Method of screening for disorders of glucose metabolism
View Patent ↗A method of screening for disorders of glucose metabolism such as impaired glucose tolerance and diabetes allows prevention, or early detection and treatment of diabetic complications such as cardiovascular disease, retinopathy, and other disorders of the major organs and systems. A mathematical algorithm evaluates the shape of a subject's glucose profile and classifies the profile into one of several predefined clusters, each cluster corresponding either to a normal condition or one of several abnormal conditions. The series of blood glucose values making up the glucose tolerance curve may be measured using any glucose analyzer including: invasive, minimally invasive and noninvasive types. The method is executed on a processing device programmed to perform the steps of the method. Depending on the outcome of the screening, a subject may be provided with additional information concerning their condition and/or counseled to consult further with their health care provider.
1. A method of screening a subject for disorders of glucose metabolism, comprising the steps of:
obtaining at least a portion of a glucose concentration profile for the subject using:
a noninvasive blood glucose concentration analyzer, said profile comprising a plurality of blood glucose values after ingestion of food and said profile being obtained within five hours of said ingestion of food;
evaluating shape of said profile using one or more parameters of said shape; and
classifying said subject into at least one predetermined cluster using evaluation of said shape,
wherein said cluster comprises at least one of
diabetes;
impaired glucose tolerance;
normal physiological response; and
low glucose tolerance;
wherein classifying said subject provides information concerning said subject's condition to said subject and/or a practitioner.
2. The method of claim 1 , wherein said plurality of blood glucose values comprises a time series.
3. The method of claim 1 , wherein said blood glucose values are actual values.
4. The method of claim 1 , wherein said blood glucose values are relative values.
5. The method of claim 1 , wherein said parameters include any of:
initial fasting glucose concentration; and
glucose concentration after elapse of a predetermined time interval.
6. The method of claim 5 , wherein said evaluating step comprises:
comparing any of said parameters with predetermined values and/or ranges of values for each parameter indicative of either a normal condition or one of a plurality of abnormal conditions.
7. The method of claim 6 , wherein each of said at least one predetermined clusters corresponds to one of said normal and abnormal conditions, said normal and abnormal conditions comprising:
normal;
impaired glucose tolerance;
diabetic; and
low glucose tolerance.
8. A method of screening a subject for disorders of glucose metabolism, comprising the steps of:
obtaining at least a portion of a glucose concentration profile using any of:
a noninvasive blood glucose concentration analyzer;
a minimally invasive blood glucose concentration analyzer; and
an invasive blood glucose concentration analyzer,
said profile comprising a plurality of blood glucose values after ingestion of food and said profile being obtained within five hours of said ingestion of food;
evaluating shape of said profile using one or more parameters of said shape; and
classifying said subject into at least one predetermined cluster using evaluation of said shape;
wherein classifying said subject provides information concerning said subject's condition to said subject and/or a practitioner,
wherein said evaluation step comprises: determining a weight for each of said parameters using a fuzzy algorithm.
9. The method of claim 8 , wherein said step of determining a weight comprises the step of:
assigning each parameter a value on either a linear or non-linear scale, wherein said assigned value comprises said weight.
10. The method of claim 9 , wherein minimum and maximum of said scale correspond to predetermined threshold values for a normal condition and a diabetic condition, respectively.
11. The method of claim 9 , wherein minimum and maximum of said scale correspond to predetermined threshold values for a low glucose tolerance and a normal condition, respectively.
12. The method of claim 9 , wherein minimum and maximum of said scale correspond to predetermined threshold values for a low glucose tolerance and a diabetic condition, respectively.
13. The method of claim 9 , wherein ranges of values represented by said scale are established according to standard diagnostic criteria.
14. The method of claim 9 , wherein missing parameters are assigned a weight of zero.
15. The method of claim 9 , wherein missing data are supplied from historical data.
16. The method of claim 9 , further comprising the step of calculating one or more screening factors based on actual or relative values of said parameters and said weights.
17. The method of claim 16 , wherein said step of calculating screening factors comprises the step of calculating a weighted average of said weighted parameters according to:
SF
=
(
P
1
W
1
+
P
2
W
2
+
P
3
W
3
+
P
4
W
4
+
P
5
W
5
+
P
6
W
6
)
(
W
1
+
W
2
+
W
3
+
W
4
+
W
5
+
W
6
)
wherein SF=said screening factor and P 1 =a first parameter, said first parameter comprising glucose concentration, P 2 =a second parameter, said second parameter comprising rate at which glucose concentration rises, P 3 =a third parameter, said third parameter comprising maximum monitored glucose concentration; P 4 =a fourth parameter, said fourth parameter comprising duration that glucose remains elevated; P 5 =a fifth parameter, said fifth parameter comprising rate of decrease of glucose concentration after a peak; and P 6 =a sixth parameter, said sixth parameter comprising minimum glucose concentration after a maximum; and
wherein W 1 =a weighting factor.
18. The method of claim 16 , wherein said step of calculating screening factors comprises the steps of:
calculating a weighted average of a first set of selected weighted parameters using the equation:
SF
1
=
(
P
1
W
1
+
P
6
W
6
)
(
W
1
+
W
6
)
wherein SF 1 =a first screening factor; and
calculating a weighted average of a second set of selected weighted parameters using the equation:
SF
2
=
(
P
2
W
2
+
P
3
W
3
+
P
4
W
4
+
P
5
W
5
)
(
W
2
+
W
3
+
W
4
+
W
5
)
wherein SF 2 =a second screening factor, and P 1 =a first parameter, said first parameter comprising glucose concentration; P 2 =a second parameter, said second parameter comprising rate at which glucose concentration rises; P 3 =a third parameter, said third parameter comprising maximum monitored glucose concentration; P 4 =a fourth parameter, said fourth parameter comprising duration that glucose remains elevated; P 5 =a fifth parameter, said fifth parameter comprising rate of decrease of glucose concentration after a peak; and P 6 =a sixth parameter, said sixth parameter comprising minimum glucose concentration after a maximum; and
wherein W 1 =a weighting factor.
19. The method of claim 16 , further comprising the step of establishing threshold screening limits using said screening factors.
20. The method of claim 1 , wherein said parameters include any of:
initial fasting glucose concentration;
rate of increase of glucose concentration following said glucose challenge;
peak monitored glucose concentration;
duration glucose remains elevated;
rate of decrease of glucose concentration following said peak concentration; and
minimum glucose concentration following said peak concentration.
21. The method of claim 1 , further comprising the step of advising said subject of screening results.
22. The method of claim 1 , further comprising the step of advising said subject of health risks from complications resulting from subject's condition.
23. The method of claim 1 , wherein a processing device so programmed executes said steps.
24. The method of claim 1 , wherein said food comprises any of a glucose beverage and a carbohydrate-rich food.