A) Simple red/green LED - (probably the best display)
In the following material a distinction will be made between
A) Cover or Cap Opening Monitors which determines when a Cover or Cap of a Container is opened, and
B) Dose Removal Monitors which determine when each dose of medication is removed from a container
As discussed in the section on the Cover and Cap Opening Monitors, one red/green LED, which can also display yellow if both LEDs are turned on simultaneously can be used for a variety of display functions:
1) informing the patient if medication needs to be taken,
2) displaying the charge remaining in the monitor's battery,
3) displaying an indication of how faithful the patient has followed the treatment regimen,
4) displaying an indication of the extent to which the patient takes medication near the same time each day, which may prove to be a useful predictor of subsequent adherence,
5) displaying the number of months since the patient started therapy,
6) displaying clinical data, such as sputum status, which can be stored in the monitor.
PATIENT DISPLAY FUNCTIONS
The red/green LED could be used to remind the patient to take medication. This would be effective as long as the device was kept in a location that it could be readily seen. There are multiple ways the LED could be used since the LED can flash red, green, or yellow. It can also flash continuously or intermittently. One suggestion would be to have it flash sequentially, red, yellow, and green when the time comes to remind the patient to take medication and remain off after the patient takes medication and at all other times.
Alternatively, a beeper or buzzer could be used to remind the patient. While this has the advantage that it could be heard if the device was kept in a location where it could not be seen, it has the disadvantage that it might annoy a family member who would open the device or remove medication to turn off the beeper when the patient was not home creating a false record of medication removal. This problem could be minimized by programming the beeper to beep late in the evening on those days when the patient had failed to take medication because at that time the patient is likely to be home.
If the patient decides to take medication without first being reminded, he or she could use the LED to answer the question, "Did I or did I not take medication today? This could be done by pushing a query button to activate a query switch or by opening the container in the case of the Cover and Cap Opening Monitor or Clip Monitor. Either of these actions would initiate illumination(s) of the LED to instruct the patient. If the patient was supposed to take the medication it would probably be best to use the same set of intermittent illuminations that were used to alert the patient. If the patient had already taken medication and was not supposed to take it a constant red illumination could be used. For the cover or cap opening monitor it would probably be best to have the LED flash yellow several seconds after the cover was opened and continue to flash yellow until the cover was closed to remind the patient to close the cover.
Since there are multiple ways the display could be used, determination of optimal combination of illuminations may need to be established with field studies.
CARE GIVER DISPLAY FUNCTIONS
Typically, the caregiver would enter a code of some sort by a sequence of button pushes to access the battery status and the indication of how faithful the patient has followed the treatment regimen. The code might be one or more of the symbols in the Morse code. The battery status would be indicated by a green, yellow, or red light indicating that the battery was fully charged, partially discharged, or in need of replacement. A subsequent single push of the button would result in the LED indicating whether the patient had a good adherence record (green), a fair adherence record (yellow), or a poor adherence record (red) since the last refill. Multiple red flashes could indicate various degrees of non-adherence. A second amber color LED costing $.06 could simultaneously flash the number of pills removed in advance of the time they were to be taken. The reason for knowing and considering information about advanced removal will be discussed later.
The caregiver could then retrieve the adherence record for the preceding interval between refills, the entire adherence record, and the number of months since the start of therapy with additional pushes of the button as described in detail in the section on the Cover and Cap Opening Monitor.
RETRIEVAL OF EXTENT TO WHICH PATIENT TAKES MEDICATION NEAR THE SAME TIME EACH DAY AND CLINICAL DATA SUCH AS SPUTUM STATUS.
To retrieve the extent to which the patient takes medication near the same time each day, and clinical data such as sputum status the care giver would enter different codes as discussed in detail in the material regarding the Cover and Cap Opening Monitors.
DEALING WITH ADVANCED REMOVAL AND CATCH UP REMOVAL FROM DOSE REMOVAL MONITORS
The material that follows differentiating advanced removal of medication from catch up removal describes a computing program feature that corrects a minor problem in interpreting the adherence record. Since the problem is minor there may be no need to include this programming feature.
1) ADVANCED REMOVAL OF EXCESS DOSES
When medication is not removed on one or more days it usually means that the patient has not taken medication those days, but not always. If the patient has removed one or more doses prior to the day it should be removed he may ingested these “advance removal” doses on those days that the adherence record shows he did not remove medication. This could happen if he is going on a trip, does not want to take the device with him, and removes several doses before he leaves for the days he plans to be on the trip. In this case he may not have missed any doses even though the adherence record shows that he did not remove medication for several days. However, there is no assurance that medication removed in advance was actually taken since the patient may have lost or sold the medication that was removed in advance, or a child may have removed excess medication and lost it.
2) CATCH UP REMOVAL OF EXCESS DOSES
There is second reason why the patient may remove more than one dose on one day. The patient may remove the medication that he or she failed to take on earlier days to "catch up" in the hope of deceiving the caregiver.
Since Dose Removal Monitors determine when each dose of medication is removed they can determine when more than the prescribed dose is removed on one day. Furthermore, the monitor's program could incorporate rules for largely but not entirely making the distinction between 1) advanced removal which suggests the patient may have ingested the medication and 2) catch up removal which shows that he did not ingest medication.
In most cases when advanced removal occurs the removal of excess doses will be followed by days when no medication is removed. When catch up removal occurs the days when no medication is removed will be followed by a day when excess medication is removed.
However, there are situations where these simple patterns will not occur. For instance, if medication was not removed for three days followed by one day when three excess doses were removed followed by three days when no medication was removed it would not be possible to know whether the three excess doses were advanced removal doses or catch up removal doses. In addition, if there was an interval of several days following the removal of excess doses and the subsequent days when no medication was removed it is less likely that the dose that were removed in advance was ingested while on a trip.
While there is no perfect set of programming rules to deal with these problems we believe the following would work well.
Rule 1: The first time excess doses are removed after the monitor was refilled those doses are regarded as catch up doses to the extent that there are earlier missed days.
Rule 2: Any excess doses, which aren't regarded as catch up doses by applying RULE 1, will be counted as advanced removal doses to the extent that there is a day, or there are days which occur in succession, when medication is not removed starting within two days of when the excess doses were removed.
RULE 3: Each subsequent time excess doses are removed, those doses are regarded as catch up doses to the extent that there are earlier missed days following the previous time excess doses were removed which were not previously accounted for by advanced removal.
RULE 4: Any subsequent time excess doses are removed which aren't regarded as catch up doses by applying RULE 3, the excess doses will be counted as advanced removal doses to the extent that there is a day, or there are days which occur in succession, when medication is not removed starting within two days of when the excess doses were removed.
The objective of these rules is to determine the number of advanced removal doses that were probably ingested. This information could be presented to the caregiver in two ways: The microprocessor could subtract the number of advanced doses from the missed doses, or show the caregiver all the missed doses and the advanced removal doses and let the caregiver use both pieces of information when deciding what to say to the patient and what if any additional action to take.
Probably the best way to display this information would be to have a second amber or yellow LED which would flash a number of times corresponding to the number of doses removed in advance. A second LED for this purpose could cost as little as 6 cents.
Modification of these procedures for devices where the patient can put strips of medication, empty strips, or other objects into the clips from which medication has been previously removed (which would only occur with one version of the clip monitor) are given in the next portion of this section.
PRESENTATION OF THE DETAILED ADHERENCE RECORD
If the patient has a poor or fair adherence record, the caregiver might want to examine the record in detail, especially if the patient may have taken medicine out in advance.
The detailed adherence record could be displayed for each interval between refills with two quick pushes of the button. The record would be presented as a series of flashes of the LED in which each flash represents one day.
The means by which the LED provides a detailed adherence record for the Cover and Cap Opening Monitor is described in the section regarding that device
With a Dose Removal Monitor the LED could also display days when more than one dose of medication was removed. When the detailed adherence record display reached a day on which several doses were removed, there could be one green flash for the medication that should be taken that day and a series of yellow flashes with each flash corresponding to one excess dose removed on that day.
Obtaining a detailed adherence record would be more time consuming than observing the percentage of medication removed. Fortunately, this detailed information would probably be needed only occasionally and might not be used at all.
A simpler display which might be useful with a dose removal monitor would show only a number of red flashes corresponding to the number of missed days and a series of yellow flashes corresponding to the number of "advanced removal" doses estimated by the monitor program.
MANAGEMENT OF INSERTION OF OBJECTS INTO EMPTY CLIPS IN THE CLIP MONITOR FOR WHO’S PACKAGED MEDICATION
The following material applies only to the Clip Monitor with clips that allow the patient to put strips of medication, empty strips, or other objects into clips from which medication has previously been removed. This potential problem could be avoided by constructing the clips so objects cannot be place in the clips without a special tool as illustrated in Figure 3 in the description of the Clip Monitor for WHO’s Packaged Medication.
One of the designs for the Clip Monitor allows the patient to put strips of medication, empty strips, or other objects into clips from which medication has previously been removed. It would be completely impractical for the monitor to determine what was inserted into these clips. And, it would be incorrect to assume that an object removed from those one of those clips was medication removed from the monitor and to record it as such.
To avoid this potentially erroneous recording of medication removal, the monitor could "ignore" clips once medication had been removed from them. These will be called "ignored clips" This could be done if the monitor recorded a "map" of the clips from which medication had been removed and either ignored indications of removal from those clips or simply stopped scanning them once medication had been removed.
To ensure that the monitor recorded medication removal when medication was removed even if an object was placed in its clip shortly after medication removal, the monitor could check the electrical continuity of each clip every 2 to 3 seconds.
If the patient reinserted a strip from which medication had been removed into an "ignored" clip and subsequently removed this empty strip, nothing would be recorded which is appropriate since the strip contained no medication.
If the patient reinserted a medication containing strip into an "ignored" clip and subsequently removed this medication containing strip, once again nothing would be recorded. However, the caregiver would have been informed that this medication containing strip had been removed 'in advance' since the first removal of this medication containing strip would have occurred in advance of the time it should be taken. The caregiver would be notified of this by the advanced removal indicator.
The only difference between allowing or not allowing strips to be reinserted into "ignored" clips would be the location where the patient kept the strips, i.e. in the clips or some other location in the home.
If the patient stores medication in "ignored" clips, there is a potential problem with the monitor's function of informing the patient whether or not medication needs to be taken: If the patient has removed a strip containing medication from an "ignored" clip where he had stored it, the monitor will record no indication that the strip has been removed. Consequently, when the patient queries the monitor whether he needs to take medication, the green light will come on, and the patient may logically conclude that he should take a second dose. This would not be appropriate and could be potentially toxic especially if he took more than two doses.
To correct this problem the monitor could survey all clips in the middle of the night, perhaps 2:00 AM, determine if any of the "ignored" clips contained objects, reactivate all clips containing objects and add these reactivated clips to the existing activated clips to create a second database (map). This second database would be used only when the microprocessor managed the red/green LED display for instructing the patient if he should or should not take medication.
If the patient had not removed medication the day on which he queries the monitor, a green light would appear telling him to remove a strip and ingest the medication. As the strip was removed a red light would appear telling him to remove no more strips that day.
There is one potential minor problem with this means of using the red/green LED to instruct the patient what to take. If the patient removed something other than a medication containing strip, the illumination of the red LED would be telling the patient not to remove any medication that day when in fact he should. If the patient queries the monitor later in the day the red LED would continue to advise him not to take medication.
Even if the patient missed an occasional dose or doses this would not result in treatment failure. Furthermore, when the patient removed some object other than a medication containing strip he would logically conclude that he should remove a medication containing strip even if the red LED instructed him not to do so. To reduce the chance that the patient doesn't take medication, the caregiver could alert the patient about this possibility and advise him to remove a medication containing strip whenever something else is removed despite the red LED.
To reduce the chance that reinsertion of empty strips will occur the patient could be given a container for the empty strips. Since many patients will probably take the medication on their own without using the red/green LED to remind them, this would further reduce what is probably a minor problem.
Finally, it needs to be reiterated that this problem of dealing with objects reinserted Into empty clips could be avoided by constructing the clips as shown in Figure 3 of the material on the Clip Monitor for WHO’s Packaged Medication.
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DISPLAYS INCORPORATED INTO COMPLIANCE MONITORS