In this study, in conjunction with a small engineering team on the west coast of the United States, we aimed to investigate whether combining an insulin delivery canula with a continuous glucose monitor was possible. Participants wore the device for 4 consecutive days and insulin was delivered through a pump. An 80g carb meal test of day was performed on Day 1 and 4. Between these meal tests, they went about their daily activities outside of the hospital. Participants also wore a Dexcom G6 CGM (Continued Glucose Monitor) and performed at least 10 glucose finger stick tests every day which gave us glucose measures in to benchmark the sensor readings in addition to those measurements performed in the laboratory during the meal tests. This was the first study in the world to investigate the use of a combined insulin delivery and continuous glucose monitoring system in humans going about their daily lives outside of a hospital setting.

Participants reported that the device was comfortable to wear, and few reported discomfort at device insertion and removal. Over the four days the device was worn, it consistently delivered insulin and reported blood glucose in an accurate and appropriate manner. It did not appear that the proximity of the glucose sensor to the insulin delivery catheter affected the device’s ability to accurately monitor blood glucose.

We concluded that devices combining insulin delivery and continuous glucose monitoring are feasible. However, we need to do more research using these devices to determine whether they continue to operate appropriately over an extended period of across a wider range of blood glucose levels. These results will help inform the design of future combined blood glucose monitoring and insulin delivery systems.

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