Measuring clinical outcome in asthma
Duncan Keeley MA MRCP FRCGP, General Practitioner, Thame, Oxfordshire
J R Coll Physicians Lond 2000;34:9-11
‘”n the last week/month
- Have you had difficulty sleeping because of your asthma symptoms (including cough)?
- Have you had your usual symptoms during the day (cough, wheeze, chest tightness, or breathlessness?
- Has your asthma interfered with your usual activities (eg housework, work/school etc)?
Each of the above questions should be answerable by a simple yes/no, but there could also be supplementary quantitative grades for answers.”
This outwardly undramatic quotation forms the kernel of a recent College publication of potentially enormous importance1. Measuring clinical outcome in asthma: a patient-focused approach, prepared by the Clinical Effectiveness and Evaluation Unit, reports on a seminar held in May 1998. The seminar brought together 14 different groups doing research work on asthma outcomes, to seek consensus on a brief symptom based outcome measure for use in the consultation; and this is what they came up with. The aim is that the three questions above should be asked, and the answers recorded, at every asthma consultation both in primary and secondary care.
Effective medical care depends on a willingness and ability to measure changes in the condition of patients as we try to make them better. Clinicians develop their own more or less reliable ways of doing this in the course of routine practice. However, the development of outcome measures capable of aggregation to measure the effectiveness of care for groups of patients poses formidable problems. Keen to move the NHS on from audit of structure and process to a greater emphasis on outcomes, the Department of Health has invested heavily in seeking answers to these problems. In 1993 it set up the Clinical Health Outcomes Unit, now known as the National Centre for Health Outcomes Development (NCHOD), to identify outcome measures for ten clinical areas. Asthma was an obvious priority; a common chronic disease responsible for an enormous burden in terms of direct and indirect costs, with effective treatments and authoritative consensus on their best use2, and documented failure to achieve the full potential of these treatments for symptom control3,4. The NCHOD report on asthma published earlier this year5 detailed 17 possible indicators, from hospital admission rates to patient satisfaction measures, by which the effects of asthma care might be assessed. Of these possible indicators one in particular – Indicator 15A – was chosen for further investigation and development. Indicator 15A consisted of ‘consultation based patient assessed impact measures’, that is to say, systematically asking patients how they are and recording the answers.
Readers may at this point be thinking that this whole exercise represents the worst sort of oversimplified cookbook medicine, but wait …
First, it is important to realise that these questions do not replace the whole clinical assessment of patients and their situation, which remains a much more subtle art. They simply standardise a small but important part of that assessment – the burden of recent symptoms experienced – for comparison over time for the individual and between groups. They do not replace or obviate the need for appropriate physiological measurements of current, predicted and best lung function, neither do they preclude the use of more detailed standardised outcome measures by researchers or enthusiasts.
Second, it does not matter that answers to the questions will not be entirely ‘objective’ owing to variable recall and to differences of interpretation by health workers and patients as to the exact meaning of the words used. We are measuring ‘patient assessed impact’ and must accept some subjective variation as inevitable.
Third, widespread use of such a measure has the potential to improve the outcome of asthma care. The easily measurable ‘hard’ outcomes of asthma care, ie deaths and hospital admissions, are rare occurrences in the overall population of asthma sufferers, the majority of whose care takes place in general practice. The three questions in the measure check for the common troublesome symptoms of poorly controlled asthma, symptoms which can almost always be improved by good treatment; they precede and predict the more serious outcomes, and are often not mentioned by patients when asked in non-specific terms ‘how is your asthma?’. Patients for whom frequent night waking is normal may consider their asthma to be fine. They may prefer the quick issue of a repeat prescription for more blue inhalers to the clinic attendance, education and inhaled steroids that will be suggested if they reveal how much asthma is interfering with their life. The discovery of these symptoms is a necessary, though not sufficient, condition for appropriate therapeutic intervention. Repeated negative answers to these questions might indicate the possibility of stepping down regular treatment, or even taking a careful look at the validity of the original diagnosis of asthma. The strength of an outcome measure of this kind lies in its immediate value in prompting better care of each individual patient, regardless of whether the data collected are, or are capable of being, meaningfully analysed to compare the care of groups of patients. The mere fact of collecting the answers to these questions would be a far more valuable process measure to include in the data requirement for the asthma Chronic Disease Management payments to GPs than the current requirement to record a single peak flow reading.
Is widespread use of the outcome measure feasible?
Eminently so. An absolute requirement for the widespread adoption of any such measure is that it should be sufficiently quick and easy to obtain and record, and sufficiently useful in the care of the individual for its routine use to make sense for every busy doctor and nurse and patient. The proposed measure meets these requirements. The majority of GPs, and a gradually increasing number of hospital doctors, work with computers on their desks. The questions could be incorporated in standard format for easy recording at the beginning of the computer asthma follow-up protocols used by doctors and nurses, which can then be made as simple or as ornate as one likes. For those who still enjoy the many advantages of paper records, a simple standard abbreviated format for recording the answers on paper needs to be agreed. It could be as simple as S0 D0 A0 (no sleep disturbance, no daytime symptoms, no activity interference). These doctors will enter their data slightly quicker than their computerised colleagues, but will have a harder job if they wish to analyse the data for groups.
Can the outcome measure be used to assess the quality of asthma care for groups?
The answer to this question is much less straightforward. The interpretation of aggregated results for groups of patients requires great care. Any crass or punitive use of the data collected is likely to result in massage of data at entry which would, in turn, invalidate the entire exercise. Distinction needs to be made between data collected at visits for exacerbations and for routine follow-up, allowing for the fact that it is difficult to give a tight definition of an ‘exacerbation’. Allowance will have to be attempted for case mix, and for social class, ethnic origin and smoking status of practice populations. Care has to be taken over the fact that the population of asthmatics in different practices will vary greatly, given the variable diagnostic labelling that goes on at the overlap between asthma and chronic obstructive pulmonary disease (COPD) (in adults), and recurrent viral associated wheezing (in children, vide infra). These considerations will make comparison between different units difficult. Perhaps, as with school league tables, a better approach would be to look at value added over time within groups, but the overall level of symptomaticity of the asthmatic patients attending a practice or hospital unit must be one factor worthy of study as we try to improve the care we provide.
Where do we go from here?
The College report represents a major step forward in the move towards routine meaningful outcome assessment in asthma care. What more is needed to make it happen?
First, agreement is needed on two unresolved issues: the time period used in the questions, and the quantification or otherwise of the answers. As for the time period, there can be no perfect answer. The shorter period of a week makes accurate recall more likely but is less likely to incorporate disturbance by intermittent symptoms. As for quantification, simple yes/no answers are easier to record but much less sensitive to change than quantified answers. The methods of quantification usually proposed involve mapping the answers to some sort of 3 or 5 point scoring system. The problem is that such methods are not immediately intuitive and therefore less likely to be used properly, or at all, by the majority of doctors and nurses. In the opinion of this writer, the answer to these two unresolved issues should be to base the questions on the last week and quantify the answers 0-7, but definitive answers are needed before any widespread implementation can take place. A swift, efficient and entirely appropriate method to decide what should be done would be to convene a one day meeting. The meeting should consist of one representative for each of the Royal Colleges of Physicians and General Practitioners, the British Thoracic Society, the GPs in Asthma Group, the National Asthma and Respiratory Training Centre, the National Asthma Campaign (as the representative of patients), and the Department of Health. A wider and longer consultation, which is what will probably happen, will take a great deal longer and almost certainly come up with a virtually identical result.
Second, the conventions need to be agreed for recording the data both on computers and on paper. Computer Read Codes already exist for ‘asthma disturbing sleep’ (663N. 00), ‘asthma not disturbing sleep’ (663O. 00), ‘asthma limiting activities’ (663P. 00) and ‘asthma not limiting activities’ (663Q. 00). The exact text of these codes might want changing, or new codes assigned to the exact questions in the outcome measure. A code for ‘daytime asthma symptoms’ needs to be created, and all three will need to be in a format and Read code chapter that allows for numeric answers if the decision went in favour of quantification. For paper recording, an agreed sequence and format for recording the answers is needed and should then be widely disseminated. Forms allowing for the answers to the three questions to be recorded could be included in inhaler package inserts and printed on prescription side slips.
Third, collection of the three question outcome measure – initially as a simple process measure – should be added to, or preferably substituted for, one or more of the existing data requirements for the asthma Chronic Disease Management payments to GPs, or to whatever may replace this small financial incentive to organised asthma care. This would encourage GP software suppliers to incorporate the questions into their default asthma management protocols in a user-friendly manner.
Fourth, the necessary research and consultation should be initiated to extend the use of the outcome measure to children. Most of the work on which the College report is based was done on adults, and paediatricians were, unfortunately, not involved in the seminar. The Report makes clear that its conclusions are intended to apply to patients over the age of 16 years. But many of a GP’s asthmatic patients are children, and matters are much simplified if a common outcome measure is used. Sleep disturbance by asthma symptoms, daytime asthma symptoms, and interference with normal activities are concepts easily applicable to persons of any age, while the diagnostic difficulties of what is and is not asthma in young children will always be with us and will certainly not be resolved by subtlety in the choice of outcome measures.
Does all this matter?
The nationwide collection of simple standardised outcome data for management of a common chronic disease would be a world first for the British NHS. It has the potential to yield real and measurable improvements in the health of patients with asthma, and to demonstrate to understandably sceptical health workers that medical audit really can be a force for getting patients better. Nothing could be a better reward for the excellent work done by the researchers in this field and by the Clinical Effectiveness and Evaluation Unit of the College in taking this initiative forward. If this model for quick, feasible, patient-centred outcome measurement were successful, for patients and health workers, not just for purchasers and auditors, it would pave the way for similar approaches to improving the care of other patient groups. Let’s go for it.
- Clinical Effectiveness and Evaluation Unit, Pearson M, Bucknall C (eds). Measuring clinical outcome in asthma: a patient focused approach. London: Royal College of Physicians, July 1999.
- British Thoracic Society, et al. Guidelines on the management of asthma. Thorax 1993;48:S1-24.
- Jones KP, Bain DJG, Middleton M, Mullee MA. Correlates of asthma morbidity in primary care. Br Med J 1992;304:361-4.
- Blackburn LA, Denn DJ, Oliver HF, Vieckery PJM, Waldron J. One year’s asthma admissions in Cornwall: still deficiencies in basic care. Thorax 1996;51:A62.
- National Centre for Health Outcomes Development. Asthma. Report of a working group to the Department of Health. London: NCHOD, 1999.
Measuring clinical outcome in asthma: a patient-focused approach
Copies of the full report can be obtained by sending a cheque for £15.00 (overseas price £17.00) to: The Publications Department, Royal College of Physicians, 11 St Andrews Place, London NW1 4LE.