Continuous glucose monitoring--coming of age

Use of Technology in Older Adults with Type 1 Diabetes: Clinical Characteristics and Glycemic Metrics

Background: The use of diabetes-related technology, both for insulin administration and glucose monitoring, has shown benefits in older adults with type 1 diabetes (T1D). However, the characteristics of older adults with T1D and their use of technology in real-world situations are not well documented. Methods: Older adults (age ≥65 years) with T1D, using insulin pump or multiple daily injections (MDI) for insulin administration, and continuous glucose monitoring (CGM) or glucometer (blood glucose monitoring [BGM]) for glucose monitoring were evaluated. Participants wore CGM for 2 weeks, completed surveys, and underwent laboratory evaluation. Results: We evaluated 165 older adults with T1D; mean age 70 ± 10 years, diabetes duration 40 ± 17 years, and A1C 7.4% ± 0.9% (57 ± 10 mmol/mol). For insulin administration, 63 (38%) were using MDI, while 102 (62%) were using pump. Compared to MDI, pump users were less likely to have cognitive dysfunction (49% vs. 65%, P = 0.04) and had lower scores on the hypoglycemia fear survey (P = 0.03). For glucose monitoring, 95 (58%) used CGM, while 70 (42%) used BGM. Compared to BGM, CGM users were more likely to report impaired awareness of hypoglycemia (IAH) (P = 0.01), and had lower A1C (P = 0.02). Participants who used any technology (pump or CGM) had lower A1C (P = 0.04, 0.006), less hypoglycemia ≤54 mg/dL (P = 0.0006, <0.0001) and <70 mg/dL (P = 0.0002, 0.0001), and fewer glycemic excursions (coefficient of variation %) (P = 0.0001, <0.0001), while reporting more IAH (P = 0.04, P = 0.006) and diabetes distress (P = 0.02, 0.004). Conclusion: Older adults with T1D who use newer diabetes-related technology had better glycemic control, lower hypoglycemia risk, and fewer glycemic excursions. However, they were more likely to report IAH and diabetes-related distress. Clinical trials.gov NCT03078491.

Enhancing the Long-Term Stability of a Polymer Dot Glucose Transducer by Using an Enzymatic Cascade Reaction System

Impaired glucose metabolism in diabetes causes severe acute and long-term complications, making real-time detection of blood glucose indispensable for diabetic patients. Existing continuous glucose monitoring systems are unsuitable for long-term clinical glycemic management due to poor long-term stability. Polymer dot (Pdot) glucose transducers are implantable optical nanosensors that exhibit excellent brightness, sensitivity, selectivity, and biocompatibility. Here, it is shown that hydrogen peroxide-a product of glucose oxidation in Pdot glucose sensors-degrades sensor performance via photobleaching, reduces glucose oxidase activity, and generates cytotoxicity. By adding catalase to a glucose oxidase-based Pdot sensor to create an enzymatic cascade, the hydrogen peroxide product of glucose oxidation is rapidly decomposed by catalase, preventing its accumulation and improving the sensor's photostability, enzymatic activity, and biocompatibility. Thus, a next-generation Pdot glucose transducer with a multienzyme reaction system (Pdot-GOx/CAT) that provides excellent sensing characteristics as well as greater detection system stability is presented. Pdot glucose transducers that incorporate this enzymatic cascade to eliminate hydrogen peroxide will possess greater long-term stability for improved continuous glucose monitoring in diabetic patients.

Continuous glucose monitoring to assess glycemic control in the first 6 weeks after pancreas transplantation

BACKGROUND

Current therapy for Type 1 diabetes (T1D) is characterized by significant glucose variability (GV). Pancreas transplantation (PT) is performed in certain T1D patients with and without end-stage renal disease. To date, GV has been examined to a limited extent after PT.

METHODS

We investigated GV using continuous glucose monitoring (CGM) 3-6 weeks after PT.

RESULTS

Eleven patients had simultaneous kidney pancreas transplantation (SPK), nine pancreas after kidney (PAK), and six pancreas transplantation alone (PTA). Mean CGM showed no difference between SPK, 126.5 ± 13.9, PAK 119.9 ± 12.8, and PTA 131.1 ± 29 mg/dL (P value .6). Percentage of time in range (TIR, 70-180 mg/dL) was 92% for SPK, 93.4% in PAK, and 88.5% in PTA with only 0.3%, 1.5%, and 0.3% of time <70 mg/dL. Percentage >180 mg/dL was 7.9% for SPK, 4.9% PAK, and 11% in PTA. Other measures of GV were similar in the three cohorts. In six patients, CGM was performed before and after PT and improved significantly. GV was also better compared with a matched cohort of T1D patients.

CONCLUSIONS

All 3 types of PT resulted in excellent glucose control 3-6 weeks post-procedure. CGM outcomes represent an important objective outcome after PT.

Gaps in Knowledge and the Need for Patient-Partners in Research Related to Physical Activity and Type 1 Diabetes: A Narrative Review

Regular physical activity (PA) is a cornerstone in the management of complications associated with type 1 diabetes (T1D). Most national guidelines advocate for regular PA for persons living with T1D, however the evidence to support these recommendations has not be reviewed recently. Additionally, in an era of patient-centered care and patient oriented research, the role of patient partners in the area of PA and T1D interventions has never been explored. The purpose of this narrative review is to overcome these two gaps in the literature. Here we review selected epidemiological evidence and identify gaps in research that would add important information to guide practitioners and future guidelines. We also provide an overview of patient-oriented research projects co-developed with persons living with T1D. Significant gaps in the field include: (1) a lack of adequately powered prospective cohort studies using serial measures of PA and hard chronic disease end-points; (2) no multi-centered, highly powered, randomized controlled trials of PA, and long-term health outcomes; (3) little data on the role of new technologies to support PA-related behavior change, and (4) no trials that involved patients in the design and execution of PA-based clinical trials. This review provides a template for scientists and patient partners to develop future research priorities and agendas in the field.

Ultrabright Polymer-Dot Transducer Enabled Wireless Glucose Monitoring via a Smartphone

Optical methods such as absorptiometry, fluorescence, and surface plasmon resonance have long been explored for sensing glucose. However, these schemes have not had the clinical success of electrochemical methods for point-of-care testing because of the limited performance of optical sensors and the bulky instruments they require. Here, we show that an ultrasensitive optical transducer can be used for wireless glucose monitoring via a smartphone. The optical transducer combines oxygen-sensitive polymer dots (Pdots) with glucose oxidase that sensitively detect glucose when oxygen is consumed in the glucose oxidation reaction. By judicious design of the Pdots with ultralong phosphorescence lifetime, the transducer exhibited a significantly enhanced sensitivity by 1 order of magnitude as compared to the one in a previous study. As a result, the optical images of subcutaneous glucose level obtained with the smartphone camera could be utilized to clearly distinguish between euglycemia and hyperglycemia. We further developed an image processing algorithm and a software application that was installed on a smartphone. Real-time dynamic glucose monitoring in live mice was demonstrated with the smartphone and the implanted Pdot transducer.

Advances on Aryldiazonium Salt Chemistry Based Interfacial Fabrication for Sensing Applications

Aryldiazonium salts as coupling agents for surface chemistry have evidenced their wide applications for the development of sensors. Combined with advances in nanomaterials, current trends in sensor science and a variety of particular advantages of aryldiazonium salt chemistry in sensing have driven the aryldiazonium salt-based sensing strategies to grow at an astonishing pace. This review focuses on the advances in the use of aryldiazonium salts for modifying interfaces in sensors and biosensors during the past decade. It will first summarize the current methods for modification of interfaces with aryldiazonium salts, and then discuss the sensing applications of aryldiazonium salts modified on different transducers (bulky solid electrodes, nanomaterials modified bulky solid electrodes, and nanoparticles). Finally, the challenges and perspectives that aryldiazonium salt chemistry is facing in sensing applications are critically discussed.

The interrelationship of HbA1c and real-time continuous glucose monitoring in children with type 1 diabetes

AIMS

The aim of this observational study is to investigate the relationship between age, duration of diabetes, HbA1c and the parameters of glucose levels measured with real-time CGM in children with type 1 diabetes.

METHODS

Glucose level was characterized with the relative time spent in hyper- and hypoglycemia, central tendency, variability and MAGE during (real-time) CGM. These parameters were measured in 57 children with type 1 diabetes mellitus. The univariate association of the measured parameters was investigated with scatterplots as well as with linear and distance correlation coefficients.

RESULTS

Age and duration of diabetes were not clinically relevantly associated with any descriptor of glucose level. HbA1c had an overall positive association with variability and MAGE observed during CGM. Slight, but non-significant, positive association of HbA1c was observed with the time spent in hyperglycemia and the central tendency of glucose level. With the exception of MAGE, the associations of the descriptors with HbA1c are non-monotonic, with a temporary break in the positive correlation at 10%.

CONCLUSIONS

The results confirmed the well-known positive association of HbA1c with the central tendency of glucose level. The non-monotonic relationship between HbA1c and the indicators of the central tendency of glucose level might be caused by the changed adherence of the patients during the period of CGM. HbA1c's positive association with MAGE without non-monotonicity underlines MAGE's usefulness in the reliable assessment of the patients' glycemic state.

Monitoring systems and quantitative measurement of biomolecules for the management of trauma

Continued high morbidity and complications due to trauma related hemorrhage underscores the fact that our understanding of the detailed molecular events of trauma are inadequate to bring life-saving changes to practice. The current state of efficacy and advances in biomedical microdevice technology for trauma diagnostics concerning hemorrhage and hemorrhagic shock was considered with respect to vital signs and metabolic biomarkers. Tachycardia and hypotension are markers of hemorrhagic shock in decompensated trauma patients. Base deficit has been predicative of injury severity at hospital admission. Tissue oxygen saturation has been predicative of onset of multiple organ dysfunction syndrome. Blood potassium levels increase with onset of hemorrhagic shock. Lactate is a surrogate for tissue hypoxia and its clearance predicts mortality. Triage glucose measurements have been shown to be specific in predicting major injuries. No vital sign has yet to be proven effective as an independent predictor of trauma severity. Point of care (POC) devices allow for rapid results, easy sample preparation and processing, small sample volumes, small footprint, multifunctional analysis, and low cost. Advances in the field of in-vivo biosensors has provided a much needed platform by which trauma related metabolites can be monitored easily, rapidly and continuously. Multi-analyte monitoring biosensors have the potential to explore areas still undiscovered in the realm of trauma physiology.

Frequency of blood glucose testing in well educated patients with diabetes mellitus type 1: how often is enough?

AIMS

Self-monitored blood glucose (SMBG) and knowledge of insulin requirements are pivotal for good metabolic control in patients with diabetes mellitus type 1. However, the SMBG-frequency needed for optimal glycaemic control especially in well educated patients is unclear.

METHODS

In patients with type 1 diabetes treated with flexible intensified insulin therapy, we evaluated HbA1c values and the directly preceding computerised SMBG-frequencies over a 12 months period. To estimate the association between HbA1c and SMBG-frequency, we fitted a piecewise linear spline model with a change in slope at 4 SMBGs per day which is the recommended minimal SMBG-frequency at our institution.

RESULTS

A total of 150 patients were available for analysis, with a median baseline HbA1c of 7.1% (interquartile range 6.6, 7.8). In the multivariable analysis (adjusted for gender and psychological problems), each additional SMBG measurement was associated with an estimated difference in HbA1c of -0.19% (95% confidence interval (CI) -0.42, 0.05) for ≤4 SMBGs per day and of -0.02% (95% CI -0.10, 0.06) for >4 SMBGs per day.

CONCLUSIONS

Good diabetes control can be achieved in routine diabetes care with flexible intensified insulin therapy based on continuing patients' education and with a minimum of 4 SMBGs per day.

Effect of short-term iPRO continuous glucose monitoring on hemoglobin A1c levels in clinical practice

OBJECTIVE

This study determined if short-term (professional) blinded continuous glucose monitoring (CGM) improves hemoglobin A1c levels in a mixed group of patients with type 1 and type 2 diabetes in the clinical setting of an office practice.

RESEARCH DESIGN AND METHODS

This was a retrospective analysis of 102 consecutive patients with diabetes over the course of 10 months in a subspecialty practice undergoing 3-day blinded CGM using the iPRO(™) device (Medtronic, Northridge, CA). Hemoglobin A1c levels were measured prior to and up to 7 months after the CGM procedure.

RESULTS

Before blinded CGM the average hemoglobin A1c level was 7.7±1.0%, and after it was 7.8±1.1%. These values are not statistically different. A subgroup analysis of subjects using continuous subcutaneous insulin infusion treatment also failed to show a significant hemoglobin A1c difference pre- and post-CGM.

CONCLUSIONS

Using the iPro device for short-term (professional) blinded CGM in an office setting to improve hemoglobin A1c levels may not be a feasible goal for patients with type 1 and type 2 diabetes. The expectations of benefit, choice of patient, and choice of technology for short-term CGM are factors requiring careful consideration before testing takes place.

Evolution of devices in diabetes management

Recent technological advancements in insulin administration and glucose monitoring have allowed patients with diabetes to become increasingly involved in their own care. Devices replacing the traditional vial and syringe, such as insulin pens, are gaining popularity and offer simple and convenient insulin administration. Pen devices are associated with improved dose accuracy, reducing the risk of hypo- or hyperglycemia, and are continually being updated with new safety features in order to optimize their performance. In patients for whom glucose variability remains a problem, continuous subcutaneous insulin infusion via an implanted canula or continuous intraperitoneal insulin infusion via an implanted pump is safe and effective when used correctly, although cost can be a limitation. More accurate retrospective and real-time continuous monitoring devices, which can better detect blood glucose excursions, have become standard components of modern-day diabetes management. The most recent devices have sensor-signaling capabilities with wireless data transmission, leading to reduced time delay and more accurate alerts. Ultimately, though, while self-management remains a critical factor in improving glycemic control at present, human error may undermine even the most accurate treatment interventions. A key long-term goal in diabetes management is, therefore, to develop an automated and accurate closed-loop system for blood glucose monitoring and insulin delivery to better reflect the physiological mechanisms of glucose homeostasis and remove the "human" element. This "artificial pancreas" would offer the most innovative intervention for diabetes management and has the potential to considerably reduce the patient's burden of self-care.

Crossing the technology divide: practical strategies for transitioning patients from multiple daily insulin injections to sensor-augmented pump therapy

PURPOSE

To describe the benefits of continuous glucose monitoring (CGM) and continuous subcutaneous insulin infusion (CSII) systems compared with self-monitoring of blood glucose (SMBG) and multiple daily injection (MDI) therapy; to assess the benefits of sensor-augmented pump therapy (SAPT) in patients with type 1 diabetes; and to present an evidence-based practical protocol for introducing SAPT in patients with no prior pump or CGM experience.

CONCLUSION

Continuous glucose monitoring and CSII have advantages over SMBG and MDI, respectively, in terms of A1C and hypoglycemia reduction. The Sensor-Augmented Pump Therapy for A1C Reduction (STAR) 3 trial demonstrated that initiating both CGM and CSII in selected adult and pediatric patients with type 1 diabetes unable to meet glycemic goals with intensive insulin injection therapy significantly improved glucose control. In all subjects using SAPT, A1C levels fell rapidly from baseline to 3 months and remained significantly lower than among subjects in the SMBG+MDI group for 1 year. A distinguishing feature of the STAR 3 study was its stepwise protocol for systematizing education and self-management support using Web-based training modules and therapy management software. The demonstrated strengths of this education protocol recommend it as a model for implementing SAPT in the broader population of patients with type 1 diabetes who have not achieved their glycemic goals with optimized MDI therapy.

Switch-based biosensors: a new approach towards real-time, in vivo molecular detection

Although the ability to monitor specific molecules in vivo in real-time could revolutionize many aspects of healthcare, the technological challenges that stand in the way of reaching this goal are considerable and are poorly met by most existing analytical approaches. Nature, however, has already solved the problem of real-time molecular detection in complex media by employing biomolecular "switches". That is, protein and nucleic acids that sense chemical cues and, by undergoing specific, binding-induced conformational changes, transduce this recognition into high-gain signal outputs. Here, we argue that devices that employ such switches represent a promising route towards versatile, real-time molecular monitoring in vivo.