Measures of glycemic variability and links with psychological functioning

Correlation Between Mean Amplitude of Glycemic Excursion and Bone Turnover Markers in Patients with Type 2 Diabetes: A Cross-Sectional Study

OBJECTIVE

The present study explores the relationship between glycemic excursion and bone turnover markers.

METHODS

A total of 250 patients with type 2 diabetes mellitus (T2DM) (142 female and 108 male patients) were enrolled in this study. All participants underwent 72 hours of continuous glycemic monitoring to evaluate the mean amplitude of glycemic excursions (MAGE) of each person. Bone turnover markers and other biochemical data were measured for each patient. Linear regression was performed to explore the relationship between bone turnover markers and glycemic excursion. A value of P < 0.05 was considered statistically significant.

RESULTS

MAGE was negatively correlated to N-terminal propeptide of type 1 collagen (P1NP) female: [odds ratios (95% confidence interval) (OR (95% CI)), -2.516 (-5.389, 0.356)]; male: [-2.895, (-6.521, -0.731)] and C-terminal telopeptide fragments of type-I collagen (β-CTX) female [-0.025, (-0.036, 0.005)]; male [-0.043, (-0.082, 0.003)]. MAGE was still negatively correlated with β-CTX female [-0.036, (-0.198, -0.030)]; male [-0.048, (-0.089, -0.007)] after adjusting for clinical data and biochemical indices.

CONCLUSION

An independent negative relationship between glycemic excursion and bone turnover markers in patients with T2DM was identified in this study.

Glucose variability and low bone turnover in people with type 2 diabetes

INTRODUCTION

Type 2 diabetes (T2D) is related to an increased fracture risk and low bone turnover. However, the mechanisms are not elucidated. In the present study we investigate the association between glycemic variability and bone turnover markers.

METHODS

100 participants with T2D and 100 age and gender matched controls were included in this cross-sectional study. All participants with T2D were equipped with a continuous glucose monitoring (CGM) sensor for 3 days (CGMS iPro Continuous Glucose Recorder; Medtronic MiniMed). The dawn glucose levels were defined as a morning period starting 1 h before breakfast ending 1 h post ingestion. On all participants serum (s)-C-terminal cross-linked telopeptide of type-I collagen (CTX), s-procollagen type 1 amino terminal propeptide (P1NP), and s-sclerostin were measured.

RESULTS

Participants with T2D displayed significantly lower levels of the bone resorption marker s-CTX and the bone formation marker s-P1NP compared to controls. S-CTX was significantly negatively associated with the mean amplitude of glycemic excursions (MAGE) and the dawn glucose levels whereas s-P1NP only was significantly negatively associated with the dawn glucose levels while it was borderline significantly associated with MAGE (p = 0.05). S-CTX and s-P1NP were significantly lower among the 50% with the highest dawn glucose levels compared to the 50% lowest dawn glucose levels also after adjustment for age, gender, glycated hemoglobin A1c (HbA1c), and body mass index (BMI).

CONCLUSION

We observed that the amplitude of glycemic excursions and rise in dawn glucose was negatively associated with bone turnover markers. Future research is needed to determine whether reduction of the amplitude of glycemic excursions increase bone turnover markers.

Glucose variability and mood in adults with diabetes: A systematic review

Aims

To systematically review the literature regarding the association between glucose variability (GV) and mood in adults with diabetes, appraise the used methods and make suggestions for future research.

Methods

A systematic review of literature published up to May 2019 was performed. Abstracts and full texts were screened independently in duplicate. Experimental and observational studies reporting the association between GV and mood in adults with type 1 diabetes or type 2 diabetes were evaluated. A descriptive analysis of the extracted data was conducted, along with a quality assessment.

Results

Out of the 2.316 studies screened, eight studies met our criteria. Studies used a variety of measures and metrics to determine GV and mood. Four studies used continuous glucose monitoring (CGM). An association between GV and mood was found in four studies when correlating either postprandial glucose rate of increase with current mood or multiday GV with mood measured retrospectively. The other four studies did not find any association.

Conclusions

There is no clear empirical support for a link between GV and mood in adults with type 1 and type 2 diabetes. More rigorous research is warranted using CGM and ecological momentary assessment of mood to assess if and under what conditions an association between GV and mood exists.

The application of continuous glucose monitoring technology to eating disorders research: An idea worth researching

Continuous glucose monitoring (CGM) devices have revolutionized our capacity to measure blood glucose levels in real time using minimally invasive technology, yet to date there are no studies using CGM in individuals with eating disorders (EDs). Preliminary evidence suggests that eating disorder behaviors (EDBs) have substantial and characteristic impacts on blood glucose levels and glucose-related variables (e.g., binge-eating episodes cause rapid spikes in blood glucose levels, purging causes rapid drops in blood glucose to below normal levels). The aims of this article are to describe the benefits of CGM technology over older methods of measuring blood glucose levels and to discuss several specific ways in which CGM technology can be applied to EDs research to (a) improve our ability to identify and predict engagement in EDBs in real time, (b) identify relationships between blood glucose levels and maintenance factors for EDs, and (c) increase our understanding of the physiological and psychological impacts of disordered eating. We also present preliminary acceptability and feasibility data on the use of CGM devices in individuals with EDs. Overall, the article will describe several applications of CGM technology in EDs research with compelling potential to improve research methodologies.

A daily study of stressors, continuously measured glucose, and diabetes symptoms in latinos with type 2 diabetes

This study examined whether daily stressors and continuously monitored glucose levels and glucose variability predict daily diabetes symptoms. Fifty Latinos with type 2 diabetes were randomized to either diabetes education (DE-only; N = 23) or DE plus stress management and relaxation training (DE + SMR; N = 32). After treatment, for 7 days they wore 'blinded' continuous glucose monitors and reported common stressors and diabetes symptoms twice daily. Between individuals, participants with more numerous overall stressors and more time in hyperglycemia reported higher symptoms. Within individuals, symptoms were higher during intervals of greater than usual stressors. Yet, diabetes symptoms did not covary with changes in glucose levels or glucose variability. The within-person stressor-symptom association was stronger among older individuals and non-significant for participants in DE + SMR condition. Diabetes symptoms were associated with recent stressor exposure, but not recent glucose level or changes in glucose. CLINICAL TRIAL NUMBER: ClinicalTrials.gov Identifier (No. NCT01578096).

Medical and Psychological Considerations for Carbohydrate-Restricted Diets in Youth With Type 1 Diabetes

PURPOSE OF REVIEW

Given the challenges achieving recommended glycemic targets in youth with type 1 diabetes (T1D), providers may consider recommending carbohydrate-restricted diets (CRDs) to optimize glycemic control. The goal of the present review is to describe relevant literature on the potential medical and psychosocial benefits and risks of CRDs in youth with T1D.

RECENT FINDINGS

Limited data exist on the effects of CRDs in pediatric populations. Findings from studies with youth and adults are mixed; some indicate that CRDs may be associated with desirable medical outcomes, such as improved glycemic control and reduced HbA1c, which may contribute to positive psychological outcomes such as reduced diabetes distress and depressive symptoms. Others suggest that CRDs may also be associated with detrimental outcomes, including mineral deficiencies and suboptimal growth, and dietary restriction has been linked to greater diabetes distress, disordered eating, and diabetes management. More research is needed to evaluate benefits and risks of CRDs in youth. Providers should exercise caution when discussing CRDs with youth and families, particularly when considering CRDs for youth at elevated risk for eating disordered behavior.

Mean Levels and Variability in Affect, Diabetes Self-Care Behaviors, and Continuously Monitored Glucose: A Daily Study of Latinos With Type 2 Diabetes

OBJECTIVE

This study investigated between- and within-person associations among mean levels and variability in affect, diabetes self-care behaviors, and continuously monitored glucose in Latinos with type 2 diabetes.

METHODS

Fifty participants (M [SD] age = 57.8 [11.7] years, 74% women, mean [SD] glycosylated hemoglobin A1c = 8.3% [1.5%]) wore a "blinded" continuous glucose monitor for 7 days, and they responded to twice daily automated phone surveys regarding positive affect, negative affect, and self-care behaviors.

RESULTS

Higher mean levels of NA were associated with higher mean glucose (r = .30), greater percent hyperglycemia (r = .34) and greater percentage of out-of-range glucose (r = .34). Higher NA variability was also related to higher mean glucose (r = .34), greater percent of hyperglycemia (r = .44) and greater percentage of out-of-range glucose (r = .43). Higher positive affect variability was related to lower percentage of hypoglycemia (r = -.33). Higher mean levels of self-care behaviors were related to lower glucose variability (r = -.35). Finally, higher self-care behavior variability was related to greater percentage of hyperglycemia (r = .31) and greater percentage of out-of-range glucose (r = -.28). In multilevel regression models, within-person increases from mean levels of self-care were associated with lower mean levels of glucose (b = -7.4, 95% confidence interval [CI] = -12.8 to -1.9), lower percentage of hyperglycemia (b = -0.04, 95% CI = -0.07 to -0.01), and higher percentage of hypoglycemia (b = 0.02, 95% CI = 0.01 to 0.03) in the subsequent 10-hour period.

CONCLUSIONS

Near-to-real time sampling documented associations of glucose with affect and diabetes self-care that are not detectable with traditional measures.

Self-Control, Daily Negative Affect, and Blood Glucose Control in Adolescents With Type 1 Diabetes

OBJECTIVE

For adolescents with Type 1 diabetes, maintaining optimal daily blood glucose control is a complex self-regulatory process that likely requires self-control. This study examined whether higher self-control was associated with lower daily negative affect about diabetes and, in turn, better daily blood glucose control, that is, lower mean daily blood glucose (MBG) and smaller standard deviations of daily blood glucose (SDBG), through 2 paths: (1) self-control maintaining lower mean level of negative affect and (2) self-control buffering the association of the number of daily diabetes problems with daily negative affect.

METHOD

Adolescents (M age = 12.87 years) with Type 1 diabetes (n = 180) completed an initial survey containing a self-report measure of self-control. Nightly electronic diaries were completed for 14 days during which adolescents reported daily problems with and negative affect about diabetes and used a study-provided blood glucose meter.

RESULTS

Hypotheses were examined through multilevel modeling. Lower mean levels of daily negative affect partially mediated the relation between higher adolescent self-control and lower MBG. Adolescent self-control also buffered the association of the number of daily problems with daily negative affect, and smaller fluctuations in daily negative affect were associated with lower SDBG.

CONCLUSIONS

Adolescent self-control is associated with daily affect regulatory processes that may influence MBG. However, fluctuations in daily negative affect about diabetes may represent a unique within-subject daily process associated with SDBG. These findings suggest that studies examining daily disease processes and interventions targeting daily affect regulation may be important to improving health in adolescents with Type 1 diabetes. (PsycINFO Database Record

Impact of Glucose Meter Error on Glycemic Variability and Time in Target Range During Glycemic Control After Cardiovascular Surgery

BACKGROUND

We retrospectively studied the impact of glucose meter error on the efficacy of glycemic control after cardiovascular surgery.

METHOD

Adult patients undergoing intravenous insulin glycemic control therapy after cardiovascular surgery, with 12-24 consecutive glucose meter measurements used to make insulin dosing decisions, had glucose values analyzed to determine glycemic variability by both standard deviation (SD) and continuous overall net glycemic action (CONGA), and percentage glucose values in target glucose range (110-150 mg/dL). Information was recorded for 70 patients during each of 2 periods, with different glucose meters used to measure glucose and dose insulin during each period but no other changes to the glycemic control protocol. Accuracy and precision of each meter were also compared using whole blood specimens from ICU patients.

RESULTS

Glucose meter 1 (GM1) had median bias of 11 mg/dL compared to a laboratory reference method, while glucose meter 2 (GM2) had a median bias of 1 mg/dL. GM1 and GM2 differed little in precision (CV = 2.0% and 2.7%, respectively). Compared to the period when GM1 was used to make insulin dosing decisions, patients whose insulin dose was managed by GM2 demonstrated reduced glycemic variability as measured by both SD (13.7 vs 21.6 mg/dL, P < .0001) and CONGA (13.5 vs 19.4 mg/dL, P < .0001) and increased percentage glucose values in target range (74.5 vs 66.7%, P = .002).

CONCLUSIONS

Decreasing glucose meter error (bias) was associated with decreased glycemic variability and increased percentage of values in target glucose range for patients placed on intravenous insulin therapy following cardiovascular surgery.

Glycemic variability is associated with reduced cardiac autonomic modulation in women with type 2 diabetes

OBJECTIVE

To investigate the sex differences in cardiac autonomic modulation in patients with newly diagnosed type 2 diabetes and to determine whether cardiac autonomic modulation is associated with glycemic variability.

RESEARCH DESIGN AND METHODS

We investigated a cohort consisting of 48 men and 39 women with non-insulin-treated type 2 diabetes and a known duration of diabetes <5 years. All patients were equipped with a continuous glucose monitoring sensor for 3 days, and the mean amplitude of glycemic excursions (MAGE) was calculated to obtain individual glycemic variability. Cardiac autonomic modulation was quantified by analysis of heart rate variability (HRV) in time and frequency domains and during cardiovascular reflex tests (response to standing [RS], deep breathing [expiration-inspiration], and Valsalva maneuver).

RESULTS

Sex differences in age- and heart rate-adjusted HRV measures were observed in both active and passive tests. Low frequency (LF; P = 0.036), LF/high frequency (HF; P < 0.001), and RS (P = 0.006) were higher in men, whereas expiration-inspiration (P < 0.001), but not HF, was higher in women. In women, reduced cardiac autonomic modulation as assessed by the standard deviation of normal-to-normal intervals (P = 0.001), the root mean square of successive differences (P = 0.018), LF (P < 0.001), HF (P = 0.005), total power (P = 0.008), RS ratio (P = 0.027), and expiration-to-inspiration ratio (P = 0.006) was significantly associated with increased glycemic variability as assessed by MAGE. This was not the case in men. The association in women persisted in a multivariate regression analysis controlling for weight, mean heart rate, blood pressure (systolic), and triglycerides.

CONCLUSIONS

In patients with newly diagnosed and well-controlled type 2 diabetes, increased glycemic variability was associated with reduced cardiac autonomic modulation in women but not in men.

Clinical impact of sample interference on intensive insulin therapy in severely burned patients: a pilot study

Severely burned patients benefit from intensive insulin therapy (IIT) for tight glycemic control (TGC). The authors evaluated the clinical impact of automatic correction of hematocrit and ascorbic acid interference for bedside glucose monitoring performance in critically ill burn patients. The performance of two point-of-care glucose monitoring systems (GMSs): 1) GMS1, an autocorrecting device, and 2) GMS2, a noncorrecting device were compared. Sixty remnant arterial blood samples were collected in a prospective observational study to evaluate hematocrit and ascorbic acid effects on GMS1 vs GMS2 accuracy paired against a plasma glucose reference. Next, we enrolled 12 patients in a pilot randomized controlled trial. Patients were randomized 1:1 to receive IIT targeting a TGC interval of 111 to 151 mg/dl and guided by either GMS1 or GMS2. GMS bias, mean insulin rate, and glycemic variability were calculated. In the prospective study, GMS1 results were similar to plasma glucose results (mean bias, -0.75 [4.0] mg/dl; n = 60; P = .214). GMS2 results significantly differed from paired plasma glucose results (mean bias, -5.66 [18.7] mg/dl; n = 60; P = .048). Ascorbic acid therapy elicited significant GMS2 performance bias (29.2 [27.2]; P < .001). Randomized controlled trial results reported lower mean bias (P < .001), glycemic variability (P < .05), mean insulin rate (P < .001), and frequency of hypoglycemia (P < .001) in the GMS1 group than in the GMS2 group. Anemia and high-dose ascorbic acid therapy negatively impact GMS accuracy and TGC in burn patients. Automatic correction of confounding factors improves glycemic control. Further studies are warranted to determine outcomes associated with accurate glucose monitoring during IIT.

Comparison of repaglinide and metformin monotherapy as an initial therapy in Chinese patients with newly diagnosed type 2 diabetes mellitus

BACKGROUND

We aimed to compare the effect of repaglinide and metformin monotherapy as an initial therapy in Chinese patients with newly diagnosed type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

In this 15-week, open-labelled, parallel-controlled, randomised study, 60 Chinese drug-naive patients with newly diagnosed T2DM were randomised (2:1) to receive repaglinide or metformin monotherapy. Primary endpoint was change in HbA1c from baseline to the end of the trial. Secondary endpoints included changes in glycaemic variability, insulin sensitivity and β-cell function.

RESULTS

Patients in both repaglinide and metformin groups achieved significant reductions in HbA1c (-1.8 ± 1.5 vs -1.6 ± 1.5%), FPG (fasting blood glucose) (-1.7 ± 1.7 vs -2.1 ± 1.7  mmol/l) and 2-h PPG (post-prandial glucose) (-3.8 ± 3.1 vs -3.8 ± 3.6  mmol/l), with no statistical differences between the groups. Glycaemic variability, glucose infusion rate and β-cell function were all significantly improved from baseline in the two groups (all P<0.05), without any statistical differences in the improvement between the groups.

CONCLUSIONS

Repaglinide and metformin achieved comparable efficacy in improving glycaemic control, reducing glycaemic variability, enhancing insulin sensitivity and ameliorating β-cell function. Therefore, repaglinide is an optional agent for initial therapy in Chinese patients with newly diagnosed T2DM.

A psychoeducational intervention (SWEEP) for depressed women with diabetes

BACKGROUND

Clinically significant depression is present in 25 % of individuals with type 2 diabetes, its risk being doubled in women.

PURPOSE

To examine the effectiveness of the Study of Women's Emotions and Evaluation of a Psychoeducational (SWEEP), a group therapy for depression treatment based on cognitive behavioral therapy principles that was developed for women with type 2 diabetes was conducted.

METHODS

Women with significantly elevated depression symptoms (Center for Epidemiologic Studies Depression Scale ≥16) were randomized to SWEEP (n = 38) or usual care (UC, n = 36).

RESULTS

Multilevel modeling indicated that SWEEP was more effective than UC in reducing depression (mean difference of -15 vs. -7, p < .01), decreasing trait anxiety (mean difference of -15 vs. -5, p < .01), and improving anger expression (mean difference of -12 vs. -5, p < .05). Although SWEEP and UC had improvements in fasting glucose (mean difference of -24 vs. -1 mg/dl) and HbA1c (mean difference of -0.4 vs. -0.1 %), there were no statistically significant differences between groups.

CONCLUSIONS

SWEEP was more effective than UC for treating depressed women with type 2 diabetes. Addition of group therapy for depression meaningfully expands the armamentarium of evidence-based treatment options for women with diabetes.

Carbohydrate counting accuracy and blood glucose variability in adults with type 1 diabetes

AIMS

Carbohydrate counting is an established approach used by patients with type 1 diabetes to improve their glycemic control. The aims of this study were to evaluate, in real life conditions, the accuracy of meal carbohydrate estimate and its impact on glycemic variability.

METHODS

In this cross-sectional study, we observed the ability of 50 adults (48% women) with type 1 diabetes (age: 42.7±11.1 years); diabetes duration: 21.4±12.7 years; HbA1c: 7.2±1.2% (60±10 mmol/mol) to accurately estimate carbohydrates by analyzing 72-h food records and their corresponding 72-h blood glucose excursions using a continuous glucose monitor.

RESULTS

The mean meal carbohydrate difference, between the patients' estimates and those assessed by a dietitian using a computerized analysis program, was 15.4±7.8 g or 20.9±9.7% of the total CHO content per meal (72.4±34.7 g per meal). Sixty-three percent of the 448 meals analyzed were underestimated. Greater differences in CHO's estimates predicted higher glycemic variability, as measured by the MAGE index and glucose standard deviation, and decreased time with glucose values between 4 and 10 mmol/L (R²=0.110, 0.114 and 0.110, respectively; P<0.05).

CONCLUSION

Inaccurate carbohydrate counting is frequent and associated with higher daily blood glucose variability in adults with type 1 diabetes.

Increasing blood glucose variability is a precursor of sepsis and mortality in burned patients

High glycemic variability, rather than a mean glucose level, is an important factor associated with sepsis and hospital mortality in critically ill patients. In this retrospective study we analyze the blood glucose data of 172 nondiabetic patients 18-60 yrs old with second and third-degree burns of total body surface area greater than 30% and 5%, respectively, admitted to ICU in 2004-2008. The analysis identified significant association of increasing daily glucose excursion (DELTA) accompanied by evident episodes of hyperglycemia (>11 mmol/l) and hypoglycemia (<2.8 mmol/l), with sepsis and forthcoming death, even when the mean daily glucose was within a range of acceptable glycemia. No association was found in sepsis complication and hospital mortality with doses of intravenous insulin and glucose infusion. A strong increase in DELTA before sepsis and death is treated as fluctuation amplification near the onset of dynamical instability.

Diabetic autonomic imbalance and glycemic variability

Diabetic autonomic neural imbalance is a severe complication of long-term diabetes patients and may progress to diabetic autonomic neuropathy (DAN). The prevalence of DAN is reported to be between 20 and 70%, depending on the studies. The pathogenesis of DAN remains unresolved. However, emerging evidence suggests that glycemic variability (GV) may be associated with autonomic imbalance in patients with both type 1 and type 2 diabetes. As symptoms are initially weak and uncharacteristic, the condition often remains undiagnosed until late manifestations present themselves. Predominant symptoms may include nausea, vomiting, gastroparesis, involuntary diarrhea, postural hypotension, voiding difficulties, and sexual dysfunction. Analyzing the patterns of heart rate variability carries the potential for detection of autonomic imbalance in the subclinical and asymptomatic stages. In this context, GV may affect the sympathovagal balance by increasing oxidative stress and proinflammatory cytokines. Establishing a GV risk profile could therefore be important in determining risk factors in diabetes patients. This review addresses the issues above and in particular the possible association between diabetic autonomic imbalance and GV.

Does glycemic variability impact mood and quality of life?

BACKGROUND

Diabetes is a chronic condition that significantly impacts quality of life. Poor glycemic control is associated with more diabetes complications, depression, and worse quality of life. The impact of glycemic variability on mood and quality of life has not been studied.

METHODS

A descriptive exploratory design was used. Twenty-three women with type 2 diabetes wore a continuous glucose monitoring system for 72 h and completed a series of questionnaires. Measurements included (1) glycemic control shown by glycated hemoglobin and 24-h mean glucose, (2) glycemic variability shown by 24-h SD of the glucose readings, continuous overall net glycemic action (CONGA), and Fourier statistical models to generate smoothed curves to assess rate of change defined as "energy," and (3) mood (depression, anxiety, anger) and quality of life by questionnaires.

RESULTS

Women with diabetes and co-morbid depression had higher anxiety, more anger, and lower quality of life than those without depression. Certain glycemic variability measures were associated with mood and quality of life. The 24-h SD of the glucose readings and the CONGA measures were significantly associated with health-related quality of life after adjusting for age and weight. Fourier models indicated that certain energy components were significantly associated with depression, trait anxiety, and overall quality of life. Finally, subjects with higher trait anxiety tended to have steeper glucose excursions.

CONCLUSIONS

Data suggest that greater glycemic variability may be associated with lower quality of life and negative moods. Implications include replication of the study in a larger sample for the assessment of blood glucose fluctuations as they impact mood and quality of life.