Calibration of a handheld diabetes managing device that receives data from a continuous glucose monitor

• US 8,589,106 B2
• Filed: 12/22/2010
• Issued: 11/19/2013
• 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, Schmitt, Nikolaus, Pash, Phillip E., Duke, David, Soni, Abhishek
• Primary Examiner(s): Taningco, Alexander H
• Assistant Examiner(s): RIVERA VARGAS, MANUEL A
• Application Number:
  US12/975,769
• Publication Number:
  US 20120166126A1
• Time in Patent Office: 1,063 Days
• Field of Search: 702/104, 600/365, 600/345, 600/347, 600/309
• 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:

receiving, by a computer processor of a handheld diabetes managing device, a plurality of current samples sampled by a continuous glucose monitor over a time period, the current being related to a glucose level of the patient;

determining, by the computer processor, a mean of the plurality of current samples;

determining, by the computer processor, a median of the plurality of current samples;

determining, by the computer processor, a standard deviation of the plurality of current samples;

determining, by the computer processor, a quantile value of the plurality of current samples;

measuring a blood glucose level of the patient at a first time using the diabetes managing device, where the first time is proximate to the sampling time period and the diabetes managing device cooperatively operates with a test strip to measure the blood glucose level in a sample of blood residing on the test strip; and

determining, by the computer processor, 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, wherein the determination of the calibration equation is in response to the standard deviation being less than a first threshold and an absolute value of a difference between the mean and the median being less than a second threshold and a difference between the median and the quantile being less than a third threshold.

2. 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 in response to an absolute value of the trend measure being less than a fifth threshold.

3. The method of claim 2, wherein the step of determining the calibration equation that associates the plurality of current samples with the estimated glucose level is not performed in response to the absolute value of the trend measure being greater than the fifth threshold.

4. The method of claim 2, wherein the trend measure is determined by the equation:

5. 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 in response to the median minus the 25% quantile value being less than a third threshold.

6. 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 in response to the median minus the 25% quantile value being greater than a third threshold.

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

8. The method of claim 7, wherein the time period is one minute.

9. 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 in response to the 75% quantile value minus the median being less than a fourth threshold.

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

11. The method of claim 1, wherein the calibration equation includes a linear equation.

12. 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 in response to the standard deviation being greater than the first threshold.

13. 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 in response to the absolute value of the difference between the mean and median being greater than the second threshold.

14. The method of claim 1, further comprising determining, via the computer processor, the estimated glucose level of the patient based on the calibration equation and the current sampled by the continuous glucose monitor.

15. A device comprising:

a communication interface;

an input interface;

an output interface;

a memory capable of storing a first threshold and a second threshold; and

a processor coupled with the communication interface, the input interface and the memory, the processor being configured to

receive, via the communication interface, a plurality of current samples sampled at a sampling interval over a time period, the current being related to a glucose level of a patient,

determine a mean of the plurality of current samples,

determine a median of the plurality of current samples,

determine a standard deviation of the plurality of current samples,

determine a quantile of the plurality of current samples;

receive a value of a measured blood glucose level of the patient at a first time, the first time being proximate to the time period, the value being derived from a sample of a bodily fluid of the patient,

determine whether the standard deviation is less than a first threshold,

determine whether an absolute value of a difference between the mean and the median is less than a second threshold,

determine whether a difference between the median and the quantile is less than a third threshold and

in response to the standard deviation being less than the first threshold and the absolute value of the difference between the mean and the median being less than the second threshold and the difference between the median and the quantile being less than the third threshold, determine a calibration equation that associates the plurality of current samples with an estimated glucose level of the patient based on the plurality of current samples and the measured blood glucose level.

16. The device of claim 15, wherein the processor is further configured to provide an indicator, via the output interface, wherein the indicator indicates a request for the value of the measured blood glucose level of the patient.

17. The device of claim 16, wherein the indicator comprises at least one of a visual indicator, a tactile indicator, and an audible indicator.

18. The device of claim 15, wherein the processor is further configured to determine an estimated glucose level of the patient based on the calibration equation and the current sampled by the continuous glucose monitor;

and present the estimated glucose level via the output interface.

19. The device of claim 15, wherein the communication interface comprises one or more of a wireless interface and a wireline interface.

20. 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, the method comprising:

receiving, by a computer processor of a handheld diabetes managing device, a plurality of current samples sampled by a continuous glucose monitor at a sampling interval over a time, the current being related to a glucose level of the patient;

determining, by the computer processor, a mean of the plurality of current samples;

determining, by the computer processor, a median of the plurality of current samples;

determining, by the computer processor, a standard deviation of the plurality of current samples;

determining, by the computer processor, a 25% quantile value of the plurality of current samples;

determining, by the computer processor, a 75% quantile value of the plurality of current samples;

determining, by the computer processor, 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 using the diabetes managing device, where the first time is proximate to the sampling time period and the diabetes managing device cooperatively operates with a test strip to measure the blood glucose level in a sample of blood residing on the test strip; and

determining, by the computer processor, 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, wherein the determination of the calibration equation is in response to (i) the standard deviation being less than a first threshold, (ii) an absolute value of a difference between the mean and median being less than a second threshold, (iii) the median minus the 25% quantile value being less than a third threshold, (iv) the 75% quantile value minus the median being less than a fourth threshold, and (v) an absolute value of the trend measure being less than a fifth threshold.

21. The method of claim 20, wherein the step of determining the calibration equation that associates the plurality of current samples with the estimated glucose level is not performed in response to (i) the standard deviation being greater than the first threshold, (ii) an absolute value of a difference between the mean and median being greater than the second threshold, (iii) the median minus the 25% quantile value being greater than the third threshold, (iv) the 75% quantile value minus the median being greater than the fourth threshold, or (v) the absolute value of the trend measure being greater than the fifth threshold.

22. The method of claim 20, wherein the trend measure is determined by the equation:

23. The method of claim 20, further comprising determining, via the computer processor, the estimated glucose level of the patient based on the linear calibration equation and the current sampled by the continuous glucose monitor.

24. A diabetes management system that periodically determines an estimated glucose level of a patient, the diabetes management system 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, and (ii) transmit the plurality of current samples; and

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

(i) receive, via a computer processor of the handheld diabetes managing device, the plurality of current samples from the continuous glucose monitor, (ii) determine, via the computer processor, a mean of the plurality of current samples, (iii) determine, via the computer processor, a median of the plurality of current samples, (iv) determine, via the computer processor, a standard deviation of the plurality of current samples, (v) measure a blood glucose level of the patient at a first time in cooperation with a test strip having a sample of blood residing thereon, the first time being proximate to the sampling time period, (vi) determine, via the computer processor, 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, wherein the handheld diabetes managing device determines the calibration equation in response to the standard deviation being less than a first threshold and an absolute value of a difference between the mean and median being less than a second threshold and a difference between the median and a quantile of the plurality of current samples being less than a third threshold, and (vii) determine, via the computer processor, the estimated glucose level of the patient based on the calibration equation and the current sampled by the continuous glucose monitor.

25. The diabetes management system of claim 24, wherein the handheld diabetes managing device is further configured to disregard the plurality of current samples in determining the calibration equation in response to the standard deviation being greater than the first threshold or the absolute value of the difference between the mean and median being greater than the second threshold.