Continuous Glucose Monitoring: A Review of Recent Studies Demonstrating Improved Glycemic Outcomes

Non-adjunctive flash glucose monitoring system use during summer-camp in children with type 1 diabetes: The free-summer study

BACKGROUND

A factory-calibrated sensor for intermittently scanned continuous glucose monitoring (isCGM) is accurate and safe in children with type 1 diabetes (T1D). Data on isCGM effectiveness as a replacement for self-monitoring of blood glucose (SMBG) in this population is scarce.

OBJECTIVE

The aim of this study was to evaluate the non-adjunctive use of isCGM in children with T1D during 2 weeks in a challenging summer-camp setting.

METHODS

In this two-arm, parallel, randomized, outpatient clinical trial we enrolled 46 children (25 females, mean ± SD: age 11.1 ± 2.6 years, glycated hemoglobin (HbA1c) 7.4% ± 0.7%): 26 in the isCGM group were blinded for the SMBG and insulin dosing was isCGM-based, whereas 20 in the control group were blinded for isCGM and performed SMBG-based insulin dosing. The primary outcome of intention-to-treat analysis was between-group difference in the proportion of time within range 3.9 to 10 mmol/L (TIR).

RESULTS

There was no significant difference in TIR (3.9-10 mmol/L) between the two groups. In participants with suboptimal metabolic control (HbA1c > 7%) we observed a significant reduction in time spent above 10 mmol/L (P < 0.05) and an improvement in TIR (P = 0.05) in the isCGM group. No severe hypoglycemic events or serious adverse events occurred. Overall mean absolute relative difference (MARD) between isCGM and SMBG was 18.3%, with median absolute relative difference (ARD) of 8%. Consensus error grid analysis demonstrated 82.2% and 95.2% of results in zone A, and zone A + B, respectively.

CONCLUSION

The non-adjunctive use of isCGM was as safe and effective as SMBG, and reduced time spent in hyperglycemia in a sub-population of children with T1D with suboptimal glycemic control.

TRIAL REGISTRATION

NCT03182842.

Understanding of type 1 diabetes mellitus: what we know and where we go

The incidence of type 1 diabetes mellitus (T1DM) in children and adolescents is increasing worldwide. Combined effects of genetic and environmental factors cause T1DM, which make it difficult to predict whether an individual will inherit the disease. Due to the level of self-care necessary in T1DM maintenance, it is crucial for pediatric settings to support achieving optimal glucose control, especially when adolescents are beginning to take more responsibility for their own health. Innovative insulin delivery systems, such as continuous subcutaneous insulin infusion (CSII), and noninvasive glucose monitoring systems, such as continuous glucose monitoring (CGM), allow patients with T1DM to achieve a normal and flexible lifestyle. However, there are still challenges in achieving optimal glucose control despite advanced technology in T1DM administration. In this article, disease prediction and current management of T1DM are reviewed with special emphasis on biomarkers of pancreatic β-cell stress, CSII, glucose monitoring, and several other adjunctive therapies.

Retrospective Analysis of 3-Month Real-World Glucose Data After the MiniMed 670G System Commercial Launch

Real-world data from the first 3141 patients who completed 3 months of SmartGuard™ Auto Mode-enabled MiniMed™ 670G system use during the MiniMed 670G System Commercial Launch are reported. CareLink™ system data uploaded by real-world patients in the Commercial Launch from March 17, 2017 to December 31, 2017 were deidentified and analyzed. Comparisons of overall and night (10:00 PM-07:00 AM) time spent below, within, and above target glucose range (TIR) (70-180 mg/dL) between the baseline Manual Mode and closed-loop Auto Mode periods were made. These were evaluated alongside data from the 124 patients (aged 14-75 years) who completed the 3-month MiniMed 670G system pivotal trial (NCT 2463097), from June 2, 2015 to March 7, 2016. Real-world patients used Auto Mode a median 80.8% of the time (19 h and 24 min of the day). The overall mean of time spent in TIR was 66.0% during baseline Manual Mode versus 73.3% during Auto Mode (P < 0.001); the mean percentage of sensor glucose values <70 mg/dL was 2.7% versus 2.1% (P < 0.001); and that >180 mg/dL was 31.4% versus 24.6% (P < 0.001). The nighttime and early morning (03:00 AM-06:00 AM) TIR during Auto Mode was greater than that during baseline Manual Mode (nighttime: 77.2% vs. 67.4% [P < 0.001], early morning: 70.9% vs. 84.6% [P < 0.001]). Similar differences between Manual Mode and Auto Mode TIR were observed across different age groups. A slight increase in total insulin delivered was also observed. Consistent with improved glycemic control demonstrated in the pivotal trial, analysis of CareLink system data from >3000 real-world patients who completed 3 months of Auto Mode-enabled MiniMed 670G system use demonstrated increased TIR and decreased time below and above TIR compared with baseline. These improved clinical outcomes were observed across a broad age range of patients with type 1 diabetes.

Evaluation of the FreeStyle® Libre Flash Glucose Monitoring System in Children and Adolescents with Type 1 Diabetes

BACKGROUND/AIMS

The FreeStyle® Libre Flash Glucose Monitoring System (FGM, Abbott) measures glucose concentrations in the interstitial fluid for up to 14 days. It has been approved for use in children aged > 4 years in January 2016. Experience in children is still limited. We evaluated the accuracy and usability of the FGM in children with type 1 diabetes mellitus (DM).

METHODS

67 children with type 1 DM (35 girls), aged 4-18 years, were included. Subjects wore a sensor on the back of their upper arm. For the first 14 days, they regularly measured capillary blood glucose (BG) with their usual BG meter (Accu-Chek® Mobile [ACM], Roche [n = 24]; Contour® Next Link [CNL], Bayer [n = 26]; OneTouch® Verio® IQ [OTV], LifeScan [n = 17]) followed by a sensor glucose (SG) scanning. SG readings were compared to BG measurements by consensus error grid (CEG) analysis; the mean difference (MD), the mean relative difference (MRD), the mean absolute difference (MAD), and the mean absolute relative difference (MARD) were calculated. After 14 days, subjects were asked to fill in a questionnaire on the usability of the FGM.

RESULTS

2,626 SG readings were paired with BG results. FGM readings were highly correlated with BG (r = 0.926, p < 0.001). 80.3% of the data pairs were in zone A (= no effect on clinical action) and 18.4% were in zone B (= altered clinical action with little or no effect on the clinical outcome) of the CEG. Overall MD was +7.5 mg/dL; MD varied with the BG meter: ACM +10.4 mg/dL, CNL +14.2 mg/dL, OTV -3.6 mg/dL (p < 0.001). Overall, MARD was 16.7%. We observed a large interindividual variability in the accuracy parameters. MD and MRD were inversely related to BMI (r = -0.261 [p < 0.05]; r = -0.266 [p < 0.05], respectively). MARD was inversely related to age (r = -0.266 [p < 0.05]). Twenty-nine patients (43.3%) reported sensor problems, mainly early detachment of the sensor. Nonetheless, the usability questionnaire indicated high levels of satisfaction.

CONCLUSIONS

Our results showed a reasonable agreement between the FGM SG readings and capillary BG measurements in children. There was, however, a large interindividual variability. The wearing of the sensor requires special attention. Further studies in children are imperative in order to document the accuracy and safety of the FGM in the paediatric population.

Self-measurement of Blood Glucose and Continuous Glucose Monitoring - Is There Only One Future?

Monitoring glycaemic control in patients with diabetes has evolved dramatically over the past decades. The introduction of easy-to-use systems for self-monitoring of blood glucose (SMBG) utilising capillary blood samples has resulted in the availability of a wide range of systems, providing different measurement quality. Systems for continuous glucose monitoring (CGM) – used mainly in patients with type 1 diabetes (T1D) – were made possible by the development of glucose sensors that measure glucose levels in the interstitial fluid (ISF) in the subcutaneous tissue of the skin. CGM readings might not correspond exactly to SMBG measurement results taken at the same time, especially during rapid changes in either blood glucose or ISF glucose levels. The mean absolute relative difference is the most popular method used for characterising the measurement performance of CGM systems. Unlike the International Organization for Standardization 15197:2013 criteria for SMBG systems, no accuracy standards for CGM systems exist. Measurement quality of CGM systems can vary based on several factors, limiting their safety and effective use in managing diabetes. Patients have to be trained adequately to make safe and efficient use of CGM systems (like with SMBG systems). Also, systems for CGM must be evaluated in terms of patient safety and the ability to provide accurate measurements regardless of the fluctuation of glucose levels. As new technological advancements in glucose monitoring are essential for improved management options of diabetes, such as automated insulin dosing systems, there is a need for a critical view of all such developments. It is likely that both, SMBG and CGM systems, will play important future roles in the treatment of diabetes.

The Digital Outcome Measure

Improving clinical outcomes remains the gold standard in advancing healthcare. Focusing on outcomes holds the potential to unite all clinical stakeholders including payers, industry, providers, and patients. Yet, the dominant ways in which outcomes are captured, provider-collected or patient-reported, have significant limitations. The emerging field of biosensors and wearables, which aims to capture many types of health data, holds promise to specifically capture outcomes while complementing existing outcome collection methods. A digital outcome measure, unlike a traditional provider-collected or patient-reported outcome measure, depends less on active patient or provider participation. Thus, digital outcome measures may be more amenable to standardization as well as greater collection consistency, frequency, and accuracy.

Diabetes Technology Update: Use of Insulin Pumps and Continuous Glucose Monitoring in the Hospital

The use of continuous subcutaneous insulin infusion (CSII) and continuous glucose monitoring (CGM) systems has gained wide acceptance in diabetes care. These devices have been demonstrated to be clinically valuable, improving glycemic control and reducing risks of hypoglycemia in ambulatory patients with type 1 diabetes and type 2 diabetes. Approximately 30-40% of patients with type 1 diabetes and an increasing number of insulin-requiring patients with type 2 diabetes are using pump and sensor technology. As the popularity of these devices increases, it becomes very likely that hospital health care providers will face the need to manage the inpatient care of patients under insulin pump therapy and CGM. The American Diabetes Association advocates allowing patients who are physically and mentally able to continue to use their pumps when hospitalized. Health care institutions must have clear policies and procedures to allow the patient to continue to receive CSII treatment to maximize safety and to comply with existing regulations related to self-management of medication. Randomized controlled trials are needed to determine whether CSII therapy and CGM systems in the hospital are associated with improved clinical outcomes compared with intermittent monitoring and conventional insulin treatment or with a favorable cost-benefit ratio.

Effectiveness and acceptability of continuous glucose monitoring for type 2 diabetes management: A narrative review

The present narrative review discusses the role of continuous glucose monitoring (CGM) in glycemic and weight control, and lifestyle behavior adherence in adults with type 2 diabetes. A literature search from January 2001 to November 2017 was carried out (MEDLINE, CINAHL, Web of Science and Scopus). Eligible studies were trials evaluating the use of CGM with the aim of achieving glucose control or lifestyle-related treatment adherence over a period of ≥8 weeks in adults with type 2 diabetes compared with usual care or another comparison intervention, or observational trials reporting CGM user experience. A total of 5,542 participants were recruited into 11 studies (eight randomized controlled trials [n = 5,346] and three observational studies [n = 196]). The sample size ranged 6-4,678 participants, the mean age was 51.7-60.0 years and diabetes duration was 2.1-19.2 years, with high heterogeneity between studies. Overall, the available evidence showed, compared with traditional self-monitoring of blood glucose levels, CGM promoted greater reductions in glycated hemoglobin, bodyweight and caloric intake; higher adherence rating to a personal eating plan; and increases in physical activity. High compliance to CGM wear-time and device calibration was reported (>90%). The addition of lifestyle and/or behavioral counseling to CGM appeared to further potentiate these improvements. Preliminary evidence suggests that CGM use promotes glycemic and weight control, and lifestyle behavior adherence in adults with type 2 diabetes. These benefits might be further enhanced with integration of diet, exercise, and glucose excursion education and counseling. However, specific attributes of effective interventions and the application of CGM information for promoting improved outcomes and healthier choices remain unclear.

The new FreeStyle libre flash glucose monitoring system improves the glycaemic control in a cohort of people with type 1 diabetes followed in real-life conditions over a period of one year

AIMS

Using the novel FreeStyle Libre (FSL), glucose monitoring (FGM) system becomes increasingly popular among people with type 1 diabetes (T1D) and is associated with less and shorter hypoglycaemic events without deterioration of HbA1c. There are not yet data reporting the impact of FGM in people with T1D in real-life conditions. We sought of evaluating the tolerance, the acceptance and the efficacy of the FGM system in routine medical practice.

METHODS

This 12-month observational study included 120 individuals with T1D evaluated every 3 months. After having been instructed about FGM utilization, participants were trained to optimize the glycaemic control.

RESULTS

Participants stopped immediately of measuring capillary blood glucose (2.88 ± 0.12 per day) (mean ± SEM) after having received the first FSL device and the number of scans per day increased up to 8.87 ± 0.58 per day. HbA1c levels decreased from 8.51% ± 0.14% at baseline to 7.77% ± 0.09% after 3 months to slightly increase to 7.92% ± 0.09% at 12 months, in correlation with the number of scans per day. The number (but not the duration) of hypoglycaemic events slightly increased from 16.9 ± 1.44 per month at baseline to 24.0 ± 2.91 per month at 12 months, after reaching a peak of 26.4 ± 2.31 per month at 6 months. They were correlated with improved HbA1c.

CONCLUSION

Our study shows that using the FGM system improves HbA1c levels in people with T1D along with a moderate increase in the number of mild hypoglycaemic events. The new FGM system facilitates the therapeutic empowerment of people with T1D, but in a context of structured education.

Skin Problems Associated with Insulin Pumps and Sensors in Adults with Type 1 Diabetes: A Cross-Sectional Study

BACKGROUND

In the future, widespread use of closed-loop infusion (artificial pancreas) systems to treat type 1 diabetes (T1D) may significantly improve glycemic control and enhance treatment flexibility. However, the infusion sets and plasters necessary for these treatments can cause dermatological complications that may hamper the spread of the new technology; few studies have investigated these complications in adults. The aim of this study was to describe the dermatological complications associated with continuous subcutaneous insulin infusion (CSII) and continuous glucose monitoring (CGM) in adults.

METHODS

A total of 118 adult patients from two different diabetes clinics completed a questionnaire concerning the dermatological complications associated with their CSII and/or CGM treatment, other treatment variables, duration of diabetes, allergies, skin care, and other pathologies.

RESULTS

CGM or CSII use was associated with current eczema, scars, and wounds. In total, 34% of CSII users and 35% of CGM users currently had one or more skin lesions due to the use of these devices. We found no significant association with glycated hemoglobin (HbA1c) levels, a history of atopic dermatitis, or other skin pathologies. However, multivariate analysis revealed associations with a history of atopy and CSII-associated dermatological complications.

CONCLUSIONS

Dermatological complications were present in one in every three patients and represent a significant challenge to using CSII and CGM to treat adults with T1D. Prospective studies on the causes of these complications will be required to develop preventive strategies and ensure that optimal diabetes treatment approaches that take advantage of the latest technology can be implemented.

Clinical value of Flash glucose monitoring in patients with type 1 diabetes treated with continuous subcutaneous insulin infusion

AIM

To analyze the clinical impact of the Flash glucose monitoring system in patients with type 1 diabetes mellitus (T1DM) treated with continuous subcutaneous insulin infusion (CSII).

METHODS

A 24-week retrospective cohort study in CSII-treated T1DM patients exposed (1:1) to the Flash glucose monitoring system vs. self-monitoring of capillary blood glucose (SMBG). The primary outcome was the difference in hemoglobin A1c (HbA1c) levels between both groups at the end of the study.

RESULTS

Thirty-six patients with a mean age of 38.2 years (range 22-55) and a mean T1DM duration of 20.9±7.8 years, treated with CSII for 7.1±5.4 years, were enrolled into the study. At the end of the study, mean HbA1c levels improved in patients in the Flash group (7.1±0.7 vs. 7.8±1.0, p=0.04). Only the Flash group showed a significant decrease in HbA1c levels of -0.4% (95% CI, -0.6, -0.2; p=0.004) during follow-up. Flash patients captured 93.9% of data through 17.8±9.9 scans daily. In fact, the Flash cohort showed a three-fold increase in daily self-monitoring of glucose, while daily frequency of SMBG decreased during the study (-1.8 tests/24h (95% CI -3, -0.7; p=0.01). No safety issues related to Flash use were recorded.

CONCLUSIONS

The Flash glucose monitoring system is a novel approach to improve blood glucose control in CSII-treated T1DM patients. Randomized controlled trials are needed to assess the effectiveness of this system in CSII-treated T1DM patients.

Glucose Management during Insulinoma Resection Using Real-Time Subcutaneous Continuous Glucose Monitoring

Insulinoma is a rare neuroendocrine tumor that causes hypoglycemia due to unregulated insulin secretion. Blood glucose management during insulinoma resection is therefore challenging. We present a case in which real-time subcutaneous continuous glucose monitoring (SCGM) in combination with intermittent blood glucose measurement was used for glycemic control during surgery for insulinoma resection. The SCGM system showed the trends and peak of interstitial glucose in response to glucose loading and the change of interstitial glucose before and after insulinoma resection. These data were helpful for adjusting the glucose infusion; therefore, we think that an SCGM system as a supportive device for glucose monitoring may be useful for glucose management during surgery.

Challenges and perspectives in continuous glucose monitoring

Diabetes is a global epidemic that threatens the health and well-being of hundreds of millions of people. The first step in patient treatment is to monitor glucose levels. Currently this is most commonly done using enzymatic strips. This approach suffers from several limitations, namely it requires a blood sample and is therefore invasive, the quality and the stability of the enzymatic strips vary widely, and the patient is burdened by performing the measurement themselves. This results in dangerous fluctuations in glucose levels often going undetected. There is currently intense research towards new approaches in glucose detection that would enable non-invasive continuous glucose monitoring (CGM). In this review, we explore the state-of-the-art in glucose detection technologies. In particular, we focus on the physical mechanisms behind different approaches, and how these influence and determine the accuracy and reliability of glucose detection. We begin by reviewing the basic physical and chemical properties of the glucose molecule. Although these play a central role in detection, especially the anomeric ratio, they are surprisingly often overlooked in the literature. We then review state-of-the art and emerging detection methods. Finally, we survey the current market for glucometers. Recent results show that past challenges in glucose detection are now being overcome, thereby enabling the development of smart wearable devices for non-invasive continuous glucose monitoring. These new directions in glucose detection have enormous potential to improve the quality of life of millions of diabetics, as well as offer insight into the development, treatment and even prevention of the disease.

Optimization of Insulin Regimen and Glucose Outcomes with Short-Term Real-Time Continuous Glucose Monitoring in Adult Type 1 Diabetes Patients with Suboptimal Control on Multiple Daily Injections: The Adult DIACCOR Study

BACKGROUND

The impact of a 7-day real-time continuous glucose monitoring (RT-CGM) on type 1 diabetes (T1D) management remains unclear in patients suboptimally controlled by multiple daily injections (MDI). The DIACCOR Study aimed to describe treatment decisions and glucose outcomes after a short-term RT-CGM sequence.

PATIENTS AND METHODS

This French multicenter longitudinal observational study included T1D patients with HbA1c >7.5% or history of severe hypoglycemia (SH) or recurrent documented hypoglycemia. A sensor was inserted at the inclusion visit, treatment changes were proposed by the investigator within 7-15 days ("INT" = MDI intensification, "CSII" = switch to continuous insulin infusion, or "ER" = educational reinforcement with no change in insulin regimen), and a 4-month follow-up visit (M4) was scheduled.

RESULTS

Four hundred fifty-nine patients were recruited by 155 diabetologists, 17.0% had SH history, and 24.2% had recurrent hypoglycemia. Baseline HbA1c was 8.34% ± 1.21% (>7.5% in 79.6%). Overall, 253 (64.4%), 64 (16.3%), and 76 patients (19.3%) were, respectively, included in the "INT," "CSII," and "ER" subgroups. The number of patients who experienced SH or recurrent hypoglycemia dropped dramatically (7.9% vs. 17.0% and 10.8% vs. 24.2%, respectively). The same trend was observed for ketoacidosis and ketosis (0.3% vs. 3.3% and 2.2% vs. 4.8%). At M4, HbA1c was significantly reduced in the whole cohort to 7.98% ± 1.01% (P < 0.0001). The adjusted differences in HbA1c level in the INT, CSII, and ER subgroups were, respectively, -0.32%, -0.69%, and -0.50% (P < 0.0001 for all).

CONCLUSION

In real-life setting, a 1-week diagnostic RT-CGM supports appropriate treatment changes in patients with uncontrolled T1D resulting in better glucose control and less hypoglycemia.

[The status of glycemic control and hypoglycemia in elderly patients visiting the outpatient department specializing in diabetes]

AIM

The Japan Diabetes Society (JDS)/Japan Geriatrics Society (JGS) Joint Committee reported 'Glycemic Targets for Elderly Patients with Diabetes' in 2016. Based on this recommendation, we aimed to clarify 1) the achievement status of glycemic targets in the elderly and 2) the presence of hypoglycemia in real life among elderly individuals with an HbA1c below the lower limit.

SUBJECTS AND METHODS

[Analysis I] In 326 elderly with diabetes ≥65 years of age visiting the outpatient department specializing in diabetes, the proportions of patients with HbA1c values below the lower limit and the use of drugs potentially associated with severe hypoglycemia (e.g. insulin formulations, sulfonylureas, glinides) were investigated. [Analysis II] Of the patients with HbA1c values below the lower limit, seven were tested for hypoglycemia in real life using a continuous glucose monitoring system (CGM).

RESULTS

[Analysis I] Among the 326 subjects, 235 (72.1%) were using drugs potentially associated with severe hypoglycemia, and 63 (19.3%) had an HbA1c value below the lower limit. [Analysis II] In the seven patients examined using CGM, hypoglycemia was detected in five, all of whom were unaware.

CONCLUSIONS

A considerable number of elderly patients were taking drugs associated with hypoglycemic risks and had an HbA1c value below the lower limit, some of whom actually had hypoglycemia as detected by CGM. Using tools such as CGM, preventive measures against hypoglycemia should be taken.

Prediction of Adverse Glycemic Events From Continuous Glucose Monitoring Signal

The most important objective of any diabetes therapy is to maintain the blood glucose concentration within the euglycemic range, avoiding or at least mitigating critical hypo/hyperglycemic episodes. Modern continuous glucose monitoring (CGM) devices bear the promise of providing the patients with an increased and timely awareness of glycemic conditions as these get dangerously near to hypo/hyperglycemia. The challenge is to detect, with reasonable advance, the patterns leading to risky situations, allowing the patient to make therapeutic decisions on the basis of future (predicted) glucose concentration levels. We underline that a technically sound performance comparison of the approaches proposed in recent years has yet to be done, thus it is unclear which one is preferred. The aim of this study is to fill this gap by carrying out a comparative analysis among the most common methods for glucose event prediction. Both regression and classification algorithms have been implemented and analyzed, including static and dynamic training approaches. The dataset consists of 89 CGM time series measured in diabetic subjects for 7 subsequent days. Performance metrics, specifically defined to assess and compare the event-prediction capabilities of the methods, have been introduced and analyzed. Our numerical results show that a static training approach exhibits better performance, in particular when regression methods are considered. However, classifiers show some improvement when trained for a specific event category, such as hyperglycemia, achieving performance comparable to the regressors, with the advantage of predicting the events sooner.

Bridging technology and clinical practice: innovating inpatient hyperglycaemia management in non-critical care settings

Emerging evidence shows that suboptimal glycaemic control is associated with increased morbidity and length of stay in hospital. Various guidelines for safe and effective inpatient glycaemic control in the non-critical care setting have been published. In spite of this, implementation in practice remains limited because of the increasing number of people with diabetes admitted to hospital and staff work burden. The use of technology in the outpatient setting has led to improved glycaemic outcomes and quality of life for people with diabetes. There remains an unmet need for technology utilisation in inpatient hyperglycaemia management in the non-critical care setting. Novel technologies have the potential to provide benefits in diabetes care in hospital by improving efficacy, safety and efficiency. Rapid analysis of glucose measurements by point-of-care devices help facilitate clinical decision-making and therapy adjustment in the hospital setting. Glucose treatment data integration with computerized glucose management systems underpins the effective use of decision support systems and may streamline clinical staff workflow. Continuous glucose monitoring and automation of insulin delivery through closed-loop systems may provide a safe and efficacious tool for hospital staff to manage inpatient hyperglycaemia whilst reducing staff workload. This review summarizes the evidence with regard to technological methods to manage inpatient glycaemic control, their limitations and the future outlook, as well as potential strategies by healthcare organizations such as the National Health Service to mediate the adoption, procurement and use of diabetes technologies in the hospital setting.

Accuracy of Continuous Glucose Monitoring before, during, and after Aerobic and Anaerobic Exercise in Patients with Type 1 Diabetes Mellitus

Continuous glucose monitoring (CGM) plays an important role in treatment decisions for patients with type 1 diabetes under conventional or closed-loop therapy. Physical activity represents a great challenge for diabetes management as well as for CGM systems. In this work, the accuracy of CGM in the context of exercise is addressed. Six adults performed aerobic and anaerobic exercise sessions and used two Medtronic Paradigm Enlite-2 sensors under closed-loop therapy. CGM readings were compared with plasma glucose during different periods: one hour before exercise, during exercise, and four hours after the end of exercise. In aerobic sessions, the median absolute relative difference (MARD) increased from 9.5% before the beginning of exercise to 16.5% during exercise (p < 0.001), and then decreased to 9.3% in the first hour after the end of exercise (p < 0.001). For the anaerobic sessions, the MARD before exercise was 15.5% and increased without statistical significance to 16.8% during exercise realisation (p = 0.993), and then decreased to 12.7% in the first hour after the cessation of anaerobic activities (p = 0.095). Results indicate that CGM might present lower accuracy during aerobic exercise, but return to regular operation a few hours after exercise cessation. No significant impact for anaerobic exercise was found.

Hope vs hype: where are we in type 1 diabetes?

Much progress has been made in type 1 diabetes research. Biological replacement of islet function has been achieved with pancreas transplantation and with islet transplantation. In the future, human embryonic stem cells and/or induced pluripotent stem cells may offer a potentially unlimited source of cells for islet replacement. Another potential strategy is to induce robust beta cell replication so that regeneration of islets can be achieved. Immune interventions are being studied with the hope of arresting the type 1 diabetes disease process to either prevent the disease or help preserve beta cell function. Mechanical replacement of islet cell function involves the use of glucose sensor-controlled insulin infusion systems. As all of these avenues are pursued, headlines often overstate the case, thus hyping any given advance, which provides enormous hope for patients and families seeking a cure for type 1 diabetes. Often, however, it is an animal study or a pilot trial that is being described. The reality is that translation to successful trials in human beings may not be readily achievable. This article discusses both the hype and the hopes in type 1 diabetes research.

Accuracy, User Acceptability, and Safety Evaluation for the FreeStyle Libre Flash Glucose Monitoring System When Used by Pregnant Women with Diabetes

BACKGROUND

Accuracy of the FreeStyle Libre™ Flash Glucose Monitoring System has not been evaluated in pregnant women with diabetes. The aim of this study was to determine accuracy (compared to self-monitoring of blood glucose [SMBG]), clinical safety, and acceptability of the FreeStyle Libre System when used at home by this population.

MATERIALS AND METHODS

Seventy-four participants, with type 1 (T1D, n = 24), type 2 (T2D, n = 11), or gestational (n = 39) diabetes, were enrolled across 13 sites (9 in United Kingdom, 4 in Austria). Average gestation was 26.6 ± 6.8 weeks (mean ± standard deviation), age was 30.5 ± 5.1 years, diabetes duration was 13.1 ± 7.3 years for T1D and 3.2 ± 2.5 years for T2D, and 49/74 (66.2%) used insulin to manage their diabetes. Sensors were worn for up to 14 days. Sensor glucose values (masked) were compared with capillary SMBG values (made at least 4 times/day).

RESULTS

Clinical accuracy of sensor results versus SMBG results was demonstrated, with 88.1% and 99.8% of results within Zone A and Zones A and B of the Consensus Error Grid, respectively. Overall mean absolute relative difference was 11.8%. Sensor accuracy was unaffected by the type of diabetes, the stage of pregnancy, whether insulin was used, age or body mass index. User questionnaires indicated high levels of satisfaction with sensor wear, system use, and comparison to SMBG. There were no unanticipated device-related adverse events.

CONCLUSIONS

Good agreement was demonstrated between the FreeStyle Libre System and SMBG. Accuracy of the system was unaffected by patient characteristics, indicating that the system is safe and accurate to use by pregnant women with diabetes.

Interstitial Glucose and Physical Exercise in Type 1 Diabetes: Integrative Physiology, Technology, and the Gap In-Between

Continuous and flash glucose monitoring systems measure interstitial fluid glucose concentrations within a body compartment that is dramatically altered by posture and is responsive to the physiological and metabolic changes that enable exercise performance in individuals with type 1 diabetes. Body fluid redistribution within the interstitial compartment, alterations in interstitial fluid volume, changes in rate and direction of fluid flow between the vasculature, interstitium and lymphatics, as well as alterations in the rate of glucose production and uptake by exercising tissues, make for caution when interpreting device read-outs in a rapidly changing internal environment during acute exercise. We present an understanding of the physiological and metabolic changes taking place with acute exercise and detail the blood and interstitial glucose responses with different forms of exercise, namely sustained endurance, high-intensity, and strength exercises in individuals with type 1 diabetes. Further, we detail novel technical information on currently available patient devices. As more health services and insurance companies advocate their use, understanding continuous and flash glucose monitoring for its strengths and limitations may offer more confidence for patients aiming to manage glycemia around exercise.

Practical guidance for treatment of patients with diabetes using flash glucose monitoring: a pilot study

BACKGROUND

Flash glucose monitoring (FGM) is a factory-calibrated, blood glucose measuring sensor system for patients with diabetes. We aimed to investigate the correlation between the sensor glucose (SG) value obtained using an FGM device and the traditional self-monitoring of blood glucose (SMBG) value.

METHODS

In 30 patients with diabetes under insulin treatment, SG and SMBG values were measured for 2 weeks, and the correlation between the values was analyzed.

RESULTS

The mean number of accumulated measurements of SG values was 1223.2 ± 193.0, whereas that of the SMBG values was 49.2 ± 21.3. Although SG and SMBG values showed a favorable correlation (R²  = 0.8413), SG values were lower than SMBG values by an average of 7.9 ± 29.8 mg/dL. The correlation patterns fell into four types: low type (SG values lower than SMBG values; n = 12), high type (SG values higher than SMBG values; n = 3), cross type (the slope of the two regression lines crossed at a certain measurement value; n = 14), and matching type (the values overlapped; n = 1).

CONCLUSIONS

Recognition of the characteristic correlation patterns between SG and SMBG values is indispensable for certified diabetes educators to provide appropriate treatment guidance to patients with diabetes.

Variables to Be Monitored via Biomedical Sensors for Complete Type 1 Diabetes Mellitus Management: An Extension of the "On-Board" Concept

Type 1 diabetes mellitus (DM1) is a growing disease, and a deep understanding of the patient is required to prescribe the most appropriate treatment, adjusted to the patient's habits and characteristics. Before now, knowledge regarding each patient has been incomplete, discontinuous, and partial. However, the recent development of continuous glucose monitoring (CGM) and new biomedical sensors/gadgets, based on automatic continuous monitoring, offers a new perspective on DM1 management, since these innovative devices allow the collection of 24-hour biomedical data in addition to blood glucose levels. With this, it is possible to deeply characterize a diabetic person, offering a better understanding of his or her illness evolution, and, going further, develop new strategies to manage DM1. This new and global monitoring makes it possible to extend the "on-board" concept to other features. This well-known approach to the processing of variable "insulin" describes some inertias and aggregated/remaining effects. In this work, such analysis is carried out along with a thorough study of the significant variables to be taken into account/monitored-and how to arrange them-for a deep characterization of diabetic patients. Lastly, we present a case study evaluating the experience of the continuous and comprehensive monitoring of a diabetic patient, concluding that the huge potential of this new perspective could provide an acute insight into the patient's status and extract the maximum amount of knowledge, thus improving the DM1 management system in order to be fully functional.

Towards a quantum cascade laser-based implant for the continuous monitoring of glucose

Anin vitroinvestigation of a quantum cascade laser-based transflection optofluidic interface for the continuous glucose monitoring in biofluids is presented with respect to its glucose sensitivity and specificity, its glucose exchange time, its resistance against temperature variations and its long-term stability.

A Pilot Randomized-Controlled Trial on the Effect of CPAP Treatment on Glycemic Control in Gestational Diabetes: Study Design and Methods

Background: Gestational diabetes (GDM) is associated with adverse short- and long-term maternal and fetal outcomes. Observational data support a link between sleep-disordered breathing (SDB) during pregnancy and GDM. However, it is unknown whether treatment of SDB with continuous positive airway pressure (CPAP) improves glucose control in this patient population. In addition, CPAP adherence and feasibility as a treatment option in pregnancy is unknown. This pilot randomized, controlled trial aims to primarily determine the feasibility of CPAP treatment in pregnant women with SDB and GDM. This study is also investigating the effect of SDB treatment on 24-h glucose profiles as an exploratory outcome. Objectives: To describe the study methodology in this ongoing study of pregnant women with GDM and SDB. Patients and Methods: Pregnant women with GDM and SDB defined by apnea-hypopnea index (AHI) ≥10 (Chicago Scoring Criteria) on level 2 polysomnography are randomized to either auto titrating CPAP (experimental group) or a nasal dilator strip (control group) until delivery. The primary outcome, objectively-assessed adherence to CPAP, is measured over the course of the treatment period using device-specific software. Recruitment and retention rates will be calculated to assess the feasibility for planning future trials. Twenty-four hour glucose profiles are measured over a 72-h period using the continuous glucose monitoring (CGM) system, before and after the intervention. Conclusion: The results of this study will be highly informative to determine whether CPAP is a feasible treatment for pregnant women with GDM and SDB, a specialized population at risk for substantial comorbidity. The trial results will ultimately be useful in planning future SDB treatment trials in pregnancy and GDM. The study is registered on clinicaltrials.gov (NCT02245659).

Interdisciplinary approach to compensation of hypoglycemia in diabetic patients with chronic heart failure

Diabetes mellitus is a chronic disease requiring lifelong control with hypoglycemic agents that must demonstrate excellent efficacy and safety profiles. In patients taking glucose-lowering drugs, hypoglycemia is a common cause of death associated with arrhythmias, increased thrombus formation, and specific effects of catecholamines due to sympathoadrenal activation. Focus is now shifting from merely glycemic control to multifactorial approach. In the context of individual drugs and classes, this article reviews interdisciplinary strategies evaluating metabolic effects of drugs for treatment of chronic heart failure (CHF) which can mask characteristic hypoglycemia symptoms. Hypoglycemia unawareness and cardiac autonomic neuropathy are discussed. Data suggesting that hypoglycemia modulates immune response are reviewed. The potential role of gut microbiota in improving health of patients with diabetes and CHF is emphasized. Reports stating that nondiabetic CHF patients can have life-threatening hypoglycemia associated with imbalance of thyroid hormones are discussed. Regular glycemic control based on HbA1c measurements and adequate pharmacotherapy remain the priorities in diabetes management. New antihyperglycemic drugs with safer profiles should be preferred in vulnerable CHF patients. Multidrug interactions must be considered. Emerging therapies with reduced hypoglycemia risk, telemedicine, sensor technologies, and genetic testing predicting hypoglycemia risk may help solving the challenges of hypoglycemia in CHF patients with diabetes. Interdisciplinary work may involve cardiologists, diabetologists/endocrinologists, immunologists, gastroenterologists, microbiologists, nutritionists, imaging specialists, geneticists, telemedicine experts, and other relevant specialists. This review emphasizes that systematic knowledge on pathophysiology of hypoglycemia in diabetic patients with CHF is largely lacking and the gaps in our understanding require further discoveries.