One Year Clinical Experience of the First Commercial Hybrid Closed-Loop System

Abstract

In September 2016, the U.S. Food and Drug Administration approved the Medtronic 670G "hybrid" closed-loop system. In Auto Mode, this system automatically controls basal insulin delivery based on continuous glucose monitoring data but requires users to enter carbohydrates and blood glucose for boluses. To track real-world experience with this first commercial closed-loop device, we prospectively followed pediatric and adult patients starting the 670G system. RESEARCH DESIGN AND METHODS This was a 1-year prospective observational study of patients with type 1 diabetes starting the 670G system between May 2017 and May 2018 in clinic. RESULTS Of the total of 84 patients who received 670G and consented, 5 never returned for follow-up, with 79 (aged 9-61 years) providing data at 1 week and 3, 6, 9, and/or 12 months after Auto Mode initiation. For the 86% (68 out of 79) with 1-week data, 99% (67 out of 68) successfully started. By 3 months, at least 28% (22 out of 79) had stopped using Auto Mode; at 6 months, 34% (27 out of 79); at 9 months, 35% (28 out of 79); and by 12 months, 33% (26 out of 79). The primary reason for continuing Auto Mode was desire for increased time in range. Reasons for discontinuation included sensor issues in 62% (16 out of 26), problems obtaining supplies in 12% (3 out of 26), hypoglycemia fear in 12% (3 out of 26), multiple daily injection preference in 8% (2 out of 26), and sports in 8% (2 out of 26). At all visits, there was a significant correlation between hemoglobin A 1c (HbA 1c) and Auto Mode utilization. CONCLUSIONS While Auto Mode utilization correlates with improved glycemic control, a focus on usability and human factors is necessary to ensure use of Auto Mode. Alarms and sensor calibration are a major patient concern, which future technology should alleviate.

Long‐term real‐life glycaemic outcomes with a hybrid closed‐loop system compared with sensor‐augmented pump therapy in patients with type 1 diabetes

“…Previous studies showed an increase in TIR after 3 months (69% to 72.4%) [6][7][8]10 and after 6 months (59% to 71.4%) 18 Previous studies showed a positive correlation between TIR and auto-mode use. 6,20 We confirmed these findings at 3 and 6 months of 670G use. Patients spent less time in hypoglycaemia and hyperglycaemia during auto-mode use at 3 and 6 months.…”

“…It is important to note that the Guardian transmitters used with the 670G system were upgraded in early 2019 to avoid repeated finger‐stick requests, and in our study first‐generation, non‐upgraded Guardian transmitters were used. In this study there was a significant decline in auto‐mode use observed in men that paralleled a decline in CGM use; however, a previous study showed a more prominent decline in auto‐mode use in all groups …”

“…In this study there was a significant decline in auto-mode use observed in men that paralleled a decline in CGM use; however, a previous study showed a more prominent decline in auto-mode use in all groups. 20 The T1D Exchange registry also showed that only a minority of adults and youths with type 1 diabetes in the United States achieve American Diabetes Association goals for HbA1c. 22 A pivotal study showed that HbA1c decreased by 0.5% at 3 months with use of the 670G.…”

Sepsis prediction model derived from hospital-arrival clinical data

“…4 However, usability can be a significant barrier to closed loop utilization and results from a recent real-world study of the first commercially available HCL system, the Medtronic 670G, showed drop-out rates of one-third with a mean time of less than 40% spent in auto-mode by 12 months. 5 In the present study HCL usage was consistently high suggesting the system is user-friendly, but it is uncertain how this might translate from a clinical trial to a real-world setting. As closed-loop treatment becomes more readily available, usability is a crucial factor in helping people with diabetes get the most out of this novel therapy.…”

Certified Interoperability Allows a More Secure Move to the Artificial Pancreas Through a New Concept: “Make-It-Yourself”

“…Annoying sensor alarms and frequent exits of auto mode have somewhat disappointed early adopters as recently reported. 10 This long road to get an approved AP system contrasting with the widespread use of insulin pumps and CGM devices in the T1D population on one side, and the ability of algorithm freelance designers to create and make easily accessible glucose controllers, such as OpenAPS, AndroidAPS, or Loop on the other side, resulted in the birth of the "Do-It-Yourself" (DIY) community. 11 Thanks to open communication with some pump models and tricks to hack CGM signal so that the AP app could drive the insulin infusion based on CGM data; DIY patients have reported dramatic improvements in glucose control with the support of the DIY community.…”