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Stephen Shrewsbury a GlaxoWellcome UK, Stockley Park West, Uxbridge,
Middlesex UB11 1BT, b St Peter's Hospital, Chertsey, Surrey
KT16 0PZ
Correspondence to: S Shrewsbury
sbs40926{at}glaxowellcome.com
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Abstract |
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Objective:
To examine the benefits of adding
salmeterol compared with increasing dose of inhaled corticosteroids.
The 1997 British Guidelines on Asthma Management1
acknowledged the landmark study of Greening et al2 and
recommended salmeterol as an alternative to increasing the dose of
inhaled corticosteroids in symptomatic patients on beclometasone
dipropionate (or budesonide) 100-400 µg (or fluticasone 50-200 µg)
twice daily. Little guidance was given as to which choice would benefit
patients most because of a lack of published data on respective
outcomes. The dilemma remains today. Usually studies have measured
improvement in lung function (peak expiratory flow (PEF) or forced
expiratory volume in one second (FEV1)) as the primary
variable, but a recent study looked at exacerbation rates as the
primary outcome measure.3 Exacerbation data had been
collected in studies that looked at the addition of salmeterol but not
formally reported. We reviewed studies that compared the addition of
salmeterol with an increased (at least double) dose of inhaled steroid
(in patients who had symptoms on low to moderate doses of inhaled
steroids) to see how rates of exacerbation were affected by the
addition of salmeterol.
Searches
Selection
Quality assessment
Data abstraction
Quantitative data synthesis
Trial flow
Table 1.
Design:
Systematic review of randomised, double blind clinical trials. Independent data extraction and validation with summary data from study reports and manuscripts. Fixed and random effects analyses.
Setting:
EMBASE, Medline, and GlaxoWellcome internal clinical study registers.
Main outcome measures:
Efficacy and exacerbations.
Results:
Among 2055 trials of treatment with
salmeterol, there were nine parallel group trials of
12 weeks with
3685 symptomatic patients aged
12 years taking inhaled steroid in
primary or secondary care. Compared with response to increased
steroids, in patients receiving salmeterol morning peak expiratory flow
was greater at three months (difference 22.4 (95% confidence interval
15.0 to 30.0) litre/min, P<0.001) and six months (27.7 (19.0 to 36.4) litre/min, P<0.001). Forced expiratory volume in one second
(FEV1) was also increased at three months (0.10 (0.04 to 0.16) litres, P<0.001) and six months (0.08 (0.02 to 0.14)
litres, P<0.01), as were mean percentage of days and nights without
symptoms (three months: days
12% (9% to 15%), nights
5% (3% to
7%); six months: days
15% (12% to 18%), nights
5% (3% to 7%);
all P<0.001) and mean percentage of days and nights without need for
rescue treatment (three months: days
17% (14% to 20%), nights
9%
(7% to 11%); six months: days
20% (17 to 23%), nights
8% (6% to
11%); all P<0.001). Fewer patients experienced any exacerbation with
salmeterol (difference 2.73% (0.43% to 5.04%), P=0.02), and the
proportion of patients with moderate or severe exacerbations was also
lower (2.42% (0.24% to 4.60%), P=0.03).
Conclusions:
Addition of salmeterol in symptomatic
patients aged 12 and over on low to moderate doses of inhaled steroid
gives improved lung function and increased number of days and nights without symptoms or need for rescue treatment with no increase in
exacerbations of any severity.
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Introduction
Top
Abstract
Introduction
Methods
Results
Discussion
References
![]()
Methods
Top
Abstract
Introduction
Methods
Results
Discussion
References
We searched EMBASE, Medline, and GlaxoWellcome databases before
the analysis started in January 1998. All publications and abstracts
from 1985 onwards in all languages were considered. In a further search
in September 1999 we identified no additional studies that fulfilled
the search criteria. Study search and selection was conducted by SS.
Criteria for selection of studies for inclusion in the review were
randomised controlled trial; direct comparison between addition of
salmeterol to current dose of inhaled steroid and increased (at least
doubling) dose of current inhaled steroid for a minimum of 12 weeks;
and adults or adolescents (age 12 years or over) with symptomatic
asthma on current dose of inhaled steroids.
All included studies were sponsored by GlaxoWellcome and all met
company-wide minimum quality thresholds. All were randomised by using
PACT (patient allocation for clinical trials), an in-house, computer
based randomisation package validated by the Food and Drug
Administration. In all studies, maintenance of the treatment blind was
carefully managed with adherence to in-house standard operating
procedures. In all studies, treatment packs were supplied numbered in
non-identifiable packaging and were dispensed by investigators to the
next sequential patient to be randomised in the trial. All studies were
conducted according to good clinical practice, and all had received
ethical approval. In all studies, appropriate statistical methods were
used for summarising and comparing treatments, and methods for handling missing data were preplanned.
Data abstraction was based on reported summary statistics (means,
SD and SE, proportions) for the intention to treat population. Two
independent coworkers extracted data from study reports and
manuscripts, and their results were compared. Discrepancies were
resolved by consensus. Severity of exacerbation was not reported in all
studies, and so individual patient datasets were sought and obtained in
all but two studies. Severity of exacerbation was assessed
independently by two coworkers, without knowledge of treatment
allocation or results, who applied the following criteria:
severe
requiring oral steroids or admission to hospital; moderate
requiring an increase in inhaled steroid medication; mild
requiring an increase in use of rescue medication.
For all measures, treatments were compared each month and for
months one to six (when available), with primary interest in the
comparisons at three and six months. For peak expiratory flow (recorded
by patients twice daily, morning and evening, on diary cards) and
forced expiratory volume in one second (FEV1) (recorded at
clinic visits) the measure of effect was the difference in means.
Previous experience with these measures provided assurance that they
have approximately normal distributions. We used reported treatment
means or medians for the week or month (as reported) immediately before
the next assessment, with previous experience again suggesting
approximate normality. For symptoms and use of rescue medication
(recorded by the patients on their diary cards) the measure was the
difference in the mean percentage of days and nights without symptoms
or use of rescue medication. For these measures treatment means were
obtained as the mean of the patient means (or medians, as reported),
which were calculated over the interval of interest. For exacerbations
(recorded in case record forms) the measure was the difference in the
percentage of participants with one or more exacerbations.
![]()
Results
Top
Abstract
Introduction
Methods
Results
Discussion
References
The results of the searches are presented in figure 1. The
presentation follows the suggested format provided in the QUOROM
statement.6 Among the nine included studies, seven have,
to date, been fully published. We did not exclude any study that
compared the addition of salmeterol to an increase in the dose of
inhaled steroid in the management of asthma in adults.

View larger version (34K):
[in a new window]
Fig 1.
Results of search of EMBASE,
Medline, and GlaxoWellcome clinical studies databases for work on
salmeterol/Serevent
Study characteristics
The inclusion criteria and designs (all were parallel group) for
the individual studies are given in tables 1 and 2. Treatment duration
was 12 weeks in two studies and six months (24-26 weeks) in the others.
To be randomised patients had to have symptoms on their current dose of
inhaled steroids, defined as having symptoms (yes or no) or a minimum
total (day plus night) symptom score of at least 2 on at least four of
the last seven days of the run in period (symptom scale: 0 (none) to 4 (causing severe discomfort and preventing normal daily
activity3). When rescue medication was required, patients
must have needed to take rescue treatment four times or more within 24 hours on four of the last seven days of the run in
period.
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Quantitative data synthesis
Mean morning PEF and FEV1 were greater
in those who received added salmeterol compared with those treated with
an increased dose of inhaled steroids (table 3). At three months,
morning PEF was 22.4 litre/min higher with the addition of salmeterol
than with increased inhaled steroid (P<0.001), and at six months (data
from only the seven studies in which treatment duration was six months)
the difference was 27.7 litre/min in favour of salmeterol (P<0.001).
The results for FEV1 were also in favour of
salmeterol by 0.10 litre (P<0.001) and 0.08 litre (P<0.01) at three
and six months respectively. There was no evidence of heterogeneity
between studies for either morning PEF or FEV1.
0.002 in all cases,
confirming the interpretation of the fixed effects model.
Results for exacerbations are shown in table 5. Total exacerbations
(any severity) were reduced significantly (P=0.020) with added
salmeterol (by 2.73%; number needed to treat=37) compared with
increased dose of inhaled steroids (figs 2 and 3). Similar results were
obtained for moderate or severe exacerbations only (reduced by 2.42%,
P=0.029; number need to treat=41). There was no evidence of
heterogeneity between studies for these
measures.
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Discussion |
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Asthma is now defined as a chronic inflammatory disease of the airways, and anti-inflammatory therapy is regarded as the cornerstone of treatment.1 Despite the use of inhaled corticosteroids to treat the inflammation, however, many patients continue to suffer from symptoms. Though the addition of salmeterol to inhaled steroids improves lung function and suppresses symptoms, previous work has not reported the effect on exacerbations, which may be regarded as a marker of underlying airway inflammation.
In this review we have shown that, compared with increased doses of steroids, additional treatment with salmeterol for symptomatic asthmatic patients on low to moderate doses of inhaled steroids leads to greater improvements in lung function and symptoms and to reduced need for rescue treatments. Moreover, we found no evidence of any increase in exacerbations, suggesting that control of airway inflammation is not compromised by this choice. For all or moderate or severe exacerbations the number needed to treat was about 40, suggesting that, compared with increasing the dose of inhaled steroid, the addition of salmeterol to the treatment of 40 patients with symptoms would prevent exacerbations in one additional patient. This updates work presented in abstract by Jenkins et al,16 who showed that in six of the studies included in this analysis in which the baseline dose of beclometasone was 400 µg/day, 2 10-15 the exacerbation rates at 24 weeks were reduced more by the addition of salmeterol than by increasing the steroid dose.
The application of these results to general practice, however, reveals
a potential weakness in the analysis because of the method used to
select patients for the individual studies. In six of the nine included
studies, a requirement for entry was a demonstrable, clinically
relevant, response to
agonist (among other requirements, see table
1). In the three other studies absolute lung function measurements and
the presence of symptoms were required but airway lability was not a
prerequisite. This meta-analysis therefore represents a comparison
among a defined population of adult or adolescent patients with asthma
who were mainly responsive to
agonist and who had symptoms on their
current dose of inhaled steroid. In this population those receiving an increase in inhaled steroid responded less well to this change in
treatment than did those receiving the addition of the long acting
bronchodilator. It might be argued, though, that this is not a
surprising finding.
The individual study entry criteria, however, were chosen to reflect the evolving guidelines for the management of asthma that currently highlight the dilemma of what option to follow for stable patients who, nevertheless, still have symptoms on low to moderate doses of inhaled steroids. The analysis presented therefore examines the common decision facing physicians in daily practice as they manage patients according to the current guidelines. Patients who fail to improve with bronchodilator are commonly classified as having chronic obstructive pulmonary disease and are treated according to a different set of agreed guidelines.
The results of this meta-analysis are consistent with those obtained in the large FACET study.3 This study examined the effect of adding eformoterol (12 µg twice daily) to either low dose (200 µg/day) or high dose (800 µg/day) budesonide in the treatment of patients who were previously symptomatic but had been stabilised over four weeks on budesonide 1600 µg per day. This trial did not meet our inclusion criteria in several respects and so was not included in this meta-analysis. The similarity in findings, however, seems to suggest that the observed treatment benefits might represent a class effect rather than being specific to the drugs used in the studies included in this meta-analysis.
In conclusion, giving salmeterol to patients who have symptoms on at least 400 µg beclomethasone per day will result in better lung function, better control of symptoms, less need for rescue medication, and fewer exacerbations than increased doses of inhaled steroid. Healthcare professionals faced with the dilemma of deciding which option to follow (in the British Guidelines on Asthma Management1 at step 3) may find this review helpful when deciding on the appropriate treatment choice.
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What is already known on this topic
Salmeterol improves lung function, alleviates symptoms, and reduces the use of rescue treatment when it is added to inhaled steroids in the treatment of mild to moderate asthma Exacerbations are regarded as a marker for underlying control of the inflammation that is a key feature of asthma What this paper addsThis meta-analysis shows that rates of exacerbation are no greater with the addition of salmeterol to moderate doses of inhaled steroids than with at least doubling the dose of steroids This should reassure prescribers still undecided about which option to pursue at step 3 of the British Guidelines on Asthma Management |
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Acknowledgments |
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Contributors: SS set up the project, organised searches and liaised with overseas operating companies, sourced study reports and datasets, arranged statistical input and helped to devise protocol, collaborated in analyses, and wrote the paper. SP designed the protocol, supervised data extraction and validation from study reports and raw data, supervised cross checking and validation work, was primarily responsible for the analyses, and provided substantial input to preparation of abstracts and publication. MB was involved in the original concept, discussed analysis and subsequent results, and contributed to preparation of abstracts and results. SS is guarantor.
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Footnotes |
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Funding: None.
Competing interests: SS has been employed full time by GlaxoWellcome as associated medical director (respiratory) for the past four years. SP is a full time employee of GlaxoWellcome and is head of statistics. MB has been taken to international conferences, received fees for speaking, received funding for research and a respiratory nurse, and has shares in GlaxoWellcome. GlaxoWellcome manufactures Serevent (salmeterol xinafoate).
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References |
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Thorax
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| 2. | Greening AP, Ind PW, Northfield M, Shaw G. Added salmeterol versus higher-dose corticosteroids in asthma patients. Lancet 1994; 344: 523-529. |
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Pauwels RA, Lofdahl C-G, Postma DS, Tattersfield AE, O'Byrne P, Barnes PJ, et al.
Effect of inhaled formoterol and budesonide on exacerbations of asthma.
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| 7. | Ind PW, Dal Negro R, Colman N, Fletcher CP, Browning DC, James MH. Inhaled fluticasone propionate and salmeterol in moderate adult asthma. I. Lung function and symptoms. Am J Resp Crit Care Med 1998; 157: A416. |
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| 11. | Murray JJ, Church NL, Anderson WH, Bernstein DI, Wenzel SE, Emmett A, et al. Concurrent use of salmeterol with inhaled corticosteroids is more effective than inhaled corticosteroid dose increases. Allergy Asthma Proc 1999; 20: 173-180[CrossRef][Medline]. |
| 12. | Kalberg CJ, Nelson H, Yancey S, Petrocella V, Emmett AH, Rickard KA. A comparison of added salmeterol versus increased-dose fluticasone in patients symptomatic on low-dose fluticasone. J Allergy Clin Immunol 1998; 101: S6. |
| 13. | Condemi JJ, Goldstein S, Kalberg C, Yancey S, Emmett A, Rickard K. The addition of salmeterol to fluticasone propionate versus increasing the dose of fluticasone propionate in patients with persistent asthma. Ann Allergy Asthma Immunol 1999; 82: 383-389[Medline]. |
| 14. |
van Noord JA, Schreurs AJM, Mol SJM, Mulder PGH.
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| 15. | Vermetten FAAM, Boermans AJM, Luiten WDVF, Mulder PGH, Vermue NA. Comparison of salmeterol with beclomethasone in adult patients with mild persistent asthma who are already on low-dose inhaled steroids. J Asthma 1999; 6: 97-106. |
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(Accepted 7 February 2000)
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