During Sunday morning’s Joint ADA/JDRF Symposium—Progress towards an Artificial Pancreas, closed-loop insulin delivery systems received mostly glowing reviews from the session’s expert presenters.
Roman Hovorka, PhD, from the University of Cambridge in the United Kingdom, shared the European perspective based on clinical trials at the University of Cambridge, throughout Europe, and Australia. Like the session’s other presenters, Dr. Hovorka focused on hybrid closed-loop insulin delivery systems that use algorithms to keep glucose levels in range.
Cambridge studies indicate that closed-loop systems increase A1C time-in-target between 10 percent and 20 percent while reducing hypoglycemia incidents, which is in line with other European and Australian studies. A meta-analysis of randomized clinical trials of outpatients found a 12.6 percent increase in A1C time-in-target, as well as a 14 percent increase in time-in-target in overnight readings.
“Overall, it was good, but there are differences between the studies,” Dr. Hovorka said. “My take on that is that the algorithms do matter.”

Eda Cengiz, MD, MHS, FAAP
Eda Cengiz, MD, MHS, FAAP, from the Yale School of Medicine, said that closed-loop system technology should be seen as an ally in diabetes management.
“This can be the beginning of a rewarding relationship with technology,” she said. “There’s obviously room for improvement, and there’s a learning curve for all of us. But despite some challenges, the clinical studies provide strong evidence that hybrid closed-loop systems outperform standard-of-care diabetes management.”
Dr. Cengiz provided the North American perspective of hybrid closed-loop systems, looking at trials involving several devices in development. The results mirrored the international studies.
An analysis from March 2017 to May 2017 of 730 people using the Medtronic 670G insulin pump system found that the patients studied wore their sensors 95 percent of the time and kept their systems in auto-mode 93 percent of the time.
“This is a motivated group—they are early adopters—but these preliminary findings are actually a good indicator that the artificial pancreas is performing in real-life scenarios,” Dr. Cengiz said.
While data indicate that hybrid closed-loop systems have taken some of the fear and worry out of people’s lives, Dr. Cengiz said that the need for multiple devices, carbohydrate counting, and manual bolus entry for mealtime-related excursions indicate that the burden of diabetes still exists. Room for improvement exists in areas such as improved device connectivity and smaller size, expanded testing to broader populations, and developing insulins fast enough to keep up with the systems’ capabilities, she said.
Stuart A. Weinzimer, MD, of Yale University, explained how inhaled insulin and intra-peritoneal insulin delivered through a port could provide small priming doses of insulin for mealtime-related excursions. Dr. Weinzimer was one of the early artificial pancreas developers.
The closed-loop systems currently under development will bring improvements, he said, but the concern is increased system complexity. How clinicians choose the systems and how they educate patients about them will be critical.
“I think it’s going to be on the backs of the device companies to at least engage with the educators and clinicians to provide the kind of education that’s going to make these systems work, not only in the lab but when we start rolling it out to more than just the early adopters,” he said.
The session’s final presenter, Richard M. Bergenstal, MD, of the International Diabetes Center, warned that the increase in data from hybrid closed-loop systems could obscure key patient goals. He talked about helping patients find a balance between happy and healthy while reaching the triple aim of diabetes care of improved quality, better patient experience, and reduced cost.
In the digital age, conversation still has value, Dr. Bergenstal added. Patients need a story, not numbers, to change their behavior. He showed several examples of ways clinicians can explain the data in a manner that makes sense to the patient.
“They know why they went up and why they went down,” he said. “They can talk through it with you if you’re willing to listen to the woes and the whats and whys.”