The British guidelines on the management of asthma first
appeared in 1990 in the BMJ.(1)(2) Two years
later revised guidelines, extended to cover asthma in childhood, were
distributed to all hospitals and general practitioners in
Britain.(3) They have come to be widely respected as a clear
and practical statement of best practice in the management of asthma.
This month sees the publication of a review and a position statement
commenting on the guidelines in the light of recent
evidence.(4)
The participants for the latest review were those from the 1993 paper,
if they wished to continue, or replacements as needed. Background
papers were produced and subsequently published.(5) The
summary statement was discussed and agreed in 1995, and it is
disappointing that publication has been delayed until 1997. The summary
statement should be read in conjunction with the 1993 guidelines.
Most of the 1993 advice remains valid, but there are important changes.
The new guidelines reiterate the importance of a correct diagnosis and
the dangers of escalation of treatment in other unresponsive
conditions. They emphasise the need to gain initial control of asthma.
This may mean starting with a higher dose of inhaled or oral
corticosteroids and then stepping down the treatment, rather than
gradually increasing the intensity of treatment until control is
achieved. The aims are to control symptoms rapidly and win patients'
confidence. Stepping down to avoid prolonged unnecessary treatment is
important, but the optimal timing of such reductions remains
uncertain.
The advice on long acting inhaled |gb agonists has also changed. The
1993 guidelines advocated these as an addition to high dose inhaled
corticosteroids or as an alternative in a few patients with particular
problems. In the latest guidelines the threshold for using long acting
|gb agonists is lower. When lower dose inhaled corticosteroids do not
give adequate control the alternatives of salmeterol and higher dose
inhaled corticosteroids are given equal weighting.
In the section on childhood asthma, children under 5 years old are
dealt with as a distinct group while older children and adults have
similar treatment programmes. For children under 5, sodium cromoglycate
and inhaled corticosteroids are now offered as alternatives for first
line regular inhaled prophylactic treatment, rather than recommending
sodium cromoglycate before inhaled corticosteroids.
The new guidelines contain useful practical information on inhaler
devices, with a recognition that the range of devices now
available may render nebulisers unnecessary in many clinical
situations. Advice is given on the forthcoming change to
non-chlorofluorocarbon propellants for metered dose inhalers, which
will feel and taste different but have been shown to be safe and
effective. As the range of inhaler devices increases, the information
on their lung deposition and delivery does not seem to expand in
parallel. Devices cannot be changed on the assumption that the same
dose will be delivered to the patient's airways, and prescribers must
be aware of the delivery characteristics of any device they prescribe.
The position on managing asthma in partnership with patients has
changed, with definite evidence of benefit from patient education and
the use of self management plans. Examples of a practical approach
might have been helpful here. In one recent survey of general
practitioners this was the commonest request for addition to the next
guidelines.(6)
Increasingly it is accepted that guidelines should have a clear
evidence base. The British guidelines represent an expert consensus
with no formal account of how the literature was searched and assessed.
Some statements in the guidelines suggest the existence of evidence
without citing the appropriate references; examples include the link
between passive smoking and childhood asthma and the use of once daily
inhaled budesonide. This contrasts with the well defined methodology of
the North of England group, which published its evidence based
guidelines for the primary care management of asthma in this journal in
1996.(7)(8)
In some areas there is a lack of reliable published evidence. The North
of England guidelines state that "as there is no good evidence of
clinically important differences between differing inhaled steroids,
patients should be treated with the cheapest inhaled steroid that they
can use and which controls their symptoms." It seems entirely
reasonable for guidelines to include considerations of cost.
Prescriptions for inhaled corticosteroids cost over £200m in England
alone in 1995 (Department of Health Statistics Division 1E, private
communication), and different preparations vary widely in price.
When there is a lack of evidence rather than evidence of lack of
benefit it can be helpful to have the opinion of experts, providing it
is made clear that this is opinion and not evidence. In places the
British guidelines do this clearly, as in their advice on doubling
inhaled corticosteroid dose if there is deterioration of control or
upper respiratory tract infection. The opinion and experience of
experts will remain important in the development of guidelines, but the
experts should take care to convince us that the evidence for their
opinions has been systematically appraised. This should be clearer in
the next full rewrite of the guidelines. The British asthma guidelines
have been widely disseminated, probably more so than any other
similar guidelines. They are highly regarded, and used
widely for clinical audit. This latest review will help to maintain
their important role in the promotion of better asthma care.
Duncan Keeley
General practitioner
The Health Centre,
East Street,
Thame,
Oxon OX9 3JZ
John Rees
Consultant physician and senior lecturer
UMDS,
Guy's Hospital,
London SE1 9RT
References
1 Statement by the British Thoracic
Society, Research Unit of the Royal College of Physicians of London,
King's Fund Centre, National Asthma Campaign. Guidelines for the
management of asthma in adults: I - chronic persistent asthma.
BMJ 1990;301:651-3.
2 Statement by the British Thoracic Society, Research Unit of
the Royal College of Physicians of London, King's Fund Centre,
National Asthma Campaign. Guidelines for the management of asthma in
adults: II - acute severe asthma. BMJ 1990;301:797-800.
3 British Thoracic Society, British Paediatric Association,
Royal College of Physicians, King's Fund Centre, National Asthma
Campaign, Royal College of General Practitioners, General Practitioners
in Asthma Group, British Association of Accident and Emergency
Medicine, British Paediatric Respiratory Group. Guidelines on the
management of asthma. Thorax 1993;48:S1-24.
4 British asthma guidelines coordinating committee.
British guidelines on asthma management: 1995 review and position
statment. Thorax 1997;52:S1-24.
5 Harrison B D W. Guidelines in asthma. Respir Med
1996;90:375-8.
6 McGovern V, Crockett A. 1993 BTS guidelines: impact and
shortfall. Asthma J 1996;1:30-1.
7 Eccles M, Clapp Z, Grimshaw J, Adams P, Higgins B, Purves I,
et al . North of England guidelines development project:
methods of guideline development. BMJ 1996;312:760-2.
8 North of England Guidelines Development Group. North of
England evidence based guidelines development project: summary version
of evidence based guidelines for the primary care management of asthma
in adults. BMJ 1996;312:762-6.
