Issue 7.
Why treatments fail
In March this year, Drug and Therapeutics Bulletin held a symposium on
‘Why Treatments Fail’. The symposium explored failure of medicines at
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molecular level
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failure of prescribers to put knowledge into practice
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failure of prescribers to cope with changes in diagnostic criteria
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problems around doctors’ and patients’ failure to communicate with each other
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failures of the NHS to meet patients’ expectations
A drug with a relevant pharmacological effect, may still offer little
or no clinical benefit. This problem is well illustrated by medicines used to treat common
cancers. For many tumours in adults, the cells are either resistant to chemotherapy from
the outset or soon become so. Resistance to therapy may also result from changes in DNA
induced by the treatment itself. Some tumour cells can, for example, develop enhanced
activity of a cell surface glycoprotein which extrudes drugs from the cells. Resistance at
a molecular level is not unique to cancer; the failure of antibiotics, for example, offers
an obvious parallel.
Sound evidence on which to base treatment can be obtained relatively
easily. A greater challenge is to change behaviour in order to put that knowledge into
practice. It helps if the new approach:
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is seen to have clear advantages
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is easy to implement
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has the support of all staff in the health team
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the doctors themselves have been involved in drawing up guidelines.
The traditional model of the partnership between doctor and patient
assumes ‘doctors know best’ and that the patient will ‘follow doctors’
orders’. Such a model can lead to conflict and the patient failing to tell the truth
or to comply with advice. Often, patients will say that ideally they would like to be
treated as individuals but then say that in reality a doctor cannot be expected to do
this. Most evidence suggests that expectations vary mainly according to a patient’s
prior experience. In studies in primary care, what matters most is the doctor-patient
relationship, rather than the practice organisation.
Improvements in understanding can be achieved through well-constructed
leaflets, by using clear language, by repeating important points, and by carefully
selecting what needs to be said. Audio-taping explanations seems to help further and
allows patients to hear the advice at home either by themselves or with family or friends.
The problem can be addressed by introducing evidence-based consultations, in which
patients are presented with graphic displays of up-to-date data using a computer programme
that quantifies and summarises the benefits of modifying risk factors.
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Do clinical guidelines improve practice?
Although interest in clinical guidelines has never been greater,
uncertainty persists about whether they are effective. Fifty nine published evaluations of
clinical guidelines that met defined criteria for scientific rigour were studied; 24
investigated guidelines for specific clinical conditions, 27 studied preventive care, and
8 looked at guidelines for prescribing or for support services. All but 4 of these studies
detected significant improvements in the process of care after the introduction of
guidelines and all but 2 of the 11 studies that assessed the outcome of care reported
significant improvements.
The authors conclude that explicit guidelines do improve clinical
practice, when introduced in the context of rigorous evaluations. However, the size of the
improvements in performance varied considerably.
Details can be obtained from Effective
Health Care Bulletin 1994; Vol. 1, No 8. Implementing clinical practice guidelines.
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Sore throats - the number needed not to treat (NNNT)
Throat infection is a common reason for a GP consultation. There is not
much support for using antibiotics. The Cochrane Collaboration has confirmed the extremely
modest effects of antibiotics in reducing the duration of throat infection. Because simple
analgesics are all that is needed, dealing with it can also be a frustrating exercise. Yet
patients still consult. Could GPs have an influence on this pattern of behaviour?
A recent randomised controlled trial explored this question in a novel
way. Patients were randomly allocated to immediate antibiotics, an offer of delayed
antibiotics (three days later, if symptoms persisted) and no antibiotics. The clinical
outcomes and patient satisfaction were the same for each. However, issuing an immediate
prescription tended to persuade patients that they were effective. It also affected their
intention to consult in the future.
From this we can work out a NNNT. For every 3 patients we "not
treat" (avoid or delay prescribing antibiotics) we persuade an additional one that
they are not effective. Similarly for every 4 patients whom we "not treat" we
persuade one that they need not consult with the problem in the future.
We can sum this up by illustrating what would happen if a GP prescribed
antibiotics to 100 fewer patients with throat infection in a year. Thirty-three fewer
would believe antibiotics were effective, 25 fewer would intend to consult with the
problem in the future and 10 fewer would come back within the next year. Game, set and
match to masterly inactivity.
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Prostatectomy in the UK
There was a recent survey of deaths and complications following
prostatectomy in 1400 men in the UK. This study looked at 12 hospitals, which undertook
prostatectomy for an eight month period in 1991.
The early mean death rate was 0.9%. There was a wide inter-site
variation, from 0 to 3.8%. There was a small bias in favour of hospitals performing over
100 operations (0.5%) compared with those performing fewer than 100 operations (1.7%).
Early mortality was lower in elective admissions (0.5%) than in emergency admissions
(2.4%).
The authors conclude with a simple take-home message. Variation exists,
there are reasons for it, audit demonstrates it, action changes it, and purchasers and
providers should be aware of it.
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