Trials and Tribulations:
The Medtronic MiniMed 670G

Medtronic introduced its MiniMed 670G last year as the first hybrid closed-loop insulin pump and continuous glucose monitor system. It was greeted with cautious optimism by the market—people with type 1 diabetes (T1D) who see the 670G as a first step to pumps and sensors working together towards a fully automated insulin delivery system. While much has been written about the promise of the 670G, less is known about how it’s actually working in the real world.


In a poster titled “Trials and Tribulations of the MiniMed 670G” and presented at the recent annual meeting of the American Association of Diabetes Educators (AADE), two Naomi Berrie Diabetes Center educators set out to analyze the data being generated by the 340 Berrie Center patients (ages 9 to 72) who received prescriptions to wear the device. “We knew we were going to have quite a substantial group of people to study,” said adult Certified Diabetes Educator (CDE), Amanda Kirpitch, MA, RD, which is why she produced the poster along with pediatric CDE, Emily Casciano, RD, CDN.

Of the 340 patients with prescriptions for the 670, only 126 people ended up using the device in auto-mode (the technology that allows the pump to communicate with the sensor and regulate basal insulin automatically) for 14 days or more. That means that two-thirds of the initial patient group dropped off, either before receiving adequate training on how to use the pump or after some of the training took place. “It’s not clear what is preventing people from actually using the technology,” said Amanda. “But it’s obvious that the learning curve for patients and clinicians is steep. Further analysis is needed to better understand why that is.” 

What is clear from the data is that more time a patient spends in auto mode correlates with a reduction in A1c and hypoglycemia, which is the second takeaway from analyzing the data, said Amanda. “The more time you spend in auto mode, the better you will be,” she said, “because that’s where the algorithm works the best. If you take yourself out of auto mode and start making adjustments, it’s not really going to work as well.”

At the AADE conference, added Emily, “we were able to connect with CDE’s from around the country who shared similar experiences, successes and concerns with using the system.” Currently, Emily said, Medtronic is submitting an updated transmitter algorithm to the FDA, “which aims to minimize the sensor requests for glucose values, repeated calibrations and sensor rejections. We look forward to the outcome as it may help increase our patients’ successful use of the device.”