The effectiveness of inhaled corticosteroids in the emergency department treatment of acute asthma: A meta-analysis

Abstract

Study objective: Inhaled corticosteroids (ICSs) are of proven benefit in the treatment of chronic asthma; however, their role in the management of acute asthma is unclear. Methods: We performed a systematic review of randomized controlled trials involving children or adults treated in the emergency department for acute asthma with or without the addition of ICSs. Outcome measures included hospital admission, pulmonary function tests, and side effects. Results: Seven trials were selected for inclusion in the primary analyses. ICSs versus placebo were compared; data were not available on 1 of these trials. In the remaining 6 trials, a total of 352 patients were studied (179 ICS-treated and 173 non-ICS-treated patients). Two trials compared ICSs plus systemic corticosteroids versus placebo plus systemic corticosteroids; 4 trials compared ICSs versus placebo. Patients treated with ICSs were less likely to be admitted to the hospital (odds ratio 0.30; 95% confidence interval [CI] 0.16 to 0.57) and showed small improvements in peak expiratory flows (weighted mean difference 8%; 95% CI 3% to 13%) Overall, the treatment was well tolerated, with few reports of adverse side effects. A secondary analysis compared ICSs alone versus systemic corticosteroids alone; in the 4 included trials, significant heterogeneity between the study results for admission rates precluded meaningful pooling of admission data. Conclusion: There is evidence of decreased admission rates for patients with acute asthma treated with ICSs. However, there is insufficient evidence that ICS therapy results in clinically important changes in pulmonary function when used in acute asthma, and there is insufficient evidence that ICSs alone are as effective as systemic corticosteroids. [Edmonds ML, Camargo CA Jr, Pollack CV Jr, Rowe BH. The effectiveness of inhaled corticosteroids in the emergency department treatment of acute asthma: a meta-analysis. Ann Emerg Med. August 2002;40:145-154.]

Introduction

Acute asthma is a common presenting complaint to the emergency department. In the United States, acute asthma accounts for almost 2 million ED visits per year.¹ Approximately 15% to 25% of these patients will require admission to the hospital, and of those discharged from the ED after apparently successful treatment, approximately 10% to 20% will relapse within the subsequent 2 weeks.2, 3 Given the magnitude of the asthma problem, it is not surprising that several national4, 5, 6 and international⁷ guidelines have been produced for the management of acute asthma.

There is general agreement that bronchodilators (β-agonists; eg, salbutamol, albuterol)⁸ and anti-inflammatory medications (systemic corticosteroids; eg, prednisone)⁹ are first-line agents for acute asthma. β-Agonists are used to provide rapid symptom relief, whereas corticosteroids are used to counter airway inflammation and hasten resolution of the asthma exacerbation. However, there remain numerous controversies regarding the optimal agent, dose, frequency of delivery, and route of delivery for both bronchodilators and corticosteroids in the acute setting. Current practice patterns usually include the use of nebulized β-agonists and oral or intravenous corticosteroids given early in the ED treatment of acute asthma.2, 3 Although inhaled corticosteroids (ICSs) are used more commonly after ED discharge,¹⁰ their use is uncommon in the ED setting.11, 12 Given the practice variation with respect to ICS treatment in acute asthma care,2, 3, 12, 13 it is realistic to assume that a systematic review in this area should provide direction for treatment or further research.

ICSs have the potential to be of benefit in the acute treatment of asthma. They have been shown to be effective alternatives to oral steroids in long-term asthma therapy, in which they can be used to reduce or even eliminate oral corticosteroid requirements.¹¹ Potential advantages of ICSs in acute asthma therapy might include their reduced systemic side effects, direct delivery to the airways, and a greater efficacy in reducing airway reactivity and edema, either alone or in addition to systemic corticosteroids.14, 15 Two studies, one in patients with stable asthma and a second in the emergency setting, demonstrated a beneficial effect of ICSs on airway inflammation and hyperresponsiveness within 6 hours of a single dose of inhaled budesonide, looking at laboratory markers of disease severity.16, 17 Furthermore, ancillary evidence from studies of patients with croup suggests that ICS agents might act on the airway over the short term to improve outcomes.¹⁸

To date, only a limited number of trials have examined the use of ICSs in acute asthma, and they have yielded inconsistent results. We are not aware of a published systematic review on the role of ICSs in the treatment of acute asthma in the ED. The objective of this meta-analysis was to determine the effect of ICS therapy for patients treated for acute asthma in the ED when compared with the effect of placebo therapy. There are 2 types of trials that investigate this question: trials comparing ICSs versus placebo with no systemic corticosteroids used in either treatment group and trials comparing ICSs plus systemic corticosteroids versus placebo plus systemic corticosteroids. Data from both types of trial were pooled to calculate the overall effect of ICSs versus placebo, with or without the concomitant use of systemic corticosteroids. In addition, subgroups on the basis of these 2 types of trials were examined separately.