*Disclaimer: All content and information in this blog is for informational and educational purposes only.

This article was written by Amanda Ciprich, MS, RD. 

iLet Bionic Pancreas System is a closed-loop system that delivers insulin based on readings from a continuous glucose monitor (CGM) in order to automatically regulate blood glucose levels. Unlike other automated insulin pumps, the iLet system uses lifelong learning to calculate and deliver insulin doses without requiring extensive user input. This blog post will explore the key features and algorithms that make the iLet an innovative update for diabetes technology.

What is the iLet Beta Bionic Pancreas?

The iLet Beta Bionic Pancreas is an automated insulin delivery system that is made up of a tubed insulin pump, Dexcom G6 CGM, and a connected smartphone or reader. When setting up this device, the only information that users need to enter is their weight. For adjustments in insulin dosing, users enter their desired target glucose (usual, lower, or higher), the type of meal (breakfast, lunch, or dinner), and the size of the meal (usual, less, or more).

The insulin pump does not require carb counting, basal rates, or insulin-to-carb ratios. When users enter their glucose targets and details about the meal, the pump’s algorithm can automatically make adjustments. It's important to note that while using the iLet, you may still encounter high and low CGM glucose levels that require your attention. Trust the iLet system and be patient as it adapts to your unique needs.

How is iLet different from other automated insulin pumps?

Some of the key differences between the iLet Pancreas and other automated insulin delivery systems include:

1. Simplified Setup: The iLet system only requires one input, your body weight, to initiate therapy.
2. Comprehensive Insulin Dosing: The iLet determines 100% of your insulin doses, eliminating the need for carb counting. You only need to be carb aware.
3. Autonomous Insulin Delivery: The iLet system adapts and delivers all insulin doses without continuous user input.
4. Automated Correction Insulin: The system automatically provides correction insulin when needed.

Understanding the iLet Algorithm

The iLet device starts regulating glucose levels automatically after you input your body weight. This sophisticated system does not require you to count carbohydrates, program basal rate settings, set insulin-to-carb ratios, program correction factors, or make corrections for high BG levels. When connected to the CGM, the iLet device calculates and delivers insulin doses every 5 minutes based on your basal needs, high or rising CGM glucose levels, and meals with carbohydrates. If your CGM detects a rapid or unsafe drop in glucose levels, the iLet device adjusts or stops insulin delivery accordingly.

See below for a closer look at the different algorithms of the iLet system.

Basal Algorithm

The basal algorithm of the iLet system determines your basal insulin requirements and continuously adapts to your changing needs. It eliminates the need for users to manually set basal rates. The algorithm develops and updates the basal rate profile for insulin delivery with 288 automatically determined basal segments per day.

Corrections Algorithm

The corrections algorithm automatically provides additional insulin beyond basal requirements and reduces insulin when necessary to protect against hypoglycemia. It removes the need for users to determine the timing or size of correction doses. The algorithm continuously adapts to changing needs and prevents insulin stacking, which can lead to hypoglycemia.

High glucose:

When your iLet detects rising or high CGM glucose levels, it automatically delivers insulin to bring your glucose level back into the target range. Keep in mind that this process may take longer than expected. While using the iLet, refrain from taking additional insulin via injections, inhalers, or other pumps unless directed by your healthcare provider. Ensure that your iLet is reading your CGM glucose level every five minutes, has sufficient battery power and insulin in the cartridge, and is not experiencing any alarms that could interrupt insulin dosing. Allow the iLet time to respond to your glucose levels, while monitoring until it returns to a normal range.

Low glucose:

The iLet system reduces or stops insulin dosing in response to low or falling CGM glucose levels. Always have rapid-acting carbohydrates and emergency glucagon available to treat hypoglycemia. Make sure your CGM alarms are turned on and set to an audible level. It's important to note that you may still experience low glucose levels that require treatment with fewer carbs than usual, as the iLet would have already adjusted insulin dosing.

Meal time Algorithm

The meal time algorithm eliminates the need for users to set or know insulin-to-carb ratios and removes carb counting. The iLet system only requires an estimate of the carbs in your meal, categorized as "Usual for me," "Less," or "More." The iLet system provides meal doses customized to each individual and adjusts based on dosing history for similar previous meal announcements. Choose "Usual for me" for most meals, "Less" for meals with approximately 50% fewer carbs, and "More" for meals with approximately 50% more carbs than your typical meal. Insulin meal doses are capped at 24 units.

Exercise

During exercise, your insulin needs can significantly change. The iLet device does not directly recognize exercise; it continues to adjust insulin dosing based on changing CGM glucose levels. To prevent hypoglycemia during and after exercise:

• Ensure your CGM glucose is within range and not falling before exercising.
• Have rapid-acting carbohydrates readily available to prevent or treat hypoglycemia. Carry an emergency glucagon kit for severe hypoglycemia.
• Confirm that your CGM alarms are enabled, and the volume is set to an audible level on your iLet device and CGM app if applicable. Respond promptly to CGM alarms.

Safety Features & Considerations

The iLet Dosing Decision Software includes safety measures to prevent excessive insulin dosing. These features include:

1. Global cap on insulin doses at 30 units.
2. Limiting routine autonomous insulin doses in response to CGM glucose values to 3 units.
3. Stopping autonomous insulin doses when low glucose levels (≤60 mg/dL) are detected and resuming once levels have improved. Individual autonomous 5-minute doses, including both bolus and basal, are limited to 3 units in response to CGM glucose values when the CGM is online and to 6 units in response to BG values when the CGM is offline. There are no additional hard limits on dosing imposed over a specific amount of time. The global dose limit of 30 units allows simultaneous delivery of a meal dose (limited to 24 units) and the maximum possible autonomous dose, should such a circumstance occur.

The iLet Beta Bionic Pancreas represents a remarkable advancement in diabetes technology. After exploring the system’s impressive features, we’re curious: will you be giving it a try? Share your thoughts with us!