CGM accuracy: Contrasting CE marking with the governmental controls of the USA (FDA) and Australia (TGA): A narrative review

Evidence-based recommendations for comprehensive regulatory guidelines in medical devices: the imperative for global harmonization

The medical device industry has experienced a significant upsurge in the number, diversity, and complexity of devices over the last two decades. As the global demand for medical devices grows, regulatory frameworks across major economies, including the USA, Europe, India, China, and Australia, have evolved to ensure safety, quality, and efficacy. This review critically examines the regulatory guidelines for medical devices across these regions, emphasizing the need for harmonization to streamline approval processes and reduce regulatory barriers. While countries like the USA and Europe have well-established regulatory systems-such as the Food and Drug Authority (FDA) and European Medicines Agency (EMA)-other nations, including India, are rapidly advancing their frameworks, as seen with the introduction of the Indian Medical Device Rules, 2017, and subsequent amendments. Global initiatives, such as the Global Harmonization Task Force (GHTF), Central Drug Standard Control Organisation (CDSCO), EU Medical Device Regulations (MDR), In Vitro Diagnostic Regulation (IVDR), and the International Medical Device Regulators Forum (IMDRF), have made strides in fostering collaboration, yet disparities remain. Harmonized regulations would mitigate challenges related to device registration, manufacturing, and post-market surveillance, expediting access to high-quality, safe medical devices. The review also highlights the growing prevalence of drug-device combination products, their regulatory complexities, and the importance of aligning regulatory practices globally. A harmonized regulatory framework is essential to promote innovation, reduce duplication of work, and ensure the timely availability of medical devices to patients in need. This review explores the evolution of medical devices from ancient practices to modern technologies, emphasizing projected market growth and the need for regulatory harmonization to facilitate innovation and access. It also assesses how emerging technologies are shaping future regulatory frameworks.

International Society for Pediatric and Adolescent Diabetes Clinical Practice Consensus Guidelines 2024 Diabetes Technologies: Glucose Monitoring

The International Society for Pediatric and Adolescent Diabetes (ISPAD) guidelines represent a rich repository that serves as the only comprehensive set of clinical recommendations for children, adolescents, and young adults living with diabetes worldwide. This chapter builds on the 2022 ISPAD guidelines, and summarizes recent advances in the technology behind glucose monitoring, and its role in glucose-responsive integrated technology that is feasible with the use of automated insulin delivery (AID) systems in children and adolescents. The International Society for Pediatric and Adolescent Diabetes (ISPAD) guidelines represent a rich repository that serves as the only comprehensive set of clinical recommendations for children, adolescents, and young adults living with diabetes worldwide. This chapter builds on the 2022 ISPAD guidelines, and summarizes recent advances in the technology behind glucose monitoring, and its role in glucose-responsive integrated technology that is feasible with the use of automated insulin delivery (AID) systems in children and adolescents.

Ethnic disparities in HbA1c and hypoglycemia among youth with type 1 diabetes: beyond access to technology, social deprivation and mean blood glucose

INTRODUCTION

The UK national pediatric diabetes audit reports higher HbA1c for children and young people (CYP) with type 1 diabetes (T1D) of Black ethnicity compared with White counterparts. This is presumably related to higher mean blood glucose (MBG) due to lower socioeconomic status (SES) and less access to technology. We aimed to determine if HbA1c ethnic disparity persists after accounting for the above variables.

RESEARCH DESIGN AND METHODS

A retrospective analysis of participants who received structured education in continuous glucose monitoring (CGM) use was conducted at a tertiary center. HbA1c was paired with glucose metrics from 90-day CGM data. The influence of ethnicity, SES determined by Index of Multiple Deprivation (IMD), MBG and other covariates on HbA1c was evaluated using multiple variable regression analysis. Occurrence of hypoglycemia was evaluated.

RESULTS

A total of 168 (79 White, 61 South Asian, 28 Black) CYP with T1D were included. There were no differences between groups for age, MBG, time in range (3.9-10.0 mmol/L), diabetes duration, gender, insulin delivery method (multiple daily injections vs continuous subcutaneous insulin infusion), or percent sensor use (PSU). In multiple variable analysis, MBG (p<0.0001), ethnicity (p<0.0001), age (p<0.001), duration of diabetes (p<0.01) and PSU (p<0.05) accounted for 81% of the variability in HbA1c. Adjusted HbA1c in the Black group (67 mmol/mol) was higher than both South Asian (63 mmol/mol) and White groups (62 mmol/mol) (p<0.001). Despite significant IMD differences between groups, it did not influence HbA1c. Multiple variable analysis showed that the Black group experienced more hypoglycemia than South Asian and White groups (<3.9 and <3.0 mmol/L, p<0.05).

CONCLUSIONS

CYP from Black ethnic backgrounds have a higher HbA1c compared with their South Asian and White counterparts which is clinically significant and independent of MBG, potentially contributing to increased complications risk. Additionally, the Black group experienced a higher incidence of hypoglycemia, possibly due to a treat-to-HbA1c target approach.

Continuous Glucose Monitoring-New Diagnostic Tool in Complex Pathophysiological Disorder of Glucose Metabolism in Children and Adolescents with Obesity

Obesity is one of the leading causes of chronic diseases, and its prevalence is still rising in children and adolescent populations. Chronic cardiovascular complications result in metabolic syndrome (MS) and type 2 diabetes mellitus. Key factors in the development of MS are insulin resistance and low-grade inflammation. The disorder of glucose and insulin metabolism has not been fully elucidated so far, and an oral glucose tolerance test (OGTT) has been the only tool used to look into the complex metabolism disorder in children and adolescents with obesity. Continuous glucose monitoring (CGM) has become commercially available for over two decades and is primarily used to manage type 1 diabetes mellitus in pediatric populations. This review aims to present the current knowledge about the use of CGM in children and adolescent populations with obesity. CGM systems have the potential to serve as valuable tools in everyday clinical practices, not only in the better diagnosis of chronic complications associated with obesity, but CGM can also assist in interventions to make better adjustments to nutritional and therapeutic approaches based on real-time glucose monitoring data. Despite these promising benefits, further research is needed to fully understand the role of CGM in metabolic disorders in pediatric populations with obesity, which will additionally strengthen the importance of CGM systems in everyday clinical practices.

Continuous glucose sensor accuracy: beyond the headline metric

The promotion of continuous glucose monitoring (CGM) to standard of care for type 1 diabetes and insulin-treated type 2 diabetes reflects a robust and wide evidence base for the technology's effectiveness supported by real-world efficacy data. Multiple CGM devices are available worldwide and are marketed, in part, based on accuracy data. In this Viewpoint, we argue that accuracy metrics are no longer a point of difference between CGM devices as almost all exceed an acceptable threshold. We also argue that domains of standardisation, clinical outcomes, and sustainability should now be given primacy as CGM devices seek to be implemented for new indications. These domains are key for the success of the next generation of CGM devices. Additionally, we discuss the need to address inequalities in accessing clinically impactful technologies.

Validating the Use of Continuous Glucose Monitors With Nondiabetic Recreational Runners

PURPOSE

Continuous glucose monitors (CGMs) are becoming increasingly popular among endurance athletes despite unconfirmed accuracy. We assessed the concurrent validity of the FreeStyle Libre 2 worn on 2 different sites at rest, during steady-state running, and postprandial.

METHODS

Thirteen nondiabetic, well-trained recreational runners (age = 40 [8] y, maximal aerobic oxygen consumption = 46.1 [6.4] mL·kg-1·min-1) wore a CGM on the upper arm and chest while treadmill running for 30, 60, and 90 minutes at intensities corresponding to 50%, 60%, and 70% of maximal aerobic oxygen consumption, respectively. Glucose was measured by manually scanning CGMs and obtaining a finger-prick capillary blood glucose sample. Mean absolute relative difference, time in range, and continuous glucose Clarke error grid analysis were used to compare paired CGM and blood glucose readings.

RESULTS

Across all intensities of steady-state running, we found a mean absolute relative difference of 13.8 (10.9) for the arm and 11.4 (9.0) for the chest. The coefficient of variation exceeded 70%. Approximately 47% of arm and 50% of chest paired glucose measurements had an absolute difference ≤10%. Continuous glucose Clarke error grid analysis indicated 99.8% (arm) and 99.6% (chest) CGM data fell in clinically acceptable zones A and B. Time-in-range analysis showed reduced accuracy at lower glucose levels. However, CGMs accurately detected trends in mean glucose readings over time.

CONCLUSIONS

CGMs are not valid for point glucose monitoring but appear to be valid for monitoring glucose trends during steady-state exercise. Accuracy is similar for arm and chest. Further research is needed to determine whether CGMs can detect important events such as hypoglycemia during exercise.

Criteria for Personalised Choice of a Continuous Glucose Monitoring System: An Expert Opinion

Despite the growing evidence supporting the outpatient use of continuous glucose monitoring (CGM) for improving glycaemic control and reducing hypoglycaemia, there is a need for a detailed understanding of the specific features of CGM devices that best meet individual patient needs. This expert opinion, based on a comprehensive literature review and the personal perspectives of clinicians, aims to provide the healthcare professionals (HCPs) with a comprehensive framework for selecting CGM devices. It evaluates the current state of CGM technology, categorizing features into essential features, major drivers of choice, and additional/useful features. Moreover, the practical model presented outlines a patient's journey with CGM, emphasising the importance of aligning device features with patient needs. This includes understanding the patient's lifestyle, clinical conditions, and personal preferences to optimize CGM use and improve diabetes management outcomes.

Performance of Continuous Glucose Monitoring System Among Patients With Acute Ischaemic Stroke Treated With Mechanical Thrombectomy

AIMS

Glucose metabolism abnormalities are prevalent in acute ischaemic stroke (AIS) patients and are associated with poor prognosis. The continuous glucose monitoring (CGM) system can provide detailed information on glucose levels and glycaemic excursions. This study aimed to evaluate the feasibility and accuracy of CGM application in the acute phase of AIS patients.

METHODS

This single-centre, prospective, and observational study consecutively enrolled patients with AIS with anterior circulation large vessel occlusion (AC-LVO) and received mechanical thrombectomy (MT) within 24 h of symptom onset. A user-retrospectively calibrated iPro2 CGM system was implanted right before the MT procedure started and removed on the fifth day after MT or at discharge. Fingertip glucose was measured as a reference. Accuracy evaluation included the Bland-Altman plot (with a proportion of CGM values within 15/15, 20/20 and 30/30), the absolute relative difference (ARD) and error grid analysis (EGA). The safety and glucose profiles were also evaluated.

RESULTS

Of the 183 patients screened, 141 were included, with a median monitoring duration of 4.49 days. Compared to reference measurements, 3097 CGM readings were matched with a mean bias of -4.16 mg/dL. The proportions of sensor readings meeting the 15/15, 20/20 and 30/30 criteria were 64.55%, 76.07% and 87.21%, respectively. The overall mean and median ARD were 14.60% ± 14.62% and 9.77% (4.15, 20.00). EGA showed that 98.97%, 99.42% and 99.06% values fall within clinically accurate zones in Clarke, Parkes and continuous glucose EGA, respectively.

CONCLUSION

The CGM system was feasible, safe and accurate for in-hospital use among AIS patients who received MT.

Innovative solution or cause for concern? The use of continuous glucose monitors in people not living with diabetes: A narrative review

AIMS

Continuous glucose monitors (CGMs) have expanded their scope beyond indicated uses for diabetes management and are gaining traction among people not living with diabetes (PNLD). CGMs track in time glucose levels and are proposed as tools for the early detection of abnormal glucose and a potential solution for its normalisation through behavioural change, particularly, diet personalisation and motivation of physical activity. This becomes relevance given the growing incidence of metabolic conditions, such as type 2 diabetes mellitus (T2DM). Clinical guidelines, however, do not recommend CGMs in contexts outside type 1 diabetes (T1DM) or insulin-treated T2DM. Therefore, there is a visible disconnect between the indicated and real-world usage of these medical devices. While the commercial market for CGMs in PNLD is expanding rapidly, a comprehensive and evidence-based evaluation of the devices' utility in this population has not been done. Therefore, this review aims to formulate a working model for CGM utility in PNLD as proposed by the 'health and wellness' market that advertises and distributes it to these individuals.

METHODS

We aim to critically analyse the available research addressing components of the working model, that is (1) detection of abnormal glucose; (2) behavioural change, and (3) metabolic health improvement.

RESULTS

We find a lack of consistent and high-quality evidence to support the utility of CGMs for these purposes. We identify significantly under-reserved areas including clinical benchmarks and scoring procedures for CGM measures, device acceptability, and potential adverse effects of CGMs on eating habits in PNLD. We also raise concerns about the robustness of available CGM research.

CONCLUSION

In the face of these research gaps, we urge for the commercial claims suggesting the utility of the device in PNLD to be labelled as misleading. We argue that there is a regulatory inadequacy that fuels 'off-label' CGM distribution and calls for the strengthening of post-market clinical follow-up oversight for CGMs. We hope this will help to avert the continued misinformation risk to PNLD and 'off-label' exacerbation of health disparities.

Stenopool: A Comprehensive Platform for Consolidating Diabetes Device Data

BACKGROUND

The growing adoption of diabetes devices has highlighted the need for integrated platforms to consolidate data from various vendors and device types, enhancing the patient experience and treatment. This shift could pave the way for a transition from conventional outpatient diabetes clinics to advanced home monitoring and virtual care methods. Overall, we wished to empower individuals with diabetes and healthcare providers to interpret and utilize information from diabetes devices more effectively.

METHODS

Stenopool integrates most diabetes devices for glucose monitoring and insulin administration in our clinic. The platform was initially developed with inspiration from open-source software, and the current version is a unique digital platform for managing and analyzing diabetes device data. The development process, outcomes, and status are described.

RESULTS

Since November 2021, Stenopool has been used in our outpatient clinic to integrate over 30 different diabetes devices from around 7000 individuals. Data are primarily uploaded via wired connections, but also using semi-automated and automated cloud-to-cloud data transfers. The platform offers a streamlined workflow for healthcare providers and displays data from various glucose meter, insulin pump, and continuous glucose monitor (CGM) vendors on a single screen in a manner that healthcare providers can modify. A data warehouse with data from Stenopool and electronical health records is nearing completion, preparing the development of tools for population health management, quality assessment, and risk stratification of patients.

CONCLUSION

Using Stenopool, we aimed to enhance diabetes device data management, facilitate the future for virtual patient care pathways, and improve outcomes. This article outlines the platform's development process and challenges.

The Glucose Management Indicator: Time to Change Course?

Laboratory measurement of hemoglobin A1c (HbA1c) has, for decades, been the standard approach to monitoring glucose control in people with diabetes. Continuous glucose monitoring (CGM) is a revolutionary technology that can also aid in the monitoring of glucose control. However, there is uncertainty in how best to use CGM technology and its resulting data to improve control of glucose and prevent complications of diabetes. The glucose management indicator, or GMI, is an equation used to estimate HbA1c based on CGM mean glucose. GMI was originally proposed to simplify and aid in the interpretation of CGM data and is now provided on all standard summary reports (i.e., average glucose profiles) produced by different CGM manufacturers. This Perspective demonstrates that GMI performs poorly as an estimate of HbA1c and suggests that GMI is a concept that has outlived its usefulness, and it argues that it is preferable to use CGM mean glucose rather than converting glucose to GMI or an estimate of HbA1c. Leaving mean glucose in its raw form is simple and reinforces that glucose and HbA1c are distinct. To reduce patient and provider confusion and optimize glycemic management, mean CGM glucose, not GMI, should be used as a complement to laboratory HbA1c testing in patients using CGM systems.

Importance of FDA-Integrated Continuous Glucose Monitors to Ensure Accuracy of Continuous Glucose Monitoring

Continuous glucose monitoring (CGM) has been shown to improve glycemic control and self-monitoring, as well as to reduce the risk of hypoglycemia. Integrated CGM (iCGM) FDA-cleared systems with published performance data are established nonadjunctive and accurate CGM tools that can directly inform decision-making in the treatment of diabetes (i.e., insulin dosing). Studies have assessed accuracy and safety data of CGMs that were eventually cleared for iCGM by the FDA and that informed the recommendation for their nonadjunctive use. Subsequent robust clinical trials and real-world studies demonstrated clinical effectiveness with improvements in a range of patient outcomes. In recent years, a number of non-iCGM-approved CGM devices have entered the market outside the United States worldwide. Some of these non-iCGM-approved CGM devices require additional user verification of blood glucose levels to be performed for making treatment decisions, termed adjunctive. Moreover, in many non-iCGM-approved CGM devices, accuracy studies published in peer-reviewed journals are scarce or have many limitations. Consequently, non-iCGM-approved CGM devices cannot be automatically perceived as having the same performance or quality standards than those approved for iCGM by the FDA. As a result, although these devices tend to cost less than iCGMs that carry FDA clearance and could therefore be attractive from the point of view of a health care payer, it must be emphasized that evaluation of costs should not be limited to the device (such as the usability preference that patients have for nonadjunctive sensors compared to adjunctive sensors) but to the wider value of the total benefit that the product provides to the patient.

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.