Diabetes management system

• US 6,544,212 B2
• Filed: 07/31/2001
• Issued: 04/08/2003
• Est. Priority Date: 07/31/2001
• Status: Expired due to Term

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diagnostics Corporation (Roche Holding AG)
• Inventors: Weinert, Stefan, Galley, Paul J., Thukral, Ajay, Chittajallu, Siva K.
• Primary Examiner(s): KENNEDY, SHARON E
• Application Number:
  US09/918,623
• Publication Number:
  US 20030028089A1
• Time in Patent Office: 616 Days
• Field of Search: 604/31, 604/48, 604/500-504, 604/131
• US Class Current: 604/31
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61P 3/10 for hyperglycaemia, e.g. antidiabetics
• CPC Class Codes: G16H 20/17 delivered via infusion or injection
• CPC Class Codes: G16H 40/63 for local operation

Abstract

A system is provided that enables glycemic control for a subject. The system includes an insulin delivery unit, a glucose sensor, and a control unit. The control unit includes a processor unit that receives glucose value readings from the glucose sensor, executes an algorithm that predicts a glucose value at a predetermined time in the future, compares that predicted glucose value to a pre-determined glucose value range, and determines a corrective amount of insulin to be administered when the predictive glucose value lies outside of the predetermined glucose value range. The control unit also includes a communication unit that transmits the corrective amount to the delivery unit.

Claims

1. A system for providing glycemic control to a subject, the system comprising:

an insulin delivery unit,

a glucose sensor, and

a control unit including a processor unit that receives glucose value readings from the glucose sensor, executes an algorithm that predicts a glucose value at a pre-determined time in the future, compares that predicted glucose value to a pre-determined glucose value range, and determines a corrective amount of insulin to be administered when the predictive glucose value lies outside of the pre-determined glucose value range and a communication unit that transmits the corrective amount to the delivery unit.

2. The system of claim 1 wherein the control unit is formed to accept data from the subject.

3. The system of claim 2 wherein the data includes information on size and type of a meal to be ingested and anticipated duration and intensity of exercise.

4. The system of claim 3 wherein the control unit includes a memory unit formed to store the data provided by the user.

5. The system of claim 4 wherein the memory unit also is formed to store an algorithm that utilizes the stored data and the processor unit is formed to execute the algorithm to determine the predictive glucose value.

6. The system of claim 1 wherein the sensor is a semi-continuous glucose-sensing unit.

7. The system of claim 1 wherein the algorithm includes the following equation:

8. The system of claim 7 further comprising a memory unit that is formed to store the algorithm and data, the data including glucose value readings from the glucose sensor, predicted glucose values, the pre-determined glucose value range, and corrective amounts of insulin.

9. The system of claim 8 wherein the memory unit is formed to store a feedforward algorithm that utilizes at least a portion of the data stored in the memory to compensate for meals.

10. The system of claim 9 wherein the feedforward algorithm includes the following equation:

11. A system for providing glycemic control to a subject comprising:

a sensor formed to conduct a glucose measurement of a subject,

a control unit including a processor unit that is formed to accept data from the subject on insulin sensitivity and basal rate, to execute an algorithm that generates a predictive value of the subject'"'"'s glucose level at a predetermined time in the future based upon the glucose measurement from the sensor and the data, and to compute a corrective action when the predictive value lies outside of a predetermined target range, and

an insulin delivery unit in communication with the control unit, the delivery unit being formed to administer automatically a dosage of insulin to the subject based upon the computed corrective action of the control unit.

12. The system of claim 11, wherein the control unit is formed to accept data from the subject regarding size and type of a meal to be ingested and anticipated duration and intensity of exercise.

13. The system of claim 11 wherein the algorithm includes the following equation:

14. The system of claim 11, wherein the control unit includes a memory that is formed to store data of the glucose concentrations as well as the time and amount of previously administered insulin.

15. The system of claim 14, wherein the memory is formed to store data regarding size and type of a meal to be ingested and anticipated duration and intensity of exercise of the subject.

16. A method for providing glycemic control to a subject, the method comprising the steps of:

determining the glucose value of a subject,

inputting the glucose value into at least one processor, the at least one processor being formed to execute at least one algorithm formed to anticipate the future effects of insulin that has been previously delivered to the subject, to incorporate constraints on insulin delivery and glucose deviations, and to determine a corrective amount of insulin to be administered when the predictive glucose value lies outside of the pre-determined glucose value range,

automatically delivering the corrective amount of insulin to the subject, and

repeating the determining and inputting steps.

17. The method of claim 16 wherein the inputting step includes providing data on size and type of a meal to be ingested t.

18. The method of claim 17 wherein the inputting step includes providing data on anticipated duration and intensity of exercise.

19. A system for providing glycemic control to a subject, the system comprising:

means for delivering insulin to a subject,

means for determining a glucose value from the subject, and

a control unit including a processor unit that is formed to compare the glucose value to a pre-determined glucose value range, to determine a corrective amount of insulin to be administered when the predictive glucose value lies outside of the pre-determined glucose value range, and to transmit the corrective amount to the delivering means.

20. A system for predicting a future glucose value of a subject at a predetermined time, the system comprising a control unit that comprises:

a processor unit formed to predict the future glucose value with an algorithm

Δ

G=—

(TotallnsuRemain—

BasalReq) * Sensitivity wherein Δ

G=future change in glucose levels at a pre-determined time, TotallnsuRemain=amount of insulin remaining in the subject'"'"'s system at a current time, and BasalReq=how much insulin the subject is estimated to need to maintain the current glucose level, and Sensitivity=Insulin sensitivity, and

wherein the processor makes a recommended insulin dose to reach a target range in full time of the insulin action according to the following equation;

21. The system of claim 20 wherein the processor is further formed to compensate for meals and exercise with a feedforward algorithm

Dose=carbohydrates * insulin-to-carb-ratio * α

_{meal type}—

intercept

wherein Dose=Total insulin dose, carbohydrates=grams of carbohydrates, insulin-to-carb-ratio=Insulin to Carbohydrate Ratio, α

_{meal type}=meal dependent scaling factor, and intercept to allow a linear fit for sizes of the meals.

22. The system of claim 21 wherein the processor is further formed to provide a constraint to the feedforward algorithm, wherein the constraint is defined by the following equation:

infusion rate ≳

β

* basal rate, wherein β

=a fraction that defines a minimum basal rate.

23. The system of claim 20 wherein the processor predicts a current glucose value using the following equation:

$G<br><br>\left(i+1\right)=G<br><br>\left(i\right)+\underset{i=1}{\overset{i-\frac{\mathrm{InsulinDuration}}{\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>T}}{\sum <br><br>}}<br><br>[\text{\hspace{1em}<br><br>}<br><br>\left(\mathrm{InsuTrace}<br><br>\left(i\right)*\mathrm{InsuGluDrop}<br><br>\left(i\right)\right)+\mathrm{BasalRequirement}<br><br>\left(i\right)]*\mathrm{Sensitivity}<br><br>\text{\hspace{1em}<br><br>}$

wherein G (i)=glucose concentration i cycles in the past, i=cycle, InsuTrace(i)=series of pulses of insulin that were administered in the past (excluding meal-related insulin doses and exercise-related insulin reductions) normalized, InsulinDuration=total time action of insulin, InsuGluDrop(i)=amount that the glucose is expected to drop on the next cycle due to insulin delivered at times in the past, Δ

T=time interval between cycles (in minutes), Basal Requirement (i)=amount of insulin required in the i'"'"'th cycle to maintain current glucose in the absence of disturbances, and Sensitivity=expected magnitude of glucose drop for IU of insulin.

24. A system for recommending an insulin dose to compensate for meals of a subject, the system comprising a control unit that comprises:

a processor formed to compensate for meals with a feedforward algorithm

Dose=carbohydrates * insulin-to-carb-ratio * α

_{meal type}—

intercept

wherein Dose=Total insulin dose, carbohydrates=grams of carbohydrates, insulin-to-carb-ratio=Insulin to Carbohydrate Ratio, α

_{meal type}=meal dependent scaling factor, and intercept to allow a linear fit for sizes of the meals.

25. The system of claim 25 wherein the processor is further formed to provide a constraint to the feedforward algorithm, wherein the constraint is defined by the following equation:

infusion rate ≳

β

* basal rate, wherein β

=a fraction that defines a minimum basal rate.