Continuous glucose monitoring sensors: Past, present and future algorithmic challenges

Continuous glucose monitoring (CGM) sensors are portable devices that allow measuring and visualizing the glucose concentration in real time almost continuously for several days and are provided with hypo/hyperglycemic alerts and glucose trend information. CGM sensors have revolutionized Type 1 diabetes (T1D) management, improving glucose control when used adjunctively to self-monitoring blood glucose systems. Furthermore, CGM devices have stimulated the development of applications that were impossible to create without a continuous-time glucose signal, e.g., real-time predictive alerts of hypo/hyperglycemic episodes based on the prediction of future glucose concentration, automatic basal insulin attenuation methods for hypoglycemia prevention, and the artificial pancreas. However, CGM sensors’ lack of accuracy and reliability limited their usability in the clinical practice, calling upon the academic community for the development of suitable signal processing methods to improve CGM performance. The aim of this paper is to review the past and present algorithmic challenges of CGM sensors, to show how they have been tackled by our research group, and to identify the possible future ones

Improving the clinical value and utility of CGM systems: issues and recommendations : a joint statement of the European Association for the Study of Diabetes and the American Diabetes Association Diabetes Technology Working Group

The first systems for continuous glucose monitoring (CGM) became available over 15 years ago. Many then believed CGM would revolutionise the use of intensive insulin therapy in diabetes; however, progress towards that vision has been gradual. Although increasing, the proportion of individuals using CGM rather than conventional systems for self-monitoring of blood glucose on a daily basis is still low in most parts of the world. Barriers to uptake include cost, measurement reliability (particularly with earlier-generation systems), human factors issues, lack of a standardised format for displaying results and uncertainty on how best to use CGM data to make therapeutic decisions. This scientific statement makes recommendations for systemic improvements in clinical use and regulatory (pre- and postmarketing) handling of CGM devices. The aim is to improve safety and efficacy in order to support the advancement of the technology in achieving its potential to improve quality of life and health outcomes for more people with diabetes

Improving the clinical value and utility of CGM systems: issues and recommendations: a joint statement of the European Association for the Study of Diabetes and the American Diabetes Association Diabetes Technology Working Group

The first systems for continuous glucose monitoring (CGM) became available over 15 years ago. Many then believed CGM would revolutionize the use of intensive insulin therapy in diabetes; however, progress toward that vision has been gradual. Although increasing, the proportion of individuals using CGM rather than conventional systems for self-monitoring of blood glucose on a daily basis is still low in most parts of the world. Barriers to uptake include cost, measurement reliability (particularly with earlier-generation systems), human factors issues, lack of a standardized format for displaying results, and uncertainty on how best to use CGM data to make therapeutic decisions. This Scientific Statement makes recommendations for systemic improvements in clinical use and regulatory (pre- and postmarketing) handling of CGM devices. The aim is to improve safety and efficacy in order to support the advancement of the technology in achieving its potential to improve quality of life and health outcomes for more people with diabetes

Anomaly Detection in the Artificial Pancreas

The integration of subcutaneous sensing and insulin delivery technologies with novel control strategies has brought closer the development of the Artificial Pancreas. Nevertheless, thought recent developments are aimed at preventing chronic complications and less patient discomfort, few works have addressed the critical issue of performance monitoring of the artificial pancreas as well as detection of abnormal functioning in any of its components. This work presents an anomaly detection monitoring tool using the widely known Clarke Error-Grid to identify functional degradation in the artificial pancreas components and guarantee safetycritical control of blood glucose levels. The effect of imperfect calibration of glucose sensors, time lag between blood glucose concentration and interstitial glucose readings, and excessive variability in glucose levels are evaluated against an expected behavior of the glucose regulation loop achieved through an optimal control policy. Results obtained evidence the feasibility of this novel use of the Clarke error grid as a comprehensive monitoring tool for the artificial pancreas.Sociedad Argentina de Informática e Investigación Operativ

Anomaly Detection in the Artificial Pancreas

The integration of subcutaneous sensing and insulin delivery technologies with novel control strategies has brought closer the development of the Artificial Pancreas. Nevertheless, thought recent developments are aimed at preventing chronic complications and less patient discomfort, few works have addressed the critical issue of performance monitoring of the artificial pancreas as well as detection of abnormal functioning in any of its components. This work presents an anomaly detection monitoring tool using the widely known Clarke Error-Grid to identify functional degradation in the artificial pancreas components and guarantee safetycritical control of blood glucose levels. The effect of imperfect calibration of glucose sensors, time lag between blood glucose concentration and interstitial glucose readings, and excessive variability in glucose levels are evaluated against an expected behavior of the glucose regulation loop achieved through an optimal control policy. Results obtained evidence the feasibility of this novel use of the Clarke error grid as a comprehensive monitoring tool for the artificial pancreas.Sociedad Argentina de Informática e Investigación Operativ

Anomaly Detection in the Artificial Pancreas

The integration of subcutaneous sensing and insulin delivery technologies with novel control strategies has brought closer the development of the Artificial Pancreas. Nevertheless, thought recent developments are aimed at preventing chronic complications and less patient discomfort, few works have addressed the critical issue of performance monitoring of the artificial pancreas as well as detection of abnormal functioning in any of its components. This work presents an anomaly detection monitoring tool using the widely known Clarke Error-Grid to identify functional degradation in the artificial pancreas components and guarantee safetycritical control of blood glucose levels. The effect of imperfect calibration of glucose sensors, time lag between blood glucose concentration and interstitial glucose readings, and excessive variability in glucose levels are evaluated against an expected behavior of the glucose regulation loop achieved through an optimal control policy. Results obtained evidence the feasibility of this novel use of the Clarke error grid as a comprehensive monitoring tool for the artificial pancreas.Sociedad Argentina de Informática e Investigación Operativ

Role of Continuous Glucose Monitoring in Clinical Trials: Recommendations on Reporting.

Thanks to significant improvements in the precision, accuracy, and usability of continuous glucose monitoring (CGM), its relevance in both ambulatory diabetes care and clinical research is increasing. In this study, we address the latter perspective and derive provisional reporting recommendations. CGM systems have been available since around the year 2000 and used primarily in people with type 1 diabetes. In contrast to self-measured glucose, CGM can provide continuous real-time measurement of glucose levels, alerts for hypoglycemia and hyperglycemia, and a detailed assessment of glycemic variability. Through a broad spectrum of derived glucose data, CGM should be a useful tool for clinical evaluation of new glucose-lowering medications and strategies. It is the only technology that can measure hyperglycemic and hypoglycemic exposure in ambulatory care, or provide data for comprehensive assessment of glucose variability. Other advantages of current CGM systems include the opportunity for improved self-management of glycemic control, with particular relevance to those at higher risk of or from hypoglycemia. We therefore summarize the current status and limitations of CGM from the perspective of clinical trials and derive suggested recommendations for how these should facilitate optimal CGM use and reporting of data in clinical research

A prolonged run-in period of standard subcutaneous microdialysis ameliorates quality of interstitial glucose signal in patients after major cardiac surgery

We evaluated a standard subcutaneous microdialysis technique for glucose monitoring in two critically ill patient populations and tested whether a prolonged run-in period improves the quality of the interstitial glucose signal. 20 surgical patients after major cardiac surgery (APACHE II score: 10.1 ± 3.2) and 10 medical patients with severe sepsis (APACHE II score: 31.1 ± 4.3) were included in this investigation. A microdialysis catheter was inserted in the subcutaneous adipose tissue of the abdominal region. Interstitial fluid and arterial blood were sampled in hourly intervals to analyse glucose concentrations. Subcutaneous adipose tissue glucose was prospectively calibrated to reference arterial blood either at hour 1 or at hour 6. Median absolute relative difference of glucose (MARD), calibrated at hour 6 (6.2 (2.6; 12.4) %) versus hour 1 (9.9 (4.2; 17.9) %) after catheter insertion indicated a significant improvement in signal quality in patients after major cardiac surgery (p < 0.001). Prolonged run-in period revealed no significant improvement in patients with severe sepsis, but the number of extreme deviations from the blood plasma values could be reduced. Improved concurrence of glucose readings via a 6-hour run-in period could only be achieved in patients after major cardiac surgery