Background: Guidelines for the management of chronic asthma have been published in several countries and all emphasise inhaled corticosteroids in the control of symptoms and the underlying inflammation of airways. In developing countries however the use of inhaled steroids at the primary care level is often limited due to cost constraints. Although specialists may be allowed to prescribe higher doses of inhaled steroids, access to them for the large number of patients with asthma is not possible. The implication of this is that patients with chronic asthma remain poorly controlled on low doses of inhaled steroids or must be controlled by the addition of oral steroids. In some countries low dose oral steroids are advocated in preference to inhaled steroids with the rationale that systemic side effects are minimal.

Objectives: To determine the therapeutically equivalent doses of inhaled versus oral steroids in the treatment of adults with chronic asthma. Search Strategy: The Cochrane Collaboration Airways Group conducted a search in MEDLINE (1966-1999), EMBASE (1980-1999) and CINAHL (1982-1999). The search included CENTRAL a database containing potential Randomised Controlled Trials (RCT) obtained by hand searching of journals within the Cochrane Collaboration.

Selection criteria: Randomised controlled trials of at least 4 weeks duration were selected and included persons over the age of 15 years with chronic asthma. Trials which compared inhaled steroids and oral prednisolone or prednisone were considered; the maximum daily dose for inhaled steroids was 2000 mcg and for oral steroids was 60 mg. Data collection & analysis: Two independent reviewers screened 1285 titles and abstracts from the electronic search. From the results of the screened electronic search, bibliography searches and other contacts, the reviewers independently selected 15 trials of which 10 met previously defined inclusion criteria. The two reviewers independently abstracted study characteristics, and outcome measures.

Main results: All trials were small and no data could be pooled. Data from six trials produced the same pattern, in which prednisolone 7.5-12 mg/day appeared to be as effective as inhaled steroid 300-2000 mcg/day. In two trials, inhaled steroid 300-400 mcg/day was more effective than prednisolone 5 mg/day. All doses of inhaled steroid appeared to be more effective than alternate day doses of prednisolone up to 60 mg on alternate days.

Reviewers' conclusions: A daily dose of prednisolone 10 mg/day appears to be equivalent to moderate-high dose inhaled corticosteroids. Alternate-day doses of oral steroids and doses < 5 mg/ day appear to be less effective than low-moderate dose inhaled steroids.