WO1997011635A1

WO1997011635A1 - Medical record system

Info

Publication number: WO1997011635A1
Application number: PCT/CA1996/000654
Authority: WO
Inventors: Sven F. H. Grail; George Christodoulou
Original assignee: Grail Sven F H; George Christodoulou
Priority date: 1995-09-28
Filing date: 1996-09-27
Publication date: 1997-04-03
Also published as: CA2232686A1; AU7081296A

Abstract

A system for providing the delivery of health care services to patients and in particular method and apparatus for monitoring the delivery of such services is disclosed. The system provides a method and apparatus by which an appropriate frequency of periodic treatment for patients is determined by scores or ratings assigned to selected criteria in a routine examination in which each of the criteria is weighted and in which each of the criteria is indicative of the health status of the patient. The ratings are combined with the weighting of its corresponding criterion, which are then accumulated to provide an overall score for the patient. The overall score is compared to a set of predetermined range of results which correspond to a particular health care servive to be provided, which is for example the recall frequency of a dental patient.

Description

MEDICAL RECORD SYSTEM

The present invention relates to the delivery of health care services and in particular to methods and apparatus for monitoring the delivery of such services. A number of health care services such as medical examinations, dental inspection, physiotherapy and optometry are provided on a periodic basis to monitor the status ofthe patient's health, ln this way, preventative or corrective health care may be provided as the need arises so that significant deterioration ofthe patient's health is avoided. The routine examinations that are performed as part of a patient^'s overall health care program are conducted at a frequency that is dictated by experience and established procedure. For example, in the dental field routine examinations are traditionally conducted on a six-month recall frequency unless, in the experience ofthe dentist, more frequent examination is required. This, however, is done at the discretion of the dentist and conventionally a six-month recall period has been established by default.

Other periods are appropriate for different fields; for example, eye inspections may only be required every one to two years although certain conditions may require more frequent inspection.

In determining the recall periods, the practitioner depends almost entirely upon experience, judgment and usual practice rather than true patient need and thus the selected period may be difficult to justify if called upon to do so. Moreover, companies that provide insurance for medical expenses anticipate a recall frequency based upon an average and any departure from that, paπicularly an increase in the recall frequency, may require further justification before the claim is paid. It has now been shown through studies such as that described by Marcus et al. in The Journal of Public Health Dentistry in a paper entitled "Construction of a Population Index of Adult Oral Health Status Derived from Dentists' Preferences" (Fall 1983, Volume 43, No. 4, page 283), that it is possible to determine the overall oral health of a patient by performing standard tests for inspection and weighting the results of those tests to get an overall index of tiie patient's health. It is suggested that such an index may be used to evaluate the overall health of a population or to evaluate the efficacy of treatment practices used on groups of patients. While this approach is useful for monitoring and evaluating the overall performance of a system, it does not address the requirements of individual patients.

It is therefore an object ofthe present invention to provide a method and apparatus by which delivery of health care systems may be provided on an individual basis according to each patient's need and probable risk. 5 In general terms, the present invention provides a method and apparatus by which an appropriate frequency of periodic treatment for patients is determined by scores or ratings assigned to selected criteria in a routine examination in which each ofthe criteria are weighted. The weighting and rating are combined to provide an overall indication ofthe status ofthe patient's health for the selected criteria. The weighted l o results are then compared to established ranges of results and a recall frequency selected which is appropriate for the status ofthe individual patient.

As a preference, selected test results may be specially weighted so that a critically identified patients' needs can be accommodated in a minimum recall period.

An embodiment ofthe invention will now be described by way of example 15 only with reference to the accompanying drawings, in which

Figure 1 is a table showing the weighting of a typical set of criteria; Figure's 2.1 - 2.4 are flowcharts showing the computation ofthe results for a patient;

Figure 3 is a block diagram of a general purpose computer programmed 20 according to an embodiment ofthe present invention;

Figure 4 is flowchart showing a sequence of steps for entering criteria and their corresponding weighting factors;

Figure 5 is a flowchart showing a sequence of steps for entering and computing the cumulative rating; 25 Figure 6 is a sequence of steps showing the input of recall frequency ranges; and

Figure 7 is a flowchart showing the selection of a specific recall frequency. Referring therefore initially to Figure 1 , a routine examination (in the example given, a dental examination) consists of a set of criteria as indicated at 10 that 30 contribute to an assessment ofthe overall health of a patient. Each criteria 10 may be assessed by a standardized test that provides quantifiable results upon which an assessment may be based. Such tests may be performed by the dentist or may be performed offsite in a laboratory. In the example given, the criteria are split into two groups 12,14, those associated with the hard tissue and those associated with the soft tissue respectively.

As indicated in the "Total" column 16, each ofthe criteria caries a weighting based upon the significance or relative contribution that should be attributed to each ofthe criteria in the overall evaluation ofthe health ofthe patient. In the example given, the group of criteria 12 associated with the hard tissue provide 50% ofthe weighting and those 14 associated with the soft tissue also provide 50%.

The hard tissue tests 12 each carry a certain weighting so that, for example, the caries screen can contribute a maximum of 10% ofthe total evaluation, the number of fillings a maximum of 6%, and so on as shown in the "Total" column. These maximum weightings are selected from clinical evaluation such as that mentioned in the introduction and similar studies that indicate the effect of individual conditions upon the overall status. Within each ofthe tests, criteria are established that determine the rank 18 to be accorded to the actual results ofthe tests and which will in turn determine the value or rating 20 to be attributed to the total. Thus, in the caries screen, three possible ranks 18 are attributed - namely low, moderate or high - which are consistent with the ranking of results that would be obtained from such a test. A value 20 is associated with each ofthe tests so that, for example, a desirable low result caries screen provides in this example a 10% value whereas a moderate result achieves only a 5% value. The value associated with the rank is then retained as a value which will be accumulated into the total.

Certain ofthe criteria 10 - for example, the number of fillings - can be evaluated directly by the dentist and again ranks based on prior studies are used to determine the value that should be attributed to that particular test. In the case ofthe number of fillings, a maximum value is attributed to less than 6 fillings, a moderate value is attributed to an examination that yields between 7-12 fillings, and a minimum value is attributed to more than 12.

The criteria selected may also attribute a rank and corresponding weighted value based upon the prior history such as the last tooth decay which accords a higher value as the period from the last detected tooth decay increases.

Similarly, the patient's own history may be taken into account by according a high value to frequent dental visits and a low value to infrequent visits. It will be noted that these values are used to counterbalance an ambiguous test result - for example, an apparently good tooth decay history - so that a high value attributed to the prolonged period from the last detected tooth decay is counterbalanced by the fact that the patient has not visited the dentist during that period. 5 Tests may also be included that rank the patient's own habits such as the amount of plaque present indicating whether or not the patient is performing an effective oral hygiene routine.

As an alternative, for example in determining weights for criteria such as numbers of filled, missing and decayed teeth, the age ofthe patient may be taken into l o consideration. Presently, a 13-year-old with four filled teeth would have a higher risk than a 55-year-old having only two fillings. Thus, when rating a 13-year-old versus a 55- year-old, the assigned rating should take into consideration the age ofthe patient. In order to achieve this, the distributions ofthe number of decayed, number of missing and number of filled teeth by age group is determined. For each age group, appropriate 15 percentiles are determined - for example, the worst (highest) 25%, the next worst 25%, the next to best 25% and the best (lowest) 25% - is determined. Using the cut points in the distribution, where these quartiles occur establishes the ranges for the number of surfaces and defines the four risk groups. These then have to be weighted - for example, using 0.75, 0.5, 0.25 and 0.0 - to give age-specific scores. This is done for each ofthe 20 criteria namely; number of teeth filled, number of teeth missing and number of teeth decayed.

A value is thus accorded to each ofthe criteria and those values accumulated to provide a subtotal for the hard tissue inspection as a percentage of an overall score. 25 The soft tissue inspection criteria 14 are considered more critical and in the example given consists of a periodontal screening test (PSR). A PSR tests provides a score from 1 through 5 with 1 considered good and 5 considered bad. Such a test is in fact a cumulative score based upon the inspection of any pockets at the gum line. The PSR test is structured so that a pocket in excess of a predetermined depth, typically 5 mm, 30 produces a maximum score, ie. a 5, and is considered sufficiently critical to require immediate corrective measures. Accordingly, on the soft tissue criteria 14, a PSR test of 5 is given a minimum value whereas a PSR test of 1 is given a maximum value.

The values obtained from each test are totaled to determine a cumulative score and that score is then compared with a set of predetermined ranges of values, as for example shown in Figure 1, are correlated to particular recall frequencies for the patient. A score of between 0 and 50 would indicate that a frequent examination is required and attribute a suggested three-month recall frequency. A score of between 51 and 69 would indicate that a six-month recall would be appropriate, with other values indicating that extended periods would be appropriate. Based on the results of the set of tests, therefore, an appropriate recall interval can be attributed based upon prior evaluations ofthe overall dental health ofthe patient.

It will be noted that where a criteria is considered critical, the values associated with it can be weighted such that a minimum recall period is automatically obtained. For example, with the PSR test, a score of 5 ensures that the total score cannot exceed 50% and therefore a three-month recall is inevitable.

The method of evaluating the recall frequency may be automated for inclusion in the overall records system ofthe practitioner as shown in the flowchart of Figure 2. Data entry could be completed in any convenient manner, including a hand-held unit that interfaces with a central records system or a terminal on a LAN. A particularly beneficial data input technique utilizes the interfaces available from commercially available medical maintenance systems, such as that sold as Dentrix 5.0 and available from Dentrix Dental Systems Inc. of American Fork, Utah. Such systems provide a graphical user interface (GUI) to record the results of a routine examination along with treatment history and personal information. The information necessary to complete an evaluation and determine a recall frequency is thus available from the database maintained by such a system and can be retrieved as described below to perform an evaluation.

Referring to Figure 2, after the data has been collected, an evaluation routine is performed. The total evaluation is stored as a cumulative value x which is initially set out at 0 and a determination is made whether optional tests have been performed. Thus the existence or otherwise of a caries test is indicated at item 1 10 and if no such test has been conducted, as determined from an appropriate field in the database, then a minimal score is attributed. If a test has been conducted, the results of that test are evaluated and the appropriate cumulative value registered.

The next criteria evaluated is the number of fillings which is then entered at box 112 and an appropriate score attributed to the result of that test to accumulate in the register. The number of fillings may be entered manually or may be derived from the number from the symbols used on the GUI to indicate fillings.

Similar loops indicated at box 1 14 and 116 are performed on whether or not teeth are missing (114) and whether or not there is tooth decay present (116).

Access may then be made to the patient's dental history as indicated at 118 to determine when the last tooth decay was detected and the period between such decay and the date ofthe inspection computed. Based on that calculated date, the interval from the last decay is computed 120 and the appropriate value added to the total.

Similar processing is applied to the balance ofthe tests through a compliance loop 122 and PSR loop 124 and the accumulated total x compared with the targeted ranges at 126. The appropriate recall period is then selected and, if appropriate, can interface with the dental appointment calendar to provide a suggested appointment date as indicated at 130.

When integrated with a computerized management system, the step wise evaluation allows the preparation of a custom report to the patient indicating specific regimes that may be implemented by the patient. This facility is indicated in Figure 2 with dashed lines. For example, a medium result from the caries test selects a standard paragraph, indicated at 132, detailing a regime that would improve the caries test. Similar paragraphs are associated with selected tests and, upon completion ofthe evaluation, the selected paragraphs are consolidated into a reporting letter 134. By utilizing the criteria set out in the tests, the patient and the insurance companies are assured of an appropriate level of care.

The criteria and weighting set out in Figure 1 and implemented in Figure 2 are of course exemplary. A more comprehensive set of criteria and weighting may be evaluated. For example, the number of criteria chosen may be increased or decreased depending upon the needs ofthe specific circumstances. Also, as shown in Figure 1 , the weighting applied to each ofthe criteria ie. 6% 21 for the criterion "number of fillings" 22 provides a scoring scale of 2 to 6 against which the patient is rated. It may therefore be seen that the scoring scale already takes into account the weighting of that criterion. In this case, whereas it may be implemented as a further embodiment ofthe invention, a fixed scale for all criteria, e.g. 1 to 10, then each ofthe ratings would have to be multiplied by the respective weighting factor of their corresponding criteria. Similarly, a non-linear weighting function may be applied to the criteria and/or the rating. This may be of use - for example, in a situation where a low rating for a particular criterion is less important than a medium or high rating.

The above examples have utilized the environment of dental care and the criteria that apply to such care. The technique is applicable to other fields of medical surveillance such as routine medical checkups, rehabilitation or optometrist's examination. In each case a suitable set of criteria can be selected which are indicative of the overall health ofthe patient and an appropriate weighting applied which can be accumulated to indicate a recall frequency. For example, with respect to a routine medical examination, criteria such as blood pressure, heart rate, urine analysis, blood analysis, patient's weight, lung capacity, height and age may be monitored and appropriate measures applied to indicate the overall well-being. Existing conditions might also be included and might act as a criticality that requires a minimum recall. Similarly, family history may be included and weighted in an appropriate manner. In the case of rehabilitation, the criteria might include the flexibility, mobility, pain, range of movement, inflammation, medication and the time since the occurrence ofthe injury which are combined with appropriate weighting to provide a cumulative total upon which recall frequency can be evaluated.

Referring to Figure 3, a general block diagram for implementing the apparatus for determining the recall frequency, as shown generally by numeral 440. The device has a keyboard input 442 for providing user data input to a processor 444. The processor includes a memory storage means 446 for storing criteria and their corresponding weighting factors and for storing ratings 450. A display 452 is connected to the processor for displaying results of computations performed by the processor 444. A data interface 454 connected with the processor 444 provides a data connection to an external program (not shown).

Figures 4, 5, 6 and 7 indicate flowcharts for performing a sequence of steps for programming a general purpose computer shown in Figure 3. Referring, firstly to Figure 4, a series of criteria are input. These criteria may be determined as described earlier. For each of these criteria a weighting factor is determined as also outlined earlier. Generally speaking this weighting factor determines the relative importance of this criteria in relation to the other criteria. Thus if a criterion is considered more important than the other criteria it may be given a much higher weighting factor than the other criteria.

Referring now to Figure 5, a patient is evaluated against each ofthe stored criteria. In one instance for example a rating scale of 0 to 100 may be chosen. An appropriate rating is assigned for a particular criterion. This rating may then be multiplied by the weighting factor for that criterion, thus producing a weighted rating which takes into account the relative importance of that particular criterion in relation to the other criteria. As is also indicated, a non-linear weighting may be applied. In either case, the weighted ratings are then accumulated to provide a total score of cumulative ratings for the patient. Referring to Figure 6, a set of recall frequencies are created , in which each recall frequency corresponds to a range of cumulative ratings. Referring to Figure 7, the accumulated rating is compared to each ofthe recall-frequency ranges to determine the particular recall frequency for that patient. Now although an embodiment ofthe invention has been described with reference to an implementation on a computer. The invention may also be implemented equally well utilizing other devices known to persons skilled in the art.

Claims

We claim:

1. A method of determining the recall frequency of periodic medical treatment of a patient by selecting a plurality of criteria each of which contributes to an assessment ofthe overall health ofthe patient, attributing to each criteria a weight indicative ofthe relative contribution of that criteria to the overall health of said patient, allocating to each of said criteria a range of values quantifiable from tests performed on said patient and indicative ofthe ranking of said patient for that criteria, selecting from the results of an examination the appropriate one of said values for each of said criteria, combining said selected values to obtain a cumulative value indicative ofthe overall health of said patient, comparing said cumulative value with a set of predetermined ranges of such cumulative values, each range of said set being indicative of a particular recall frequency, and selecting a recall frequency corresponding to the range in which said cumulative value falls. 5

2. A method according to claim 1 wherein criteria considered critical to the overall health are weighted to ensure a minimum period between treatments in the event of a ranking indicative of unsatisfactory results in such criteria.

o 3. A method according to claim 1 or 2 wherein said criteria include historical data from the patient.

4. A method according to claim 3 wherein said historical data is weighted to resolve an ambiguous test result. 5

5. A method according to claims 1 to 4 wherein a report is generated based upon said values selected.

6. A device for determining the recall frequency for periodic medical o treatment of a patient comprising : means for storing a plurality of criteria, each of which is indicative ofthe overall health ofthe patient; means for storing for each of said criteria, a weight indicative ofthe relative contribution of that criteria in determining the overall health ofthe patient; means for storing a rating for each of said criteria, said rating being indicative of the ranking of said patient for that criteria; means for combining said stored rating with its corresponding stored criterion weight to produce a weighted rating; means for combining said weighted ratings to obtain a cumulative rating indicative ofthe overall health of said patient; and means for comparing said cumulative rating with a set of predetermined ranges of predetermined cumulative values, each range of said set being indicative of a particular recall frequency, whereby said patient's recall frequency corresponds to the range in which said cumulative rating falls.