‘Artificial Pancreas’ Best in Poorly Controlled Type 1 Diabetes

In adults with poorly controlled type 1 diabetes, the Medtronic 780G “artificial pancreas” system improves glycemic control compared with multiple daily injections of insulin plus intermittently scanned continuous glucose monitoring (isCGM), new data suggest.

The Medtronic Minimed 780G advanced hybrid closed loop (AHCL) algorithm — the official name for an artificial pancreas system — produced a significant 1.42 percentage point decrease in A1c compared with multiple daily injections plus isCGM and a 1.54 percentage point drop relative to baseline at 6 months, from a baseline average of about 9% in both groups.

This is in line with previous findings from earlier automated insulin delivery systems but of greater magnitude, likely owing at least in part to the population of poorly controlled patients with diabetes that were studied, the authors say.

“In studies such as ADAPT, the choice of comparator is a crucial consideration. Multiple daily injections of insulin plus isCGM was chosen as this represents the standard of care or first-line treatment for type 1 diabetes across most of western Europe,” say Pratik Choudhary, MD, MBBS, and colleagues in their paper, published September 1, 2022 in The Lancet Diabetes & Endocrinology. isCGM represents use of devices such as the Abbott FreeStyle Libre.

“Insulin pump therapy could have been considered as a third comparator, but previous studies have shown only small incremental benefits of adding continuous subcutaneous insulin infusion to CGMs without automation,” add Choudary, of Leciester Diabetes Centre, UK, and co-authors.

The extent of the observed benefit, they say, “is likely to be translated into long-term benefits in terms of reduced risk of long-term complications and suggests that AHCL should be considered at the early stages in the type 1 diabetes treatment pathway. Future health economic analyses are warranted to determine the long-term health economic implications of the use of AHCL relative to multiple daily injections of insulin plus isCGM.”

In an accompanying editorial, Peter G. Jacobs, PhD, echoes the importance of the comparator group, noting that previous studies of commercial closed-loop systems have shown A1c reductions in the range of just 0.2-0.5 percentage points compared with prior use of noncommunicating pumps and sensors.

However, Jacobs, associate professor of biomedical engineering at Oregon Health & Science University, also notes that despite the significant findings of the current study, only 27.8% were able to achieve an A1c below 7.0% compared with none of those on multiple daily insulin injections. Though this finding again shows the benefit of AHCL, he said, “Nonetheless, this low percentage of people achieving the target A1c highlights shortcomings of closed-loop technologies and the need for improvements.”

Despite Benefit, Few Still Meet A1c Target

In the Advanced Hybrid Closed Loop Study in Adult Population with Type 1 Diabetes (ADAPT), 82 adults with type 1 diabetes all taking multiple daily injections with iCGM at baseline were randomly assigned to either AHCL or multiple daily injections plus isCGM arms, with 36 and 39, respectively, completing the 6-month treatment phase. Baseline A1c levels were 9.0% and 9.07%, respectively.

At 6 months, the respective A1c percentage point decreases from baseline were 1.54 with ACHL vs 0.20 for multiple daily injections plus isCGM, which resulted in a treatment effect of 1.42 percentage points in favor of AHCL (P < .0001).

Participants in the AHCL group spent 70.6% of time in the target glucose range of 70-180mg/dL compared with just 43.6% of the injections-plus-isCGM group, a significant difference (P < .0001).

Time spent in hypoglycemia didn’t differ significantly between the groups, with both spending just 2.6% of the time at sensor glucose levels below 70mg/dL and less than 1% for time below 54mg/dL. However, time spent above 180mg/dL and 250mg/dL, respectively, were 26.7% and 6.6% for AHCL vs 53.8% and 22.5% for multiple daily injections plus isCGM.

No severe hypoglycemic or diabetic ketoacidosis events occurred during the 6-month study phase.

Mean sensor glucose levels were 152.2mg/dL for the AHCL group vs 194.7mg/dL with multiple daily injections plus isCGM (P <.0001).

Correspondingly, 10 in 36 in the AHCL group (27.8%) achieved an A1c below 7.0% at 6 months, whereas none in the multiple daily injections–plus-isCGM group did.

Choudhary and colleagues hypothesize that “Some of the behaviours associated with raised baseline A1c could have also contributed to the lower percentage of people achieving target levels with AHCL. These include missed or late boluses, more errors in carbohydrate counting, or greater fear or anxiety relating to hypoglycaemia resulting in higher glucose levels or increased carbohydrate intake when in the lower levels of target range. An example of this is the lower proportion of people using optimal settings for AHCL.”

Jacobs comments, “Future advances could include fully closed-loop systems that do not require entry of carbohydrates, integration of additional hormones including co-formulation of insulin with pramlintide, and more personalised and adaptive systems that can respond automatically to exercise and other life events.”

Jacobs also points out that “Reimbursement from insurance companies is essential to enable use of closed-loop technologies more broadly in the US, Europe, and other countries around the world.”

“More work is needed to assess the economic burden of closed-loop therapies compared with isCGM plus multiple daily injections. Improvements in A1c observed in the study by Choudhary and colleagues indicate the importance of comparing these cost differences to make closed-loop therapy more broadly reimbursable to people currently on isCGM and multiple daily injections with poorly controlled glucose,” he concludes.

The Medtronic MiniMed 780G is approved for use in Europe and the United Kingdom, where it is approved for those aged 7 years or older, but has not yet been approved in the United States.

Choudhary has received consulting fees from Medtronic, Dexcom, Insulet Corporation, Abbott Diabetes, Lilly Diabetes, and Sanofi; honoraria or payment for lectures, presentations, speaker bureaus, manuscript writing, and educational events from Novo Nordisk, Medtronic, Insulet Corporation, Lilly Diabetes, Sanofi Diabetes, and Glooko; payment for expert testimony and support for travel and attending meetings from Abbott Diabetes; participation on Data Safety Monitoring Boards or Advisory Boards for Medtronic; is the Chair of the Diabetes Technology Network–UK and the Lead for Type 1 Diabetes Midlands UK; was supported by NIHR Welcome Trust clinical Research facility at King’s College Hospital and the NIHR patient recruitment centre at University Hospitals Leicester, United Kingdom.

Jacobs has received travel honorarium and research support from Dexcom; has received research support and licensing revenue from Agamatrix; and is a co-founder and owns stock in Pacific Diabetes Technologies.

Lancet Diabetes Endocrinol. Published online September 1, 2022. Article; editorial

Miriam E. Tucker is a freelance journalist based in the Washington DC area. She is a regular contributor to Medscape, with other work appearing in the Washington Post, NPR’s Shots blog, and Diabetes Forecast magazine. She is on Twitter @MiriamETucker.

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