Inhaled long acting beta agonists for stable chronic asthma.
BACKGROUND
Asthma is a common respiratory disease among both adults and children and short acting inhaled beta-2 agonists are used widely for 'reliever' bronchodilator therapy. Long acting beta-2 agonists were introduced as prospective 'symptom controllers' in addition to inhaled corticosteroid 'preventer' therapy (ICS).


OBJECTIVE
This review aimed to determine the benefit or detriment on the primary outcome of asthma control with the regular use of long acting inhaled beta-2 agonists compared with placebo.


METHODS
We carried out searches using the Cochrane Airways Group trial register, most recently in October 2002. We searched bibliographies of identified RCTs for additional relevant RCTs and contacted authors of identified RCTs for other published and unpublished studies.


METHODS
All randomised studies of at least two weeks duration, comparing a long acting inhaled beta-agonist given twice daily with a placebo, in chronic asthma.


METHODS
Two reviewers performed data extraction and study quality assessment independently. We contacted authors of studies for missing data.


RESULTS
Eighty five studies met the inclusion criteria, 56 parallel group and 29 cross over design. Salmeterol xinafoate was used as long acting agent in 60 studies and formoterol fumarate in 25. The treatment period was two to four weeks in 32 studies, and 12 to 52 weeks in 53 studies. 34 study groups used concurrent inhaled corticosteroid treatment, 21 studies did not permit their use and 35 permitted either inhaled corticosteroid or cromones. There were significant advantages to long acting beta-2 agonist treatment compared to placebo for a variety of measurements of airway calibre including morning peak expiratory flow (PEF) (weighted mean difference (WMD) 26.78 L/min 95%CI 20.36 to 33.20), evening PEF (WMD 19.17 L/min 95%CI 11.63 to 26.73). They were associated with significantly fewer symptoms, less use of rescue medication and higher quality of life scores. The risk of exacerbation was lower in adults using regular inhaled corticosteroids.


CONCLUSIONS
Long acting beta-2 agonists are effective in the control of chronic asthma, and the evidence supports their use in addition to inhaled corticosteroids, as emphasised in current guidelines. Further research is needed on their use in children under 12 and in mild asthmatics not taking ICS.
Discipline of Medicine, University of Tasmania Medical School, 43 , Collins Street, PO BOX 252-34, Hobart, 7001, Tasmania, Australia. Haydn.Walters @utas.edu.au
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Walters
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Walters
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Gibson
D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000420:Albuterol / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy*; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D004983:Ethanolamines / Q000627:therapeutic use*; D000068759:Formoterol Fumarate; D006801:Humans; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D000068299:Salmeterol Xinafoate
D000318:Adrenergic beta-Agonists; D001993:Bronchodilator Agents; D004983:Ethanolamines; D000068299:Salmeterol Xinafoate; D000420:Albuterol; D000068759:Formoterol Fumarate