WO2011021163A1

WO2011021163A1 - Medication and/or treatment regimen compliance

Info

Publication number: WO2011021163A1
Application number: PCT/IB2010/053743
Authority: WO
Inventors: Matthew Harris; Cristina Bescos Del Castillo; Elke Naujokat; Richard Daniel Willmann; Harald Reiter; Pradyumna Dutta
Original assignee: Koninklijke Philips Electronics N.V.; Philips Intellectual Property & Standards Gmbh
Priority date: 2009-08-20
Filing date: 2010-08-19
Publication date: 2011-02-24

Abstract

There is provided a method of measuring a patient's compliance to a medication or treatment regimen, the method comprising obtaining measurements of one or more physiological characteristics of the patient; and determining a level of compliance of the patient with the medication or treatment regimen using the obtained measurements and a model estimating the effect of the medication or treatment regimen on values of the physiological characteristics.

Description

Medication and/or treatment regimen compliance

TECHNICAL FIELD OF THE INVENTION

The invention relates to a method and system for providing an indication of a patient's compliance with a particular medication and/or treatment regimen. BACKGROUND TO THE INVENTION

Compliance describes the extent to which a patient follows recommendations from a physician, nurse or other health practitioner to take a medication or follow a treatment regimen (which could include taking medication, following a diet, performing particular exercises and/or making other lifestyle changes).

The failure of a patient to adhere or comply with a specified medication or treatment regimen is a significant problem, and results in a suboptimal clinical benefit to the patient from the medication or treatment. Failures can range from missing a single dose of a medication to taking the medication at the wrong time of day to failing to follow the treatment regimen at all.

It has been estimated by the American National Pharmaceutical Council that non-compliance with medication adds over $100 billion annually to the U.S. health care system and a significant percentage of hospitalizations are estimated to result from poor compliance with prescribed medication ("The issue of patient non-compliance: response to a costly health problem" by A. Wilson).

Compliance is a particular problem in long term treatments, and this problem will only increase as the population ages and chronic diseases become more prominent. There is strong evidence that increasing the compliance may have a far greater impact on the health of the population than any improvement in specific medical treatments. For example, in "A question of choice - compliance in medicine taking, a preliminary review" by S. Carter and D. Taylor, it was found that patients with, or at risk for, coronary artery disease or congestive heart failure and who were classified as non-compliant were twice as likely to die from these conditions as those who were compliant.

The World Health Organization (WHO) has identified five factors contributing to non-compliance: social and economic factors, the healthcare system, characteristics of the disease, disease therapies and patient-related factors, and it is thought that the most promising methods of improving compliance use a combination of patient education, behavioral skills, self-rewards, social support and telephone follow-up.

At present, patient compliance is determined by a healthcare professional during a patient visit. The professional asks the patient about their compliance with the medication or treatment regimen, and then estimates the patient compliance, factoring in the professional's estimate on how truthful the patient was in answering the questions. Most patients overestimate their level of compliance to a medication or treatment.

However, such an estimate of compliance is clearly non-subjective, and can only be done through direct contact between the professional and the patient. If the professional suspects or detects a low compliance level, it is only during the patient visit that the professional can take steps to improve the compliance. There is currently no way for a professional to detect problems with compliance between patient visits.

Although compliance can be measured and improved using automatic medication dispenser units, such as the Monitored Automatic Medication Dispenser MD.2 from Philips, which collect information on whether the medication has been taken out of the dispenser, they cannot provide information on whether the patient has actually taken the medication.

Thus, it is difficult to obtain an objective measure of the patient's compliance to a medication or treatment regimen, and there is no system or method available that can alert a healthcare professional to a decrease in compliance between patient-professional encounters.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a method of measuring a patient's compliance to a medication or treatment regimen, the method comprising obtaining measurements of one or more physiological characteristics of the patient; and determining a level of compliance of the patient with the medication or treatment regimen using the obtained measurements and a model estimating the effect of the medication or treatment regimen on values of the physiological characteristics.

According to a second aspect of the invention, there is provided a system for measuring a patient's compliance with a medication or treatment regimen, the system comprising one or more physiological characteristic sensors for taking measurements of one or more physiological characteristics of the patient; processing means for determining a level of compliance of the patient with the medication or treatment regimen using the measurements and a model estimating the effect of the medication or treatment regimen on values of the physiological characteristics.

According to a third aspect of the invention, there is provided a computer program product comprising computer-readable code that, when executed on a suitable computer or processor, is configured to cause the computer or processor to perform the steps in the method described above.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the following drawings, in which:

Fig. 1 is a block diagram of a system for determining a level of compliance in accordance with the invention;

Fig. 2 is a flow chart of a method of determining a level of compliance in accordance with the invention;

Fig. 3 indicates the inputs and output of the model in accordance with the invention;

Fig. 4 is a graph indicating an exemplary change in a physiological

characteristic in response to regular doses of medication; and

Fig. 5 is an exemplary model of the effect of a beta blocker on blood pressure in a patient.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, the user of the system according to the invention whose compliance is being measured is referred to as a patient. The use of the word "patient" or

"patients" in the description or claims is not intended to limit the scope of the invention or to require any kind of doctor/patient relationship.

In accordance with the invention, an objective measure of the level of a patient's compliance to a medication or treatment regimen is determined by obtaining and analyzing measurements of one or more physiological characteristics of the patient. By using a model of the effect of the prescribed medication or treatment on the physiological characteristic(s), it is possible to determine if the patient has taken the medication or followed the treatment plan (and if the treatment is effective) by comparing the measurements to those predicted by the model. Figure 1 shows a system 2 for determining a level of compliance in accordance with the invention. The system 2 comprises one or more physiological characteristic sensors 4 for obtaining measurements of physiological characteristics of the patient. The physiological characteristic(s) measured by the physiological characteristic sensor(s) 4 can include, but is not limited to, any of the following: blood pressure, heart rate, blood sugar levels, blood oxygen levels, breathing rate, heart function (including an electrocardiogram), motion or weight. Those skilled in the art will be aware of other physiological characteristics of a patient that can be measured, and the appropriate sensors 4 for doing so.

The numbers and types of physiological characteristic sensors 4 present in the system 2 can be determined by the medication or treatment regimen specified for the patient, or whether the system 2 is intended to be suitable for use with more than one type of medication and/or treatment regimen. The underlying principle is that in order for the system 2 to provide a level of compliance for the patient, it is necessary to obtain measurements of the physiological characteristic(s) of the patient that are affected by taking or not taking the medication(s) or following or not following the treatment regimen(s).

So, for example in an embodiment in which the system 2 is intended to be used in connection with a medication for reducing blood pressure, the physiological characteristic sensors 4 will include at least a blood pressure sensor.

If the system 2 is intended to be adaptable to a number of different types of medications or treatment regimens, the system 2 can be provided with sensors 4 for many or all of the physiological characteristics indicated above.

The system 2 also comprises a processor 6 that is connected to, and receives the outputs from, the physiological characteristic sensor(s) 4, a memory 8 that is connected to the processor 6, a user interface 10 (that can comprise means for receiving a patient input, such as a keypad, keyboard, mouse, a touch screen, etc., and/or means for presenting information to the patient, such as a display, one or more lights, a loudspeaker, etc.) that is connected to the processor 6 and a terminal 12 used by a healthcare professional. The processor 6 can communicate and exchange data with the terminal 12, as indicated by dashed arrow 14.

It will be appreciated that the system 2 according to the invention may take many forms, and may include many more components than those shown in Figure 1. In one implementation, the sensor(s) 4, processor 6, memory 8 and user interface 10 may be integrated into a small handheld unit that has some means (for example wireless Internet access or mobile telephony circuitry) for communicating with the terminal 12, while in another implementation the processor 6, memory 8 and user interface 10 may be in the form of a personal computer or laptop, with the sensor(s) 4 being peripheral components that can be attached to the computer or laptop (in this implementation the computer or laptop can again communicate with the terminal 12 via the Internet). In yet another alternative implementation, the processor 6 that determines the level of compliance for the patient may located remotely from the sensor(s) 4 (and therefore the patient). The processing may be carried out in a remote server before being communicated to the terminal 12, or the processing may be carried out in the terminal 12 itself. Those skilled in the art will be aware of many other configurations for a system 2 in which the invention can be implemented.

A flow chart of the method according to the invention is shown in Figure 2. In step 101, measurements of the required physiological characteristics of the patient are collected using the sensor(s) 4. In some implementations, the system 2 can prompt the patient to take a measurement using the user interface 10. Such a prompt could be issued in accordance with a schedule that indicates when measurements should be taken. The time between measurements can be set based on the particular medication or treatment regimen that the patient is undergoing.

Once the measurements have been collected, they are passed to the processor 6 which compares the measurements to a model that predicts the effects of the medication or treatment regimen on the particular physiological characteristics (step 103). The data for the model may be stored in the memory 8, along with data for models relating to other medication or treatment regimens if the system 2 is to be able to determine a level of compliance for different medication and treatment types.

From the comparison, the processor 105 can then determine a level of compliance for the patient with the medication or treatment regimen. Clearly, the closer that the physiological characteristics get to the values predicted by the model, the more compliant the patient has been with the medication or treatment regimen.

The level of compliance can be given at any desired level of granularity. For example, the processor 6 can provide a positive or negative indication of the compliance of the patient (for example "compliant" or "non-compliant") based on whether the deviation of the patient's physiological characteristic(s) from those predicted by the model is above or below a threshold. Alternatively, multiple thresholds can be used, with each one indicating a different level of compliance for the patient. In yet further alternative embodiments, the level of compliance can be given as a percentage value of the number of doses of medication or exercise routines, etc. completed by the patient.

In a preferred embodiment of the invention, in order for the processor 6 to improve the estimate of the level of compliance, the model also receives initial and/or previous measurements of the physiological characteristics of the patient. These

measurements can also be stored in the memory 8. This allows the processor 6 to determine the change in the physiological characteristic(s) of the patient in response to the medication or treatment regimen over time, and the processor 6 can compare this or these changes to those predicted by the model to determine if the patient is complying with the medication or treatment regimen.

In yet further preferred embodiments, the patient can also be presented with a question or series of questions by the user interface 10 in order to obtain information relevant to the medication or treatment regimen from the patient that cannot otherwise be obtained by sensor(s) 4. This information can also be input to the model by the processor 6 (optionally along with initial and/or previous responses stored in the memory 8) and used to determine the level of compliance in conjunction with the collected measurements. The patient can answer the question(s) at the same time or around the same time that the measurements of the physiological characteristics are taken.

The question or series of questions could ascertain information about the patient's symptoms, such as whether the patient is in any pain, whether the pain has improved or worsened, its location, their mental state, etc. Questions could also be asked about whether the patient believes they have complied with the medication or treatment regimen so far. This information could be used to provide an indication of the confidence of the determined level of compliance (for example if the patient suggests that they have taken every dose of the medication so far and the comparison agrees, the confidence in the determined level of compliance will be high). This information can also highlight cases where the medication or treatment regimen is not having the desired effect (for example the patient will indicate that they have followed the regimen properly but the model will indicate that there is a low level of compliance).

Figure 3 illustrates the different types of information that can be input to the model. Thus, the model can receive information about the medication or treatment regimen (for example a specific dosage amount and/or frequency for a medication), the initial and/or previous measurements of the physiological characteristics of the patient, the new/current measurements of the physiological characteristics of the patient and responses to any questions presented to the patient. As described above, the output of the model, or the result of a comparison of the new measurements of the physiological characteristics to the predicted values for the physiological characteristics is a level of compliance of the patient to the medication or treatment regimen.

It will be appreciated that the system 2 may take measurements of physiological characteristics of the patient that are not directly affected by the medication or treatment regimen, but which are used to adapt or personalize the model to the patient. For example, the system 2 may measure the weight of the patient (either initially or on a regular basis), and this weight measurement can be used to calibrate the model to the particular size of the patient since it is known that the effect of various medications can depend on the size of the patient.

The precise details and operation of the model will depend on the particular medication or treatment regimen. Information relating to the effect of a medication or treatment regimen over time can be obtained through trials and/or from existing medical literature. In some implementations, the effect of a medication over time given regular doses of the medication can be modeled as exponentially approaching its maximal effect as shown in medical literature. For example, Figure 4 shows how the value of a particular physiological characteristic is expected to fall in response to starting to regularly take a medication at time 0.

The model may also be able to predict the effect of several medications and/or treatment regimens taken in parallel or in combination, even where doses of particular medications are not taken at the same time. Where appropriate, the effect of the different medications on the physiological characteristics can simply be added, otherwise, a more involved medication combination function must be used. Those skilled in the art will be aware of suitable functions for implementing this.

The model may also be able to predict the effect on the physiological characteristics of under or over dosage of the medication with respect to the prescription. For example, the comparison of the measurements of the physiological characteristic(s) to the model may indicate that the medication is too effective on the patient (indicating to the healthcare professional that the medication regimen should be reduced) or insufficiently effective (indicating to the healthcare professional that the medication regimen should be increased).

It will be appreciated that the model shown in Figure 4 represents relatively slow working medication whose effects are cumulative over the course of the medication or treatment regimen. However, there are relatively fast working medications whose effect can be noticed after just a single dose (and therefore the effect of missing a dose can also be noticed). In both (and intermediate) cases, the level of compliance to the medication or treatment regimen can be determined by comparing the observed progression of the physiological characteristic^) to that predicted by the model.

Beta blockers are one example of a class of medication that is relatively fast working on blood pressure. It has been found that the effect of a beta blocker on reducing blood pressure can be seen after each dose. Therefore, it is also possible to see when the patient has missed just a single dose of the beta blocker. In addition, it can also be possible to see an increase in blood pressure between regular doses of the medication (i.e. regular doses in accordance with the medication regimen), which can allow a healthcare professional to determine that the medication regimen may need to be changed (for example by increasing the frequency of the dose, increasing the dosage or changing to a stronger medication).

Figure 5 is an example of a model of the effect of a beta blocker on blood pressure in a given patient. Line 200 shows the model's prediction of the change in blood pressure of the patient over time, given regular doses of the beta blocker. The model shows a "safe" range for the blood pressure which is bounded by lines 202 and 204.

At time t_{l s} the patient takes a dose of beta blocker in accordance with the medication regimen, and it can be seen that the measurements of the blood pressure of the patient (line 210) initially track that predicted by the model. However, the patient misses the next dose of the beta blocker at t₂ and the measurements of the blood pressure indicate a substantial deviation from that predicted by the model. In this case, the blood pressure measurements indicate that the blood pressure is outside of the "safe" range. The system 2 compares the current measurements to those predicted by the model and determines a level of compliance for the patient. The level of compliance can be given by the magnitude of the deviation between the current measurements and those predicted by the model or by evaluating the integrated absolute difference between the model and actual blood pressure curves (200, 210) with respect to a threshold.

As described above, the indication of the level of compliance provided by the system 2 can be reviewed by a healthcare professional during a patient visit to determine if the medication or treatment regimen is effective or between patient visits to allow the professional to intervene earlier than with conventional systems if the patient is not complying with the regimen. It will also be appreciated that the fact that the patient may be aware that the system 2 is providing the healthcare professional with an indication of their level of compliance with the regimen could induce the patient to try harder to follow the regimen fully.

There is therefore provided a system and method that can provide an objective measure of a patient's compliance to a medication or treatment regimen.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless

telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS:

1. A method of measuring a patient's compliance to a medication or treatment regimen, the method comprising:

obtaining measurements of one or more physiological characteristics of the patient (101); and

determining a level of compliance of the patient with the medication or treatment regimen using the obtained measurements and a model estimating the effect of the medication or treatment regimen on values of the physiological characteristics (103, 105).

2. A method as claimed in claim 1, wherein the level of compliance is based on the amount of deviation between the obtained measurements and the effect estimated from the model.

3. A method as claimed in claim 2, wherein the amount of deviation is determined by integrating the absolute difference between the obtained measurements and the effect estimated from the model.

4. A method as claimed in claim 2 or 3, wherein the level of compliance is determined to be high if the amount of deviation is less than a threshold value and low if the amount of deviation is greater than the threshold value.

5. A method as claimed in any of claims 1 to 4, wherein the step of determining (103, 105) further comprises using previous measurements of the one or more physiological characteristics with the obtained measurements and the model to determine the level of compliance of the patient with the medication or treatment regimen.

6. A method as claimed in any of claims 1 to 5, further comprising the steps of:

presenting the patient with one or more questions relating to the medication or treatment regimen; and

obtaining the patient's responses to the one or more questions; wherein the step of determining (103, 105) further comprises using the responses with the obtained measurements and the model to determine the level of compliance.

7. A method as claimed in any of claims 1 to 6, further comprising the step of:

sending an indication of the determined level of compliance to a remote terminal.

8. A system for measuring a patient's compliance with a medication or treatment regimen, the system comprising:

one or more physiological characteristic sensors (4) for taking measurements of one or more physiological characteristics of the patient;

processing means (6) for determining a level of compliance of the patient with the medication or treatment regimen using the measurements and a model estimating the effect of the medication or treatment regimen on values of the physiological characteristics.

9. A system as claimed in claim 8, wherein the processing means (6) is configured to determine a level of compliance based on the amount of deviation between the obtained measurements and the effect estimated from the model.

10. A system as claimed in claim 9, wherein the processing means (6) is configured to determine the amount of deviation by integrating the absolute difference between the obtained measurements and the effect estimated from the model.

11. A system as claimed in claim 8 or 9, wherein processing means (6) is configured to determine the level of compliance as high if the amount of deviation is less than a threshold value and low if the amount of deviation is greater than the threshold value.

12. A system as claimed in any of claims 8 to 11, wherein the processing means (6) is configured to use previous measurements of the one or more physiological

characteristics with the obtained measurements and the model to determine the level of compliance of the patient with the medication or treatment regimen.

13. A system as claimed in any of claims 8 to 12, further comprising:

a user interface (10) for presenting the patient with one or more questions relating to the medication or treatment regimen and receiving the patient's responses to the one or more questions;

wherein the processing means (6) is further configured to use the responses with the obtained measurements and the model to determine the level of compliance.

14. A system as claimed in any of claims 8 to 13, further comprising:

a remote terminal (12); and

communication means coupled to the processing means (6) for sending an indication of the determined level of compliance to the remote terminal (12).

15. A computer program product comprising computer-readable code that, when executed on a suitable computer or processor, is configured to cause the computer or processor to perform the steps in the method claimed in any of claims 1 to 7.