Comparative Dose Accuracy of Durable and Patch Insulin Pumps Under Laboratory Conditions

Bench-Side Dose Accuracy of an Open-Source Ultra-Low-Cost Insulin-Pump, With Testing Conducted to IEC 60601-2-24

With the prevalence of diabetes higher than ever, governments and people with diabetes are facing significant treatment and indirect costs associated with managing their condition. An ultra-low-cost insulin pump is a possible solution to improving health disparities. This article presents test results for an insulin-pump built from low-cost components (bill of materials < $US100). All testing was completed in accordance with IEC60601-2-24, and results were benchmarked against a commercial pump. Results showed the ultra-low-cost pump has comparable accuracy to the commercially available insulin pump with testing displaying an overall accuracy of 0.089% and -0.392%, respectively. These results show that an ultra-low-cost pump can accurately deliver insulin in limited bench testing. Testing in other environments and scenarios is required to fully meet IEC60601-2-24 standards.

Comparing Equil patch versus traditional catheter insulin pump in type 2 diabetes using continuous glucose monitoring metrics and profiles

AIMS

It is not clear whether there are differences in glycemic control between the Equil patch and the MMT-712 insulin pump. Our objective was to compare two types of insulin pumps in the treatment of type 2 diabetes mellitus (T2DM), using continuous glucose monitoring (CGM) metrics and profiles.

METHODS

This was a randomized case-crossover clinical trial. Participants were hospitalized and randomly allocated to two groups and underwent two types of insulin pump treatments (group A: Equil patch-Medtronic MMT-712 insulin pump; group B: Medtronic MMT-712-Equil patch insulin pump) separated by a 1-day washout period. Glycemic control was achieved after 7-8 days of insulin pump therapy. Each patient received CGM for 5 consecutive days (from day 1 to day 5). On day 3 of CGM performance, the Equil patch insulin pump treatment was switched to Medtronic MMT-712 insulin pump treatment at the same basal and bolus insulin doses or vice versa. CGM metrics and profiles including glycemic variability (GV), time in range (TIR, 3.9-10.0 mmol/L), time below range (TBR, <3.9 mmol/L), time above range (TAR, >10.0 mmol/L), and postprandial glucose excursions, as well as incidence of hypoglycemia.

RESULTS

Forty-six T2DM patients completed the study. There was no significant difference in parameters of daily GV and postprandial glucose excursions between the Equil patch insulin pump treatment and the Medtronic insulin pump treatment. Similarly, there was no between-treatment difference in TIR, TBR, and TAR, as well as the incidence of hypoglycemia.

CONCLUSION

The Equil patch insulin pump was similar to the traditional MMT-712 insulin pump in terms of glycemic control. Equil patch insulin pump is a reliable tool for glycemic management of diabetes mellitus.

Opportunities to overcome underutilization of enhanced insulin delivery technologies in people with type 2 diabetes: a narrative review

Use of innovative technologies such as continuous glucose monitoring (CGM) and insulin delivery systems have been shown to be safe and effective in helping patients with diabetes achieve significantly improved glycemic outcomes compared to their previous therapies. However, these technologies are underutilized in many primary care practices. This narrative review discusses some of the clinical and economic benefits of tubeless insulin delivery devices and discusses how this technology can overcome the main obstacles inherent to use of conventional insulin delivery devices.

Design of an open source ultra low cost insulin pump

In this report we present a design for an open source low cost insulin pump. The pump has been designed to provide an alternative to commercially available pumps costing upwards of US$6500, making them inaccessible to many. The hardware described in this article can be produced for a materials cost of US$89.85. Compared to other devices on the market, the design presented has the obvious advantage of being low cost, but is also highly customisable as it is run using open source software. The device is housed in a case of size 85 mm x 55 mm x 25 mm making it small enough to fit in a pocket, and equivalent to other devices on the market. The device is designed to work with insulin cartridges currently available on the market. Power is provided through the use of AAA batteries, and the pump is able to be recharged through a USB mini port. The accuracy of the pump has been tested and compared to data obtained from an in-warranty commercial insulin pump model using an identical testing methodology, with the ultra-low-cost pump performing similarly to the commercial model. The system can be readily extended to be controlled from external bluetooth or wired mobile devices using their built in security, offloading computation from the device and onto a phone.

The Relationship Between Different Bench Test Methodologies and Accuracy of Insulin Infusion Pumps: A Systematic Literature Review

Diabetes technology has rapidly evolved, and insulin infusion pumps (IIPs) have gained worldwide acceptance in diabetes care. The safety of medical equipment is highly discussed, imposing complex challenges in its use. The accuracy of IIPs can be determined through laboratory tests, generally following the IEC 60601-2-24 protocol. Studies have evaluated the accuracy and precision of IIPs, and there are discrepant results. So, we conducted a Systematic Literature Review to assess the methodologies used to evaluate the accuracy of IIPs, organizing the findings in a compiled perspective. The methodology was based on Kitchenham and Biolchini guidelines, and when possible it was carried out the Bayesian meta-analyses to compare the accuracy of IIPs. Most studies used the microgravimetric technique to evaluate the device accuracy, and some proposed adaptations for the standard protocol. The variation of results was recurrent, and the establishment of a protocol, especially to evaluate patch pumps, is necessary. The present study gives enough data to understand the scenario of the IIPs evaluation, as well as the different protocols that can be explored for its evaluation. This highlights the need for a reliable, practical, and low-cost methodology to assist the evaluation of IIPs.

Patch Pumps: What are the advantages for people with diabetes?

AIM

Patch pumps, i.e. insulin pumps without tubing, are an attractive alternative to conventional insulin pumps for people with type 1 diabetes and type 2 diabetes on insulin therapy. In this review, potential patient-relevant advantages and disadvantages of patch pumps are summarized and respective studies on patient-reported outcomes (PROs) are assessed.

METHODS

Relevant studies were identified through a systematic PubMed search. Reference lists in respective articles and Google Scholar were also checked for additional references. Articles in English published before June 30, 2021, were included; no other criteria on publication dates were set.

RESULTS

A total of 12 studies were included. The results of this analysis provide evidence that patch pumps improve quality of life, reduce diabetes-related distress, increase patient satisfaction, and are preferred by patients compared to conventional insulin pumps and multiple daily injection therapy (MDI). However, several methodological limitations of the studies identified constrain the significance of this analysis.

CONCLUSIONS

Despite the limited number of studies evaluating the benefits of patch pumps on PROs, there is increasing evidence that people with diabetes prefer patch pumps. Although there are numerous PROs for patch pumps, it is surprising that this aspect has been relatively understudied. More systematic evaluation studies of the benefits of patch pumps on PROs are needed.

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. However, there was a large variability in the periodic delivery patterns between individual devices of the same PP model. Examining their pumping techniques indicated a connection between the insulin delivery mechanism and observed delivery patterns of the PP. However, the clinical impact of such patterns is unclear.

Piezoelectric Silicon Micropump for Drug Delivery Applications

Subcutaneous injection is crucial for the treatment of many diseases. Especially for regular or continuous injections, automated dosing is beneficial. However, existing devices are large, uncomfortable, visible under clothing, or interfere with physical activity. Thus, the development of small, energy efficient and reliable patch pumps or implantable systems is necessary and research on microelectromechanical system (MEMS) based drug delivery devices has gained increasing interest. However, the requirements of medical applications are challenging and especially the dosing precision and reliability of MEMS pumps are not yet sufficiently evaluated. To enable further miniaturization, we propose a precise 5 × 5 mm2 silicon micropump. Detailed experimental evaluation of ten pumps proves a backpressure capability with air of 12.5 ± 0.8 kPa, which indicates the ability to transport bubbles. The maximal water flow rate is 74 ± 6 µL/min and the pumps’ average blocking pressure is 51 kPa. The evaluation of the dosing precision for bolus deliveries with water and insulin shows a high repeatability of dosed package volumes. The pumps show a mean standard deviation of only 0.02 mg for 0.5 mg packages, and therefore, stay below the generally accepted 5% deviation, even for this extremely small amount. The high precision enables the combination with higher concentrated medication and is the foundation for the development of an extremely miniaturized patch pump.

The impact of chemical engineering and technological advances on managing diabetes: present and future concepts

Monitoring blood glucose levels for diabetic patients is critical to achieve tight glycaemic control. As none of the current antidiabetic treatments restore lost functional β-cell mass in diabetic patients, insulin injections and the use of insulin pumps are most widely used in the management of glycaemia. The use of advanced and intelligent chemical engineering, together with the incorporation of micro- and nanotechnological-based processes have lately revolutionized diabetic management. The start of this concept goes back to 1974 with the description of an electrode that repeatedly measures the level of blood glucose and triggers insulin release from an infusion pump to enter the blood stream from a small reservoir upon need. Next to the insulin pumps, other drug delivery routes, including nasal, transdermal and buccal, are currently investigated. These processes necessitate competences from chemists, engineers-alike and innovative views of pharmacologists and diabetologists. Engineered micro and nanostructures hold a unique potential when it comes to drug delivery applications required for the treatment of diabetic patients. As the technical aspects of chemistry, biology and informatics on medicine are expanding fast, time has come to step back and to evaluate the impact of technology-driven chemistry on diabetics and how the bridges from research laboratories to market products are established. In this review, the large variety of therapeutic approaches proposed in the last five years for diabetic patients are discussed in an applied context. A survey of the state of the art of closed-loop insulin delivery strategies in response to blood glucose level fluctuation is provided together with insights into the emerging key technologies for diagnosis and drug development. Chemical engineering strategies centered on preserving and regenerating functional pancreatic β-cell mass are evoked in addition as they represent a permanent solution for diabetic patients.

Evaluation of the Accuracy of Current Tubeless Pumps for Continuous Subcutaneous Insulin Infusion

Background: Recently two new tubeless pumps for insulin therapy were introduced. They were tested for accuracy and occlusion detection and compared with the established patch pump Omnipod^® (OP). Methods: Using a modified setup for tubeless pumps based on IEC 60601-2-24, the basal rate and bolus delivery of the Accu-Chek^® Solo micropump system (ACS) and the A6 TouchCare^® System (A6) were measured with a microgravimetric method. Bolus sizes of 0.2, 1, and 10 U, and basal rates of 0.1 and 1 U/h were evaluated in nine repetitions. For each parameter, mean deviation and number of individual boluses or 1-h basal rate windows within ±15% from target were calculated. In addition, occlusion detection time at basal rates of 0.1 and 1 U/h was determined. Results: Mean deviation of boluses of different volumes in the pumps ranged from -3.3% to +4.0% and 40%-100% of individual boluses were within ±15% of the target. During basal rate delivery, 48% to 98% of 1-h windows were within ±15% of the target with a mean deviation between -5.3% and +6.5%. In general, considerable differences between pump models were observed and deviations decreased with increasing doses. In most parameters, ACS was more accurate, and A6 less accurate, than OP. Mean occlusion detection time ranged from ∼3 to 7.5 h at 1 U/h and was >24 h or absent at 0.1 U/h. Conclusions: In this evaluation, significant differences between the tested tubeless pump models were observed that became most evident when regarding delivery errors over short time and small volumes.

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.

METHODS

In total, 13 insulin pump systems were tested: eight durable pumps with different infusion sets and one patch pump. Based on IEC 60601-2-24, insulin delivery was measured by recording weight gain of a beaker into which insulin was infused by the pumps. Bolus accuracy was determined by individually weighing 25 consecutive 0.1 or 1.0 U boluses and basal rate accuracy was determined during basal rate delivery of 0.1 or 1.0 U/h for 72 hours. For analyses, basal rate delivery was divided into 1-hour windows and deviation from target was calculated.

RESULTS

Regarding different systems, average 0.1 U bolus delivery was -2% to +9% of the intended volume with 53% to 96% of boluses within ±15% of target. During 0.1 U/h basal rate delivery, most pumps showed an initial over-delivery for the first few hours. Three systems reached a total basal rate error <5%; others showed up to +24%. In general, delivery was more accurate when using larger doses.

CONCLUSIONS

Considerable differences in insulin delivery accuracy were observed between the tested pumps. In general, when using very low doses, accuracy of insulin delivery is limited in most insulin pumps. This should be considered for CSII therapy in children.

All Insulin Pumps Are Not Equivalent: A Bench Test Assessment for Several Basal Rates

Background and Aims: Continuous subcutaneous insulin infusion (CSII) is a widely adopted treatment for type 1 diabetes and is a component of an artificial pancreas. CSII accuracy is essential for glycemic control, however, this metric has not been given sufficient study, especially at the range of the lowest basal rates (BRs), which are commonly used in a pediatric population and in closed-loop systems (CLSs). Our study presents accuracy results of four off-the-shelf CSII systems using a new accurate method for CSII system evaluation. Materials and Methods: The accuracy of four off-the-shelf CSII systems was assessed: Medtronic MiniMed 640G^®, Ypsomed YpsoPump^®, Insulet Omnipod^®, and Tandem t:slim X2^®. The assessment was performed using a double-measurement approach through a direct mass flow meter and a time-stamped microgravimetric test bench combined with a Kalman mathematical filter. CSII accuracy was evaluated using mean of dose error. Mean absolute relative difference (MARD) of error was calculated at different observation windows over the whole series of tests. Peakwise insulin deliverance was assessed regarding stroke regularity in terms of frequency and volume. Results: Mean error values indicate a general tendency to underdeliver with up to -16%. MARD of error shows very wide results for each pump and each BR from 7.4% (2 UI/h) to 61.3% (0.1 UI/h). Peakwise analysis shows several choices for BR adaptation (frequency for Omnipod, volume for Tandem, both for YpsoPump and MiniMed 640G). Precision in interstroke time appears to be better (standard deviation [SD] at 0.1 UI/h: 4.6%-12.9%) than stroke volume precision (SD at 0.1 UI/h 38.3%-46.4%). Conclusions: The accuracy of four off-the-shelf CSII systems is model and BR dependent. CSII imprecision could be due to a variability in volume and/or frequency of strokes for every pump. Some models appear better adapted for the smallest insulin needs, or for inclusion in a CLS. The clinical implications of these delivery errors on glucose instability must be evaluated.