HK1117923A

HK1117923A - System and method for determining insulin bolus quantities

Info

Publication number: HK1117923A
Application number: HK08108432.1A
Authority: HK
Inventors: Robert Hellwig; Stefan Weinert
Original assignee: F. Hoffmann-La Roche Ag
Priority date: 2004-12-23
Filing date: 2005-12-22
Publication date: 2009-01-23

Description

System and method for determining insulin bolus quantity

Technical Field

The present invention relates generally to techniques for managing glucose levels in diabetic individuals, and more particularly to a system for determining and recommending insulin management as a method of managing glucose levels.

Background

There are currently many handheld and other systems for managing diabetes care. Many such systems provide for dividing a sustained period of time, such as one or more days, into a plurality of adjacent time intervals. Within each time interval, a specific glucose target and a specific insulin sensitivity value, e.g., in units of mg/dl per International Unit (IU) of insulin, may be determined. It is desirable to utilize such systems to provide accurate determinations and recommendations for additional corrected insulin bolus use (bolus) regardless of when such bolus use may occur relative to adjacent time intervals to thereby closely track and meet the insulin needs of the user.

Disclosure of Invention

The invention may comprise one or more of the features recited in the attached claims, and/or one or more of the following features and combinations thereof. A diabetes care system can have a plurality of adjacent time intervals, each time interval defining an associated target glucose value and an insulin sensitivity value. A method for calculating a recommended insulin bolus quantity when a measured glucose value in a current time interval exceeds a target glucose value for the current time interval and when a time interval of glucose lowering action of the recommended insulin bolus quantity to be administered spans the current time interval and a next adjacent time interval may comprise: a respective plurality of percentages are determined that each correspond to a percentage of insulin action of the recommended bolus quantity that will be used to lower the glucose level during a respective one of a plurality of time intervals between the current time interval and a plurality of subsequent adjacent time intervals. The recommended bolus quantity may be calculated as a function of the measured glucose value, the target blood glucose level for the last of the plurality of subsequent adjacent time intervals, the insulin sensitivities for the current time interval and each of the plurality of subsequent adjacent time intervals, and the respective plurality of percentages.

The number of subsequent adjacent time intervals may be 1, and the step of determining the respective plurality of percentages may comprise: determining a first percentage corresponding to a percentage of insulin action of the recommended bolus quantity that will be used to reduce the glucose level during the current time interval; and determining a second percentage of the percentage of insulin action corresponding to the recommended bolus quantity to be used to lower the glucose level during the next time interval. The calculating may then include calculating the recommended bolus quantity as a function of the measured glucose value, the target blood glucose level for the next adjacent time interval, the insulin sensitivities for the current and subsequent adjacent time intervals, and the first and second percentages.

The step of determining a first percentage may include determining the first percentage as a function of at least a current time in a current time interval measured by the measured bolus value, a start time of a next adjacent time interval, and a duration of glucose lowering action of a subsequently administered recommended insulin bolus quantity. The method may further comprise the step of calculating a current interval bolus activity time as the difference between the start time of the next adjacent time interval and the current time. The step of determining the first percentage may then comprise determining the first percentage as a function of the current interval bolus activity time and the duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity. The step of determining the first percentage may include extracting a first percentage value from a table populated with the first percentage value as a function of the current interval bolus activity time value and the time duration value of the glucose lowering action of the subsequently administered recommended insulin bolus quantity. The step of determining the second percentage may include calculating the second percentage as a difference between the percentage and the first percentage.

Alternatively, the step of determining the second percentage may comprise determining the second percentage as a function of at least a current time in the current time interval at which the measured bolus value is measured, a start time of a next adjacent time interval, and a duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity. In this embodiment, the method may further include the step of calculating a next interval bolus activity time as the difference between the duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity and a current interval bolus activity time corresponding to the difference between the start time of the next adjacent time interval and the current time. The step of determining the second percentage may then comprise determining the second percentage as a function of the next interval bolus activity time and the duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity. The step of determining the second percentage may include extracting the second percentage value from a table populated with second percentage values as a function of the next interval bolus activity time value and the time duration value of glucose lowering action of the subsequently administered recommended insulin bolus quantity. The step of determining the first percentage may include calculating the first percentage as a difference between one hundred percent and the second percentage.

In either case, the method may further comprise the step of performing the determining step and the calculating step only if the duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity extends into the next adjacent time interval by a predefined amount of time.

A method for calculating a recommended insulin bolus quantity when a measured glucose value in a current one of the time intervals exceeds a target glucose value for the current time interval may include determining whether a duration of glucose lowering action of the recommended insulin bolus quantity to be administered spans the current time interval and at least a next adjacent time interval. The method may further comprise: the recommended bolus quantity is calculated as a function of the measured glucose value, the target glucose value for the current time interval, and the insulin sensitivity value for the current time interval only when the duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity is limited to the current time interval. If the duration of the glucose lowering action of the subsequently administered recommended insulin bolus quantity otherwise spans the current time interval and at least the next adjacent time interval, the method may further comprise a number of additional steps. For example, the method may include determining a first percentage corresponding to a percentage of insulin action of the recommended bolus quantity to be used to lower the glucose level during the current time interval. The method may further include determining a second percentage corresponding to a percentage of insulin action of the recommended bolus quantity that will be used to decrease the glucose level during the next time interval. The method may further include calculating the recommended bolus quantity as a function of the measured glucose value, the target blood glucose level for the next adjacent time interval, the insulin sensitivities for the current and next adjacent time intervals, and the first and second percentages.

A method for calculating a recommended insulin bolus quantity when a measured glucose value in a current one of the time intervals exceeds a target glucose value for the current time interval and when a duration of glucose lowering action of a subsequently administered recommended insulin bolus quantity spans the current time interval and a next adjacent time interval may include determining a first difference value as a difference between the target glucose value for the current time interval and the target glucose value for the next adjacent time interval. The method may further comprise determining a second difference value as a difference between the insulin sensitivity value of the current time interval and the insulin sensitivity value of the next adjacent time interval. The method may further comprise: the recommended bolus amount is calculated as a function of the measured glucose value, the target glucose value for the current time interval, and the insulin sensitivity value for the current time interval only if the first difference is less than the first threshold and the second difference is less than the second threshold. The method may further comprise a number of additional steps if the first difference exceeds the first threshold or the second difference exceeds the second threshold. For example, the method may include determining a first percentage corresponding to a percentage of insulin action of the recommended bolus quantity that will be used to lower the glucose level during the current time interval. The method may further include determining a second percentage corresponding to a percentage of insulin action of the recommended bolus quantity to be used to lower the glucose level during the next time interval. The method may further include calculating the recommended bolus quantity as a function of the measured glucose value, the target blood glucose level for the next adjacent time interval, the insulin sensitivities for the current time interval and the subsequent adjacent time intervals, and the first and second percentages.

These and other features of the present invention will become more apparent from the following description of illustrative embodiments.

Drawings

FIG. 1 is a block diagram of one illustrative embodiment of an insulin bolus recommendation system.

Fig. 2 is a graph of glycemic time showing multiple instances of insulin administration (bolus administration) relative to current and next adjacent time intervals.

FIG. 3 is a flow chart of one illustrative embodiment of an insulin bolus recommendation software algorithm executable by the system of FIG. 1 for determining and recommending insulin bolus quantities.

Fig. 4A and 4B show a flow chart of another illustrative embodiment of an insulin bolus recommendation software algorithm executable by the system of fig. 1 for determining and recommending insulin bolus quantities.

Detailed Description

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to a number of illustrative embodiments shown in the drawings and specific language will be used to describe the same.

Referring now to fig. 1, a block diagram of one illustrative embodiment of an insulin bolus recommendation system 10 is shown. In the illustrated embodiment, the insulin bolus recommendation system 10 includes a bolus recommendation unit 12 having at least one control circuit 14 electrically connected to a visual display unit 16 and also connected to a data input unit 18. The control circuit 14 may illustratively be a conventional, microprocessor-based control computer capable of executing one or more software algorithms, although the control circuit 14 may alternatively be any single electronic circuit or collection of electronic circuits capable of operating as described hereinafter. In some embodiments, the control circuit 14 may be electrically connected to a conventional memory cell 20, as shown in dashed lines. The visual display unit 16 may be or include any conventional display screen including, but not limited to, a Cathode Ray Tube (CRT) display, a Liquid Crystal Display (LCD), a plasma display, a monochrome or multi-color monitor, a touch-sensitive data entry screen, and the like. The data input unit 18 may be or include any conventional data input device including, but not limited to, a keyboard or keypad, a mouse or similar pointing device, one or more coded or non-coded touch-sensitive switches associated with the display unit 16, a voice-activated data input device, and the like.

In some embodiments, the insulin bolus recommendation system 10 may further include an additional bolus recommendation unit 30, as shown in phantom in FIG. 1. The unit 30 may include a control circuit 32 electrically connected to a visual display unit 34 and a data input unit 36, wherein the control circuit 32, display unit 34 and data input unit 36 may be provided in any of the forms described above for the bolus recommendation unit 12. The control circuit 32 may further be electrically connected to a conventional memory unit 38. In this embodiment, the bolus recommendation unit 12 and the bolus recommendation unit 30 may each be configured to share information using conventional techniques through a wired connection 40 comprising one or more signal paths physically connecting the two units, through a wireless signal path 42, such as a radio signal or cellular telephone link, and/or through the World Wide Web (WWW) 44, respectively.

The insulin bolus recommendation system 10 is configured for determining and recommending the administration of one or more specific insulin bolus quantities into the bloodstream of a user of the system 10 in accordance with an insulin bolus recommendation protocol implemented in the system 10 as one or more executable software algorithms. The physical structure of the insulin bolus recommendation system 10 for executing such software algorithms and for communicating useful information between the system 10 and the user may take different forms. For example, in one illustrative embodiment, the bolus recommendation system 10 includes only the bolus recommendation unit 12 implemented as a conventional Personal Computer (PC), laptop or notebook computer, personal Data Assistant (PDA), or the like, or as a handheld, laptop or desktop dedicated bolus recommendation unit. In either of these cases, the bolus recommendation unit 12 includes a storage unit 20 having stored therein a plurality of executable software algorithms, and the control circuit 14 is operable to execute these software algorithms to determine and recommend one or more injections of a particular bolus quantity of insulin into the blood stream of the user in accordance with an insulin bolus recommendation protocol as will be described in detail hereinafter. In this embodiment, the display unit 16 is controlled by the control circuit 14 under the direction of the software algorithm to communicate information to the user and to prompt the user to enter information, which may be entered by the user through the data entry unit 18.

In another illustrative embodiment, the insulin bolus recommendation system 10 includes the bolus recommendation unit 12 and the bolus recommendation unit 30. As an example of this embodiment, the bolus recommendation unit 12 may be a PDA or a dedicated bolus recommendation unit as described above, while the bolus recommendation unit 30 may be a PC, laptop or notebook computer. In this embodiment, unit 12 may communicate with unit 30 via wireless interface 42 or wired interface 40, which may be electrically connected to a PDA or a dedicated bolus recommendation unit cradle configured to receive unit 12 and to electrically connect unit 12 and unit 30 in data communication. In this example, the storage units 20 and 38 of the units 12 and 30, respectively, may each have a plurality of software algorithms stored therein, and the user may use the bolus recommendation unit 12 as a mobile insulin bolus recommendation unit and/or the bolus recommendation unit 30 as a fixed insulin bolus recommendation unit. In this case, the user would maintain the current database for each unit 12 and 30 by periodically synchronizing the databases of units 12 and 30 via wired or wireless interfaces 40 or 42, respectively.

As another example of an embodiment of the insulin bolus recommendation system 10 that includes the bolus recommendation unit 12 and the bolus recommendation unit 30, the bolus recommendation unit 12 may be a PDA, PC, laptop or notebook computer, cell phone, or any other unit or device capable of accessing the WWW 44. In this example, the bolus recommendation unit 12 need not have the plurality of software algorithms stored in the storage unit 20, and need not include the storage unit 20 at all. In this example, the bolus recommendation unit 30 may be a remote computer or a conventional web server also configured for accessing the WWW 44 and having a plurality of software algorithms stored in the storage unit 38. In this example, the control circuit 32 of the remote computer or web server 30 is operable to execute a variety of software algorithms based on information provided over the WWW 44 by the user via the bolus recommendation unit 12. In this particular embodiment, the user and/or healthcare provider may access a web page or website controlled by the bolus recommendation unit 30 and provide the initial operating parameters and/or limits of the insulin bolus recommendation protocol to the control circuit 32. The user may then and accordingly access a web page or website and input current blood glucose information, and the control circuit 32 may then determine and recommend one or more specific insulin bolus injections into the user's bloodstream via the web page or website based on the current blood glucose information according to an insulin bolus recommendation protocol as will be described in detail below.

In this particular embodiment, the insulin bolus recommendation software algorithm is therefore resident in the remote computer or web server 30, and in this regard, the bolus recommendation unit 12 need only include sufficient hardware to be able to provide current blood glucose information to a web page or web site and to be able to view the recommendation generated on the web page or web site by the remote computer or web server 30. However, as a practical matter, it may be desirable in this embodiment to additionally provide the bolus recommendation unit 12 with the storage unit 20 and to store a plurality of bolus recommendation software algorithms in the storage unit so that the bolus recommendation unit 12 may independently execute these software algorithms when access to the WWW 44 and/or appropriate web pages or sites is also unlikely or impractical. In such an embodiment, it would further be desirable to provide synchronization between the remote and/or web-based database and the database stored in the storage unit 20 of the bolus recommendation unit 12.

It should be understood that the insulin bolus recommendation system 10 may be configured to cooperate with a glucose meter or other automatic blood glucose determination unit and/or an insulin pump or other automatic insulin dosing (posing) or administration unit. In embodiments where a glucose meter or other automatic blood glucose determination unit is included with the insulin bolus recommendation system 10, as will be described in detail below, the control computer 14 may be configured to prompt such unit, using conventional techniques, to automatically generate current blood glucose information that the system 10 may subsequently use in order to determine and recommend administration of one or more insulin bolus quantities. In embodiments where an insulin pump or other automatic insulin dosing unit is included with the insulin bolus recommendation system 10, the control computer 14 may be configured to prompt such unit to automatically administer a recommended insulin bolus quantity to the user using conventional techniques.

As described above, the insulin bolus recommendation system 10 shown in FIG. 1 is operable to execute a variety of software algorithms for determining and recommending the administration of one or more particular insulin bolus quantities into the blood stream of a user in accordance with an insulin bolus recommendation protocol. As the insulin bolus protocol relates to the present invention, the insulin bolus protocol provides for dividing a sustained period of time, such as one or more days, into a plurality of adjacent time intervals. With any such time interval, a specific target glucose level and a specific insulin sensitivity value may be defined. The target glucose level for any time interval corresponds to a constant glucose value that the user would like to maintain during that time interval. One example target glucose level may be 120mg/dl, although the various target glucose levels defined over multiple time intervals may take on other values. The insulin sensitivity value for any time interval corresponds to, for example, a reduced glucose in mg/dl per unit of infused insulin. One example insulin sensitivity value may be 30mg/dl/IU, although other insulin sensitivity values may alternatively be used. Details regarding exemplary software algorithms suitable for execution by the system 10 to implement such an insulin bolus protocol are described in U.S. patent application Ser. No. 10/927,614, which is assigned to the assignee of the subject invention and the disclosure of which is incorporated herein by reference. It should be understood, however, that the system 10 may alternatively or additionally be programmed to execute other conventional software algorithms for implementing such an insulin bolus protocol.

Referring now to fig. 2, a plot of blood glucose versus time is shown illustrating two time intervals according to the insulin bolus protocol described above. The current time interval begins at a "begin current interval" time T _BCI And ends at a subsequent "end current interval" time T _ECI . The target blood glucose 50 defined during the current interval is designated as BGT _CI And the insulin sensitivity defined during the current interval IS designated as IS _CI . The next adjacent time interval starts at the "start next interval" time T _BNI Which is equal to "end current interval" time T _ECI Coincide and end at a subsequent "end next interval" time T _ENI . The target blood glucose 52 defined during the next adjacent interval is designated as BGT _NI And the insulin sensitivity defined during the next adjacent interval IS designated as IS _NI 。

A user of the system 10 may obtain a measurement of the user's glucose level at any time by one or more conventional techniques. If the current measurement of the user's glucose level exceeds the target blood glucose level BGT for the current interval _CI Then the conventional bolus recommendation system is typically operable to calculate the recommended corrected insulin bolus CB according to the following equation:

CB＝(BGM-BGT _CI )/IS _CI ，(1)

wherein BGM is at the current time T _C The measured blood glucose level. The user then at time T _C The recommended corrective insulin bolus is administered nearby and the administered insulin bolus acts in a known manner to last for a time period T _M Internally lowering the glucose level, wherein T _M For the purposes herein defined as the duration of the glucose lowering action of the administered insulin bolus.

Referring again to FIG. 2, the above situation is shown in the current interval, where the blood glucose value 54 is at the current time T _C Is measured. In this example, the calculated at T as just described is utilized _C A correction bolus CB administered nearby, the blood glucose is reduced over time 56 to a target glucose value 50 corresponding to the target blood glucose value BGT for the current interval _CI And at a duration T _M Internal retention at BGT _CI . Using one numerical example, assuming that the measured blood glucose value, BGM, corresponding to point 54 is 200mg/dl, the target blood glucose value, BGT, during the current interval _CI IS 120mg/dl and insulin sensitivity IS during the current interval _CI Is 30mg/dl/IU. Substituting these numbers into the conventional calibration bolus equation described above yields (200 mg/dl-120 mg/dl)/30 mg/dl/IU =2.667, or approximately 2.7IU. Thus, during the current interval, approximately 2.7IU of insulin is employed to lower the user's glucose level from 200mg/dl to the target 120mg/dl.

As shown in the example just given, as long as the correction bolus is in the current time intervalIs administered sufficiently early that the duration T of the glucose lowering effect of the administered insulin bolus _M Constrained to the current interval, the conventional correction bolus equation applies. However, using the conventional correction bolus equation as a calculation and at a current time T occurring later in the current time interval _C The basis for taking the correction pill, so that the duration T of the glucose-lowering effect of the pill taken is _M Spanning the current and next adjacent time intervals may produce undesirable results. For example, consider the case where the blood glucose value 58 is at the end T of the current time interval _ECI (corresponding to the start time T of the next adjacent time interval _BNI ) Nearby current time T _C Is measured. In this example, calculated using the conventional equation described above and at T _C Correction pill CB taken nearby, blood sugar coming next over timeAdjacent time intervals are decreased 60 and to a glucose level 62 that may be significantly below the target glucose value 52 of the next adjacent time interval. Using another numerical example, assuming that the measured blood glucose value BGM corresponding to point 58 is again 200mg/dl, the target blood glucose value BGT during the current interval _CI Again 120mg/dl, insulin sensitivity IS during the current interval _CI Again 30mg/dl/IU, the target blood glucose value BGT during the next adjacent time interval _NI IS 150mg/dl and insulin sensitivity IS during the next adjacent time interval _NI Is 40mg/dl/IU. Due to T _C Still in the current time interval, the conventional correction bolus equation described above again yields (200 mg/dl-20 mg/dl)/30 mg/dl/IU =2.667, or approximately 2.7IU. However, assume T in this example _C Is located at T _BNI Within one minute of (a). If the user has waited another minute for a blood glucose measurement so that the next adjacent time interval is now the current time interval, the conventional corrective bolus equation described above will yield (200 mg/dl-150 mg/dl)/40 mg/dl/IU =1.25, or approximately 1.3IU. In this example at T _C Or a bolus of 2.7IU of insulin IS administered, thereby resulting in an unnecessary amount of insulin of 1.4IU, at the insulin sensitivity IS _NI At 40mg/dl/IU, this unnecessary insulin results in a lower than glycemic target BGT _NI (40 mg/dl/IU 1.4 IU) =56mg/dl blood glucose undershoot 62, corresponding to a final glucose reduction from 200mg/dl at point 58 to 94mg/dl at point 62.

Duration T of glucose lowering action in administered insulin bolus _M An effective technique for improving the accuracy of the correction bolus determination across the current and next time intervals is to take into account the time-dependent characteristics of the target glucose level and insulin sensitivity. For example, if h (τ) is the relative amount of insulin activity spent for a bolus of insulin (of a given type) taken at τ = 0. At T ≧ T _M Then, h (τ) =1. If IS (T) IS islets as a function of timeSensitivity of the element, then at any time T = T _A The given insulin pillThe following impulse responses are present:

where h (τ) is the time derivative of h (τ).

If D (T) is a time-dependent insulin bolus injection rate function, then relative to BG _-∞ Glucose drop production for a given time of = BG (T → - ∞):

to at the current time T = T _C Calculating the blood glucose decrease Δ BG caused by past insulin boluses that have been taken that will occur later _pb Using the following equation:

for calculation at T = T _C Shortly thereafter to relative to T _M A correction bolus amount CB given by a negligible bolus infusion duration using the following equation:

required BG reduction Δ BG _needed Must be based on the fact that at T = T _C +T _M Temporal target blood glucose value or BGT _NI To calculate. The results of (1), (2) and (5) were combined and BG was assumed _pb =0, that is, it is assumed that at the interval [ T ] _C -T _M ，T _C ]During which no insulin is taken, for calculating the time T = T to be taken at the current time _C Or taken in the vicinity thereof and for a time duration T _M Spanning the current time interval and starting at time T = T _BNI The next time interval of correction bolus quantityThe equation for CB is thus given as follows:

integrating (6) yields the equation:

CB＝(BGM-BGT _NI )/{[IS _CI ＊(h(T _BNI -T _C )-h(0))]+[IS _NI ＊(h(T _M )-h(T _BNI -T _C ))]}(7)

wherein amount (h (T) _BNI -T _C ) -h (0)) corresponds to T = T _C Or a fraction or percentage P of insulin action given in the vicinity thereof, of a bolus that will be spent or used to reduce the measured blood glucose value BGM during the current time interval _CI And amount (h (T) _M )-h(T _BNI -T _C ) Corresponding to a change in T = T) _C Or a fraction or percentage P of insulin action of a bolus, given in the vicinity thereof, which will be spent or used to reduce the measured blood glucose value BGM during the next adjacent time interval _NI . Substituting the percent insulin action variable into equation (7) yields the equation:

CB＝(BGM-BGT _NI )/[(IS _CI ＊P _CI )+(IS _NI ＊P _NI )](8)

referring again to fig. 2, another numerical example will be used to illustrate the effect of equation (8) on the blood glucose measurement value 58. Assuming that the measured blood glucose value BGM corresponding to point 58 is again 200mg/dl, the target blood glucose value BGT during the current interval _CI Again 120mg/dl, insulin sensitivity IS during the current interval _CI Again 30mg/dl/IU, the target blood glucose value BGT during the next adjacent time interval _NI Again 150mg/dl and insulin sensitivity IS during the next adjacent time interval _NI And 40mg/dl/IU. Also assume that at T = T _BNI At T = T _C (corresponding to point 58) or a vicinity thereof, 40% of the insulin action of a given insulin bolus will have been presentThe inter-interval period is spent lowering glucose levels. This is left at T = T _C Or 1-0.4=60% of the insulin action of a given insulin bolus in its vicinity, for lowering the glucose level during the next adjacent time interval. Then according to equation (8), at T _C (corresponding to point 58) or a correction pill CB to be administered in the vicinity thereof is CB = (200 mg/dl-50 mg/dl)/[ (30 mg/dl/IU 0.4) + (40 mg/dl/IU 0.6)]=1.388IU, or about 1.4IU. In case the insulin sensitivity during the next adjacent time interval is 40mg/dl, at time T = T _C (corresponding to point 58) administration of 1.4IU of insulin resulted in a 64[ (30 mg/dl) by 0.4 IU) reduction in blood glucose]+[(40mg/dl)* (1.4IU)*0.6]=50.4mg/dl, corresponding to a decrease in blood glucose from 200mg/dl at point 58 to equal target glucose level in the next adjacent time interval (BGT) _NI ) 52 at a final glucose level.

Referring now to fig. 3, a flow chart of one illustrative embodiment of a software algorithm 100 for determining a recommended insulin bolus quantity under the various conditions provided by the foregoing example is shown. The insulin bolus recommendation software algorithm 100 of fig. 3 will be described as being implemented with the insulin bolus recommendation unit 12 and executed by the control circuit 14, wherein the insulin bolus recommendation unit 12 is provided in the form of a conventional PDA or a hand-held dedicated insulin bolus recommendation unit, however those skilled in the art will recognize that the algorithm 100 may alternatively be implemented with the bolus recommendation unit 12 and/or the bolus recommendation unit 30 provided in any one or more of the physical forms described above.

In the illustrated embodiment, the algorithm 100 begins at step 102 where the control circuit 14 is operable to determine whether a newly measured glucose value, BGM, is available. In the exemplary embodiment, the algorithm 100 assumes at any current time T _C The glucose measurement obtained will be entered, or at time T _C Or its vicinity, is acquired by the system 10. The control circuit 14 will continue to return to the beginning of step 102 until a new glucose value BGM is received. OtherwiseWhen a new glucose measurement BGM becomes available, the algorithm is pre-executedProceeding to step 104, the control circuit is operable in this step 104 to obtain the necessary parameters regarding the current and next adjacent time intervals. In an embodiment, the necessary parameters are stored in the memory unit 20 and/or within an executable memory of the control circuit 14, and the control circuit 14 is operable to perform step 104 by retrieving these parameters from the memory unit 20 and/or from the executable memory of the control circuit 14. Alternatively, the necessary parameters may be input into the system 10 or otherwise provided to the system 10 using any one or more of the components described above with respect to fig. 1. In either case, the necessary parameters obtained in step 104 in the exemplary embodiment include the current time value T _C The starting time value T of the next adjacent time interval _BNI Possibly at T _C Or a bolus of insulin administered thereabout, has a duration T of glucose lowering action _M A glucose measurement value BGM, a glucose target BGT for a current time interval _CI Glucose target BGT for next adjacent time interval _NI Insulin sensitivity IS of the current time interval _CI And insulin sensitivity IS of next adjacent time interval _NI 。

Following step 104, the control circuit 14 is operable to compare the measured glucose value, BGM, with a glucose target value, BGT, for the current time interval in step 106 _CI . If BGM does not exceed BGT _CI Execution of the algorithm 100 returns to the beginning of step 102, otherwise algorithm execution proceeds to step 108. Thus, the algorithm 100 cannot proceed through step 106 unless and until a new glucose measurement, BGM, is available and BGM exceeds BGT _CI . It should be understood that the algorithm 100 may be incorporated into another insulin bolus recommendation algorithm operable to perform steps 102 and 106. In this case, the algorithm 100 may be modified to be so by omitting steps 102 and 106Insulin bolus recommendation algorithm containment.

In step 108, the control circuit 14 is operable to convert T _C 、T _M And a constant time value T _K Sum of (d) and the start time T of the next adjacent time interval _BNI A comparison is made. If this sum is greater than T _BMI Algorithm execution advances to step 110. Otherwise, if this sum is less than or equal to T _BNI Algorithm execution advances to step 112. In one embodiment, T _K Is 0, and T _C And T _M The sum of (A) indicates that the insulin activity of the bolus relative to the current and next adjacent time intervals lies at the current time T _C Time value to end in case of administration. Therefore, if T _C And T _M Is less than or equal to T _BNI This indicates T in the current time interval _C Is sufficiently early that at time T _C Duration T of glucose lowering action of administered insulin bolus _M Is limited to the current time interval. In this case, the calculation of the accurate value of the correction bolus CB can be performed using the conventional equation (1). On the other hand, if T _C And T _M Is greater than T _BNI This indicates T in the current time interval _C Is sufficiently late that at time T _C Is taken orallyDuration T of glucose lowering action of the insulin bolus _M Spanning the current and next adjacent time intervals. In this case, the calculation of the accurate value of the correction bolus CB must be done using the correction bolus equation (7) or (8) as described above. Consider embodiments of the algorithm 100 in which only at time T _C Duration T of glucose lowering action of the administered correction pill _M The control circuit 14 is operable to calculate the correction bolus CB according to equation (7) or (8) when extended into the next adjacent time interval by a predefined amount of time. In such an embodiment, the time constant T _K Will not be 0 but will instead be some positive time value that guaranteesThe inequality of step 108 does not result in step 110 unless T _M Extending into the next adjacent time interval by a predefined amount of time. As a particular example, the predefined amount of time may be T _M 30%, however, it should be understood that other values using a predefined amount of time may be used.

In any case, if the control circuit 14 determines in step 108 that it is at time T _C Duration T of glucose lowering action of the administered correction pill _M Sufficiently extending into the next adjacent time interval, algorithm execution proceeds to step 110 where the control circuit is operable to direct the BGT at step 110 _CI And BGT _NI The absolute value of the difference IS compared with a constant K1 and IS _CI And IS _NI The absolute value of the difference is compared with another constant K2. In one embodiment, both K1 and K2 are 0, and the absolute value of the difference is 0 only if the target glucose and insulin sensitivity values do not change between the current and next adjacent time intervals. In this case, the calculation of the accurate value of the correction bolus CB can be performed using the conventional equation (1). On the other hand, if either or both of the target glucose or insulin sensitivity values change between the current and next adjacent time intervals, the calculation of the exact value of correction bolus CB must be done using correction bolus equations (7) or (8) as described above. Consider an embodiment of the algorithm 100 in which the constant values K1 and K2 are set to some positive constant value to thereby require that the target glucose and/or insulin sensitivity values be changed by more than a predefined amount before the correction bolus CB is calculated according to equation (7) or (8). As a particular example, K1 and K2 may both be 5, however, it should be understood that other values for K1 and K2 may be employed, where K1 may or may not be equal to K2.

In any case, if at time T _C Duration of glucose lowering action of administered insulin bolus T _M Will be limited to the current time interval or at least not sufficientlyExtending into the next adjacent time interval and the glucose target value and the insulin sensitivity value do not change significantly between the current and next adjacent time intervals, the control circuit 14 is operable in step 112 to calculate a correction bolus CB in accordance with equation (1) such thatCB＝(BGM-BGT _CI )/IS _CI . On the other hand, if the duration T is longer than the predetermined duration _M Sufficiently extending into the next available time interval or one or both of the glucose target value and the insulin sensitivity value changing significantly between the current and next available time intervals, the control circuit 14 is operable in step 114 to determine the fraction or percentage P of bolus insulin action that will be used or spent to reduce the glucose level in the current time interval _CI 。

In the illustrated embodiment, the control circuit 14 is operable to determine as the current time T _C The start time T of the next adjacent time interval _BNI And will be at T _C Or a correction pill administered thereabout for a duration T of glucose lowering action _M The fraction or percentage of the function of (a). The function may be stored in the memory unit 20 in the form of one or more tables, graphs, charts, equations, etc., and in one particular embodiment, the function is stored in the memory unit 20 in the form of a two-dimensional look-up table. In this embodiment, the look-up table has a table corresponding to T _BNI Value sum T _C The difference between the values being the time value of one axis and the duration value T of the other axis _M . In this embodiment, the table is populated as T _M The sum of values corresponding to T _BNI -T _C Corresponding to the percentage of bolus insulin action that will be used or spent to lower the glucose level in the current time interval. Subsequently in step 116 the control circuit 14 is operable to determine the current time interval by subtracting the hundred for the current time interval determined in step 114 from 100%Than P _CI To determine the fraction or percentage P of bolus insulin action that will be used or spent to reduce glucose levels in the next adjacent time interval _NI 。

Those skilled in the art will recognize that steps 114 and 116 may alternatively be modified so that the control circuit 14 is operable to calculate T as T using any of the techniques described above with respect to step 114 _C 、T _BNI And T _M Fraction or percentage P of bolus insulin action to be used or spent for lowering glucose level in the next adjacent time interval _NI And then by subtracting the percentage P determined in step 114 for the next adjacent time interval from 100% _NI To determine the fraction or percentage P of bolus insulin action to be used or spent to reduce glucose levels in the current time interval _CI . In any case, algorithm execution advances from step 116 to step 118, where the control circuit 14 is operable in step 118 to calculate the corrected bolus quantity, CB, in accordance with equation (7) such that CB = (BGM-BGT) _NI )/[(IS _CI *P _CI )+(IS _NI *P _NI )]. Algorithm execution returns from either of steps 112 or 118 to the beginning of step 102.

The present disclosure contemplates at T _C Glucose lowering of insulin bolus taken at or near the sameDuration of Low Effect T _M Possibly spanning one or more of the subsequent adjacent time intervals. This may be due to a sufficiently long duration T _M A sufficiently short duration of the current time interval and/or one or more of an arbitrary number of subsequent adjacent time intervals, a current time T relative to the current time interval _C Timing of the same, and so on. In any case, equation (8) may be modified to account for the duration T of subsequent adjacent time intervals spanning any number j _M Where j may be any positive integer. One form of such equation based on equation (8)As follows:

wherein when n = -1, IS _NI+n ＝IS _CI And P is _NI+n ＝P _CI . According to equation (9), the blood glucose target value BGT used is the blood glucose target value for the last, i.e. jth, of the subsequent adjacent time intervals, and the denominator of equation (9) is expressed at T _M The sum of the products of IS and P in all time intervals spanned, wherein all time intervals include the current time interval and all "j" subsequent adjacent time intervals.

Referring now to fig. 4A and 4B, a flow chart is shown illustrating another illustrative embodiment of an insulin bolus recommendation software algorithm 100' that may be executed by the system of fig. 1 for determining and recommending insulin bolus quantities. The insulin bolus recommendation software algorithm 100 'of fig. 4A and 4B will be described as being implemented with the insulin bolus recommendation unit 12 and executed by the control circuit 14, wherein the insulin bolus recommendation unit 12 is provided in the form of a conventional PDA or a hand-held dedicated insulin bolus recommendation unit, however those skilled in the art will recognize that the algorithm 100' may alternatively be implemented with the bolus recommendation unit 12 and/or the bolus recommendation unit 30 provided in any one or more of the physical forms described above. In any case, the algorithm 100' extends the scheme shown in FIG. 3 to embodiments in which the time T of the current interval is to be at _C Or a bolus of insulin administered thereabout, has a duration T of glucose lowering action _M May be limited to a current time interval, may span at least a portion of the current time interval and a next adjacent time interval, or may span the current time interval and a plurality, i.e., j, of subsequent adjacent time intervals, where j may be any positive integer.

In the illustrated embodiment, the algorithm 100' includesIncludes a number of steps in common with the software algorithm 100 shown in fig. 3, and therefore like numbers are used to identify like steps. The algorithm 100' is identical to the algorithm 100 in performing steps 102-108. Following the yes branch of step 108, however, the algorithm 100' includes an additional block 109 containing steps 130-134,for determining that it is to be at the current time T after the current time interval _C Or a time duration T of glucose lowering action of an insulin bolus administered in the vicinity thereof _M The total number j of subsequent adjacent time intervals spanned. For example, in step 130, the control circuit 14 is operable to convert T _M The counter j of the subsequent adjacent time interval spanned is set to 0. Thereafter in step 132 the control circuit 14 is operable to increment the counter j by 1. Thereafter in step 134, the control circuit 14 is operable to determine T _C 、T _M And T _K Whether or not the sum of (A) is less than T _BNI+j Wherein the term T _C 、T _M And T _K Each of which is described above, and wherein the term T _BNI+j Indicating the start time of the jth time interval of the subsequent consecutive, adjacent time intervals. As long as T _C 、T _M And T _K Is less than or equal to T _BNI+j The algorithm 100' returns to step 132. Thus, when the inequality of step 134 is true, the variable j indicates that it is to be at the current time T _C Or a time duration T of glucose lowering action of an insulin bolus administered thereto _M A total number of subsequent adjacent time intervals that span more than the current time interval.

Step 110 'of algorithm 100' is similar to step 110 of algorithm 100 of FIG. 3, but is modified to account for T _M The likelihood of spanning more than one of the subsequent adjacent time intervals. In particular, step 110 begins at step 140, where the control circuit 14 is operable to set a counter f equal to 0 and a counter g equal to 1 at step 140. Thereafter at step 142, the control circuit 14 is operable to determine a glucose difference value, BGT _NI+f -BGT _NI-g IS greater than the constant K1, or the insulin sensitivity difference IS _NI+f -IS _NI-g Is greater than the constant K2. BGT when counter g equals 1 _NI-g ＝BGT _CI And IS _NI-g ＝IS _CI . If neither of these inequalities is true, algorithm execution advances to steps 144 and 146 where the control circuit 14 is operable to set the counter g equal to 0 and increment the counter f by 1. Thereafter in step 148, the control circuit 14 is operable to compare the value of f to T _M The total number j of subsequent adjacent time intervals spanned. If f is less than j, this indicates a duration of T _M At least a subsequent f +1 adjacent time intervals are spanned and algorithm execution returns to the beginning of step 142. On the other hand, if f equals j in step 148, this indicates that all "j" subsequent adjacent time intervals have been tested and that the two inequalities of step 142 have not been true for any of the "j" subsequent adjacent time intervals. This means that neither the glucose target BGT nor the insulin sensitivity IS has changed sufficiently between the current time interval and any of the subsequent "j" time intervals to warrant calculation of a correction bolus using equation (9) above, and instead the "NO" branch of step 148 proceeds to step 112, which step 112 IS the same as step 112 of algorithm 100 of FIG. 3 for calculating a correction bolus according to conventional equation (1)CB。

If at any time during the execution of the loop defined by steps 142-148, any of the inequalities of step 142 are satisfied, this indicates that the glucose target BGT or the insulin sensitivity IS has changed sufficiently between the current time interval and any of the next j time intervals to warrant calculation of a correction bolus using equation (9) above. Thus, execution of the algorithm 100' proceeds from the "YES" branch of step 142 to step 114, which step 114 is the same as step 114 of the algorithm 100 of FIG. 3, and the calculation is to be at time T _C Percent of insulin action P of the administered insulin bolus _CI This percentage will be spent lowering the glucose level during the current time interval. After step 114, execution of the algorithm 100' proceeds to additional step 115, comprising steps 150-156, for determining to be at time T _C A percentage P of insulin action of the administered insulin bolus that will be spent lowering the glucose level during each of the subsequent "j" adjacent time intervals. For example, in step 150, the control circuit 14 is operable to set the counter p equal to 1. Thereafter in step 152 the control circuit 14 is operable to determine whether the counter value p is equal to T _M The number j of subsequent adjacent time intervals spanned. If not, algorithm execution advances to step 154 where the control circuit 14 is operable to utilize P as described above for step 154 _CI Any of the techniques described to calculate the value to be at T _C Percent of insulin action P of the administered pills _CI+p Wherein the percentage will be spent lowering glucose levels during the P-th one of the subsequent adjacent time intervals, the percentage P _CI+p Is T _BNI+p 、T _M And T _BNI+p+1 As a function of (c). Thereafter in step 156 the control circuit 14 is operable to increment the counter value p by 1 and from step 156 the algorithm execution returns to the start of step 152. Thus, step 115, comprising steps 150-156, is operable to calculate a value to be at T _C The percentage of insulin action of the bolus administered, which percentage will be at T _M All but the last of the subsequent adjacent time intervals spanned are spent reducing glucose levels.

From the YES branch of step 152, algorithm execution advances to step 116', which step 116' is a modified version of step 116 of FIG. 3, because the control circuit 14 is operable in step 116' to operate in accordance with the equationCome to countAll at T _C Percentage of insulin action P of the bolus administered _CI+p Said percentage will be at T _M The last of the subsequent adjacent time intervals that are spanned is spent reducing glucose levels. From step 116', algorithm execution advances to step 118', which step 118' is of step 118 of FIG. 3Modified version in that the control circuit 14 is operable in step 118' to operate according to equation (9), i.e.To calculate a correction bolus CB. Algorithm execution returns to step 102 from either of steps 112 and 118'.

The present disclosure contemplates that either or both of the target glucose value, BGT, and the insulin sensitivity value, IS, may change as a function of time during any one or more time intervals. In this case, equation (6) may be modified to account for the duration T spanning any number, i.e., j, of subsequent adjacent time intervals _M Where j may be any positive integer, and so as to take into account either or both of the time-dependent glucose target and the insulin sensitivity value. One form of such equation based on equation (6) is shown below:

wherein BGT (T) _C +T _M ) Is shown at time T _C +T _M The target glucose value of (a). In such an embodiment, a modified version of the algorithm 100 'of fig. 4A and 4B may be used to calculate CB according to equation (10), where steps 108 and 110' would be omitted and step 114 would be modified to calculate the first integral termStep 154 would be modified to calculate an intermediate integral term, e.g.And step 116' would be modified to calculate the final integral term. Step 118 will also be modified to calculate CB according to equation (10).

Wherein IS when n = -1 _NI+n ＝IS _CI And P is _NI+n ＝P _CI . According to equation (9), the blood glucose target value BGT used is the blood glucose target value of the last, i.e. jth, time interval of the subsequent adjacent time intervals, and the denominator of equation (9) is expressed at T _M The sum of the products of IS and P in all time intervals spanned, wherein all time intervals include the current time interval and all "j" subsequent adjacent time intervals.

The present disclosure contemplates embodiments of a diabetes care system in which a sustained time period, e.g., one or more days, IS not divided into a plurality of time intervals, but rather a continuous function of glucose target BGT and insulin sensitivity IS defined for the entire sustained time period. In this case, the correction bolus equation may take the form:

in such an embodiment, another modified version of the algorithm 100 'of fig. 4A and 4B may be used to calculate CB according to equation (11), where steps 108, 109, 110', 114, 115, and 116 'would be omitted, and step 118' would be modified to calculate CB according to equation (11).

While the invention has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as illustrative and not restrictive in character, it being understood that only illustrative embodiments thereof have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.

Claims

1. In the case of a diabetes care system having a plurality of adjacent time intervals each defining an associated target glucose value and insulin sensitivity value, a method for calculating a recommended insulin bolus quantity when a measured glucose value in a current time interval exceeds the target glucose value for the current time interval and when a duration of glucose lowering action of the recommended insulin bolus quantity to be administered spans the current time interval and a plurality of subsequent adjacent time intervals, the method comprising the steps of:

determining a respective plurality of percentages each corresponding to a percentage of insulin action of the recommended bolus quantity to be used to lower the glucose level during a respective one of a plurality of time intervals between the current time interval and a plurality of subsequent adjacent time intervals, and

a recommended bolus quantity is calculated as a function of the measured glucose value, the target blood glucose level for the last of the plurality of subsequent adjacent time intervals, the insulin sensitivities for the current time interval and each of the plurality of subsequent adjacent time intervals, and the respective plurality of percentages.

2. The method of claim 1, wherein the number of subsequent adjacent time intervals is 1, and wherein the step of determining the respective plurality of percentages comprises:

determining a first percentage corresponding to a percentage of insulin action of the recommended bolus quantity that will be used to reduce the glucose level during the current time interval,

determining a second percentage corresponding to a percentage of insulin action of the recommended bolus quantity to be used to lower the glucose level during a next time interval,

and wherein the calculating step comprises calculating the recommended bolus quantity as a function of the measured glucose value, the target blood glucose level for the next adjacent time interval, the insulin sensitivities for the current and subsequent adjacent time intervals, and the first and second percentages.

3. The method of claim 2, wherein the step of determining the first percentage comprises determining the first percentage as a function of at least a current time in the current time interval at which the measured bolus value was measured, a start time of a next adjacent time interval, and a duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity.

4. The method of claim 3, further comprising the step of calculating a current interval bolus activity time as a difference between a start time of a next adjacent time interval and a current time,

and wherein the step of determining a first percentage comprises determining the first percentage as a function of the current interval bolus activity time and the duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity.

5. The method of claim 4 wherein the step of determining a first percentage includes extracting a first percentage value from a table populated with the first percentage value as a function of the current interval bolus activity time value and the time duration value of glucose lowering action of the subsequently administered recommended insulin bolus quantity.

6. The method of claim 3, wherein the step of determining the second percentage comprises calculating the second percentage as a difference between one hundred percent and the first percentage.

7. The method of claim 2 wherein the step of determining the second percentage comprises determining the second percentage as a function of at least a current time in the current time interval at which the measured bolus value is measured, a start time of a next adjacent time interval, and a duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity.

8. The method of claim 7, further comprising the step of calculating a next interval bolus activity time as a difference between the duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity and a current interval bolus activity time, the current interval bolus activity time corresponding to a difference between a start time of a next adjacent time interval and the current time,

and wherein the step of determining the second percentage comprises determining the second percentage as a function of the next interval bolus activity time and the duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity.

9. The method of claim 8 wherein the step of determining a second percentage includes extracting a second percentage value from a table populated with second percentage values as a function of the next interval bolus activity time value and the time duration value of glucose lowering action of the subsequently administered recommended insulin bolus quantity.

10. The method of claim 7, wherein the step of determining the first percentage comprises calculating the first percentage as a difference between one hundred percent and the second percentage.

11. The method of claim 2, further comprising the step of performing the determining step and the calculating step only if the duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity extends into the next adjacent time interval by a predefined amount of time.

12. In the case of a diabetes care system having a plurality of adjacent time intervals each defining an associated target glucose value and insulin sensitivity value, a method for calculating a recommended insulin bolus quantity when a measured glucose value in a current one of the time intervals exceeds the target glucose value for the current time interval, the method comprising:

determining whether the duration of the glucose lowering action of the subsequently administered recommended insulin bolus quantity spans the current time interval and at least the next adjacent time interval, an

The recommended bolus quantity is calculated as a function of the measured glucose value, the target glucose value for the current time interval, and the insulin sensitivity value for the current time interval only if the duration of the glucose lowering action of the subsequently administered recommended insulin bolus quantity is limited to the current time interval.

13. The method of claim 12, further comprising the steps of, if the duration of glucose lowering action of the subsequently administered recommended insulin bolus dose otherwise spans the current time interval and a plurality of subsequent adjacent time intervals:

14. The method of claim 13, wherein the number of subsequent adjacent time intervals is 1,

and wherein the step of determining the respective plurality of percentages comprises:

determining a second percentage corresponding to a percentage of insulin action of the recommended bolus quantity that will be used to lower the glucose level during a next time interval,

15. The method of claim 14, wherein the step of determining the first percentage comprises determining the first percentage as a function of at least one current time in the current time interval at which the measured bolus value was measured, a start time of a next adjacent time interval, and a duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity.

16. The method of claim 15, wherein the step of determining the second percentage comprises calculating the second percentage as a difference between one hundred percent and the first percentage.

17. The method of claim 14 wherein the step of determining a second percentage comprises determining the second percentage as a function of at least one of a current time in a current time interval at which the measured bolus value is measured, a start time of a next adjacent time interval, and a duration of glucose lowering action of a subsequently administered recommended insulin bolus quantity.

18. The method of claim 17, wherein the step of determining the first percentage comprises calculating the first percentage as a difference between one hundred percent and the second percentage.

19. The method of claim 14, further comprising the step of determining the first and second percentages and the step of calculating the recommended bolus quantity as a function of the measured glucose value, the target blood glucose level for the next adjacent time interval, the insulin sensitivities for the current and subsequent adjacent time intervals, and the first and second percentages are performed only if the duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity extends into the next adjacent time interval by a predefined amount of time.

20. In the case of a diabetes care system having a plurality of adjacent time intervals each defining an associated target glucose value and insulin sensitivity value, a method for calculating a recommended insulin bolus quantity when a measured glucose value in a current one of the time intervals exceeds the target glucose value for the current time interval and when a duration of glucose lowering action of the recommended insulin bolus quantity to be administered spans the current time interval and a next adjacent time interval, the method comprising:

determining a first difference value as a difference between the target glucose value of the current time interval and the target glucose value of the next adjacent time interval,

determining a second difference value as a difference between the insulin sensitivity value of the current time interval and the insulin sensitivity value of the next adjacent time interval, an

The recommended bolus quantity is calculated as a function of the measured glucose value, the target glucose value for the current time interval, and the insulin sensitivity value for the current time interval only if the first difference is less than the first threshold and the second difference is less than the second threshold.

21. The method of claim 20, further comprising the step of, if the first difference exceeds the first threshold or the second difference exceeds the second threshold:

determining a second percentage corresponding to a percentage of insulin action of the recommended bolus quantity that will be used to lower the glucose level during a next time interval, an

A recommended bolus quantity is calculated as a function of the measured glucose value, the target blood glucose level for the next adjacent time interval, the insulin sensitivities for the current and subsequent adjacent time intervals, and the first and second percentages.

22. The method of claim 21 wherein the step of determining a first percentage comprises determining the first percentage as a function of at least one of a current time in a current time interval at which the measured bolus value is measured, a start time of a next adjacent time interval, and a duration of glucose lowering action of a subsequently administered recommended insulin bolus quantity.

23. The method of claim 22, wherein the step of determining the second percentage comprises calculating the second percentage as a difference between one hundred percent and the first percentage.

24. The method of claim 21, wherein the step of determining the second percentage comprises determining the second percentage as a function of at least a current time in the current time interval at which the measured bolus value is measured, a start time of a next adjacent time interval, and a duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity.

25. The method of claim 24, wherein the step of determining the first percentage comprises calculating the first percentage as a difference between one hundred percent and the second percentage.

26. The method of claim 21, further comprising the step of determining the first and second percentages and the step of calculating the recommended bolus quantity as a function of the measured glucose value, the target blood glucose level for the next adjacent time interval, the insulin sensitivities for the current and subsequent adjacent time intervals, and the first and second percentages are performed only if the duration of glucose lowering action of the subsequently administered recommended insulin bolus quantity extends into the next adjacent time interval by a predefined amount of time.