Benefits and limitations of continuous glucose monitoring in type 1 diabetes

Accuracy of continuous glucose monitoring during exercise-related hypoglycemia in individuals with type 1 diabetes

Background

Hypoglycemia is common in individuals with type 1 diabetes, especially during exercise. We investigated the accuracy of two different continuous glucose monitoring systems during exercise-related hypoglycemia in an experimental setting.

Materials and methods

Fifteen individuals with type 1 diabetes participated in two separate euglycemic-hypoglycemic clamp days (Clamp-exercise and Clamp-rest) including five phases: 1) baseline euglycemia, 2) plasma glucose (PG) decline ± exercise, 3) 15-minute hypoglycemia ± exercise, 4) 45-minute hypoglycemia, and 5) recovery euglycemia. Interstitial PG levels were measured every five minutes, using Dexcom G6 (DG6) and FreeStyle Libre 1 (FSL1). Yellow Springs Instruments 2900 was used as PG reference method, enabling mean absolute relative difference (MARD) assessment for each phase and Clarke error grid analysis for each day.

Results

Exercise had a negative effect on FSL1 accuracy in phase 2 and 3 compared to rest (ΔMARD = +5.3 percentage points [(95% CI): 1.6, 9.1] and +13.5 percentage points [6.4, 20.5], respectively). In contrast, exercise had a positive effect on DG6 accuracy during phase 2 and 4 compared to rest (ΔMARD = -6.2 percentage points [-11.2, -1.2] and -8.4 percentage points [-12.4, -4.3], respectively). Clarke error grid analysis showed a decrease in clinically acceptable treatment decisions during Clamp-exercise for FSL1 while a contrary increase was observed for DG6.

Conclusion

Physical exercise had clinically relevant impact on the accuracy of the investigated continuous glucose monitoring systems and their ability to accurately detect hypoglycemia.

Muscle-to-fat ratio in children and adolescents with type 1 diabetes in predicting glycaemic control and partial clinical remission

BACKGROUND

Advances in treatment could mitigate the expected adverse changes in the body composition of children and adolescents with type 1 diabetes (T1D).

OBJECTIVES

To examine the evolution of weight status and body composition and their association with glycaemic control and partial clinical remission in youth with T1D.

METHODS

Ninety-nine participants with T1D (median age 9.5 years [interquartile range 7.3, 12.9], 59.6% boys) were longitudinally followed for 3 years since diagnosis. Data at seven pre-determined time points were extracted from medical files. Outcome measures included body mass index (BMI) z-scores, muscle-to-fat ratio (MFR) z-scores, haemoglobin A1c (HbA1c) levels, continuous glucose monitoring metrics, and insulin dose-adjusted HbA1c (IDAA1c) levels.

RESULTS

The BMI z-scores increased significantly (p < 0.001) for both sexes, with no significant change in MFR z-scores over time. The girls had higher BMI z-scores (p < 0.001) and lower MFR z-scores than the boys (p = 0.016). The mean HbA1c levels decreased during the first month and at 3 months since diagnosis (p < 0.001), then plateaued and achieved a median overall HbA1c of 7.1% for the entire cohort. At 12 months, 37 participants (37.6%) were in partial clinical remission, as evidenced by IDAA1c ≤ 9. The odds of partial clinical remission at 2 years increased by 2.1-fold for each standard deviation increase in the MFR z-score (p < 0.001). Higher MFR z-scores were associated with better metabolic control.

CONCLUSIONS

Integration of body composition assessments could mitigate adverse body changes in paediatric patients with T1D.

Cost-effectiveness of continuous glucose monitoring with FreeStyle Libre® in Brazilian insulin-treated patients with types 1 and 2 diabetes mellitus

BACKGROUND

Hypoglycemia is a barrier to optimal glucose control in the treatment of both type 1 (T1DM) and type 2 diabetes mellitus (T2DM). Blood glucose monitoring is essential in diabetes management. Inappropriate glucose management is associated with high mortality and morbidity. FreeStyle Libre® (FSL) is a continuous glucose monitoring (CGM) system that provides effective, safe, and convenient glucose monitoring, without routine finger pricking. This study aims to estimate the incremental cost-effectiveness ratio (ICER) of the FSL system in comparison to conventional Self-monitoring of blood glucose (SMBG) in T1DM and T2DM patients that require intensive insulin therapy.

METHODS

A decision-tree model was developed to compare the cost-effectiveness ratio between FSL and conventional SMBG from the perspective of the Brazilian Public Healthcare System (SUS). The model captures the cumulative rates of acute complications such as severe hypoglicemia and diabetic ketoacidosis, per-event costs, and quality-adjusted life-years (QALYs) gained over a 1-year time horizon in adult and pediatric patients (≥ 4 years old) with T1DM or T2DM. Inputs from the Brazilian health databases, clinical trials, and real-world data were used in the study.

RESULTS

The results demonstrated that, regarding solely severe hypoglicemia and diabetic ketoacidosis events, T1DM have a QALY difference of 0.276, a cost difference of R$ 7.255, and an ICER of R$ 26,267.69 per QALY gained for CGM with FSL, when compared to conventional SMBG. T2DM results demonstrated equally a QALY difference of 0.184, a cost difference of R$ 7290, and an ICER of R$ 39,692.67 per QALY gained, in favour of CGM with FSL.

CONCLUSION

Our findings demonstrated that FSL is cost-effective in T1DM and T2DM for acute diabetic complications, from a SUS perspective. CGM with FSL can promote safe, convenient, and cost-effective glucose monitoring, therefore contributing to the improvement of the incidence of complications and quality of life.

Pathological mechanisms of type 1 diabetes in children: investigation of the exosomal protein expression profile

Introduction

Type 1 diabetes (T1D) is a serious autoimmune disease with high morbidity and mortality. Early diagnosis and treatment remain unsatisfactory. While the potential for development of T1D biomarkers in circulating exosomes has attracted interest, progress has been limited. This study endeavors to explore the molecular dynamics of plasma exosome proteins in pediatric T1D patients and potential mechanisms correlated with T1D progression.

Methods

Liquid chromatography-tandem mass spectrometry with tandem mass tag (TMT)6 labeling was used to quantify exosomal protein expression profiles in 12 healthy controls and 24 T1D patients stratified by age (≤ 6 years old and > 6 years old) and glycated hemoglobin (HbA1c) levels (> 7% or > 7%). Integrated bioinformatics analysis was employed to decipher the functions of differentially expressed proteins, and Western blotting was used for validation of selected proteins' expression levels.

Results

We identified 1035 differentially expressed proteins (fold change > 1.3) between the T1D patients and healthy controls: 558 in those ≤ 6-year-old and 588 in those > 6-year-old. In those who reached an HbA1c level < 7% following 3 or more months of insulin therapy, the expression levels of most altered proteins in both T1D age groups returned to levels comparable to those in the healthy control group. Bioinformatics analysis revealed that differentially expressed exosome proteins are primarily related to immune function, hemostasis, cellular stress responses, and matrix organization. Western blotting confirmed the alterations in RAB40A, SEMA6D, COL6A5, and TTR proteins.

Discussion

This study delivers valuable insights into the fundamental molecular mechanisms contributing to T1D pathology. Moreover, it proposes potential therapeutic targets for improved T1D management.

Assessing depressive symptoms and diabetes distress in Type 1 diabetic adults: A comparison of continuous subcutaneous insulin infusion (CSII) and multiple daily injections (MDI) users

This cross-sectional observational study assesses differences in depressive symptoms and diabetes-distress between adults with type 1 diabetes using continuous subcutaneous insulin infusion (CSII) or multiple daily injections (MDI) insulin delivery methods. Two-hundred and seventy-one adults with type 1 diabetes were recruited who used CSII (n = 104) or MDI (n = 167). Results show that, compared to CSII users, scores on the Severity Measure for Depression - Adult questionnaire and Management and Physician subscales on the Type 1 Diabetes Distress Scale were significantly greater in users of MDI. Thus, MDI users may require greater targetted support to improve these aspects of psychological wellbeing.

Managing Severe Hypoglycaemia in Patients with Diabetes: Current Challenges and Emerging Therapies

Hypoglycaemia is common in patients with diabetes mellitus and is a limiting factor for achieving adequate glycaemic control. In the vast majority of cases, hypoglycaemia develops due to the imbalance between food intake and insulin injections. As recurrent hypoglycaemia leads to significant morbidity and mortality, the recognition and immediate treatment of hypoglycaemia in diabetic patients is thus important. In the last 20 years, the introduction of improved insulin analogues, insulin pump therapy, continuous glucose monitoring (CGM), and sensor-augmented pump therapy have all made significant improvements in helping to reduce and prevent hypoglycaemia. In terms of treatment, the American Diabetes Association recommends oral glucose as the first-line treatment option for all conscious patients with hypoglycaemia. The second line of treatment (or first line in unconscious patients) is the use of glucagon. Novel formulations of glucagon include the nasal form, the Gvoke HypoPen which is a ready-to-deliver auto-injector packaged formulation and finally a glucagon analogue, Dasiglucagon. The Dasiglucagon formulation has recently been approved for the treatment of severe hypoglycaemia. It is a ready-to-use, similar to endogenous glucagon and its potency is also the same as native glucagon. It does not require reconstitution before injection and therefore ensures better compliance. Thus, significant improvements including development of newer insulin analogues, insulin pump therapy, continuous glucose monitoring (CGM), sensor-augmented pump therapy and novel formulations of glucagon have all contributed to reducing and preventing hypoglycaemia in diabetic individuals. However, considerable challenges remain as not all patients have access to diabetes technologies and to the newer glucagon formulations to help reduce and prevent hypoglycaemia.

Level of Agreement and Correlation Between the Estimated Hemoglobin A1c Results Derived by Continuous or Conventional Glucose Monitoring Systems Compared with the Point-of-Care or Laboratory-Based Measurements: An Observational Study

INTRODUCTION

Hemoglobin A1C (HbA1c) is an important marker for diabetes care management. With the increasing use of new technologies such as continuous glucose monitoring (CGM) and point-of-care testing (POCT), patients and their physicians have been able to monitor and continuously check their blood glucose levels in an efficient and timely manner. This study aimed to investigate the level of agreement between the standard laboratory test for HbA1c (Lab-HbA1c) with point-of-care testing (POCT-HbA1c) and glucose monitoring index (GMI) derived by intermittently scanned CGM (isCGM) or estimated average glucose (eAG) derived by conventional self-monitored blood glucose (SMBG) devices.

METHODS

A cross-sectional study was conducted at the Diabetes Treatment Center, Prince Sultan Military Medical City, Saudi Arabia, between May and December 2020 with 81 patients with diabetes who used the isCGM system (n = 30) or conventional finger-pricking SMBG system (n = 51). At the same visit, venous and capillary blood samples were taken for routine HbA1c analysis by the standard laboratory and POCT methods, respectively. Also, for isCGM users, the GMI data for 28 days (GMI-28) and 90 days (GMI-90) were obtained, while for SMBG users, eAG data for 30 days (eAG-30) and 90 days (eAG-90) were calculated. The limits of agreement in different HbA1c measurements were evaluated using a Bland-Altman analysis. Pearson correlation and multivariate linear regression analyses were also performed.

RESULTS

Based on the Bland-Altman analysis, HbA1c levels for 96.7% and 96.1% of the patients analyzed by the POCT and the standard laboratory methods were within the range of the 95% limit of agreement in both isCGM and conventional SMBG users, respectively. About 93.3% of the GMI measurements were within the 95% limit of agreement. Also, about 94.12% of the eAG-30 and 90.2% of the eAG-90 measurements were within the 95% limit of agreement. Moreover, the correlation analysis revealed a statistically significant positive correlation and linear regression among Lab-HbA1c, POCT-HbA1c, GMI, and eAG in both conventional SMBG and isCGM users (all p < 0.001). These positive results persisted significantly after adjusting for different factors (all p < 0.001).

CONCLUSION

GMI derived by isCGM or eAG derived by conventional SMBG systems, as well as the POCT-HbA1c measurements, showed a high level of agreement; therefore, we recommend them as potential methods for diabetes monitoring, especially when a rapid result is needed or with patients with uncontrolled diabetes or on intensive insulin therapy.

Improvement in Mean CGM Glucose in Young People with Type 1 Diabetes During 1 Year of the COVID-19 Pandemic

The coronavirus disease 2019 (COVID-19) pandemic likely affected youth with type 1 diabetes (T1D). We used electronic health record-extracted data to compare continuous glucose monitoring (CGM) metrics during 1 year of the pandemic with those of the previous year. The sample comprised CGM users, aged 1 to <18 years, with T1D duration ≥6 months (age <6 years) or ≥1 year (age ≥6 years). The prepandemic sample comprised 641 youth (52% female, aged 12.3 ± 3.5, T1D duration 6.0 ± 3.5 years). The pandemic sample comprised 648 youth (52% female, age 13.3 ± 3.5, duration 6.7 ± 3.8 years), with care delivered primarily through telemedicine. Mean CGM glucose was 6.3 mg/dL lower during the pandemic (187.3 ± 35.6) versus prepandemic (193.6 ± 33.0) (P < 0.001). A higher percentage of youth achieved glucose management indicator <7% during the pandemic than the prior year (P < 0.001). Lower CGM glucose values were observed during the COVID-19 pandemic. Future studies are needed to assess how changes in health care delivery, including telemedicine, and lifestyle during this time may have supported this improvement.

Glucose biosensors in clinical practice: principles, limits and perspectives of currently used devices

The demand of glucose monitoring devices and even of updated guidelines for the management of diabetic patients is dramatically increasing due to the progressive rise in the prevalence of diabetes mellitus and the need to prevent its complications. Even though the introduction of the first glucose sensor occurred decades ago, important advances both from the technological and clinical point of view have contributed to a substantial improvement in quality healthcare. This review aims to bring together purely technological and clinical aspects of interest in the field of glucose devices by proposing a roadmap in glucose monitoring and management of patients with diabetes. Also, it prospects other biological fluids to be examined as further options in diabetes care, and suggests, throughout the technology innovation process, future directions to improve the follow-up, treatment, and clinical outcomes of patients.

Barriers and facilitators of diabetes management by continuous glucose monitoring systems among adults with type 2 diabetes: a protocol of qualitative systematic review

INTRODUCTION

Studies suggest that continuous glucose monitors (CGMs) play an important role in the management of diabetes. Although general acceptance has been reported by patients with type 2 diabetes towards the use of CGMs, potential barriers exist like pain due to sensor insertion, accidental removal of the device or adhesive strip, impacts of daily activities, skin reactions to sensor adhesive, etc. This systematic review of qualitative studies aims to explore the perspectives, experiences and narratives of patients and caregivers about CGM use, and its barriers and facilitators.

METHODS AND ANALYSIS

This review will include qualitative studies and cross-sectional and longitudinal cohort studies using open-ended questions, published in English by 30 October 2021. The following electronic databases will be searched: Cochrane Library, PubMed, EMBASE, CINAHL, PsycINFO and Scopus. A search of grey literature will be conducted via an online search of Google Scholar, WorldCat, ClinicalTrials.gov and OpenGrey A combined search strategy using medical subject headings (MeSH), controlled vocabulary and 'free-text' terms will be appropriately revised to suit each database. Primary outcomes will include patient and caregiver perspectives on diabetes management regarding glucose control; living with CGM (quality of life, experience of wearing a CGM); psychological aspects (anxiety, depression, emotional burden); barriers (technical issues, financial issues) to use of CGM and thoughts (interpretation, understanding) on the CGM report. A qualitative meta-synthesis will be conducted employing a systematic literature search of existing literature, quality assessment using study-specific tools and an aggregative thematic synthesis by a multidisciplinary team.

ETHICS AND DISSEMINATION

Ethical approval is not required since this is a systematic review. The results will help improve clinical implementation of CGMs on part of both patients and caregivers.

PROSPERO REGISTRATION NUMBER

CRD42020152211.

Flash Glucose Monitoring in the Netherlands: Increased monitoring frequency is associated with improvement of glycemic parameters

AIMS

To evaluate the association between Flash Glucose Monitoring (FLASH) frequency and glycemic parameters during real-life circumstances in the Netherlands.

METHODS

Obtained glucose readings were de-identified and uploaded to a dedicated database when FLASH reading devices were connected to internet. Data between September 2014 and March 2020, comprising 16,331 analyzable readers (163,762 sensors) were analyzed. Scan rate per reader was determined and each reader was sorted into 20 equally sized rank ordered groups (n = 817 each).

RESULTS

Users performed a median of 11.5 [IQR 7.7-16.7] scans per day. Those in the lowest and highest ventiles scanned on average 3.7 and 40.0 times per day and had an eHbA1c of 8.6% (71 mmol/mol) and 6.9% (52 mmol/mol), respectively. Increasing scan rates were associated with more time in target range (3.9-10 mmol/L), less time in hyperglycemia (>10 mmol/L), and a lower standard deviation of glucose. An eHbA1c of 7.0% (53 mmol/mol) translated in approximately 65% time in target range, 30% time in hyperglycemia and 5% time in hypoglycemia (<3.9 mmol/L).

CONCLUSIONS

These outcomes among Dutch FLASH users suggest that with higher scan rate glycemic control improves.

Temperature Correction to Enhance Blood Glucose Monitoring Accuracy Using Electrical Impedance Spectroscopy

Electrical methods are among the primarily studied non-invasive glucose measurement techniques; however, various factors affect the accuracy of the sensors used. Of these, the temperature is a critical factor; hence, the effects of temperature on the electrical properties of blood components are investigated in this study. Furthermore, the changes in the electrical properties of blood according to the glucose level are corrected by considering the effects of temperature on the electrical properties. An impedance sensor is developed and used to measure whole blood impedance in 10 healthy participants at various temperatures and glucose levels. Subsequently, the conductivities of the plasma and cytoplasm were extracted. Changes in the electrical properties of the blood components are then analyzed using linear regression and repeated measures ANOVA. The electrical conductivities of plasma and cytoplasm increased with increasing temperatures (plasma: 0.0397 (slope), 0.7814 (R²), cytoplasm: 0.014 (slope), 0.694 (R²)). At three values of increasing glucose levels (85.4, 158.1, and 271.8 mg/dL), the electrical conductivities of the plasma and cytoplasm decreased. These tendencies are more significant upon temperature corrections (p-values; plasma: 0.001, 0.001, cytoplasm: 0.003, 0.002). The relationships between temperature and electrical conductivity changes can thus be used for temperature corrections in blood glucose measurement.

An analytical approach to determine the optimal duration of continuous glucose monitoring data required to reliably estimate time in hypoglycemia

Diabetes is a chronic metabolic disease that causes blood glucose (BG) concentration to make dangerous excursions outside its physiological range. Measuring the fraction of time spent by BG outside this range, and, specifically, the time-below-range (TBR), is a clinically common way to quantify the effectiveness of therapies. TBR is estimated from data recorded by continuous glucose monitoring (CGM) sensors, but the duration of CGM recording guaranteeing a reliable indicator is under debate in the literature. Here we framed the problem as random variable estimation problem and studied the convergence of the estimator, deriving a formula that links the TBR estimation error variance with the CGM recording length. Validation is performed on CGM data of 148 subjects with type-1-diabetes. First, we show the ability of the formula to predict the uncertainty of the TBR estimate in a single patient, using patient-specific parameters; then, we prove its applicability on population data, without the need of parameters individualization. The approach can be straightforwardly extended to other similar metrics, such as time-in-range and time-above-range, widely adopted by clinicians. This strengthens its potential utility in diabetes research, e.g., in the design of those clinical trials where minimal CGM monitoring duration is crucial in cost-effectiveness terms.

Artificial Pancreas Control Strategies Used for Type 1 Diabetes Control and Treatment: A Comprehensive Analysis

This paper presents a comprehensive survey about the fundamental components of the artificial pancreas (AP) system including insulin administration and delivery, glucose measurement (GM), and control strategies/algorithms used for type 1 diabetes mellitus (T1DM) treatment and control. Our main focus is on the T1DM that emerges due to pancreas’s failure to produce sufficient insulin due to the loss of beta cells (β-cells). We discuss various insulin administration and delivery methods including physiological methods, open-loop, and closed-loop schemes. Furthermore, we report several factors such as hyperglycemia, hypoglycemia, and many other physical factors that need to be considered while infusing insulin in human body via AP systems. We discuss three prominent control algorithms including proportional-integral- derivative (PID), fuzzy logic, and model predictive, which have been clinically evaluated and have all shown promising results. In addition, linear and non-linear insulin infusion control schemes have been formally discussed. To the best of our knowledge, this is the first work which systematically covers recent developments in the AP components with a solid foundation for future studies in the T1DM field.