipid profile, blood glucose stability, and reductions in diabetes medication requirements, suggesting an effective strategy for the optimization of T2D management. This trial was registered at www.anzctr.org.au as ACTRN12612000369820.

Glycemic Variability on Continuous Glucose Monitoring System Predicts Rapid Progression of Non-Culprit Lesions in Patients With Acute Coronary Syndrome

BACKGROUND

Although rapid progression (RP) of coronary artery disease (CAD) has been shown to be a powerful predictor of cardiovascular events, predictors of RP are not fully understood in patients with acute coronary syndrome (ACS).

METHODS AND RESULTS

We prospectively investigated the clinical impact of glycemic variability (GV), as determined on continuous glucose monitoring system (CGMS), on RP of non-culprit lesions in 88 patients with ACS. RP was defined as ≥10% diameter reduction in a pre-existing stenosis ≥50%; ≥30% diameter reduction in a stenosis <50%; development of a new stenosis ≥30% in a previously normal segment; or progression of any stenosis to total occlusion. Patients were classified into 2 groups according to the presence (progressor, n=20) or absence (non-progressor, n=68) of RP. All patients were equipped with a CGMS during the stable phase, and mean amplitude of glycemic excursion (MAGE) was calculated as a marker of GV. Mean MAGE was significantly higher in progressors than in non-progressors (55±19 mg/dl vs. 37±18 mg/dl, P<0.01). On multiple logistic regression analysis, MAGE was an independent predictor of RP (odds ratio, 1.06 per 1 mg/dl; P<0.01).

CONCLUSIONS

MAGE early after the onset of ACS is a predictor of RP of non-culprit lesions.

Glycemic Variability: Assessing Glycemia Differently and the Implications for Dietary Management of Diabetes

The primary therapeutic target for diabetes management is the achievement of good glycemic control, of which glycated hemoglobin (HbA1c) remains the standard clinical marker. However, glycemic variability (GV; the amplitude, frequency, and duration of glycemic fluctuations around mean blood glucose) is an emerging target for blood glucose control. A growing body of evidence supports GV as an independent risk factor for diabetes complications. Several techniques have been developed to assess and quantify intraday and interday GV. Additionally, GV can be influenced by several nutritional factors, including carbohydrate quality, quantity; and distribution; protein intake; and fiber intake. These factors have important implications for clinical nutrition practice and for optimizing blood glucose control for diabetes management. This review discusses the available evidence for GV as a marker of glycemic control and risk factor for diabetes complications. GV quantification techniques and the influence of nutritional considerations for diabetes management are also discussed.

Postprandial Dysmetabolism and Oxidative Stress in Type 2 Diabetes: Pathogenetic Mechanisms and Therapeutic Strategies

Postprandial dysmetabolism in type 2 diabetes (T2D) is known to impact the progression and evolution of this complex disease process. However, the underlying pathogenetic mechanisms still require full elucidation to provide guidance for disease prevention and treatment. This review focuses on the marked redox changes and inflammatory stimuli provoked by the spike in blood glucose and lipids in T2D individuals after meals. All the causes of exacerbated postprandial oxidative stress in T2D were analyzed, also considering the consequence of enhanced inflammation on vascular damage. Based on this in-depth analysis, current strategies of prevention and pharmacologic management of T2D were critically reexamined with particular emphasis on their potential redox-related rationale.

Glycemic Variability Assessed by Continuous Glucose Monitoring and Short-Term Outcome in Diabetic Patients Undergoing Percutaneous Coronary Intervention: An Observational Pilot Study

Poor glycemic control is associated with unfavorable outcome in patients undergoing percutaneous coronary intervention (PCI), irrespective of diabetes mellitus. However a complete assessment of glycemic status may not be fully described by glycated hemoglobin or fasting blood glucose levels, whereas daily glycemic fluctuations may influence cardiovascular risk and have even more deleterious effects than sustained hyperglycemia. Thus, this paper investigated the effectiveness of a continuous glucose monitoring (CGM), registering the mean level of glycemic values but also the extent of glucose excursions during coronary revascularization, in detecting periprocedural outcome such as renal or myocardial damage, assessed by serum creatinine, neutrophil gelatinase-associated lipocalin (NGAL), and troponin I levels. High glycemic variability (GV) has been associated with worse postprocedural creatinine and NGAL variations. Moreover, GV, and predominantly hypoglycemic variations, has been observed to increase in patients with periprocedural myocardial infarction. Thus, our study investigated the usefulness of CGM in the setting of PCI where an optimal glycemic control should be achieved in order to prevent complications and improve outcome.

Glycemic variability in nondiabetic morbidly obese persons: results of an observational study and review of the literature

Glycemic variability (GV) is correlated with oxidative stress which may lead to increased cardiovascular risk and poor clinical outcomes in people with prediabetes and diabetes. We sought to understand whether morbidly obese persons without diabetes by standard criteria have dysglycemia as measured by GV. We performed an observational study of GV metrics and carotid intima media thickness (CIMT) in 21 morbidly obese normoglycemic and 15 morbidly obese prediabetic applicants to The Biggest Loser television show. The results were compared to previously published studies in normoglycemic nonobese and obese individuals. Glucose was measured with a masked continuous glucose monitor (CGM) over 3 to 8 days and carotid intima media thickness (CIMT) was determined by ultrasound. CGM-derived GV metrics for GV were coefficient of variation (CV), standard deviation (SD), mean amplitude of glycemic excursions (MAGE), continuous overall net glycemic action-1 hour (CONGA1), and mean of daily differences (MODD). We found that morbidly obese subjects (n = 21) who were normoglycemic by standard criteria had higher GV (CV = 22%, SD = 24.2 mg/dl and MAGE = 48.6 mg/dl) than previous reports of normoglycemic, nonobese individuals (CV = 12-18%, SD = 11.5-15.0 mg/dl, and MAGE = 26.3-28.3 mg/dl). Morbidly obese prediabetic subjects (n = 15) had GV metrics indistinguishable from those morbidly obese subjects who were normoglycemic. CIMT was higher in both morbidly obese groups compared with historical age- and sex-matched controls. Normoglycemic and prediabetic morbidly obese individuals have higher GV compared with normal weight, nondiabetic individuals. We speculate that this may increase the risk for macrovascular disease through excessive oxidative stress.

Acute hyperglycemia reduces cerebrovascular reactivity: the role of glycemic variability

CONTEXT

Cerebral vasomotor reactivity (CVR) is reduced in patients with diabetes mellitus (DM), and glucose variability (GV) might be responsible for cerebrovascular damage.

OBJECTIVE

Studying patients with insulin resistance without DM, we explored the role of GV in impairing CVR.

PATIENTS

We studied 18 metabolic syndrome (MS) patients without DM, 9 controls (C), and 26 patients with DM.

MAIN OUTCOME MEASURES

Groups were compared in terms of CVR, GV, and 24-hour blood pressure. To evaluate the impact of acute hyperglycemia on CVR, a hyperglycemic clamp was performed in MS patients and controls.

RESULTS

Baseline CVR was reduced in DM vs C and MS (C vs DM = 20.2, 95% CI = 3.5-36.9, P = .014; and MS vs DM = 22.2, 95% CI = 8.6-35.8, P = .001), but similar between MS and C (MS vs C = 2.0, 95% CI = -14.7 to 18.7, P = .643). During acute hyperglycemia, CVR fell in MS and C to values comparable to DM. GV progressively increased from C to MS to DM. In MS, CVR at 120 minutes and GV displayed a negative correlation (r = -0.48, P = .043), which did not change after controlling for mean 24-hour systolic and diastolic blood pressure. In MS, the CVR reduction was significantly correlated to GV (r = 0.55, P = .02).

CONCLUSIONS

GV is increased in patients with MS but without DM and is the major predictor of CVR reduction induced by acute hyperglycemia, possibly representing the earliest cause of cerebrovascular damage in DM.

The role of self-monitoring of blood glucose in patients treated with SGLT-2 inhibitors: a European expert recommendation

The role for the novel treatment approach of sodium-glucose cotransporter-2 (SGLT-2) in type 2 diabetes is increasing. Structured self-monitoring of blood glucose (SMBG), based on a less intensive and a more intensive scheme, may contribute to an optimization of SGLT-2 inhibitor based treatment. The current expert recommendation suggests individualized approaches of SMBG, using simple and clinically applicable schemes. Potential benefits of SMBG in SGLT-2 inhibitor based treatment approaches are early assessment of treatment success or failure, timely modification of treatment, detection of hypoglycemic episodes, assessment of glucose excursions, and support of diabetes management and education. The length and frequency of SMBG should depend on the clinical setting and the quality of metabolic control.

Self-monitoring of blood glucose: a prerequisite for diabetes management in outcome trials

Evidence for the value of self-monitoring of blood glucose (SMBG) with regard to the achievement of treatment targets, detection of postprandial glucose excursions, and minimization of glycemic variability is increasing. In large clinical trials, SMBG is a key component for the optimization of diabetes treatment in insulin-treated diabetes. It also plays an essential role in outcome studies. However, details of SMBG use in both the methods and results sections of clinical articles are frequently scarce. Also, a discussion of the SMBG data and its impact on insulin therapy is valuable. In the recently completed Outcome Reduction with an Initial Glargine INtervention (ORIGIN) trial, SMBG was described in detail and insulin titration was largely driven by SMBG. Both aspects largely contributed to the fact that near-normal control was achieved over a long-term period.

Test-retest reliability of peripheral arterial tonometry in the metabolic syndrome

Endothelial dysfunction is an important contributor to atherosclerosis and cardiovascular disease. However, routine assessment via angiography or flow-mediated dilation is difficult due to technical limitations. Peripheral arterial tonometry (PAT) is a promising alternative method for non-invasive assessment of endothelial dysfunction. This study assessed the test-retest reliability of PAT in adults with the metabolic syndrome (n = 20) and provides sample size and power estimates for study design. Participants completed five PAT tests each separated by 1 week. The PAT-derived reactive hyperaemia index (RHI) showed robust repeatability (intra-class correlation = 0.74). A parallel-arm study powered at 0.90 would require 22 participants to detect an absolute change in RHI of 0.40 units (equal to ~25% change in this sample), whereas a crossover study would require 12 participants. In conclusion, we have demonstrated that PAT can be used to assess endothelial dysfunction in adults with the metabolic syndrome as reliably as in healthy samples.

A randomized controlled trial to evaluate the effect of incorporating peanuts into an American Diabetes Association meal plan on the nutrient profile of the total diet and cardiometabolic parameters of adults with type 2 diabetes

Background

According to the American Diabetes Association (ADA), the nutritional goals for patients with type 2 diabetes (T2D) are to achieve an optimal nutrient intake to achieve normoglycemia and a cardioprotective lipid profile. Peanuts are nutrient dense foods that contain high levels of monounsaturated fat (MUFA) and are a natural source of arginine, fiber, phytosterols, resveritrol, niacin, folate, vitamin E and magnesium, which have the potential for improving blood lipids and glycemic control. This study sought to evaluate the effect of a peanut enriched ADA meal plan on the nutrient profile of the total diet and cardiometabolic parameters in adults with T2D.

Methods

This was a randomized, prospective 24-week parallel-group clinical trial with 60 adults with T2D [age range 34–84 years; body mass index (BMI) range 17.2-48.7 kg/m²]. Subjects consumed an ADA meal plan containing ~20% of energy from peanuts (peanut group) or a peanut-free ADA meal plan (control group). Weight, BMI, waist circumference (WC) and nutrient intake from 24-hour recalls were measured every 4 weeks and fasting blood glucose (FBG), HbA1c and blood lipids were measured every 12 weeks. A mixed-model repeated-measures analysis of covariance was performed to assess the significance of changes in the cardiometabolic parameters.

Results

A higher polyunsaturated fat (PUFA) to saturated fat diet ratio and higher intake of MUFA, PUFA, α-tocopherol, niacin and magnesium was observed in the peanut group as compared to the control group (P < 0.01-P = 0.04). Both groups experienced mild reductions in weight, BMI, and WC during the study (P = 0.01-P = 0.03), however there were no differences between the two groups in these measurements or in FBG, HbA1c or blood lipids. For each kilogram of weight loss in the entire cohort there were associations for reductions in WC of 0.48 cm (P < 0.01), FBG of 0.11 mmol/l (P = 0.01) and HbA1c of 0.07% (P < 0.01).

Conclusions

Daily consumption of a peanut enriched (46 g/d) ADA meal plan over 24 weeks improves the nutrient profile of the total diet and is compatible with weight management and improvement in specific blood lipids.

Trial registration

ClinicalTrials.gov NCT00937222

Vascular function and glucose variability improve transiently following initiation of continuous subcutaneous insulin infusion in children with type 1 diabetes

OBJECTIVE

The effect of continuous subcutaneous insulin infusion (CSII) and glucose variability on vascular health in type 1 diabetes (T1D) is not known. We aimed to determine whether initiation of CSII improves vascular function and reduces glucose variability, independent of changes in HbA1c.

METHODS

Twenty-two children with T1D (12.5 ± 2.9 yr) were reviewed immediately prior, 3 wk, and 12 months after initiation of CSII. Vascular function [flow-mediated dilatation (FMD), glyceryl trinitrate-mediated dilatation (GTN)], glucose variability [mean of daily differences (MODD), mean amplitude of glycaemic excursions (MAGE) and continuous overlapping net glycaemic action (CONGA)], and clinical and biochemical data were measured at each visit. Results for the first two visits were compared to a previously studied cohort of 31 children with T1D who remained on multiple daily injections (MDI).

RESULTS

FMD, GTN, blood pressure, HbA1c, fructosamine, and glucose variability significantly improved 3 wk after CSII commencement (all p < 0.05), but there was no change in the MDI control group. At 3 wk, vascular function related to glucose variability [(FMD: MODD, r = -0.62, p = 0.002) and (GTN: MAGE, r = -0.59, p = 0.004; CONGA-4, r = -0.51, p = 0.01; MODD, r = -0.62, p = 0.002)] but not to blood pressure, HbA1c, or fructosamine. At 12 months, FMD, GTN, blood pressure, and glucose variability returned to baseline levels, while HbA1c deteriorated. Carotid intima media thickness was unchanged over 12 months.

CONCLUSIONS

Initiation of CSII rapidly improves vascular function in association with decreased glucose variability; however, the effects are not sustained with deterioration of metabolic control and glucose variability.