Note: Descriptions are shown in the official language in which they were submitted.
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MEDICAL RECORD SYSTEM
The present invention relates to the deliver,v of health care services and in
particular to m~thl~tlc and ~ dLUS for monitoring the delivery of such services.A number of health care services such as medical ~ tions. dental
;"~e~,L;on, physiotherapy and o~ llclly are provided on a periodic basis to monitor the
status of the patient's health. In this way, preventative or corrective health care may be
provided as the need arises so that significant deterioration of the patient's health is
avoided.
0 The routine ~ ions 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 e~c~min~tions are
traditionally conducted on a six-month recall frequencv unless. in the experience of the
dentist, more frequent ~ rnin~tion 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 ap~ liate 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 tl~L~ . " ~ ing the recall periods. the practitioner depends almost entirely
upon experience, j~ gment 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, particularly 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 bv Marcus et
al. in The Journal of Public Health Dentistrv 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 ~ r~llllhlg standard tests for inspection and weighting the results of those
tests to get an overall index of the 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
tre~trn~nt practices used on groups of patients. While this approach is useful for
monitoring and ev~ ting the overall performance of a system. it does not address the
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requirements of individual patients.
It is therefore an object of the present invention to provide a method and
d~pdldLIls by which delivery of health care systems may be provided on an individual
basis according to each patient's need and probable risk.
In general terms, the present invention provides a method and a~p~dL-Is by
which an d~,propl;ate frequency of periodic tre~tment for patients is ~let~?rmin~-l by scores
or ratings assigned to selected criteria in a routine exS~min~tion in which each of the
criteria are weighted. The weighting and rating are combined to provide an overall
indication of the status of the patient's health for the selected criteria. The weighted
0 results are then co.l.l~dlcd to established ranges of results and a recall frequency selected
which is a~lo~.;ate for the status of the individual patient.
As a ~cr.,~ellce, selected test results may be specially weighted so that a
critically identified patients' needs can be accommodated in a 111;11;11111111 recall period.
An embodiment of the invention will now be described by way of example
only with reference to t_e accc~.pal.ying drawings, in which
Figure l is a table showing the weighting of a typical set of criteria;
Figure's 2. l - 2.4 are flowcharts showing the computation of the results for
a patient;
Figure 3 is a block diagram of a general purpose co~ uLel programmed
according to an embodiment ofthe present invention;
Figure 4 is flowchart showing a sequence of steps for entloring criteria and
their corresponding weighting factors;
Figure 5 is a flowchart showing a sequence of steps for entering and
colll~uLillg the cumulative rating;
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 l, a routine e~min~tion (in the
example given, a dental ex~min~tion) consists of a set of criteria as indicated at l 0 that
3 o contribute to an ~eeeement of the overall health of a patient. Each criteria l 0 may be
s~eses~e~l by a standardized test that provides qu~ntifi~hle results upon which an
~eseeement may be based. Such tests may be performed by the dentist or may be
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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 ~ e~;Li~ely.
As indicated in the "Total" column 16, each of the criteria caries a
5 wei~htin~ based upon the significance or relative contribution that should be attributed to
each of the criteria in the overall evaluation of the health of the patient. In the example
given, the group of criteria 12 associated with the hard tissue provide 50% of the
wei~hting 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,
0 the caries screen can contribute a m~rimurn of 10% of the total evaluation, the number of
fillings a m~xi,.,l.... of 6%, and so on as shown in the "Total" column. These maximum
wei~htings 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 of the tests, criteria are established that determine the rank 18
5 to be accorded to the actual results of the 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 con~i~tent with the r~nking of
results that would be obtained from such a test. A value 20 is associated with each of the
tests so that, for example, a desirable low result caries screen provides in this example a
20 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 accnrn~ tecl into the total.
Certain of the 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
det~rmine the value that should be attributed to that particular test. In the case of the
25 number of fillings, a m~hllull~ value is attributed to less than 6 fillin~, a moderate value
is attributed to an t;xs....i..~ n that yields between 7-12 fillin~.~, and a minimnrn 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
30 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
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will be noted that these values are used to counterbalance an ambiguous test result - for
exarnple, an a~pal~ y 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.
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 ~,.rc lllling an effective
oral hygiene routine.
As an ~lt~m~tive~ for example in detemmining weights for criteria such as
numbers of filled, mi~ing and decayed teeth, the age of the patient may be taken into
0 consideration. Pl~ ;,cnlly, a 13-year-old with four filled teeth would have a higher risk
than a 55-year-old having only two fillinp;s Thus, when rating a 13-year-old versus a 55-
year-old, the assigned rating should take into consideration the age of the patient. In
order to achieve this, the distributions of the number of decayed, number of mi~cing and
number of filled teeth by age group is determined. For each age group, a~lv~l;ate
pe.cellliles are determined - for exarnple, the worst (highest) 25%, the next worst 25%,
the next to best 25% and the best (lowest) 25% - is dett?mmin~d Using the cut points in
the distribution, where these quartiles occur establishes the ranges for the number of
s-lrf~f es 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 of the
2 o criteria namely; number of teeth filled, number of teeth mi.~in~ and number of teeth
decayed.
A value is thus accorded to each of the criteria and those values
accumulated to provide a subtotal for the hard tissue inspection as a percentage of an
overall score.
The soft tissue inspection criteria 14 are considered more critical and in the
exarnple 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 pre-iet~rmined depth, typically S mm,
produces a m~ximllm score, ie. a 5, and is considered sufficiently critical to require
immediate corrective measures.
~ _ _
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Accordingly, on the soft tissue criteria 14, a PSR test of 5 is given a
"~ value whereas a PSR test of 1 is given a m~xi"~n." value.
The values obtained from each test are totaled to clet~rmine a cumulative
score and that score is then co-l-p&l~d with a set of pre~1etermined ranges of values, as for
example shown in Figure 1, are correlated to particular recall frequencies for the patient.
A score of between O and 50 would indicate that a frequent ex~min~tion 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 a~pru~-;ate, with other values indicating that
çxt~n-lecl periods would be a~l).up~iate. Based on the results of the set of tests, therefore,
o an a~plv~l;ate recall interval can be attributed based upon prior evaluations of the overall
dental health of the 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 ~utom~tic~lly
obtained. For exarnple, with the PSR test, a score of S 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 of the 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 termin~l on a LAN. A
2 o particularly beneficial data input technique utilizes the interfaces available from
commercially available medical m~int~n~nce 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 cx~min~tion
along with trç~tment history and personal information.
The information necessary to complete an evaluation and determine a
recall frequency is thus available from the ~l~t~h~ee m~int~in~d 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 O and a ~lçt~rmin~tion is made whether optional tests have been
.r~,lllcd. Thus the exi~te~nce or otherwise of a caries test is indicated at item 110 and if
no such test has been con-lucte-l, as determined from an ~r~p-iate field in the ~t~b~e,
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then a minim~l score is attributed. If a test has been con~lncte~ the results of that test are
evaluated and the a~.v~fiate cumulative value registered.
The next criteria evaluated is the number of fillings which is then entered
at box 112 and an a~.v~.iate score attributed to the result of that test to acc-lmnl~te in the
5 register. The number of fillings may be entered m~nll~lly or may be derived from the
number from the symbols used on the GUI to indicate fillings.
Similar loops in-lir~tecl at box l 14 and 116 are p.,.r~-l..cd on whether or
not teeth are mi~ing (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
0 to ~i~termine when the last tooth decay was detected and the period between such decay
and the date of the h.~e~Lion computed. Based on that calculated date, the interval from
the last decay is co~ uled 120 and the a~.o~.iate value added to the total.
Similar procec~inp is applied to the balance of the tests through a
compliance loop 122 and PSR loop 124 and the ~cllmlll~t~l total x co---~.,d with the
targeted ranges at 126. The d~p.~.iate recall period is then selected and, if a~ vpl;ate~
can interface with the dental appointm~nt calendar to provide a suggested appointment
date as indicated at 130.
When integrated with a colll~ .;,e-l management system, the step wise
evaluation allows the ~ alalion of a custom report to the patient indicating specific
regimes that may be implemente~l 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
p~r~gr~rh7 indicated at 132, ~let~ilin~ a regime that would improve the caries test. Similar
paragraphs are associated with selected tests and, upon completion of the evaluation, the
selected paragraphs are consolidated into a reporting letter 134.
By lltili~ing the criteria set out in the tests, the patient and the insurance
colll~ies are assured of an a~lvpliate level of care.
The criteria and weighting set out in Figure 1 and implementeci in Figure 2
are of course exemplary. A more comprehensive set of criteria and weighting may be
ev~hl~te-l For example, the number of criteria chosen may be increased or decreased
depending upon the needs of the specific circnm~t~nces. Also, as shown in Figure l, the
wei~htin~ applied to each of the 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
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seen that the scoring scale already takes into account the weighting of that criterion. In
this case, whereas it may be implem~nte-1 as a further embodiment of the invention, a
fixed scale for all criteria, e.g. 1 to 10, then each of the ratings would have to be
multiplied by the ~ e~;Li~e weightin~ factor of their corresponding criteria. Similarly, a
5 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
o surveillance such as routine medical checkups, rehabilitation or optometrist'sex; ~ ion. In each case a suitable set of criteria can be selected which are indicative of
the overall health of the patient and an a~plvpliate weighting applied which can be
accllm~ te~l to indicate a recall frequency. For example, with respect to a routine
medical eX~min~ti~ n, criteria such as blood pl~,S~Ul~, heart rate, urine analysis, blood
5 analysis, patient's weight, lung capacity, height and age may be monitored and,io~liate measures applied to indicate the overall well-being. F~i~tinp conditions
might also be included and might act as a criticality that requires a minimllm recall.
Similarly, family history may be included and weighted in an applvpliate manner.In the case of rehabilitation, the criteria might include the flexibility,
20 mobility, pain, range of movement, infl~mm~ti~n, medication and the time since the
occurrence of the injury which are combined with a~lopliate weighting to provide a
cumulative total upon which recall frequency can be ev~ tecl
~eferring to Figure 3, a general block diagram for implementing the
~L,p~ us for d~;t~....i..i..~ the recall frequency, as shown generally by numeral 440. The
2 5 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 colll~u~lions performed by the processor 444.
A data interf~r~e 454 connected with the processor 444 provides a data connection to an
e~t~rn~l program (not shown).
Figures 4, 5, 6 and 7 indicate flowcharts for performing a sequence of
steps for progr~mmin~ a general purpose COlnl~ULt;i shown in Figure 3. Referring, firstly
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to Figure 4, a series of criteria are input. These criteria may be cleterminec~ as described
earlier. For each of t_ese criteria a weightinf~ factor is ~leterrnined as also outlined earlier.
Generally speaking this weighting factor detl?rminf~s 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 weightin~ factor than the other
criteria.
Referring now to Figure 5, a patient is evaluated against each of the stored
criteria. In one instance for example a rating scale of 0 to l 00 may be chosen. An
a~plo~.iate rating is ~ign~l for a particular criterion. This rating may then be0 multiplied by the wei~hting 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 wçighting may be applied. In either
case, the weighted ratings are then ~cnm~ tec~ 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 cnm~ tive ratings. Referring to Figure 7, the
~ccnmlll~t~ rating is compared to each of the recall-frequency ranges to determine the
particular recall frequency for that patient. Now although an embodiment of the invention
has been described with reference to an implement~tion on a conl~uLei. The invention
may also be implementecl equally well lltili7ing other devices known to persons skilled in
the art.
