Evaluating the Performance of a Novel Embedded Closed-loop System

Abstract

Despite significant improvements in the care of type 1 diabetes, achieving tight glycemic control while avoiding hypoglycemia 1,2 remains a challenge for many patients and novel therapeutic approaches are required. Closed-loop insulin delivery is an emerging treatment option for patients with type 1 diabetes. 3 Compared to preprogrammed basal insulin rates in insulin pumps, closed-loop insulin delivery systems modulate insulin delivery in glucose-responsive fashion based on subcutaneous sensor glucose levels utilizing advanced computer algorithms. 3Several studies have evaluated the safety and efficacy of closed-loop under laboratory conditions and shown promising results. These include evaluations using a randomized design by our group in youths, 4,5 adults, 6 and pregnant women 7 and by others using the model predictive control algorithm, 8,9 , the proportional-integral-derivative approach, 10,11 and the fuzzy logic controller. 12,13 Insulin and glucagon coadministration have also been applied in randomized studies.14-16 Several of above studies [4][5][6][7] were conducted in the manual operational mode where sensor glucose values were entered into a laptop computer running the algorithm followed by manual adjustment of the insulin pump. More recently automated closed-loop control systems utilizing an ultra-portable laptop computer 17 or mobile phone platform 18 have also been described. In February 2010, the European Union granted funding for the AP@home project (Artificial Pancreas at Home), a consortium of European academic medical centers, biotechnology companies, and industrial partners, to carry out closed-loop glucose control research. 19 The ultimate goal of the AP@home project is to develop a closed-loop system for use outside clinical research centers. The primary objective of the current study was to evaluate the reliability of the first , on behalf of the AP@home consortium AbstractThe objective was to assess the reliability of a novel automated closed-loop glucose control system developed within the AP@home consortium in adults with type 1 diabetes. Eight adults with type 1 diabetes on insulin pump therapy (3 men; ages 40.5 ± 14.3 years; HbA1c 8.2 ± 0.8%) participated in an open-label, single-center, single-arm, 12-hour overnight study performed at the clinical research facility. A standardized evening meal (80 g CHO) accompanied by prandial insulin boluses were given at 19:00 followed by an optional snack of 15 g at 22:00 without insulin bolus. Automated closed-loop glucose control was started at 19:00 and continued until 07:00 the next day. Basal insulin delivery (Accu-Chek Spirit, Roche) was automatically adjusted by Cambridge model predictive control algorithm, running on a purpose-built embedded device, based on real-time continuous glucose monitor readings (Dexcom G4 Platinum). Closed-loop system was operational as intended over 99% of the time. Overnight plasma glucose levels (22:00 to 07:00) were within the target range (3.9 to 8.0 mmol/l) for 75.4% (37.5, 92.9) of the time without any ti...

Efficacy of the Diabeloop closed‐loop system to improve glycaemic control in patients with type 1 diabetes exposed to gastronomic dinners or to sustained physical exercise

“…This value is higher than the 4% reported by Reddy et al and the 11% reported by Kovatchev et al in previous adult inpatient short‐term studies. Overnight, the reference time in the range of 3.9 to 10.0 mmol/L was 83% with Diabeloop, a value similar to the 82% to 90% values previously reported The reduction in average glucose reported in the present study (1.0 mmol/L) compares well with the 0.3 to 2.1 mmol/L reduction observed by others …”

“…This value is higher than the 4% reported by Reddy et al 38 and the 11% reported by Kovatchev et al 20 in previous adult inpatient short-term studies. Overnight, the reference time in the range of 3.9 to 10.0 mmol/L was 83% with Diabeloop, a value similar tothe 82% to 90% values previously reported [20][21][22].…”

“…Most studies on CL systems have been conducted in current life conditions with standardized meals . However, it appears that CL systems perform markedly better at night because daytime glycaemia is constantly challenged by casual events, such as meals of varied composition and exercise bouts of varying intensities and/or frequencies .…”

“…Most studies on CL systems have been conducted in current life conditions with standardized meals. [20][21][22] However, it appears that CL systems perform markedly better at night because daytime glycaemia is constantly challenged by casual events, such as meals of varied composition and exercise bouts of varying intensities and/or frequencies. 6 Thus, we decided to investigate the efficacy of the Diabeloop CL system in challenging real-life situations such as very large meals, which amplify hyperglycaemic excursions, a risk factor for chronic vascular complications [23][24][25] (see also high glycaemic variability as an aggravating factor for diabetes complications 24,[26][27][28] ).…”

The Diabetes Assistant: A Smartphone-Based System for Real-Time Control of Blood Glucose

“…The pathway to the use of consumer electronics to perform medical functions is discussed in recent FDA guidance [30], which defines medical mobile applications and the process of their regulatory approval. The Medtronic 530G insulin pump with a low glucose suspend feature provides some of the safety features of a full artificial pancreas system and several research groups [31,32], have conducted AP clinical trials with smartphone or purpose-built portable systems. A comprehensive discussion of the current status of artificial pancreas systems is presented in [33].…”