CALIBRATION OF A HANDHELD DIABETES MANAGING DEVICE THAT RECEIVES DATA FROM A CONTINUOUS GLUCOSE MONITOR

• US 20120166126A1
• Filed: 12/22/2010
• Published: 06/28/2012
• Est. Priority Date: 12/22/2010
• Status: Active Grant

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Engelhardt, Timothy Peter, Pash, Phillip E., Duke, David, Soni, Abhishek, Schmitt, Nikolaus
• Granted Patent: US 8,589,106 B2
• Time in Patent Office: Days
• US Class Current: 702/104
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: G16H 40/40 for the management of medical equipment or devices, e.g. scheduling maintenance or upgrades

Abstract

A method for calibrating a handheld diabetes managing device based on data generated by a continuous glucose monitor. The method can include sampling a current of the continuous glucose monitor at a sampling interval over a time period to generate a plurality of current samples for the time period. The method can also include determining a mean, median and standard deviation of the plurality of current samples. The blood glucose level of the patient can be measured at a first time and a calibration equation that associates the plurality of current samples with the estimated glucose level of the patient based on the measured blood glucose level and the plurality of current samples can be determined when the standard deviation is less than a first threshold and an absolute value of a difference between the mean and median is less than a second threshold.

Claims

1. A method for calibrating a handheld diabetes managing device to determine an estimated glucose level of a patient from data generated by a continuous glucose monitor, comprising:

sampling a current of the continuous glucose monitor at a sampling interval over a time period to generate a plurality of current samples for the time period, the current being related to a glucose level of the patient;

determining a mean of the plurality of current samples;

determining a median of the plurality of current samples;

determining a standard deviation of the plurality of current samples;

measuring a blood glucose level of the patient at a first time; and

determining a calibration equation that associates the plurality of current samples with the estimated glucose level of the patient based on the measured blood glucose level and the plurality of current samples when the standard deviation is less than a first threshold and an absolute value of a difference between the mean and median is less than a second threshold.

2. The method of claim 1, wherein the calibration equation is a linear equation.

3. The method of claim 1, further comprising determining a 25% quantile value of the plurality of current samples, wherein the step of determining the calibration equation that associates the plurality of current samples with the estimated glucose level is performed when the median minus the 25% quantile value is less than a third threshold.

4. The method of claim 3, wherein the step of determining the calibration equation that associates the plurality of current samples with the estimated glucose level is not performed when the median minus the 25% quantile value is greater than a third threshold.

5. The method of claim 1, wherein the sampling interval is once per second.

6. The method of claim 5, wherein the time period is one minute.

7. The method of claim 1, wherein the first time corresponds to the time period.

8. The method of claim 1, further comprising determining a 75% quantile of the plurality of current samples, wherein the step of determining the calibration equation that associates the plurality of current samples with the estimated glucose level is performed when the 75% quantile value minus the median is less than a fourth threshold.

9. The method of claim 8, wherein the step of determining the calibration equation that associates the plurality of current samples with the estimated glucose level is not performed when the 75% quantile value minus the median is greater than the fourth threshold.

10. The method of claim 1, wherein the step of determining the calibration equation that associates the plurality of current samples with the estimated glucose level is not performed when the standard deviation is greater than the first threshold.

11. The method of claim 1, wherein the step of determining the calibration equation that associates the plurality of current samples with the estimated glucose level is not performed when the absolute value of the difference between the mean and median is greater than the second threshold.

12. The method of claim 1, further comprising determining a trend measure of the plurality of current samples, the trend measure corresponding to a change in the current over the time period, wherein the step of determining the calibration equation that associates the plurality of current samples with the estimated glucose level is performed when an absolute value of the trend measure is less than a fifth threshold.

13. The method of claim 12, wherein the step of determining the calibration equation that associates the plurality of current samples with the estimated glucose level is not performed when the absolute value of the trend measure is greater than the fifth threshold.

14. The method of claim 12, wherein the trend measure is determined by the equation:

15. A method for calibrating a handheld diabetes managing device to determine an estimated glucose level of a patient from data generated by a continuous glucose monitor, comprising:

sampling a current of the continuous glucose monitor at a sampling interval over a time period to generate a plurality of current samples for the time period, the current being related to a glucose level of the patient;

determining a mean of the plurality of current samples;

determining a median of the plurality of current samples;

determining a standard deviation of the plurality of current samples;

determining a 25% quantile value of the plurality of current samples;

determining a 75% quantile value of the plurality of current samples;

determining a trend measure of the plurality of current samples, the trend measure corresponding to a change in the current over the time period;

measuring a blood glucose level of the patient at a first time; and

determining a linear calibration equation that associates the plurality of current samples with the estimated glucose level of the patient based on the measured blood glucose level and the plurality of current samples when (i) the standard deviation is less than a first threshold, (ii) an absolute value of a difference between the mean and median is less than a second threshold, (iii) the median minus the 25% quantile value is less than a third threshold, (iv) the 75% quantile value minus the median is less than a fourth threshold, and (v) an absolute value of the trend measure is less than a fifth threshold.

16. The method of claim 15, wherein the step of determining the calibration equation that associates the plurality of current samples with the estimated glucose level is not performed when (i) the standard deviation is greater than the first threshold, (ii) an absolute value of a difference between the mean and median is greater than the second threshold, (iii) the median minus the 25% quantile value is greater than the third threshold, (iv) the 75% quantile value minus the median is greater than the fourth threshold, or (v) the absolute value of the trend measure is greater than the fifth threshold.

17. The method of claim 16, wherein the calibration equation is a linear equation.

18. The method of claim 17, wherein the trend measure is determined by the equation:

20. The diabetes care system of claim 17, wherein the handheld diabetes managing device is further configured to disregard the plurality of current samples in determining the calibration equation when the standard deviation is greater than the first threshold and the absolute value of the difference between the mean and median is greater than the second threshold.

19. A diabetes management system that periodically determines an estimated glucose level of a patient, comprising:

a continuous glucose monitor configured to;

(i) sample a current related to a glucose level of the patient at a sampling interval over a time period to generate a plurality of current samples for the time period, (ii) determine a mean of the plurality of current samples, (iii) determine a median of the plurality of current samples, and (iv) determine a standard deviation of the plurality of current samples; and

a handheld diabetes managing device in communication with the continuous glucose monitor and configured to;

(i) measure a blood glucose level of the patient at a first time, (ii) receive the mean, median and standard deviation of the plurality of current samples from the continuous glucose monitor, (iii) determine a calibration equation that associates the plurality of current samples with the estimated glucose level of the patient based on the measured blood glucose level and the plurality of current samples when the standard deviation is less than a first threshold and an absolute value of a difference between the mean and median is less than a second threshold, and (iv) determine the estimated glucose level of the patient based on the calibration equation and the current sampled by the continuous glucose monitor.