Pilot Studies of Wearable Outpatient Artificial Pancreas in Type 1 Diabetes

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Background: Studies of closed-loop control (CLC) systems have improved glucose levels in patients with type 1 diabetes. In this study we test a new CLC concept aiming to ''reset'' the patient overnight to nearnormoglycemia each morning, for several consecutive nights. Subjects and Methods: Ten insulin pump users with type 1 diabetes (mean age, 46.4 -8.5 years) were enrolled in a two-center (in the United States and Italy) randomized crossover trial comparing 5 consecutive nights of CLC (23:00-07:00 h) in an outpatient setting versus sensor-augmented insulin pump therapy of the same duration at home. Primary end points included time spent in 80-140 mg/dL as measured by continuous glucose monitoring overnight and fasting blood glucose distribution at 7:00 h. Results: Compared with sensor-augmented pump therapy, CLC improved significantly time spent between 80 and 140 mg/dL (54.5% vs. 32.2%; P < 0.001) and between 70 and 180 mg/dL (85.4% vs. 59.1%; P < 0.001); CLC reduced the mean glucose level at 07:00 h (119.3 vs. 152.9 mg/dL; P < 0.001) and overnight mean glucose level (139.0 vs. 170.3 mg/dL; P < 0.001) using a marginally lower amount of insulin (6.1 vs. 6.8 units; P = 0.1). Tighter overnight control led to improved daytime control on the next day: the overnight/next-day control correlation was r = 0.52, P < 0.01. Conclusions: Multinight CLC of insulin delivery (artificial pancreas) results in significant improvement in morning and overnight glucose levels and time in target range, with the potential to improve daytime control when glucose levels were ''reset'' to near-normoglycemia each morning.

Section: Clc Technologymentioning

confidence: 99%

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confidence: 93%

Multinight “Bedside” Closed-Loop Control for Patients with Type 1 Diabetes

BrownSue

KovatchevBoris²,

BretonMarc³

et al. 2015

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“…11,12 Recent closed-loop control artificial pancreas (AP) studies have shown reduction in the risk for hypoglycemia in T1DM subjects, increase of the time in near-normoglycemia (70-180 mg/dL), and reduction in average glucose level, both in the hospital and in home-like settings, with and without exercise. [13][14][15][16][17][18][19][20][21][22] However, although overnight hypoglycemia can be reduced severalfold, preventing hypoglycemia during and immediately after exercise remains a hurdle, likely due to the inherent delay of the glycemic response to exercise coupled with delays due to subcutaneously injected insulin. 13 Informing insulin dosing of physical activity could theoretically decrease these risks.…”

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confidence: 99%

Adding Heart Rate Signal to a Control-to-Range Artificial Pancreas System Improves the Protection Against Hypoglycemia During Exercise in Type 1 Diabetes

Breton

Brown²,

Karvetski³

et al. 2014

Self Cite

113

Background: We present a clinical trial establishing the feasibility of a control-to-range (CTR) closed-loop system informed by heart rate (HR) and assess the effect of HR information added to CTR on the risk for hypoglycemia during and after exercise. Subjects and Methods: Twelve subjects with type 1 diabetes (five men, seven women; weight, 68.9 -3.1 kg; age, 38 -3.3 years; glycated hemoglobin, 6.9 -0.2%) participated in a randomized crossover clinical trial comparing CTR versus CTR + HR in two 26-h admissions, each including 30 min of mild exercise. The CTR algorithm was implemented in the DiAs portable artificial pancreas platform based on an Android Ò (Google, Mountainview, CA) smartphone. We assessed blood glucose (BG) decline during exercise, the Low BG Index (LBGI) (a measure of hypoglycemic risk), number of hypoglycemic episodes (BG < 70 mg/dL) and overall glucose control (percentage time within the target range 70 mg/dL £ BG £ 180 mg/dL). Results: Using HR to inform the CTR algorithm reduced significantly the BG decline during exercise (P = 0.022), indicated marginally lower LBGI (P = 0.3) and fewer hypoglycemic events during exercise (none vs. two events; P = 0.16), and resulted in overall higher percentage time within the target range (81% vs. 75%; P = 0.2). LBGI and average BG remained unchanged overall, during recovery, and overnight. Conclusions: HR-informed closed-loop control can be implemented in a portable artificial pancreas. Although closed loop has been shown to reduce hypoglycemia, adding HR signal may further limit the risk for hypoglycemia during and immediately after exercise. The most prominent effect of adding HR information is reduced BG decline during exercise, without deterioration of overall glycemic control.

“…30 The DiAs was subsequently used in a randomized clinical trial published in 2014 31 and in long-term trials of 24/7 AID. [32][33][34] Since 2011, the number of published studies on this topic increased exponentially.…”

Section: Automated Insulin Deliverymentioning

confidence: 99%

Future of Automated Insulin Delivery Systems

Castle

DeVries

Kovatchev

2017

Advances in continuous glucose monitoring (CGM) have brought on a paradigm shift in the management of type 1 diabetes. These advances have enabled the automation of insulin delivery, where an algorithm determines the insulin delivery rate in response to the CGM values. There are multiple automated insulin delivery (AID) systems in development. A system that automates basal insulin delivery has already received Food and Drug Administration approval, and more systems are likely to follow. As the field of AID matures, future systems may incorporate additional hormones and/or multiple inputs, such as activity level. All AID systems are impacted by CGM accuracy and future CGM devices must be shown to be sufficiently accurate to be safely incorporated into AID. In this article, we summarize recent achievements in AID development, with a special emphasis on CGM sensor performance, and discuss the future of AID systems from the point of view of their input-output characteristics, form factor, and adaptability.