Method to determine the degree and stability of blood glucose control in patients with diabetes mellitus via creation and continuous updating of new statistical indicators

• US 8,117,020 B2
• Filed: 05/08/2009
• Issued: 02/14/2012
• Est. Priority Date: 12/03/2004
• Status: Active Grant

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Harrell, R. Mack, Abensour, Daniel S.
• Primary Examiner(s): NEGIN, RUSSELL SCOTT
• Application Number:
  US12/437,933
• Publication Number:
  US 20090216460A1
• Time in Patent Office: 1,012 Days
• Field of Search: None
• US Class Current: 703/11
• CPC Class Codes: A61B 2562/0295 Strip shaped analyte sensors for apparatus classified in A61B5/145 or A61B5/157 disposable multilayered or laminated electrodes G01N27/307; details of handling chemical test elements G01N33/4875
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: G16H 15/00 ICT specially adapted for medical reports, e.g. generation or transmission thereof
• CPC Class Codes: G16H 20/17 delivered via infusion or injection
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16H 50/50 for simulation or modelling of medical disorders

Abstract

Systems and methods for determining a stability of a blood glucose concentration of a patient are provided. The system comprises a processor that may be programmed to receive blood glucose concentration test results each taken from the patient at a different time over a time period and to compute a time-averaged glucose parameter indicative of blood glucose concentration control over the time period. In addition, the processor may be programmed to compute a virtual blood hemoglobin parameter through a simulated measurement of a blood hemoglobin, the virtual blood hemoglobin parameter being indicative of blood glucose concentration control over an extended time period encompassing the time period. Further, the processor may be programmed to compute a lability factor parameter indicative of a variability in blood glucose concentration over the time period.

Claims

1. A method for determining a stability of a blood glucose concentration of a patient, the method comprising:

receiving, at a processor, a plurality of blood glucose concentration test results each taken from the patient at a different time over a time period;

approximating, by the processor, a plurality of blood glucose concentration test result values as functions of time from consecutive samples of the plurality of blood glucose concentration test results;

computing, by the processor, a time averaged glucose value as a first indicator by averaging the approximated blood glucose concentration test result values over the time period such that the first indicator is an indication of a blood glucose control normalized for each time interval between the consecutive samples;

applying, by the processor, a time-based weight to each of the blood glucose concentration test results by multiplying each of the blood glucose concentration test results by a respective coefficient, wherein the weights are time-based such that each successive coefficient is less than each previous coefficient as a function of increasing time;

computing, by the processor, a weighted average by averaging the time-based weighted blood glucose concentration test results;

computing, by the processor, a simulated measurement of a blood hemoglobin as a second indicator by correlating with a pre-determined formula the weighted average of the time-based weighted blood glucose concentration test results and the blood hemoglobin;

computing, by the processor, a variance of the blood glucose concentration test results;

computing, by the processor, a standard deviation from of the variance of the blood glucose concentration test results;

computing, by the processor, a ratio of the standard deviation to the time averaged glucose value to give a third indicator representing variability of blood glucose concentration over the time period; and

providing, by the processor, the first, second, and third indicators to a user interface or display.

2. The method of claim 1, wherein at least one of the averaging and computing the variance steps is performed in a recursive manner.

3. The method of claim 1, wherein the approximating is accomplished using the trapezoidal rule.

4. The method of claim 1 wherein the pre-determined formula correlating the average of time-based weighted blood glucose concentration test results and the blood hemoglobin is a linear regression formula.

5. The method of claim 1, wherein the blood hemoglobin is A1c.

6. The method of claim 1, further comprises representing the ratio as a percentage.

7. A system for determining a stability of a blood glucose concentration of a patient, the system comprising:

a processor programmed to;

receive a plurality of blood glucose concentration test results each taken from the patient at a different time over a time period;

compute a time-averaged glucose parameter through an averaging of approximated blood glucose concentration test result values as functions of time, such that in this average, each successive result value in time is weighted less than each previous result value in time as a function of increasing time, wherein the time-averaged glucose parameter is indicative of a blood glucose concentration control normalized for each time interval between the consecutive samples over the time period;

compute a virtual blood hemoglobin parameter through a simulated measurement of a blood hemoglobin through a pre-determined formula correlating an average of time-based weighted blood glucose concentration test results and the blood hemoglobin, the virtual blood hemoglobin parameter being indicative of blood glucose concentration control over an extended time period encompassing the time period;

compute a lability factor parameter through a ratio of a standard deviation calculated from a variance of the blood glucose concentration test results to the approximated blood glucose concentration test result values average, the lability factor parameter being indicative of a variability in blood glucose concentration over the time period; and

provide the time-averaged glucose parameter, the virtual blood hemoglobin parameter, and the lability factor parameter to a user interface or display.

8. The system of claim 7, wherein the processor is programmed to compute at least one of the time-averaged glucose parameter, the virtual blood hemoglobin parameter, and the lability factor parameter in a recursive manner.

9. The system of claim 7, wherein the time-averaged glucose parameter is computed by the processor by being programmed to:

use a rule to approximate a plurality of blood glucose concentration test result values as functions of time from consecutive ones of the plurality of blood glucose concentration test results; and

average the approximated blood glucose concentration test result values over the time period.

10. The system of claim 9, wherein rule is a Newton-Cotes formula rule.

11. The system of claim 9, wherein rule is the trapezoidal rule.

12. The system of claim 9, wherein the lability factor parameter is computed by the processor:

computing a variance of the blood glucose concentration test results;

computing a standard deviation of the variance of the blood glucose concentration test results; and

computing the ratio of the standard deviation to the time-averaged glucose parameter.

13. The system of claim 7, wherein the virtual blood hemoglobin parameter is computed by the processor being programmed to:

apply a time-based weight to each of the blood glucose concentration test results by multiplying each of the blood glucose concentration test results by a respective coefficient;

compute a weighted average by averaging the time-based weighted blood glucose concentration test results; and

correlating the weighted average of the time-based weighted blood glucose concentration test results and the blood hemoglobin with a pre-determined formula.

14. The system of claim 7, wherein the system is provided to a blood glucose meter.

15. The system of claim 7, wherein the system is provided to a computer.

16. The system of claim 7, wherein the processor is programmed to receive the plurality of glucose measurements from memory.

17. The system of claim 16, wherein the memory is external to the system.

18. A non-transitory computer-usable medium providing computer readable instructions for execution by a processor to perform a method comprising:

approximating a plurality of blood glucose concentration test result values as functions of time from consecutive samples of a plurality of blood glucose concentration test results;

computing a time averaged glucose value as a first indicator by averaging the approximated blood glucose concentration test result values over the time period such that the first indicator is an indication of a blood glucose control normalized for each time interval between the consecutive samples;

applying a time-based weight to each of the blood glucose concentration test results by multiplying each of the blood glucose concentration test results by a respective coefficient, wherein the weights are time-based such that each successive coefficient is less than each previous coefficient as a function of increasing time;

computing a weighted average by averaging the time-based weighted blood glucose concentration test results;

computing a simulated measurement of a blood hemoglobin as a second indicator by correlating with a pre-determined formula the weighted average of the time-based weighted blood glucose concentration test results and the blood hemoglobin;

computing a variance of the blood glucose concentration test results;

computing a standard deviation from of the variance of the blood glucose concentration test results;

computing a ratio of the standard deviation to the time averaged glucose value to give a third indicator representing variability of blood glucose concentration over the time period; and

providing the first, second, and third indicators to a user interface or display.