How Can Automated Insulin Delivery Affect Your Sleep?
By Andrew Briskin
Automated insulin delivery (AID) systems have helped many people with diabetes improve their glucose management and Time in Range, both during the day and overnight. However, a recent study shows that using the auto mode with the Medtronic 670G pump led to lower sleep quality compared to using the manual mode.
Advancements in diabetes technology such as continuous glucose monitors (CGM) and automated insulin delivery (AID) systems, have helped many people with diabetes improve their glucose management and feel safer and more prepared to address highs and lows.
While these devices can lead to dramatic improvements in glucose levels, their effect on another key aspect of diabetes management, sleep, needs to be investigated. The ORACL study, published in Diabetes Technology and Therapeutics on July 22, found an interesting difference in sleep quality between using the hybrid closed-loop auto mode with the Medtronic 670G pump (recently discontinued) compared to using the manual mode.
The trial included 60 participants with type 1 diabetes, focusing primarily on older adults (all participants were age 60 and over). Everyone in the study used a Medtronic MiniMed 670G insulin pump, and each participant was randomly assigned to use either the “auto” mode or “manual” mode. Auto mode incorporates glucose readings from the CGM and automatically delivers insulin based on glucose levels. In contrast, manual mode requires users to manually bolus insulin, but can temporarily suspend insulin delivery based on glucose levels to try to prevent hypoglycemia. During the 8-month study, all participants switched to the opposite group at the halfway point (4 months).
Investigators measured sleep quality using an actigraph, a wearable device that looks similar to a wristwatch, that tracks movement, amount of sleep, and other measures of sleep quality. Participants were also asked to keep a diary for two weeks, to self-report when they went to bed and woke up each day.
Over the course of the 8-month study, those using the auto mode setting had greater average Time in Range (90.3%) throughout the night than those using the manual mode (78.7%). The study demonstrated that most of the glucose management benefits from auto mode were observed after 4 hours of sleep. People on auto mode also experienced significantly fewer sensor alarms for hypoglycemia. Because this study focused on glucose patterns during sleep, CGM readings during the day were not reported.
However, despite the greater amount of time spent in range, auto mode users reported significantly lower sleep quality compared to manual mode users. Additionally, while the auto mode group had fewer alerts due to lows, the total number of alarms was actually 30% higher in this group, presumably related to hyperglycemia.
According to the study’s authors, this is the first-ever randomized trial to provide evidence that, during objectively-measured sleep, auto mode using the 670G (a hybrid closed-loop AID system) improved time in range and reduced the number of hypoglycemia alerts in older adults with type 1 diabetes.
More research is needed in this area, but advances in AID systems and glucose monitoring technology that lead to fewer alarms, particularly for high glucose levels, may improve sleep quality in people with type 1 diabetes.
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