How Closed Loop Systems Are Changing the Game For People with T1D

It was arguably the most significant technology to hit the type 1 diabetes (T1D) management market in 2017—a combined insulin pump and continuous glucose monitoring system where an algorithm allows the pump to communicate with the sensor and regulate basal insulin automatically. The first of many companies expected to introduce “closed loop systems” is Medtronic with its MiniMed 670G. The 670G is considered a hybrid closed loop because the patient is still responsible for entering carb ratios and insulin action settings, but it is the first step to pumps and sensors working together towards a fully automated insulin delivery system.

At the Naomi Berrie Diabetes Center, which has one of the highest populations of patients with T1D in the country, the reviews of the new 670G are coming in. “Now that we have seen the 670G in action, and learned how to use the system more effectively, we have been able to not only help patients improve A1c values to lower levels than they have been able to achieve before,” said Certified Diabetes Educator Emily Casciano, “but we are improving quality of life for so many.” 

Dylan Senkiw, 18, a patient at the Berrie Center and a freshman at the John Jay College of Criminal Justice at City University of New York (CUNY) would have to agree. “It could not have come at a better time, and for me, it was a game changer,” said Dylan, an honors student, and an NCAA Volleyball player, who went on the 670G before going off to school in Manhattan. “What I like most about it is that I do not have as pronounced highs and lows. The lows had been hard for me because I participated in two sports throughout high school. Therefore, I would sometimes drop very rapidly at night and for extended periods of time.  It was difficult to get the ideal combination of long acting and short acting carbs because my activities were both cardio and strength training. The 670G regulates the basal rates and helps predict my lows even when I’m sleeping. Because of this, my ‘mental load’ has become much lighter.”

At first, Oliver Krohn, 15, also a Berrie Center patient and a sophomore at Scarsdale High School was less than enthusiastic about his 670G. Mostly, it has been hard for him to get accustomed to its new continuous glucose monitor (CGM). He has found it neither as comfortable to wear, as friendly to use or as easy to insert as his old Dexcom CGM.  As well, the 670G CGM needs to be charged (which takes about 15 minutes) something that the Dexcom did not need.  For a busy teenage boy—he is one of four brothers and plays varsity lacrosse—he thought the CGM slowed him down. “There are some aspects of it that are a little bit more of a hassle than he originally thought,” said Kirsten Krohn, Oliver’s mom.

Then, over the course of a recent weekend, Oliver was forced to live without the 670G after it broke in a freak accident. “Fortunately we were able to borrow an older Medtronic pump,” said Kirsten, “and it really showed us the difference his new pump has been affording him in terms of flexibility of time and a good night’s sleep because you don’t have to test your blood sugar every two hours. All of a sudden his respect for the 670G and what it does for him changed, and I think he stopped taking it for granted.”

Oliver’s mom says that the 670G is definitely helping him. “It’s not something that Oliver, as a teenage boy notices, but I have seen an improvement in his mood, simply because he is able to sleep through the night without being awakened. On the new pump, if he goes low, it automatically shuts off, if he goes high it gives more insulin automatically. I’ve also seen an improvement in his health because he’s in range for longer periods of time. I think this also helps with his mood and behavior.”

Dylan, who was put on his first pump when he was 4 years old, has noticed many changes in life on his 670G in addition to less pronounced highs and lows, the new-found ability to sleep through the night, lower A1Cs (despite his “college food choices”) more time (as a result of not having to test all the time on the 670 and the automatic basal insulin function). “My mother no longer sends me automated texts every two hours asking, ‘What’s your number?’ I am busy being a college student rather than a person with T1D.”

Like any first-generation hardware and software system, there's room to apply the learning from the first generation to improve the product over time—and the 670G is no exception. “I would like the CGM on the 670G to operate longer without the need for a site change, said Dylan. “I would also like to see a smaller sleeker pump, maybe one where the insulin cartridges are longer and slimmer and easily replaced without having to change the site. In any case, I am confident that if we can have self-driving cars, we will have self-administering insulin technologies that will greatly improve quality of life for all types of diabetes. We’ve already come a long way.”

Our diabetes educators stress that with any new, hard and software system, it will take time, patience and a fair amount of back and forth to program the correct settings on your device before the technology will be most effective.