Corticosteroids for acute severe asthma in hospitalised patients.

BACKGROUND: Corticosteroids are currently used routinely in the management of acute severe asthma. The optimal dose and route of administration continues to be debated. Some investigators have reported a greater benefit of higher doses of corticosteroids in the management of severe asthma, while others have not.
OBJECTIVES: To determine whether higher doses of systemic corticosteroids (oral, intravenous or intramuscular) are more effective than lower doses in the management of patients with acute severe asthma requiring hospital admission. SEARCH STRATEGY: Randomised controlled trials were identified from the Cochrane Airways Group Asthma Register. In addition, primary authors and content experts were contacted to identify eligible studies. Bibliographies from included studies, known reviews and texts were also searched. SELECTION CRITERIA: Studies were selected for inclusion in the review if they met the following broad inclusion criteria: described as randomised controlled trials, included patients with acute severe asthma, compared different doses of corticosteroids (any route) in 2 or more treatment arms, and had a minimum period of follow up of 24 hours. Two reviewers independently assessed the studies for inclusion and disagreement was resolved by third party adjudication. DATA COLLECTION AND ANALYSIS: Data were extracted independently by two reviewers if the authors were unable to verify the validity of information. Missing data were obtained from authors or calculated from other data presented in the paper. The data were analysed as weighted mean differences (WMD) for primary pulmonary function outcomes using a fixed effects model. For the purposes of the review, three broad categories of corticosteroid dose (equivalent dose of methylprednisolone in 24 hours) were defined in advance: low dose (< or = 80 mg), medium dose (> 80 mg and < or = 360 mg) and high dose (> 360 mg). There were thus 3 main comparison groups: low versus medium dose, medium versus high dose and low versus high dose. MAIN
RESULTS: Nine trials were included; a total of 344 adult patients have been studied (96 with low dose, 85 with medium dose and 163 with high dose corticosteroids). Only 6 trials provided sufficient data for the meta-analysis. There were no clinically or statistically significant differences detected in % predicted FEV1 among comparison groups after 24, 48 or 72 hours. At 48 hours, the weighted mean difference was -3.3% predicted (95% confidence interval -12.4 to + 5.8) for the low vs medium dose comparison, -1.9% predicted (95% CI -8.1 to + 4.3) for the medium vs high dose comparison and + 0.5% predicted (95% CI - 7.8 to + 8.8) for the low vs high dose comparison. There appeared to be no significant differences in side effects or rates of respiratory failure among the varying doses of corticosteroids. A further search was conducted on 3rd August 2000. No new trials were identified. REVIEWER'S
CONCLUSIONS: No differences were identified among the different doses of corticosteroids in acute asthma requiring hospital admission. Low dose corticosteroids (< or = 80 mg/day of methylprednisolone or < or = 400 mg/day of hydrocortisone) appear to be adequate in the initial management of these adult patients. Higher doses do not appear to offer a therapeutic advantage.