The Landmark JDRF Continuous Glucose Monitoring Randomized Trials: a Look Back at the Accumulated Evidence

Effect of nationwide reimbursement of real-time continuous glucose monitoring on HbA1c, hypoglycemia and quality of life in a pediatric type 1 diabetes population: The RESCUE-pediatrics study

OBJECTIVE

Real-time continuous glucose monitoring (RT-CGM) can improve metabolic control and quality of life (QoL), but long-term real-world data in children with type 1 diabetes (T1D) are scarce. Over a period of 24 months, we assessed the impact of RT-CGM reimbursement on glycemic control and QoL in children/adolescents with T1D treated with insulin pumps.

RESEARCH DESIGN AND METHODS

We conducted a multicenter prospective observational study. Primary endpoint was the change in HbA1c. Secondary endpoints included change in time in hypoglycemia, QoL, hospitalizations for hypoglycemia and/or ketoacidosis and absenteeism (school for children, work for parents).

RESULTS

Between December 2014 and February 2019, 75 children/adolescents were followed for 12 (n = 62) and 24 months (n = 50). Baseline HbA1c was 7.2 ± 0.7% (55 ± 8mmol/mol) compared to 7.1 ± 0.8% (54 ± 9mmol/mol) at 24 months (p = 1.0). Participants with a baseline HbA1c ≥ 7.5% (n = 27, mean 8.0 ± 0.3%; 64 ± 3mmol/mol) showed an improvement at 4 months (7.6 ± 0.7%; 60 ± 8mmol/mol; p = 0.009) and at 8 months (7.5 ± 0.6%; 58 ± 7mmol/mol; p = 0.006), but not anymore thereafter (endpoint 24 months: 7.7 ± 0.9%; 61 ± 10mmol/mol; p = 0.2). Time in hypoglycemia did not change over time. QoL for parents and children remained stable. Need for assistance by ambulance due to hypoglycemia reduced from 8 to zero times per 100 patient-years (p = 0.02) and work absenteeism for parents decreased from 411 to 214 days per 100 patient-years (p = 0.03), after 24 months.

CONCLUSION

RT-CGM in pump-treated children/adolescents with T1D showed a temporary improvement in HbA1c in participants with a baseline HbA1c ≥ 7.5%, without increasing time in hypoglycemia. QoL was not affected. Importantly, RT-CGM reduced the need for assistance by ambulance due to hypoglycemia and reduced work absenteeism for parents after 24 months.

CLINICAL TRIAL REGISTRATION

[ClinicalTrials.gov], identifier [NCT02601729].

Survey about do-it-yourself closed loop systems in the treatment of diabetes in Germany

Continuous glucose monitoring (CGM) improves treatment with lower blood glucose levels and less patient effort. In combination with continuous insulin application, glycemic control improves and hypoglycemic episodes should decrease. Direct feedback of CGM to continuous subcutaneous insulin application, using an algorithm is called a closed-loop (CL) artificial pancreas system. Commercial devices stop insulin application by predicting hypoglycemic blood glucose levels through direct interaction between the sensor and pump. The prediction is usually made for about 30 minutes and insulin delivery is restarted at the previous level if a rise in blood glucose is predicted within the next 30 minutes (hybrid closed loop system, HCL this is known as a predictive low glucose suspend system (PLGS)). In a fully CL system, sensor and pump communicate permanently with each other. Hybrid closed-loop (HCL) systems, which require the user to estimate the meal size and provide a meal insulin basis, are commercially available in Germany at the moment. These systems result in fewer hyperglycemic and hypoglycemic episodes with improved glucose control. Open source initiatives have provided support by building do-it-yourself CL (DIYCL) devices for automated insulin application since 2014, and are used by a tech-savvy subgroup of patients. The first commercial hybrid CL system has been available in Germany since September 2019. We surveyed 1054 patients to determine which devices are currently used, which features would be in demand by potential users, and the benefits of DIYCL systems. 9.7% of these used a DIYCL system, while 50% would most likely trust these systems but more than 85% of the patients would use a commercial closed loop system, if available. The DIYCL users had a better glucose control regarding their time in range (TIR) and glycated hemoglobin (HbA1c).

Intersecting Health Policy and the Social Determinants of Health in Pediatric Type 1 Diabetes Management and Care

THEORETICAL PRINCIPLES

Type 1 diabetes health technologies are evolving. This is an expensive chronic condition to manage, hence a combination of public and private healthcare funding sources, as well as out-of-pocket payments support disease management. The aim of this paper is to describe two conceptual underpinnings, which can appropriately position the health policy and clinical context of pediatric type 1 diabetes management and care. PHENOMENA ADDRESSED: "The Main Determinants of Health" framework is used to position pediatric T1D management and care within the model's four interconnected layers: the structural environment, social and material conditions, support systems and individual health behaviors. A health policy in Ontario, Canada, the Assistive Devices Program for insulin pump therapy is also discussed relative to the model's outermost layer: the structural environment. Four dimensions of control, which characterize the "street-level bureaucrat" role including "distributing benefits and sanctions; structuring the context; teaching the client role; and, psychological benefits and sanctions" then position the policy context of the diabetes nurse educator role relative to the Assistive Devices Program policy.

RESEARCH LINKAGES

These conceptual underpinnings could extend beyond the pediatric T1D landscape to position global research in other nursing practice areas, as well as with other patient populations and professional disciplines such as social work and medicine.

Analyzing breath samples of hypoglycemic events in type 1 diabetes patients: towards developing an alternative to diabetes alert dogs

Diabetes is a disease that involves dysregulation of metabolic processes. Patients with type 1 diabetes (T1D) require insulin injections and measured food intake to maintain clinical stability, manually tracking their results by measuring blood glucose levels. Low blood glucose levels, hypoglycemia, can be extremely dangerous and can result in seizures, coma, or even death. Canines trained as diabetes alert dogs (DADs) have demonstrated the ability to detect hypoglycemia from breath, which led us to hypothesize that hypoglycemia, a metabolic dysregulation leading to low blood glucose levels, could be identified through analyzing volatile organic compounds (VOCs) contained within breath. We hoped to replicate the canines' detection ability and success by analytically using gas chromatography/mass spectrometry of VOCs in 128 breath samples collected from 52 youths with T1D at two different diabetes camps. We used different tests for significance including Ranksum, Student's T-test, and difference between means, and found a subset of 56 traces of potential metabolites. Principle component and linear discriminant analysis (LDA) confirmed a hypoglycemic signature likely resides within this group. Supervised machine learning combined with LDA narrowed the list of likely components to seven. The technique of leave one out cross validation demonstrated the model thus developed has a sensitivity of 91% (95% confidence interval (CI) [57.1, 94.7]) and a specificity of 84% (95% CI [73.0, 92.7]) at identifying hypoglycemia. Confidence intervals were obtained by bootstrapping. These results demonstrate that it is possible to differentiate breath samples obtained during hypoglycemic events from all other breath samples by analytical means and could lead to developing a simple analytical monitoring device as an alternative to using DADs.

A Simple Composite Metric for the Assessment of Glycemic Status from Continuous Glucose Monitoring Data: Implications for Clinical Practice and the Artificial Pancreas

BACKGROUND

The potential clinical benefits of continuous glucose monitoring (CGM) have been recognized for many years, but CGM is used by a small fraction of patients with diabetes. One obstacle to greater use of the technology is the lack of simplified tools for assessing glycemic control from CGM data without complicated visual displays of data.

METHODS

We developed a simple new metric, the personal glycemic state (PGS), to assess glycemic control solely from continuous glucose monitoring data. PGS is a composite index that assesses four domains of glycemic control: mean glucose, glycemic variability, time in range and frequency and severity of hypoglycemia. The metric was applied to data from six clinical studies for the G4 Platinum continuous glucose monitoring system (Dexcom, San Diego, CA). The PGS was also applied to data from a study of artificial pancreas comparing results from open loop and closed loop in adolescents and in adults.

RESULTS

The new metric for glycemic control, PGS, was able to characterize the quality of glycemic control in a wide range of study subjects with various mean glucose, minimal, moderate, and excessive glycemic variability and subjects on open loop versus closed loop control.

CONCLUSION

A new composite metric for the assessment of glycemic control based on CGM data has been defined for use in assessing glycemic control in clinical practice and research settings. The new metric may help rapidly identify problems in glycemic control and may assist with optimizing diabetes therapy during time-constrained physician office visits.

How Can We Realize the Clinical Benefits of Continuous Glucose Monitoring?

Controlling glycemia in diabetes remains key to prevent complications in this condition. However, glucose levels can undergo large fluctuations secondary to daily activities, consequently creating management difficulties. The current review summarizes the basics of glucose management in diabetes by addressing the main glycemic parameters. The advantages and limitation of HbA1c, the gold standard measure of glucose control, are discussed together with the clinical importance of hypoglycemia and glycemic variability. The review subsequently moves focus to glucose monitoring techniques in diabetes, assessing advantages and limitations. Monitoring glucose levels is crucial for effective and safe adjustment of hypoglycemic therapy, particularly in insulin users. Self-monitoring of blood glucose (SMBG), based on capillary glucose testing, remains one of the most widely used methods to monitor glucose levels, given the relative accuracy, familiarity, and manageable costs. However, patient inconvenience and the sporadic nature of SMBG limit clinical effectiveness of this approach. In contrast, continuous glucose monitoring (CGM) provides a more comprehensive picture of glucose levels, but these systems are expensive and require constant calibration which, together with concerns over accuracy of earlier devices, restrict CGM use to special groups of patients. The newer flash continuous glucose monitoring (FCGM) system, which is more affordable than conventional CGM devices and does not require calibration, offers an alternative glucose monitoring strategy that comprehensively analyzes glucose profile while sparing patients the inconvenience of capillary glucose testing for therapy adjustment or CGM calibration. The fast development of new CGM devices will gradually displace SMBG as the main glucose testing method. Avoiding the inconvenience of SMBG and optimizing glycemia through alternative glucose testing strategies will help to reduce the risk of complications and improve quality of life in patients with diabetes.

Utility of Continuous Glucose Monitoring in Type 1 and Type 2 Diabetes

A consensus conference of the American Association of Clinical Endocrinologists and American College of Endocrinology held in February 2016 advocated expanding the use of continuous glucose monitoring (CGM) in the management of diabetes. Based on the data described in this paper, CGM use is shown to improve glucose control and reduce hypoglycemic events, and therefore has the potential to reduce the risk of acute and chronic complications of diabetes. Likely, all of the above would not only improve the quality of life and life expectancy of people with diabetes, but would also have a positive impact on health-related cost.

Continuous Glucose Monitoring, Future Products, and Update on Worldwide Artificial Pancreas Projects

The development of accurate and easy-to-use continuous glucose monitoring (CGM) improved diabetes treatment by providing additional temporal information on glycemia and glucose trends to patient and physician. Although CGM enables users to lower their average glucose level without an increased incidence of hypoglycemia, this comes at the price of additional patient effort. Automation of insulin administration, also known as closed-loop (CL) or artificial pancreas treatment, has the promise to reduce patient effort and improve glycemic control. CGM data serve as the conditional input for insulin automation devices. The first commercial product for partial automation of insulin administration used insulin delivery shutoff at a predefined glucose level. These systems showed a reduction in hypoglycemia. Insulin-only CL devices show increased time spent in euglycemia and a reduction of hypo- and hyperglycemia. Improved glycemic control, coinciding with a minor decrease in hemoglobin A1c level, was confirmed in recent long-term home studies investigating these devices, paving the way for pivotal studies for commercialization of the artificial pancreas. Although the first results from dual-hormone CL systems are promising, because of increased cost of consumables of these systems, long-term head-to-head studies will have to prove superiority over insulin-only approaches. Now CL glucose control for daily use might finally become reality. Improved continuous glucose sensing technology, miniaturization of electrical devices, and development of algorithms were key in making this possible. Clinical adoption challenges, including device usability and reimbursement, need to be addressed. Time will tell for which patient groups CL systems will be reimbursed and whether these devices can deliver the promise that they hold.

Hypoglycemic Accuracy and Improved Low Glucose Alerts of the Latest Dexcom G4 Platinum Continuous Glucose Monitoring System

OBJECTIVE

Accuracy of continuous glucose monitoring (CGM) devices in hypoglycemia has been a widely reported shortcoming of this technology. We report the accuracy in hypoglycemia of a new version of the Dexcom (San Diego, CA) G4 Platinum CGM system (software 505) and present results regarding the optimum setting of CGM hypoglycemic alerts.

MATERIALS AND METHODS

CGM values were compared with YSI analyzer (YSI Life Sciences, Yellow Springs, OH) measurements every 15 min. We reviewed the accuracy of the CGM system in the hypoglycemic range using standard metrics. We analyzed the time required for the CGM system to detect biochemical hypoglycemia (70 mg/dL) compared with the YSI with alert settings at 70 mg/dL and 80 mg/dL. We also analyzed the time between the YSI value crossing 55 mg/dL, defined as the threshold for cognitive impairment due to hypoglycemia, and when the CGM system alerted for hypoglycemia.

RESULTS

The mean absolute difference for a glucose level of less than 70 mg/dL was 6 mg/dL. Ninety-six percent of CGM values were within 20 mg/dL of the YSI values between 40 and 80 mg/dL. When the CGM hypoglycemic alert was set at 80 mg/dL, the device provided an alert for biochemical hypoglycemia within 10 min in 95% of instances and at least a 10-min advance warning before the cognitive impairment threshold in 91% of instances in the study.

CONCLUSIONS

Use of an 80 mg/dL threshold setting for hypoglycemic alerts on the G4 Platinum (software 505) may provide patients with timely warning of hypoglycemia before the onset of cognitive impairment, enabling them to treat themselves for hypoglycemia with fast-acting carbohydrates and prevent neuroglycopenia associated with very low glucose levels.

Q-Score: development of a new metric for continuous glucose monitoring that enables stratification of antihyperglycaemic therapies

BACKGROUND

Continuous glucose monitoring (CGM) has revolutionised diabetes management. CGM enables complete visualisation of the glucose profile, and the uncovering of metabolic 'weak points'. A standardised procedure to evaluate the complex data acquired by CGM, and to create patient-tailored recommendations has not yet been developed. We aimed to develop a new patient-tailored approach for the routine clinical evaluation of CGM profiles. We developed a metric allowing screening for profiles that require therapeutic action and a method to identify the individual CGM parameters with improvement potential.

METHODS

Fifteen parameters frequently used to assess CGM profiles were calculated for 1,562 historic CGM profiles from subjects with type 1 or type 2 diabetes. Factor analysis and varimax rotation was performed to identify factors that accounted for the quality of the profiles.

RESULTS

We identified five primary factors that determined CGM profiles (central tendency, hyperglycaemia, hypoglycaemia, intra- and inter-daily variations). One parameter from each factor was selected for constructing the formula for the screening metric, (the 'Q-Score'). To derive Q-Score classifications, three diabetes specialists independently categorised 766 CGM profiles into groups of 'very good', 'good', 'satisfactory', 'fair', and 'poor' metabolic control. The Q-Score was then calculated for all profiles, and limits were defined based on the categorised groups (<4.0, very good; 4.0-5.9, good; 6.0-8.4, satisfactory; 8.5-11.9, fair; and ≥12.0, poor). Q-Scores increased significantly (P <0.01) with increasing antihyperglycaemic therapy complexity. Accordingly, the percentage of fair and poor profiles was higher in insulin-treated compared with diet-treated subjects (58.4% vs. 9.3%). In total, 90% of profiles categorised as fair or poor had at least three parameters that could potentially be optimised. The improvement potential of those parameters can be categorised as 'low', 'moderate' and 'high'.

CONCLUSIONS

The Q-Score is a new metric suitable to screen for CGM profiles that require therapeutic action. Moreover, because single components of the Q-Score formula respond to individual weak points in glycaemic control, parameters with improvement potential can be identified and used as targets for optimising patient-tailored therapies.

Real-time continuous glucose monitoring versus internet-based blood glucose monitoring in adults with type 2 diabetes: a study of treatment satisfaction

AIMS

To compare treatment satisfaction between real-time continuous glucose monitoring (RT-CGM) and internet-blood glucose monitoring (IBGM) in adults with type 2 diabetes treated with insulin.

METHODS

This study recruited 40 patients who completed a parallel randomized controlled trial comparing a RT-CGM to an IBGM. Patients in the RT-CGM group monitored their blood-glucose levels bi-weekly and emailed results to their endocrinologist. Patients in the IBGM group also monitored their blood-glucose levels bi-weekly, but entered their data into an IBGM. Both groups used a secure website to submit blood-glucose readings and to receive feedback from their endocrinologist. Feedback included changes in therapy, suggestions on testing frequency, lifestyle modifications and/or encouragement to continue with no changes. At the end of 6 months, treatment satisfaction was measured using the 8-item Diabetes Treatment Satisfaction Questionnaire. In this study, "treatment" refers to the blood glucose monitoring system to which patients were randomized.

RESULTS

Thirty-two of the 40 patients completed the treatment satisfaction questionnaire (80%). Compared to the RT-CGM group, the IBGM group reported a significantly higher level of overall treatment satisfaction (24.80 vs. 33.41, p<0.000). Ratings of individual satisfaction components including convenience, flexibility, likelihood of recommending treatment to others, and willingness to continue with treatment were also found to be significantly higher in the IBGM group.

CONCLUSION

Patients using IBGM are more satisfied with their blood glucose monitoring system compared to those using RT-CGM.

Glucose sensing by waveguide-based absorption spectroscopy on a silicon chip

In this work, we demonstrate in vitro detection of glucose by means of a lab-on-chip absorption spectroscopy approach. This optical method allows label-free and specific detection of glucose. We show glucose detection in aqueous glucose solutions in the clinically relevant concentration range with a silicon-based optofluidic chip. The sample interface is a spiral-shaped rib waveguide integrated on a silicon-on-insulator (SOI) photonic chip. This SOI chip is combined with micro-fluidics in poly(dimethylsiloxane) (PDMS). We apply aqueous glucose solutions with different concentrations and monitor continuously how the transmission spectrum changes due to glucose. Based on these measurements, we derived a linear regression model, to relate the measured glucose spectra with concentration with an error-of-fitting of only 1.14 mM. This paper explains the challenges involved and discusses the optimal configuration for on-chip evanescent absorption spectroscopy. In addition, the prospects for using this sensor for glucose detection in complex physiological media (e.g. serum) is briefly discussed.

A randomized trial comparing the rate of hypoglycemia--assessed using continuous glucose monitoring--in 125 preschool children with type 1 diabetes treated with insulin glargine or NPH insulin (the PRESCHOOL study)

BACKGROUND

Avoidance of hypoglycemia is a key consideration in treating young children with type 1 diabetes (T1DM).

KEY OBJECTIVE

To evaluate hypoglycemia with insulin glargine vs. neutral protamine Hagedorn (NPH) insulin in young children, using continuous glucose monitoring (CGM).

SUBJECTS

Children of 1 to <6 yr treated with once-daily glargine vs. once- or twice-daily NPH, with bolus insulin lispro/regular human insulin provided to all.

METHODS

Twenty-four week, multicenter, randomized, open-label study. Primary endpoint was event rate of composite hypoglycemia [symptomatic hypoglycemia, low CGM excursions (<3.9 mmol/L) or low fingerstick blood glucose (FSBG; <3.9 mmol/L)]. Noninferiority of glargine vs. NPH was assessed for the primary endpoint.

RESULTS

One hundred and twenty-five patients (mean age, 4.2 yr) were randomized to treatment (glargine, n = 61; NPH, n = 64). At baseline, mean HbA1c was 8.0 and 8.2% with glargine and NPH, respectively. Composite hypoglycemia episodes/100 patient-yr was 1.93 for glargine and 1.69 for NPH; glargine noninferiority was not met. Events/100 patient-yr of symptomatic hypoglycemia were 0.26 for glargine vs. 0.33 for NPH; low CGM excursions 0.75 vs. 0.72; and low FSBG 1.93 vs.1.68. There was a slight difference in between-group severe/nocturnal/severe nocturnal hypoglycemia and glycemic control. All glargine-treated patients received once-daily injections; on most study days NPH-treated patients received twice-daily injections.

CONCLUSIONS

While glargine noninferiority was not achieved, in young children with T1DM, there was a slight difference in hypoglycemia outcomes and glycemic control between glargine and NPH. Once-daily glargine may therefore be a feasible alternative basal insulin in young populations, in whom administering injections can be problematic.

Continuous glucose monitors: current status and future developments

PURPOSE OF REVIEW

Advances in diabetes technologies allow patients to manage their diabetes with greater precision and flexibility. Many recent studies show that continuous glucose monitors (CGMs) can be used to tighten glycemic control safely and to ease certain burdens of diabetes self-management.

RECENT FINDINGS

The following summary reflects the most recent findings in CGM and provides an overall review of who would most benefit from CGM use. Benefits of CGM may vary based on age, type of diabetes, pregnancy, health, sleep, or heart rate. Accuracy and reliability are critical in current uses of CGM and especially for new and future systems that automate insulin partially (e.g., low glucose suspend) or entirely (e.g., 'fully closed-loop' artificial pancreas). Clinicians are simultaneously testing available products in new patient groups such as the critically ill and type 2 diabetes patients not using mealtime insulin.

SUMMARY

In a widening set of circumstances, use of CGM has been shown to promote safer and more effective glycemic control than self-monitoring of blood glucose. Imperfections remain in certain scenarios such as hypoglycemia and in certain populations such as young children. Ongoing research on sensors and calibration software should translate to better systems.