Systems and methods for automated insulin delivery for diabetes therapy
Disclosed herein are systems and methods for mitigating the risk of insulin stacking in automated insulin delivery systems. In AID systems configured to both automatically calculate insulin delivery based on glucose levels and receive manual programming of meal boluses configured to counteract carbohydrates in a meal, insulin stacking can result if the system automatically increases insulin delivery based on a rise in glucose levels in response to consumption of a meal and the user later programs a meal bolus for the meal. The risk of such double dosing is mitigated by the systems and methods disclosed herein by enabling the system to account for recent automated insulin increases when a meal bolus is programmed.
1. An ambulatory infusion pump system, comprising:
a pump mechanism configured to facilitate delivery of insulin to a user;
a user interface;
a communications device adapted to receive glucose levels from a continuous glucose monitor; and
a processor functionally linked to the pump mechanism, the user interface and the communications device, the processor configured to:
automatically calculate insulin doses with a closed loop delivery algorithm based on glucose levels received from the continuous glucose monitor;
receive user input through the user interface programming a meal bolus configured to deliver insulin to counteract carbohydrates consumed in a meal;
determine if the meal bolus is programmed within a predetermined time of one or more automatically calculated insulin doses that increased an amount of insulin delivered to the user; and
automatically modify the meal bolus if the meal bolus was programmed within the predetermined time of the automatically calculated insulin dose that increased the amount of insulin delivered to the user.
2. The system of claim 1 , wherein the processor is configured to cause the meal bolus to be delivered without modifying the meal bolus if the meal bolus was not programmed within the predetermined time of an automatically calculated insulin dose that increased the amount of insulin delivered to the user.
3. The system of claim 1 , wherein the processor is configured to automatically modify the meal bolus if the meal bolus was programmed within the predetermined time by reducing an amount of the meal bolus.
4. The system of claim 3 , wherein the processor is configured to reduce the amount of the meal bolus based on an amount of increase of the one or more automatically calculated insulin doses that increased the amount of insulin delivered to the user.
5. The system of claim 4 , wherein the amount of increase of the one or more automatically calculated insulin doses utilized by the processor includes amounts of automatic correction boluses.
6. The system of claim 4 , wherein the amount of increase of the one or more automatically calculated insulin doses utilized by the processor includes basal insulin delivery greater than an open loop basal rate profile.
7. The system of claim 4 , wherein the processor is configured to reduce the amount of the meal bolus by a predetermined percentage of the amount of increase of the one or more automatically calculated insulin doses that increased the amount of insulin delivered to the user.
8. The system of claim 7 , wherein the predetermined percentage varies based on a time that has elapsed since the one or more automatically calculated insulin doses that increased the amount of insulin delivered to the user.
9. The system of claim 3 , wherein the wherein the processor is configured to reduce the amount of the meal bolus by delivering a first portion of the meal bolus.
10. The system of claim 9 , wherein the processor is configured to deliver a second portion of the meal bolus after a predetermined period of time only if a glucose level of the user is above a threshold level.
11. The system of claim 3 , wherein the processor is configured to reduce the amount of the meal bolus based on an insulin decay curve that accounts for blood glucose burned in the user after the meal was consumed.
12. The system of claim 1 , wherein the pump mechanism and processor are disposed within a housing of an ambulatory infusion pump.
13. The system of claim 1 , wherein the processor and user interface are part of a remote control device for remotely controlling an ambulatory infusion pump.
14. An ambulatory infusion pump system, comprising:
a pump mechanism configured to facilitate delivery of insulin to a user;
a user interface;
a communications device adapted to receive glucose levels from a continuous glucose monitor; and
a processor functionally linked to the pump mechanism, the user interface and the communications device, the processor configured to:
receive user input through the user interface programming a meal bolus configured to deliver insulin to counteract carbohydrates consumed in a meal;
determine if a closed loop delivery algorithm calculated an increase in insulin based on glucose levels received from the continuous glucose monitor that was delivered within a predetermined time prior to programming of the meal bolus; and
automatically modify the meal bolus if the increase in insulin based on glucose levels received from the continuous glucose monitor was delivered within the predetermined time prior to programming of the meal bolus.
15. The system of claim 14 , wherein the processor is configured to automatically modify the meal bolus by reducing an amount of the meal bolus if the increase in insulin based on glucose levels received from the continuous glucose monitor was delivered within the predetermined time prior to programming of the meal bolus.
16. The system of claim 15 , wherein the processor is configured to reduce the amount of the meal bolus based on an amount of the increase in insulin.
17. The system of claim 16 , wherein the amount of the increase in insulin utilized by the processor can include automatic correction boluses and basal insulin delivery greater than an open loop basal rate profile.
18. The system of claim 16 , wherein the processor is configured to reduce the amount of the meal bolus by a predetermined percentage of the amount of the increase in insulin.
19. The system of claim 15 , wherein the wherein the processor is configured to reduce the amount of the meal bolus by delivering a first portion of the meal bolus.
20. The system of claim 19 , wherein the processor is configured to deliver a second portion of the meal bolus after a predetermined period of time only if a glucose level of the user is above a threshold level.