Award winning coronary prevention scheme.
Takeheart Health Check
The John Perry Prize
Proceedings of the Annual Conference of the Primary Health Care Specialist Group of the British Computer Society 1990 p13-21.
The John Perry Prize
TAKEHEART- Screening for coronary heart disease risk factors.
G.M.Clayton MB.BS.BSc.FRCGP.MBCS General Practitioner, Norwich, England.
That Britain is in the first division so far as coronary heart disease is concerned is undeniable.(29) That we as a nation should be doing something about it is self evident.(35)
The British Hyperlipidaemia Society advised in 1985 that we should adopt the approaches reported by the Committee on Medical Aspects of Food Policy and by the National Advisory Committee on Nutrition Education. They also outlined a strategy for individual subjects:-
- Everyone should have their blood lipids measured at least once before the age of thirty.
- Those with levels between 5.2 mmols/l and 6.5 mmols/l should be given dietary counselling and advice on the other risk factors.
- Those with levels above this figure should enter clinical care.(43)
The Coronary Prevention Group advised in 1987 that:-
- Appropriate risk assessment should be carried out at GP and hospital level by obtaining family histories of coronary heart disease and related disorders and assessment of smoking habits. The blood pressure of all adults should be tested at least every five years.
- A serious national discussion is urgently needed about assessment of risk factors in children and young people in the UK.
- Priority should be given to making blood cholesterol measurements available to those at particularly high risk of coronary heart disease.
- The Coronary Prevention Group recognises that there will be increasing demand for serum cholesterol testing. Such testing should be available on request. A person's desire to know his own blood cholesterol concentration may help him to modify his future risk.
- All forms of assessment, including serum cholesterol measurement should be accompanied by facilities for appropriate advice on diet, smoking habits, exercise etc.(79, 491)
Wilson listed a number of criteria to be applied by those contemplating a screening programme.(74,76) These can be applied to screening for a high risk for coronary artery disease.
- The condition should be important.
It should be remembered that the screening procedure contemplated is to locate people with a high risk factor for coronary heart disease, which is not the same as coronary heart disease itself.
The condition of having a high risk factor is important. It is arguably more important than the subsequent heart attack as there is still an opportunity to change the course of events.
- An acceptable treatment must be available for the condition.
There has been controversy about whether it is possible to lower morbidity and mortality in those at high risk.(17, 68, 72) The chief strategy has been an attempt to modify the national life style.(23) Secondary strategies include hypertension and hypercholesterolaemia control.(25)
Evidence is emerging that life style intervention (by which is meant effective advice about diet, smoking and exercise) does have an effect on mortality in middle aged men when observed over about a ten year period.(66, 90)
There is therefore an acceptable treatment for those at high risk.
- The facilities for diagnosis and treatment must be available.
There are facilities within the National Health Service for the diagnosis and treatment of those shown by a screening process as being at high risk. Whether these are adequate is a different matter. In particular it is difficult to provide advice about diet, this being a field where general practitioners do not feel at home and there are not enough dietitians working in primary care.
- A latent or early symptomatic stage must exist.
Being at high risk is a latent stage of coronary heart disease. A rising risk can be looked upon as a latent stage of a high risk.
- A sensitive and specific screening test must be available.
There is no such thing as a single test for high risk of coronary heart disease. It must be multiphasic.(55) There is controversy about which tests should make up a multiphasic test
and indeed how to interpret the results.
Professor Shaper has devised a multiphasic test which gives a score for risk such that a score of a thousand or over can be considered a high risk.(6,7) He has validated his scoring system on seven thousand men in the age group 40-59 yrs. Even so the interpretation of the tests and the score is by no means straightforward. If applied correctly his system can arrive at a figure for the probability of suffering a heart attack in the next five years. There is controversy over the accuracy of near patient testing of cholesterol.(52) It would appear that there is little to fear if care is taken over technique and if proper safety and quality control procedures are followed.(38,50,82)
- The test must be acceptable to the population.
- Free or inexpensive.
- No unpleasantness.
- No second trip.
- No unnecessary referral.
- Proper referral when clinical care is indicated.
- Sufficient explanation and information.
- There has been some anxiety expressed lest screening should be harmful.(21,24,65,71,81)
- The natural history of the condition must be properly understood.
It is a moot point as to whether the natural history of high risk or indeed of coronary heart disease itself is properly understood. Enough is known about it to make it worth detecting - it is certainly too late to wait for the development of frank disease.(43,25,34)
- An agreed treatment policy must exist.
The Hyperlipidaemia Society has put forward just such a policy.(43)
- The cost must be acceptable.
It is impossible to put a precise monetary value on detecting those at high risk. It is possible to locate areas of potential high cost and devise methods to keep these down. The equipment needed for multiphasic screening is not prohibitively expensive.
Oportunistically putting people through a multiphasic screen is not expensive.(17)
Population screening is expensive in terms of clerical work in organising a clinic and keeping records, operator time in running a clinic and doctor time in counselling. An overlooked area of cost is in the patient's time in terms of attending the clinic and possible subsequent trips for counselling, to say nothing of anxieties provoked by inadequate explanation.
The cost of coping with those found to be at high risk is considerable, but this is not a cost that falls upon the screening process.
- Case finding must be on a continuing basis.
The basic tool for case finding is the record of each person kept by the general practitioner. A computer is helpful to keep track of all these, to know where each patient stands in the coronary risk factor table and to follow those with unacceptable scores.
TAKEHEART is a method of screening for high risk for coronary heart disease. It takes account of the points raised above. It is inexpensive. It is repeatable. It assesses the risk. It provides written information to the patient. It undertakes the counselling. It keeps records. It provides means for follow up and research.
TAKEHEART consists of three main parts. It is designed to function on a sessional basis. The first part is concerned with setting up the session, next comes the data acquisition and reporting loop and finally close down. Several miscellaneous activities are available by menu.
Setting up the session concerns itself with identifying the operators by means of passwords, recording the session address and the identity of the local organiser, quality control protocols for the cholesterol analyser and the setting of a number of constants. These constants are matters such as the date/time, the type of analyser, avoir du pois/metric, mmols/l or mgs/dl, usable lines, language to be used, units of money and user controlled messages for the report. An audit trail is set up so that each record bears the signature of the operator whose identity is recorded in the operator file.
Stress is laid upon the question of quality control. There are protocols for checking both the physics and the chemistry of the Reflotron. These are incorporated in the setting up routine and the results retained on file so that the quality assurance history of the machine can be referred to at any time. Only operators who can satisfy the system operator in matters of training and competence can find their way into the operator file. Membership of an external laboratory quality assurance scheme is insisted upon.
Close down has two functions. Firstly the production of a session summary report. This identifies the operators and the session, reports on numbers and money, and counts the numbers of the various health education packages used. This latter is useful in providing a non-attributable summary of health to the management of a factory or office as well as an indication as to which need replacing. The close down report should be signed by the operator. Finally there is a reminder of the maintenance routine for the Reflotron - the results being filed.
At the core of TAKEHEART lies the patient data acquisition loop. This is where data from the patient is entered into the system. The user is taken through a series of screens asking for data concerning the identification of the patient and that from the Shaper tests. These Shaper tests are age, smoking history, personal and family history, blood pressure and cholesterol. Weight and height are also measured. In addition there is a measure of the peak flow rate and of the alveolar carbon monoxide, these form the springboard for life style intervention for smokers, smoking being the single most important controllable risk factor. Recently gamma-glutamyl-transpeptidase estimation has been added, alcohol being another important risk factor. Also the Goldberg anxiety/depression scores are determined in order to get a line on stress. There is ample on line help.
The results are analysed and a report printed for the patient to take away. The results are kept on file (registration under the Data Protection Act is necessary). The report records each test separately, explains, comments on normality and offers advice. The coronary risk factor score and a figure for the probability of a heart attack in the next five years is calculated and recorded according to the method described by Shaper. Advice is offered and a summary and a recommended reading list is provided. At the end of the report there is an opportunity to insert one of a number of pre-recorded user controlled messages. Finally a package of health education literature is supplied. This package contains material relevant to the situation in hand, being selected by the software from one of 32 prepacked folders. Typically the report is four to five A4 pages long.
The opportunity is taken to insert into the folders advice specific to the situation in hand, more general advice about heart disease, advice about exercise, stress and alcohol and that on some other general health problems.
Housekeeping procedures are available by menu. These include back up, passwords, setting up constants, introducing operators and file editing. File editing is limited. Data files can be viewed but no field may be altered and no record erased. There are two exceptions to this. There is a six haracter flagging field on the patient file that is accessible. Records that begin with "ZZ" in a key field are allowed to be deleted in order to accommodate trial runs and demonstrations.
A report generator is supplied and can be used to provide a number of useful and interesting reports. Data can be written to DIF, SILK or SDF files. Parameters can be filed and used when required, such as follow up listings or tables of risk factors.
There is a catalogue of useful leaflets for incorporation into the health education folders.
Professor Shaper and his coworkers have evaluated their method for coronary risk factor scoring and for calculating the probability of a heart attack in the next five years.(6,7) In essence what they did was to recruit 7000 middle aged men from all over the Kingdom. Measurements were made and recorded.
Five years later it was possible to learn what had happened to these men and come to some conclusion about the discriminatory power of each test. From these results it was also possible to construct a scoring method such that the probability of a heart attack could be calculated. It seems reasonable to extrapolate these findings by analogy to younger men and to women - bearing in mind that these groups have not been validated experimentally.
The software has been tested in the usual way. Each segment is tested before being established in the whole, the whole is then tested using invented data and finally trials are held with real people - friends and colleagues are often the severest critics. Testing is a time consuming business, every eventuality has to be considered and tried out.
The capital costs are significant. TAKEHEART was designed using an Amstrad P.C. 1640 with a hard disc. It has been successfully installed on a Hewlett Packard Vectra and a Toshiba laptop. There is no reason to believe that it cannot be installed on any similar machine. The most expensive item is the chemical analyser but also required are a carbon monoxide monitor, sphygmomanometer, peak flow meter, scales, height gauge. Altogether these costs come to about £7,000. (The major part of this sum is attributable to the Reflotron).
There has been considerable intellectual investment which must be considered under the heading of capital costs although this is notoriously difficult to estimate. Much of this is library time, plenty of sitting in the bath time, much paper and pencil work and lastly putting ideas into practice at the keyboard. There is a policy of continuous development.
Running costs need to take account of the following:-
Operationally TAKEHEART conforms to the Wilson criteria. There is no doubt from personal experience that the TAKEHEART approach is appreciated by the clients/patients. As the data grows and recalls begin to appear it will be possible to form some view about the effect of a TAKEHEART experience on life style. To demonstrate an effect on mortality would take a Multiple Risk Factor Intervention Trial scale operation and at least ten years.
- Chemical reagents - about £10 for each test.
- Cardboard tubes for carbon monoxide and peak flow rate.
- Blood sampling - pipettes, wipes, cotton wool, gloves, lancets.
- Sharps and contaminated disposal.
- Computer paper and ribbons.
- Stationary, postage and telephone.
- Leaflets and folders
- Operators time. It takes about 20 mins per client, but there is also considerable behind the scenes effort needed to organise clinics.
- Accountants and lawyers.
- Data Protection Act registration.
WWhat of the future? Plans are afoot to write the reports in a language of choice. This is only limited by the need to make a translation and to use a printer and control characters suitable for another alphabet. It may be possible to include a "What If?" section in the report. Thought is being given to develop the idea to detect two other cryptic and important conditions in the context of general practice or occupational practice. Depression/anxiety and alcohol.
In the mean time it is suggested that TAKEHEART will:-
- Satisfy the healthy curiosity of patients about the risk.
- Provoke a greater interest in the issues than the more usual verbal harangue by providing a detailed, personalised written report to take away.
- Start the life style intervention process before the risk factors really get a hold.
- Detect and direct those who need clinical care.
- Assist in the selection of patients for life style intervention clinics.
- Provide a standard and repeatable format to monitor progress.
© G.M.Clayton 1997
GMC Register Number 0147091