Patch Pumps: Periodic Insulin Delivery Patterns.

Recent in vitro experiments with patch pumps (PP) Omnipod (OP), Omnipod DASH (OP-D), A6 TouchCare (A6), and Accu-Chek Solo (ACS) have observed periodic fluctuations in the delivered amount of insulin during basal rate and consecutive bolus delivery in some PP, calling for a more systematic characterization of these periodic delivery patterns. Here, it was found that during basal rate delivery of 1 U/h, some devices of OP, OP-D, and A6 showed deviations of up to ±30% from target delivery that consistently repeated every 5 hours, whereas ACS showed no clear periodicity with considerably lower deviations. Similar results were found during consecutive bolus delivery of 1 U, where deviations repeated consistently every five boluses in some devices of OP, OP-D, and A6.

Time in Specific Glucose Ranges, Glucose Management Indicator, and Glycemic Variability: Impact of Continuous Glucose Monitoring (CGM) System Model and Sensor on CGM Metrics.

Background: International consensus recommends a set of continuous glucose monitoring (CGM) metrics to assess quality of diabetes therapy. The impact of individual CGM sensors on these metrics has not been thoroughly studied yet. This post hoc analysis aimed at comparing time in specific glucose ranges, coefficient of variation (CV) of glucose concentrations, and glucose management indicator (GMI) between different CGM systems and different sensors of the same system.

Accuracy assessment of bolus and basal rate delivery of different insulin pump systems used in insulin pump therapy of children and adolescents.

Background: Continuous subcutaneous insulin infusion (CSII) is commonly used in patients with diabetes. Accurate and reliable delivery by insulin pumps is essential for a safe and effective therapy, particularly when using small doses. In this study, accuracy of bolus and basal rate delivery of various available insulin pumps was evaluated.

Comparative Accuracy Analysis of a Real-time and an Intermittent-Scanning Continuous Glucose Monitoring System.

Background: Currently, two different types of continuous glucose monitoring (CGM) systems are available: real time (rt) CGM systems that continuously provide glucose values and intermittent-scanning (is) CGM systems. This study compared accuracy of an rtCGM and an isCGM system when worn in parallel.

Methods: Dexcom G5 Mobile (DG5) and FreeStyle Libre (FL) were worn in parallel by 27 subjects for 14 days including two clinic sessions with induced glucose excursions.

Measurement accuracy of two professional-use systems for point-of-care testing of blood glucose.

Background The professional-use systems HemoCue® Glucose 201+ (HC201+) and HemoCue® Glucose 201 RT (HC201RT) are widely used for point-of-care testing (POCT) of blood glucose (BG). HC201RT utilizes unit-use microcuvettes which can be stored at room temperature, whereas HC201+ microcuvettes have to be stored at <8 °C. In this study, system accuracy of HC201+ and HC201RT was evaluated using capillary and venous blood samples.

Accuracy of Bolus and Basal Rate Delivery of Different Insulin Pump Systems.

Background: Insulin pumps are used for basal rate and bolus insulin delivery in patients with diabetes. In this in vitro study, accuracy of delivery of different commercial insulin pumps was evaluated.

Materials And Methods: Accuracy of 10 different insulin pump systems (5 durable pumps with different insulin infusion sets and 1 patch pump) was tested with a microgravimetric method.

Performance and Usability of Three Systems for Continuous Glucose Monitoring in Direct Comparison.

Background: To be able to compare continuous glucose monitoring (CGM) systems, they have to be worn in parallel by the same subjects. This study evaluated the performance and usability of three different CGM systems in direct comparison.

Method: In this open, prospective study at two sites, 54 patients with diabetes wore three CGM systems each (Dexcom G5™ Mobile CGM system [DG5], Guardian™ Connect system [GC], and a Roche CGM system [RCGM]) in parallel for 6 or 7 days in a mixed inpatient and outpatient setting.

Reporting Insulin Pump Accuracy: Trumpet Curves According to IEC 60601-2-24 and Beyond.

Accuracy of insulin pump basal rate delivery, if tested according to the standard IEC 60601-2-24 for infusion pumps, shall be presented as a trumpet curve. This way of graphical presentation is common; however, it is often misunderstood and misinterpreted by people. It is often assumed that a trumpet curve shows the error rate as a function of time, thus implying an increasing accuracy in the course of time.

Measurement Performance of Two Continuous Tissue Glucose Monitoring Systems Intended for Replacement of Blood Glucose Monitoring.

Background: Currently, two systems for continuous tissue glucose monitoring (CGM) (Dexcom G5 [DG5] and FreeStyle Libre [FL]) are intended to replace blood glucose monitoring (BGM) and, according to manufacturer labeling, are distributed as such in some jurisdictions, including the United States and the European Union.

Methods: The measurement performance of these two systems in comparison with a BGM system was analyzed in a 14-day study with 20 participants comprising study site visits, which included phases of induced rapid glucose changes, and home use phases. Performance analysis was mainly based on deviations between CGM readings and BGM results.

Prediction Quality of Glucose Trend Indicators in Two Continuous Tissue Glucose Monitoring Systems.

Background: Continuous interstitial glucose monitoring (CGM) systems often provide glucose trend indicators (e.g., arrows) in addition to current glucose values.

Establishing Methods to Determine Clinically Relevant Bolus and Basal Rate Delivery Accuracy of Insulin Pumps.

Background: Adequate testing of delivery accuracy of insulin pumps is under discussion. Especially for patch pumps, test settings are challenging. In addition, evaluation and presentation of accuracy results in a way that is reasonable and useful for clinicians, not only for technicians, is important.

Accuracy of five systems for self-monitoring of blood glucose in the hands of adult lay-users and professionals applying ISO 15197:2013 accuracy criteria and potential insulin dosing errors.

Objective: In this study, accuracy in the hands of intended users was evaluated for five self-monitoring of blood glucose (SMBG) systems based on ISO 15197:2013, and possibly related insulin dosing errors were calculated. In addition, accuracy was assessed in the hands of study personnel.

Methods: For each system (Accu-Chek Aviva Connect [A], Contour Next One [B], FreeStyle Freedom Lite [C], GlucoMen areo [D] and OneTouch Verio [E]) one test strip lot was evaluated as required by ISO 15197:2013, clause 8.

Occlusion Detection Time in Insulin Pumps at Two Different Basal Rates.

Background: The detection of insulin infusion set (IIS) occlusions is an important feature of insulin pumps with regard to patient safety. However, there are no requirements for a time limit until an alarm has to be triggered after an occlusion occurred. The standard IEC 60601-2-24 is applicable for insulin pumps and describes test settings and procedures to determine occlusion detection time (ODT).

Flash Glucose Monitoring: Differences Between Intermittently Scanned and Continuously Stored Data.

The flash glucose monitoring system FreeStyle Libre (Abbott Diabetes Care Ltd., Witney, UK) measures interstitial glucose concentrations and continuously stores measurement values every 15 minutes. To obtain a current glucose reading, users have to scan the sensor with the reader.

TheClinical Research Tool: a high-performance microdialysis-based system for reliably measuring interstitial fluid glucose concentration.

Background: A novel microdialysis-based continuous glucose monitoring system, the so-called Clinical Research Tool (CRT), is presented. The CRT was designed exclusively for investigational use to offer high analytical accuracy and reliability. The CRT was built to avoid signal artifacts due to catheter clogging, flow obstruction by air bubbles, and flow variation caused by inconstant pumping.

Continuous glucose monitoring in interstitial fluid using glucose oxidase-based sensor compared to established blood glucose measurement in rats.

Glucose monitoring is of importance for success of complex therapeutic interventions in diabetic patients. Its impact on treatment and glycemic control is demonstrated in large clinical trials. Up to eight blood glucose measurements per day are recommended.