First assessment of the performance of an implantable continuous glucose monitoring system through 180 days in a primarily adolescent population with type 1 diabetes

Evidence from clinical trials on high-risk medical devices in children: a scoping review

BACKGROUND

Meeting increased regulatory requirements for clinical evaluation of medical devices marketed in Europe in accordance with the Medical Device Regulation (EU 2017/745) is challenging, particularly for high-risk devices used in children.

METHODS

Within the CORE-MD project, we performed a scoping review on evidence from clinical trials investigating high-risk paediatric medical devices used in paediatric cardiology, diabetology, orthopaedics and surgery, in patients aged 0-21 years. We searched Medline and Embase from 1st January 2017 to 9th November 2022.

RESULTS

From 1692 records screened, 99 trials were included. Most were multicentre studies performed in North America and Europe that mainly had evaluated medical devices from the specialty of diabetology. Most had enrolled adolescents and 39% of trials included both children and adults. Randomized controlled trials accounted for 38% of the sample. Other frequently used designs were before-after studies (21%) and crossover trials (20%). Included trials were mainly small, with a sample size <100 participants in 64% of the studies. Most frequently assessed outcomes were efficacy and effectiveness as well as safety.

CONCLUSION

Within the assessed sample, clinical trials on high-risk medical devices in children were of various designs, often lacked a concurrent control group, and recruited few infants and young children.

IMPACT

In the assessed sample, clinical trials on high-risk medical devices in children were mainly small, with variable study designs (often without concurrent control), and they mostly enrolled adolescents. We provide a systematic summary of methodologies applied in clinical trials of medical devices in the paediatric population, reflecting obstacles in this research area that make it challenging to conduct adequately powered randomized controlled trials. In view of changing European regulations and related concerns about shortages of high-risk medical devices for children, our findings may assist competent authorities in setting realistic requirements for the evidence level to support device conformity certification.

Clinical Performance Evaluation of Continuous Glucose Monitoring Systems: A Scoping Review and Recommendations for Reporting

The use of different approaches for design and results presentation of studies for the clinical performance evaluation of continuous glucose monitoring (CGM) systems has long been recognized as a major challenge in comparing their results. However, a comprehensive characterization of the variability in study designs is currently unavailable. This article presents a scoping review of clinical CGM performance evaluations published between 2002 and 2022. Specifically, this review quantifies the prevalence of numerous options associated with various aspects of study design, including subject population, comparator (reference) method selection, testing procedures, and statistical accuracy evaluation. We found that there is a large variability in nearly all of those aspects and, in particular, in the characteristics of the comparator measurements. Furthermore, these characteristics as well as other crucial aspects of study design are often not reported in sufficient detail to allow an informed interpretation of study results. We therefore provide recommendations for reporting the general study design, CGM system use, comparator measurement approach, testing procedures, and data analysis/statistical performance evaluation. Additionally, this review aims to serve as a foundation for the development of a standardized CGM performance evaluation procedure, thereby supporting the goals and objectives of the Working Group on CGM established by the Scientific Division of the International Federation of Clinical Chemistry and Laboratory Medicine.

Miniaturization of an Osmotic Pressure-Based Glucose Sensor for Continuous Intraperitoneal and Subcutaneous Glucose Monitoring by Means of Nanotechnology

The Sencell sensor uses glucose-induced changes in an osmotic pressure chamber for continuous glucose measurement. A final device shall have the size of a grain of rice. The size limiting factor is the piezo-resistive pressure transducers inside the core sensor technology (resulting chamber volume: 70 µL. To achieve the necessary miniaturization, these pressure transducers were replaced by small (4000 × 400 × 150 nm³) nano-granular tunneling resistive (NTR) pressure sensors (chamber volume: 750 nL). For benchmark testing, we filled the miniaturized chamber with bovine serum albumin (BSA, 1 mM) and exposed it repeatedly to distilled water followed by 1 mM BSA solution. Thereafter, we manufactured sensors with glucose testing chemistry (ConcanavalinA/dextran) and investigated sensor performance with dynamic glucose changes between 0 and 300 mg/dL. Evaluation of the miniaturized sensors resulted in reliable pressure changes, both in the BSA benchmark experiment (30-35 mBar) and in the dynamic in vitro continuous glucose test (40-50 mBar). These pressure results were comparable to similar experiments with the previous larger in vitro sensors (30-50 mBar). In conclusion, the NTR pressure sensor technology was successfully employed to reduce the size of the core osmotic pressure chamber by more than 95% without loss in the osmotic pressure signal.

In vivo photoacoustic monitoring of vasoconstriction induced by acute hyperglycemia

Postprandial hyperglycemia, blood glucose spikes, induces endothelial dysfunction, increasing cardiovascular risks. Endothelial dysfunction leads to vasoconstriction, and observation of this phenomenon is important for understanding acute hyperglycemia. However, high-resolution imaging of microvessels during acute hyperglycemia has not been fully developed. Here, we demonstrate that photoacoustic microscopy can noninvasively monitor morphological changes in blood vessels of live animals' extremities when blood glucose rises rapidly. As blood glucose level rose from 100 to 400 mg/dL following intraperitoneal glucose injection, heart/breath rate, and body temperature remained constant, but arterioles constricted by approximately -5.7 ± 1.1% within 20 min, and gradually recovered for another 40 min. In contrast, venular diameters remained within about 0.6 ± 1.5% during arteriolar constriction. Our results experimentally and statistically demonstrate that acute hyperglycemia produces transitory vasoconstriction in arterioles, with an opposite trend of change in blood glucose. These findings could help understanding vascular glucose homeostasis and the relationship between diabetes and cardiovascular diseases.

Continuous Glucose Monitoring in Dogs and Cats: Application of New Technology to an Old Problem

In recent years, glucose monitoring has been revolutionized by the development of continuous glucose monitoring systems (CGMS), which are wearable non/minimally invasive devices that measure glucose concentration almost continuously for several consecutive d/wk. The Abbott FreeStyle Libre is the CGMS used most commonly. It has adequate clinical accuracy both in dogs and cats, even though the accuracy is lower in the hypoglycemic range. It allows an accurate identification of glycemic excursions occurring throughout the day as well as of glucose variations during consecutive days, enabling the clinician to make a more informed decision about the insulin dose and frequency of administration.

Catalytic Biosensors Operating under Quasi-Equilibrium Conditions for Mitigating the Changes in Substrate Diffusion

Despite the success of continuous glucose measuring systems operating through the skin for about 14 days, long-term implantable biosensors are facing challenges caused by the foreign-body reaction. We present a conceptually new strategy using catalytic enzyme-based biosensors based on a measuring sequence leading to minimum disturbance of the substrate equilibrium concentration by controlling the sensor between "on" and "off" state combined with short potentiometric data acquisition. It is required that the enzyme activity can be completely switched off and no parasitic side reactions allow substrate turnover. This is achieved by using an O₂ -independent FAD-dependent glucose dehydrogenase embedded within a crosslinked redox polymer. A short measuring interval allows the glucose concentration equilibrium to be restored quickly which enables the biosensor to operate under quasi-equilibrium conditions.

Historical aspects of diagnosis and control of diabetes mellitus

Diabetes mellitus is a group of metabolic diseases affecting carbohydrate, lipid, and protein metabolism. This pathology has a long history, and it was considered a disease of the kidneys until the middle of the 19th century. Descriptions have been found in Egyptian papyri, in ancient Indian and Chinese medical literature, in the writings of ancient Greek and Arab doctors. Aretaeus of Cappadocia gave the first accurate description of the disease, coining the term diabetes. Thomas Willis first differentiated diabetes from other causes of polyuria by the sweet taste of urine. Matthew Dobson proved the presence of glucose in urine by evaporation. Claude Bernard demonstrated that hyperglycemia contributes to glucosuria. This is how the concept of the renal threshold appeared. In domestic practice, the term "renal threshold" was introduced by endocrinologist V.G. Baranov. The development of qualitative tests for determining glucose in the urine, the creation of test strips and glucometers has significantly improved the quality of life of patients with diabetes. The current stage of development of glucometry includes the determination of fasting plasma glucose, postprandial glycemia, glycated hemoglobin, as well as continuous glucose monitoring. Continuous glucose monitoring systems make it possible to estimate the time in target range, show the rate of rise or fall of glucose levels. It affects the rate and degree of carbohydrate metabolism compensation and allows for maximum control of the disease.

Technologies for Diabetes Self-Monitoring: A Scoping Review and Assessment Using the REASSURED Criteria

BACKGROUND

Self-management is an important pillar for diabetes control and to achieve it, glucose self-monitoring devices are needed. Currently, there exist several different devices in the market and many others are being developed. However, whether these devices are suitable to be used in resource constrained settings is yet to be evaluated.

AIMS

To assess existing glucose monitoring tools and also those in development against the REASSURED which have been previously used to evaluate diagnostic tools for communicable diseases.

METHODS

We conducted a scoping review by searching PubMed for peer-review articles published in either English, Spanish or Portuguese in the last 5 years. We selected papers including information about devices used for self-monitoring and tested on humans with diabetes; then, the REASSURED criteria were used to assess them.

RESULTS

We found a total of 7 continuous glucose monitoring device groups, 6 non-continuous, and 6 devices in development. Accuracy varied between devices and most of them were either invasive or minimally invasive. Little to no evidence is published around robustness, affordability and delivery to those in need. However, when reviewing publicly available prices, none of the devices would be affordable for people living in low- and middle-income countries.

CONCLUSIONS

Available devices cannot be considered adapted for use in self-monitoring in resource constraints settings. Further studies should aim to develop less-invasive devices that do not require a large set of components. Additionally, we suggest some improvement in the REASSURED criteria such as the inclusion of patient-important outcomes to increase its appropriateness to assess non-communicable diseases devices.

Reduction of clinically important low glucose excursions with a long-term implantable continuous glucose monitoring system in adults with type 1 diabetes prone to hypoglycaemia: the France Adoption Randomized Clinical Trial

AIM

To assess the glucose control outcomes of the implantable Eversense real-time continuous glucose monitoring (CGM) system compared to self-monitoring of blood glucose or intermittently scanned CGM in patients with type 1 (T1D) or type 2 diabetes (T2D).

PATIENTS AND METHODS

This was a randomized (2:1), prospective, national, multicentre study. All participants, aged >18 years and on multiple daily insulin injections or insulin pump treatment, had a sensor inserted, which was activated only in the "enabled" group. Included patients had T1D or T2D with a glycated haemoglobin (HbA1c) level > 8% (64 mmol/mol) (Cohort 1) or T1D with a time spent with glucose values below 70 mg/dL (3.8 mmol/l) (TBR^<70 ) for >1.5 h/d during the previous 28 days (Cohort 2). The primary outcomes were HbA1c change at D180 (Cohort 1) or change in time spent with glucose values below 54 mg/dL (TBR^<54 ) during the period of Day (D)90 to D120 (Cohort 2). A covariance model (analyses of covariance) was used for endpoint analyses.

RESULTS

Overall, 149 patients were included in Cohort 1 and 90 in Cohort 2. In Cohort 1, the adjusted mean difference (enabled - control) in HbA1c at D180 was -0.1% (95% confidence interval [CI] -0.4; 0.1; P = 0.341). No significant difference in time with values in the range 70 to 180 mg/dL or time with values above range (>180 mg/dL) was observed. In Cohort 2, the mean adjusted difference in TBR^<54 was -1.6% (95% CI -3.1; -0.1; P = 0.039) during D90 to D120 and remained at -2.6% (95% CI -4.5; -0.6; P = 0.011) during D150 to D180 (prespecified secondary outcome). The CGM system was found to be safe.

CONCLUSION

This study shows that the Eversense CGM system can significantly decrease TBR^<54 in patients with T1D prone to hypoglycaemia.

Clinical Use of a 180-Day Implantable Glucose Monitoring System in Dogs with Diabetes Mellitus: A Case Series

Simple Summary

A novel continuous glucose monitoring system (CGMS) equipped with a long-term sensor has recently been developed for humans with diabetes mellitus. The sensor is inserted under the skin and continuously measures the glucose in the interstitial fluid over a period of up to 180 days. The aim of this study was to describe, for the first time, the clinical use of this novel CGMS in three diabetic dogs (DD). The insertion and use of the device were straightforward and well tolerated by the dogs. Some device-related issues, such as sensor dislocation and trouble with daily calibrations, were reported. A good correlation between the glucose values measured by this CGMS and those obtained with a flash glucose monitoring system and a portable-blood glucose meter, previously validated for use in DD, was found (rs = 0.85 and rs = 0.81, respectively). The functional life of the sensor was 180 days in two of the three dogs, and the use of the device provided high satisfaction to the owners. This innovative device might be considered a future alternative for continuous glucose monitoring in dogs with diabetes mellitus.

Abstract

The novel Eversense XL continuous glucose monitoring system (Senseonics, Inc., Germantown, Maryland) has recently been developed for monitoring diabetes in humans. The sensor is fully implanted and has a functional life of up to 180 days. The present study describes the use of Eversense XL in three diabetic dogs (DD) with good glycemic control managed by motivated owners. The insertion and use of the device were straightforward and well tolerated by the dogs. During the wearing period, some device-related drawbacks, such as sensor dislocation and daily calibrations, were reported. A good correlation between the glucose values measured by the Eversense XL and those obtained with two commercially available devices, previously validated for use in DD, was found (r_s = 0.85 and r_s = 0.81, respectively). The life of the sensor was 180 days in two of the DD and provided high satisfaction. This innovative device might be considered a future alternative for home glucose monitoring in DD.

Evaluation of Accuracy and Safety of the Next-Generation Up to 180-Day Long-Term Implantable Eversense Continuous Glucose Monitoring System: The PROMISE Study

Background: Use of continuous glucose monitoring (CGM) systems is being rapidly adopted as standard of care for insulin-requiring patients with diabetes. The PROMISE study (NCT03808376) evaluated the accuracy and safety of the next-generation implantable Eversense CGM system for up to 180 days. Methods: This was a prospective multicenter study involving 181 subjects with diabetes at 8 USA sites. All subjects were inserted with a primary sensor. Ninety-six subjects had a second sensor, either an identical sensor or a modified sensor (sacrificial boronic acid [SBA]), inserted in their other arm (53 and 43 subjects, respectively). Accuracy was evaluated by comparing CGM to YSI 2300 glucose analyzer (Yellow Springs Instrument [YSI]) values during 10 clinic visits (day 1-180). Confirmed event detection rates, calibration stability, sensor survival, and serious adverse events (SAEs) were evaluated. Results: For primary sensors, the percent CGM readings within 20%/20% of YSI values was 92.9%; overall mean absolute relative difference (MARD) was 9.1%. The confirmed alert detection rate at 70 mg/dL was 93% and at 180 mg/dL was 99%. The median percentage of time for one calibration per day was 56%. Sixty-five percent of the primary sensors survived to 180 days. For the SBA sensors, the percent CGM readings within 20%/20% of YSI values was 93.9%; overall MARD was 8.5%. The confirmed alert detection rate at 70 mg/dL was 94% and at 180 mg/dL was 99%. The median percentage of time for one calibration per day was 63%. Ninety percent of the SBA sensors survived to 180 days. No device- or insertion/removal procedure-related SAEs were reported. Conclusion: These data show the next-generation Eversense CGM system had sustained accuracy and safety up to 180 days, with an improved calibration scheme and survival, using the primary or SBA sensors.

Device profile of the eversense continuous glucose monitoring system for glycemic control in type-1 diabetes: overview of its safety and efficacy

INTRODUCTION

Continuous glucose monitoring (CGM) systems offer real-time data to facilitate diabetes management. The novel Eversense CGM has been approved in Europe and the US. The unique characteristics are the fully implantable sensor and the sensor life up to 180 days.

AREAS COVERED

This expert review describes the results of clinical trials, and the accuracy and safety of the Eversense system. The overall MARD ranges from 8.5% to 9.4%, the 20/20% agreement rate ranges from 84% to 94%, and the percent of values in zones A and B on the Clarke Error Grid is 99.2%. No device-related serious adverse events have been described during pivotal trial studies. The most frequently reported device- or procedure-related adverse events are sensor adhesive patch location site irritation (0.66%), inability to remove the sensor upon first attempt (0.76%), and location site infection (0.96%). Mean A1c reduction is about 0.4% from pivotal trials and real-world studies.

EXPERT OPINION

The Eversense system is novel and differentiated from transcutaneous CGM systems. The long life, the removable transmitter, and the on-body vibration alerts offer opportunities to properly manage diabetes with both MDI and insulin pump therapy.

Modeling continuous glucose monitoring with fractional differential equations subject to shocks

Continuous Glucose Monitoring (CGM) produces long time-series of noisy observations of a single variable (tissue glucose concentration), whose evolution may be explained by a dynamical model. In order to represent the unknown mixture of possible control mechanisms of different orders affecting the measured variable, a fractional differential approach seems justified. In any case, variations in food intake and/or physical activity ought to be taken into account if a plausible interpretation of the dynamics is to be obtained. In the present work, the mathematical construction and the numerical implementation of a Fractional Differential Equations (FDE) initial value problem are systematically reviewed, with the intent of offering the reader a concise and mathematically rigorous description of this approach. An FDE model for CGM is formulated: the model includes compartments for stomach and intestinal glucose contents and for blood and tissue (subcutaneous) glucose concentrations, as well as the shock effects of food ingestion and of increased glucose consumption due to physical activity. The model parameters, including the (non-integer) order of differentiation, are estimated from CGM observations on six Type 1 diabetic patients. The best-fit fractional orders for the six subjects range from 1.59 to 2.13. For comparison, best fits have also been computed for all subjects using an average fractional order of 1.9 and integer orders of 1 and 2.The results indicate that in the case of CGM the fractional differential model, which should be physiologically more appropriate, in fact fits the data much better than the first-order model and also better than the 2nd-order model.

Continuous Glucose Monitoring Devices: Past, Present, and Future Focus on the History and Evolution of Technological Innovation

The concept of implantable glucose sensors has been promulgated for more than 40 years. It is now accepted that continuous glucose monitoring (CGM) increases quality of life by allowing informed diabetes management decisions as a result of more optimized glucose control. The focus of this article is to provide a brief overview of the CGM market history, emerging technologies, and the foreseeable challenges for the next CGM generations as well as proposing possible solutions in an effort to advance the next generation of implantable sensor.

Coexistence of medium chain acyl-CoA dehydrogenase deficiency (MCADD) and type 1 diabetes (T1D): a management challenge

Medium chain acyl-CoA dehydrogenase deficiency (MCADD) is an autosomal recessive fatty acid β-oxidation defect. The enzyme, medium chain acyl-CoA dehydrogenase is important in the breakdown of medium chain fats into acetyl-CoA to produce ketones. Ketones are used as an alternative energy source when glucose or hepatic glycogen stores become depleted during prolonged fasting. In MCADD during periods of fasting or acute illness, there are insufficient ketones to compensate for the glucose energy deficit, resulting in an hypoketotic hypoglycaemia alongside a build-up of fatty acids. This build-up of fatty acids can be neurotoxic and lead to altered brain function and even unexpected death. Management includes avoiding prolonged periods of starvation, consuming high carbohydrate drinks during periods of illness and in symptomatic patients, reversal of catabolism and sustained anabolism by provision of simple carbohydrates by mouth or intravenously. Coexistence of MCADD and type 1 diabetes (T1D) is rare, there is no causal association though there are some documented cases. A key goal of management in T1D is achievement of good glycaemic control to reduce risk of long-term complications. This can in some cases increase the risk of hypoglycaemia which can be catastrophic in the presence of MCAD.

A Review of the First Long-term Implantable Continuous Glucose Monitoring System Available in the United States

BACKGROUND

Although real-time continuous glucose monitoring (rtCGM) has been shown to improve glycemic control in patients with type 1 diabetes mellitus and type 2 diabetes mellitus treated with insulin, rates of adoption have been low. A novel approach, with the use of a long-term implantable continuous glucose monitoring (LTI CGM) has the potential to overcome barriers to rtCGM. The purpose of this review is to provide a background on the first LTI CGM technology to be approved, along with a review of contraindications, interference, safety, accuracy, and efficacy. Considerations for patient selection are discussed based on the available evidence.

METHODS

PubMed, EMBASE, and Cochrane Library were searched for keywords and subject headings to identify studies assessing LTI CGM.

RESULTS

Seven studies were identified which assessed LTI CGM. Mean absolute relative difference is similar to available CGM devices. Rates of adverse events were low. Change in hemoglobin A1c with LTI CGM may be comparable to rtCGM.

CONCLUSIONS

Based on the available evidence, LTI CGM appears to be safe and accurate. Additional clinical trial investigation is warranted to evaluate the glycemic efficacy of LTI CGM.

Review of the Long-Term Implantable Senseonics Continuous Glucose Monitoring System and Other Continuous Glucose Monitoring Systems

The article published by Kevin Cowart in this issue of the Journal of Diabetes Science and Technology (JDST) is a detailed overview of the clinical trial data and analysis used to demonstrate the safety and effectiveness of the Eversense continuous glucose monitoring (CGM) System for regulatory approval and clinical acceptance. The article describes the published study results for safety, accuracy, reliability, ease of insertion/removal, adverse events, and ease of diabetes patient-use for controlling their glucose levels short and long term. The author nicely compares Eversense CGM System safety and performance with the short-term subcutaneous tissue CGM systems being commercialized by Dexcom, Medtronic Diabetes, and Abbott Diabetes. This comparison may help the clinician define which type of patient with diabetes might benefit the most from the long-term implantable CGM system. The majority of studied patients describe a positive experience managing their diabetes with the Eversense CGM System and request implantation of a new sensor 90 or 180 days later.

Advancing continuous subcutaneous insulin infusion in vivo: New insights into tissue challenges

Continuous Subcutaneous Insulin Infusion (CSII) is superior to conventional insulin therapy as it improves glycemic control thus reducing the probability of diabetic complications. Notwithstanding CSII's benefits, insulin dependent diabetic patients rarely achieve optimal glucose control. Moreover, CSII is only FDA approved for 3 days and often fails prematurely for reasons that have not been fully elucidated. We hypothesize that phenolic compounds, such as m-cresol and phenol, which are present in all commercial insulin formulations are responsible for the tissue reaction occurring at the insulin infusion site. This hypothesis was examined with in vitro cell cultures and a mouse air-pouch model to determine cellular and tissue reactions following infusions with saline, phenolic compounds, (i.e., commercial diluent), and insulin. We demonstrated that diluent and insulin were cytotoxic to cells in culture at sub-clinical concentrations (e.g., >1:10 of commercial insulin). Air pouch studies demonstrated that infusion of either diluted insulin or diluent itself induced three to five-fold level of recruited leukocytes as compared to saline. At both 3- and 7-days post infusion, these were predominantly neutrophils and macrophages. We conclude that phenolic compounds in commercial insulin preparations are cell and tissue toxic, which contributes to the failure of effective insulin infusion therapy.

Noninvasive, wearable, and tunable electromagnetic multisensing system for continuous glucose monitoring, mimicking vasculature anatomy

Painless, needle-free, and continuous glucose monitoring sensors are needed to enhance the life quality of diabetic patients. To that extent, we propose a first-of-its-kind, highly sensitive, noninvasive continuous glycemic monitoring wearable multisensor system. The proposed sensors are validated on serum, animal tissues, and animal models of diabetes and in a clinical setting. The noninvasive measurement results during human trials reported high correlation (>0.9) between the system's physical parameters and blood glucose levels, without any time lag. The accurate real-time responses of the sensors are attributed to their unique vasculature anatomy-inspired tunable electromagnetic topologies. These wearable apparels wirelessly sense hypo- to hyperglycemic variations with high fidelity. These components are designed to simultaneously target multiple body locations, which opens the door for the development of a closed-loop artificial pancreas.

12th Roche Diabetes Care Network Meeting: April 11-13, 2019, Copenhagen, Denmark

A panel of international experts in the field of diabetes and diabetes technology met in Copenhagen, Denmark, for the 12th Roche Diabetes Care Network Meeting. The goal of these meetings is to share current knowledge, facilitate new collaborations, and encourage further research projects that can improve the lives of people with diabetes. Specific areas of interest included use of telemedicine and mobile health technologies, behavior change, patient-centered care, and multifactorial approaches to addressing all metabolic abnormalities associated with diabetes. The 2019 meeting covered a comprehensive scientific program and four keynote lectures.

Identification of hypoglycemia-specific neural signals by decoding murine vagus nerve activity

BACKGROUND

Glucose is a crucial energy source. In humans, it is the primary sugar for high energy demanding cells in brain, muscle and peripheral neurons. Deviations of blood glucose levels from normal levels for an extended period of time is dangerous or even fatal, so regulation of blood glucose levels is a biological imperative. The vagus nerve, comprised of sensory and motor fibres, provides a major anatomical substrate for regulating metabolism. While prior studies have implicated the vagus nerve in the neurometabolic interface, its specific role in either the afferent or efferent arc of this reflex remains elusive.

METHODS

Here we use recently developed methods to isolate and decode specific neural signals acquired from the surface of the vagus nerve in BALB/c wild type mice to identify those that respond robustly to hypoglycemia. We also attempted to decode neural signals related to hyperglycemia. In addition to wild type mice, we analyzed the responses to acute hypo- and hyperglycemia in transient receptor potential cation channel subfamily V member 1 (TRPV1) cell depleted mice. The decoding algorithm uses neural signals as input and reconstructs blood glucose levels.

RESULTS

Our algorithm was able to reconstruct the blood glucose levels with high accuracy (median error 18.6 mg/dl). Hyperglycemia did not induce robust vagus nerve responses, and deletion of TRPV1 nociceptors attenuated the hypoglycemia-dependent vagus nerve signals.

CONCLUSION

These results provide insight to the sensory vagal signaling that encodes hypoglycemic states and suggest a method to measure blood glucose levels by decoding nerve signals.

TRIAL REGISTRATION

Not applicable.

First assessment of the performance of an implantable continuous glucose monitoring system through 180 days in a primarily adolescent population with type 1 diabetes

AIM

To investigate the performance of the Eversense XL implantable continuous glucose monitoring (CGM) system through 180 days in a primarily adolescent population with type 1 diabetes (T1D).

MATERIALS AND METHODS

This prospective, single-centre, single-arm, 180-day study evaluated the effectiveness and safety of the implantable CGM system in Canadian adolescent and adult subjects with T1D. Accuracy measures included mean absolute relative difference (MARD), 15/15% agreement between CGM glucose and blood glucose measured by Yellow Springs Instruments and surveillance error grid analysis. Adolescent subjects received one sensor in the upper arm and adult subjects received one sensor in each upper arm. In-clinic CGM system accuracy studies were performed every 30 days. The safety assessment included the incidence of adverse events related to either device or the insertion/removal procedure through 180 days.

RESULTS

Thirty-six subjects (30 adolescent/6 adult, 13 female/23 male, mean age 17 ± 9.2 years, mean body mass index 22 ± 4 kg/m² ) received the CGM system. Overall MARD was 9.4% (95% CI: 8.6%-10.5%). CGM system agreement at 15/15% (N = 7163) through 60, 120 and 180 days was 82.9% (95% CI: 78.4%-86.1%), 83.6% (95% CI: 80.4%-85.7%) and 83.4% (95% CI: 79.7%-85.5%), respectively. Surveillance error grid analysis showed 98.4% of paired values in clinically acceptable error zones A and B. No insertion/removal or device-related serious adverse events were reported.

CONCLUSION

The Eversense XL CGM system is safe and accurate through 180 days in a primarily adolescent population of subjects with T1D.

Clinical Practice Recommendations on the Routine Use of Eversense, the First Long-Term Implantable Continuous Glucose Monitoring System

Background: The use of real-time continuous glucose monitoring (rtCGM) systems has proved to positively impact the management of type 1 diabetes with the potential to lower HbA1c, reduce frequency and time spent in hypoglycemia, and lower glycemic variability. Nevertheless, the acceptance of rtCGM remains below expectations and the dropout rate within the first year has been reported to be 27%. Besides financial reasons due to limited reimbursement, reasons include the need for frequent sensor replacement, the discomfort of wearing a sensor, the presence of adverse skin reactions, or privacy. Thus, novel approaches to rtCGM are desired to overcome these barriers. The first long-term implantable rtCGM system diversifies the field of glucose monitoring further. However, due to its novelty, there are no published clinical practice guidelines available. Aims: The aim of this article is to set the foundation for a best clinical practice for the everyday clinical care using a long-term implantable CGM system. Methods: An international expert panel for the long-term implantable CGM system developed this best practice guidance. All participants were certified and experienced in the use of the Eversense® long-term implantable CGM system. The workflows from the respective clinics were presented, discussed and are summarized in an ideal care workflow outlined in these practice recommendations. Results: The participants agreed on the following aspects: definition of the patient population that will benefit from a long-term implantable CGM device; real-world experience on safety and accuracy of a long-term CGM; definition of the ideal sensor position; description of the optimal process for sensor insertion, removal, and replacement.