Glycemic Status Assessment by the Latest Glucose Monitoring Technologies

Celebration of a century of insulin therapy in children with type 1 diabetes

Insulin is the key anabolic hormone of metabolism, with clear effects on glycaemia. Near-complete insulin deficiency occurs in type 1 diabetes (T1D), the predominant form affecting children, and uniformly fatal until the discovery of insulin. By the early 20th century, it was known that T1D was caused by the lack of a factor from pancreatic islets, but isolation of this substance proved elusive. In 1921, an unusual team in Toronto comprising a surgeon, a medical student, a physiologist and a biochemist successfully isolated a glucose-lowering pancreatic endocrine secretion. They treated an emaciated 14-year-old boy in 1922, restoring his health and allowing him to live for another 13 years. Thus began an era of remarkable progress and partnership between academia and the pharmaceutical industry to produce drugs that benefit sick people. The Toronto team received the 1923 Nobel Prize, and more Nobel Prizes for work with insulin followed: for elucidation of its amino acid sequence and crystalline structure, and for its role in the development of radioimmunoassays to measure circulating hormone concentrations. Human insulin was the first hormone synthesised by recombinant methods, permitting modifications to enable improved absorption rates and alterations in duration of action. Coupled with delivery via insulin pens, programmable pumps and continuous glucose monitors, metabolic control and quality of life vastly improved and T1D in children was converted from uniformly fatal to a manageable chronic condition. We describe this remarkable ongoing story as insulin remains a paradigm for human ingenuity to heal nature's maladies.

Software Packages and Tools for the Analysis of Continuous Glucose Monitoring Data

The advancement of technology in the field of glycemic control has led to the widespread use of continuous glucose monitoring (CGM), which can be nowadays obtained from wearable devices equipped with a minimally invasive sensor, that is, transcutaneous needle type or implantable, and a transmitter that sends information to a receiver or smart device for data storage and display. This work aims to review the currently available software packages and tools for the analysis of CGM data. Based on the purposes of this work, 12 software packages have been identified from the literature, published until December 2021, namely: GlyCulator, EasyGV (Easy Glycemic Variability), CGM-GUIDE^© (Continuous Glucose Monitoring Graphical User Interface for Diabetes Evaluation), GVAP (Glycemic Variability Analyzer Program), Tidepool, CGManalyzer, cgmanalysis, GLU, CGMStatsAnalyser, iglu, rGV, and cgmquantify. Comparison of available software packages and tools has been done in terms of main characteristics (i.e., publication year, presence of a graphical user interface, availability, open-source code, number of citations, programming language, supported devices, supported data format and organization of the data structure, documentation, presence of a toy example, video tutorial, data upload and download, measurement-units conversion), preprocessing procedures, data display options, and computed metrics; also, each of the computed metrics has been analyzed in terms of its adherence to the American Diabetes Association (ADA) 2017 international consensus on CGM data analysis and the ADA 2019 international consensus on time in range. Eventually, the agreement between metrics computed by different software and tools has been investigated. Based on such comparison, usability and complexity of data management, as well as the possibility to perform customized or patients-group analyses, have been discussed by highlighting limitations and strengths, also in relation to possible different user categories (i.e., patients, clinicians, researchers). The information provided could be useful to researchers interested in working in the diabetic research field as to clinicians and endocrinologists who need tools capable of handling CGM data effectively.

Acceptability and feasibility of continuous glucose monitoring in people with diabetes: protocol for a mixed-methods systematic review of quantitative and qualitative evidence

BACKGROUND

Good glycaemic control is a crucial part of diabetes management. Traditional assessment methods, including HbA1c checks and self-monitoring of blood glucose, can be unreliable and inaccurate. Continuous glucose monitoring (CGM) offers a non-invasive and more detailed alternative. Availability of this technology is increasing worldwide. However, there is no current comprehensive evidence on the acceptability and feasibility of these devices. This is a protocol for a mixed-methods systematic review of qualitative and quantitative evidence about acceptability and feasibility of CGM in people with diabetes.

METHODS

We will search MEDLINE, Embase, CINAHL, and CENTRAL for qualitative and quantitative evidence about the feasibility and acceptability of CGM in all populations with diabetes (any type) using search terms for "continuous glucose monitoring" and "diabetes". We will not apply any study-type filters. Searches will be restricted to studies conducted in humans and those published from 2011 onwards. We will not restrict the search by language. Study selection and data extraction will be carried out by two reviewers independently using Rayyan and Eppi-Reviewer, respectively, with disagreements resolved by discussion. Data extraction will include key information about each study, as well as qualitative evidence in the form of participant quotes from primary studies and themes and subthemes based on the authors' analysis. Quantitative data relating to acceptability and feasibility including data loss, adherence, and quantitative ratings of acceptability will be extracted as means and standard deviations or n/N as appropriate. Qualitative evidence will be analysed using framework analysis informed by the Theoretical Framework of Acceptability. Where possible, quantitative evidence will be combined using random-effects meta-analysis; otherwise, a narrative synthesis will be performed. The most appropriate method for integrating qualitative and quantitative findings will be selected based on the data available.

DISCUSSION

Ongoing assessment of the acceptability of interventions has been identified as crucially important to scale-up and implementation. This review will provide new knowledge with the potential to inform a programme theory of CGM as well as future roll-out to potentially vulnerable populations, including those with severe mental illness.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021255141.

The Association of Personality Traits and Parameters of Glycemic Regulation in Type 1 Diabetes Mellitus Patients Using isCGM

This study aimed to examine the impact of personality on glycemic regulation in adult patients with type 1 diabetes mellitus (T1DM). The study group consisted of subjects with T1DM, who were ≥ 18 years of age. The study was conducted in two phases: At baseline, subjects completed the Croatian version of the International Personality Item Pool scale (IPIP50s) and a questionnaire designed to gather socioeconomic data, duration of diabetes, presence of chronic complications, presence of cardiovascular risk factors, frequency, and type of pre-existing hypoglycemic episodes per week. Blood and urine samples were collected and body mass index (BMI) was calculated. Each participant was provided with the intermittently scanned glucose monitoring system (isCGM) Freestyle Libre. During the second visit (3 months from the start of the trial), glycemic parameters were collected from the reports generated from the Freestyle Libre system. Estimated glycated hemoglobin (HbA1c) values were significantly lower after three months compared to baseline HbA1c (Wilcoxon test, p < 0.001). An inverse correlation between the number of daily scans and degree of extraversion among subjects was observed, e.g., higher degrees of extraversion resulted in lower numbers of daily scans, while lower degrees of extraversion, i.e., introvertedness, resulted in higher numbers of daily scans (Rho = −0.238 p = 0.009). There was a positive correlation between emotional stability and time spent in hypoglycemia (Rho = 0.214; p = 0.02). In addition, a shorter duration of diabetes was associated with higher percentages of TIR and vice versa (p = 0.02). Investigating personality traits can be a useful tool for identifying patients predisposed to hypoglycemia and lower scanning frequency. Patients with a longer history of T1DM require closer follow-up and should be re-educated when necessary.

Evaluation of the performance and usability of a novel continuous glucose monitoring system

Background

Continuous glucose monitoring (CGM) can help manage diabetes mellitus (DM) and prevent hypoglycemia. This study aimed to evaluate the performance and usability of a novel SiJoy GS1 CGM system.

Methods

This multicenter trial enrolled participants with DM. Based on the comparison of glucose values measured by SiJoy GS1 CGM and venous blood glucose test, the 20/20% consistency and mean absolute relative difference (MARD%) were calculated, as well as Clarke and consensus error grid analysis. Product usability was evaluated by questionnaire completed by participants. Any occurrence of adverse events (AE) was documented.

Results

Seventy participants were included in the study. The mean age of participants was 41.5 ± 13.2 years, among which 29 (42.0%) were male, with the DM course of 8.6 ± 7.5 years. A total of 39 (56.5%) of them had type 1 DM, 24 (34.8%) had type 2 DM, and 6 (8.7%) were others for DM. The 20/20% consistency achieved 91.82%, which was higher than the target 65%. The percentage of A + B zones of Clarke and consensus error grid was 99.22% and 99.90%, respectively. The MARD value was 8.83% ± 4.03%. The mean score of usability questionnaire was 86.59 ± 5.17 out of 90. AE were observed in only one participant (mild fever), and no severe AEs occurred.

Conclusions

The SiJoy GS1 CGM system achieved satisfactory performance and usability. No severe AEs occurred and mild AE was reported in only one case.

Possibility of Venous Serum Cl- Concentration ([Cl-]s) as a Marker for Human Metabolic Status: Correlation of [Cl-]s to Age, Fasting Blood Sugar (FBS), and Glycated Hemoglobin (HbA1c)

The HCO₃⁻ concentration in venous serum ([HCO₃⁻]_s) is a factor commonly used for detecting the body pH and metabolic conditions. To exactly detect [HCO₃⁻]_s, the venous CO₂ pressure should be kept as it is in the vein. The [HCO₃⁻]_s measurement is technically complicated to apply for huge numbers of almost heathy persons taking only basic medical examinations. The summation of [HCO₃⁻]_s and the venous serum Cl⁻ concentration ([Cl⁻]_s) is approximately constant; therefore, we studied if [Cl⁻]_s could be a marker detecting metabolic conditions instead of [HCO₃⁻]_s. Venous blood was obtained from persons taking basic medical examinations (the number of persons = 107,630). Older persons showed higher values of [Cl⁻]_s, fasting blood sugar (FBS), and glycated hemoglobin (HbA1c) than younger ones. [Cl⁻]_s showed positive correlation to age and negative correlation to FBS and HBA1c. The negative correlation of [Cl⁻]_s to FBS/HbA1c was obvious in persons with high FBS/HbA1c, leading us to an idea that persons with high FBS/HbA1c show high [HCO₃⁻]_s, which might be caused by low activity of carbonic anhydrase in the lung observed in persons with diabetes mellitus under acidotic conditions. Taken together, an easily measured serum electrolyte, [Cl⁻]_s, could be a useful marker estimating metabolic conditions.

Time in Range as a Research Outcome Measure

Time in range (TIR) is gaining ground as an outcome measure in type 1 diabetes trials. However, inclusion of TIR raises several issues for trial design. In this article, the authors begin by defining TIR and describing the current international consensus around TIR targets. They then expand on evidence for the validity of TIR as a primary clinical trial outcome before concluding with some practical, ethical, and logistical implications.