Randomised pragmatic comparison of UK and US treatment of acute asthma presenting to hospital

Different oral corticosteroid regimens for acute asthma

BACKGROUND

Asthma is a common long-term breathing condition that affects approximately 300 million people worldwide. People with asthma may experience short-term worsening of their asthma symptoms; these episodes are often known as 'exacerbations', 'flare-ups', 'attacks' or 'acute asthma'. Oral steroids, which have a potent anti-inflammatory effect, are recommended for all but the most mild asthma exacerbations; they should be initiated promptly. The most often prescribed oral steroids are prednisolone and dexamethasone, but current guidelines on dosing vary between countries, and often among different guideline producers within the same country. Despite their proven efficacy, use of steroids needs to be balanced against their potential to cause important adverse events. Evidence is somewhat limited regarding optimal dosing of oral steroids for asthma exacerbations to maximise recovery while minimising potential side effects, which is the topic of this review.

OBJECTIVES

To assess the efficacy and safety of any dose or duration of oral steroids versus any other dose or duration of oral steroids for adults and children with an asthma exacerbation.

SEARCH METHODS

We identified trials from the Cochrane Airways Group Specialised Register (CAGR), ClinicalTrials.gov (www.ClinicalTrials.gov), the World Health Organization (WHO) trials portal (www.who.int/ictrp/en/) and reference lists of all primary studies and review articles. This search was up to date as of April 2016.

SELECTION CRITERIA

We included parallel randomised controlled trials (RCTs), irrespective of blinding or duration, that evaluated one dose or duration of oral steroid versus any other dose or duration, for management of asthma exacerbations. We included studies involving both adults and children with asthma of any severity, in which investigators analysed adults and children separately. We allowed any other co-intervention in the management of an asthma exacerbation, provided it was not part of the randomised treatment. We included studies reported as full text, those published as abstract only and unpublished data.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results for included trials, extracted numerical data and assessed risk of bias; all data were cross-checked for accuracy. We resolved disagreements by discussion with the third review author or with an external advisor.We analysed dichotomous data as odds ratios (ORs) or risk differences (RDs) using study participants as the unit of analysis; we analysed continuous data as mean differences (MDs). We used a random-effects model, and we carried out a fixed-effect analysis if we detected statistical heterogeneity. We rated all outcomes using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) system and presented results in 'Summary of findings' tables.

MAIN RESULTS

We included 18 studies that randomised a total of 2438 participants - both adults and children - and performed comparisons of interest. Included studies assessed higher versus lower doses of prednisolone (n = 4); longer versus shorter courses of prednisolone (n = 3) or dexamethasone (n = 1); tapered versus non-tapered courses of prednisolone (n = 4); and prednisolone versus dexamethasone (n = 6). Follow-up duration ranged from seven days to six months. The smallest study randomised just 15 participants, and the largest 638 (median 93). The varied interventions and outcomes reported limited the number of meaningful meta-analyses that we could perform.For two of our primary outcomes - hospital admission and serious adverse events - events were too infrequent to permit conclusions about the superiority of one treatment over the other, or their equivalence. Researchers in the included studies reported asthma symptoms in different ways and rarely used validated scales, again limiting our conclusions. Secondary outcome meta-analysis was similarly hampered by heterogeneity among interventions and outcome measures used. Overall, we found no convincing evidence of differences in outcomes between a higher dose or longer course and a lower dose or shorter course of prednisolone or dexamethasone, or between prednisolone and dexamethasone.Included studies were generally of reasonable methodological quality. Review authors assessed most outcomes in the review as having low or very low quality, meaning we are not confident in the effect estimates. The predominant reason for downgrading was imprecision, but indirectness and risk of bias also reduced our confidence in some estimates.

AUTHORS' CONCLUSIONS

Evidence is not strong enough to reveal whether shorter or lower-dose regimens are generally less effective than longer or higher-dose regimens, or indeed that the latter are associated with more adverse events. Any changes recommended for current practice should be supported by data from larger, well-designed trials. Varied study design and outcome measures limited the number of meta-analyses that we could perform. Greater emphasis on palatability and on whether some regimens might be easier to adhere to than others could better inform clinical decisions for individual patients.

Inhaled budesonide in the management of acute worsenings and exacerbations of asthma: a review of the evidence

The use of systemic corticosteroids, together with bronchodilators and oxygen therapy, has become established for the management of acute asthma. These agents are undoubtedly effective, but are also associated with problems such as metabolic adverse effects. Inhaled corticosteroids (ICS) offer potential benefit in the acute setting because they are delivered directly to the airways. They are also likely to reduce systemic exposure, which would lead in turn to reductions in rates of unwanted systemic effects. In order to evaluate the role of budesonide in the management of acute asthma exacerbations we conducted a review of the literature and critically evaluated the rationale for the use of ICS in general in this setting. Trials in adults and children requiring treatment for acute exacerbation of asthma have shown clinical and/or spirometric benefit for budesonide when delivered via nebulizer, dry powder inhaler, or aerosol in the emergency department, hospital and follow-up settings. The efficacy seems to benefit from high doses given repeatedly during the initial phase of an acute exacerbation. These acute effects are likely to be linked to the drug's distinctive pharmacokinetic and pharmacodynamic profile. The current evidence base revealed encouraging results regarding the efficacy of the ICS budesonide in patients with wheeze and acute worsening of asthma. Future studies should focus on the efficacy of these agents in more severe asthma worsenings.

Acute asthma in adults: a review

All patients with asthma are at risk of having exacerbations. Hospitalizations and emergency department (ED) visits account for a large proportion of the health-care cost burden of asthma, and avoidance or proper management of acute asthma (AA) episodes represent an area with the potential for large reductions in health-care costs. The severity of exacerbations may range from mild to life threatening, and mortality is most often associated with failure to appreciate the severity of the exacerbation, resulting in inadequate emergency treatment and delay in referring to hospital. This review describes the epidemiology, costs, pathophysiology, mortality, and management of adult AA in the ED and in the ICU.

Inhaled therapy for acute adult asthma

PURPOSE OF REVIEW

To evaluate recent developments on emergency department inhalotherapy in non-intubated acute adult asthma patients.

RECENT FINDINGS

There is evidence that high-flow oxygen can be associated with hypercarbia, and that full humidification of the inspired gases should be recommended. On the contrary, there is a lack of evidence to support the role of heliox in the initial treatment of acute asthma. Specific short-acting inhaled beta(2)-agonists are the drugs of choice. A more rapid and profound bronchodilatation with fewer side effects and less time of treatment can be achieved when sufficient doses are given using pressurized meter dose inhalers and large-volume valved-spacers, particularly in patients with the most severe obstruction. Findings argue against the routine use of continuous nebulization. High and repetitive doses of ipratropium bromide in combination with beta(2)-agonists are indicated as first line treatment of severe acute asthma. There is insufficient evidence that inhaled corticosteroids alone are as effective as systemic corticosteroids. Finally, the combination of nebulized magnesium and albuterol provides no benefit in addition to that provided by therapy with albuterol in patients with mild-to-moderate asthma exacerbations.

SUMMARY

According to the latest evidence, the goals of treatment may be summarized as follows: maintenance of adequate arterial oxygen saturation with supplemental oxygen, relief of airflow obstruction by administration of inhaled beta-agonists and anticholinergics, and reduction of airway inflammation and prevention of future relapses by using early administration of systemic corticosteroids.

Continuous versus intermittent beta-agonists in the treatment of acute asthma

BACKGROUND

Patients with acute asthma treated in the emergency department are frequently treated with intermittent inhaled beta-agonists delivered by nebulisation. The use of continuous beta-agonist (CBA) via nebulisation in the emergency setting may offer additional benefits in acute asthma.

OBJECTIVES

To determine the efficacy (e.g., reductions in admission, improvement in pulmonary functions) and risks (e.g., adverse events, effects on vital signs) of continuous versus intermittent inhaled beta-agonists for the treatment of patients with acute asthma managed in the emergency department.

SEARCH STRATEGY

Randomised controlled trials were identified from the Cochrane Airways Review Group "Asthma and WHEEZ*" Register which is a compilation of systematic searches of CINAHL, EMBASE, MEDLINE and CENTRAL and hand searching of 20 respiratory journals. In addition, primary authors and content experts were contacted to identify eligible studies. Bibliographies from included studies, known reviews and texts were also searched. The search is considered updated to June 2003.

SELECTION CRITERIA

Only randomised controlled trials (RCTs) were eligible for inclusion. Studies were included if patients presented with acute asthma and were treated with either continuous or intermittent inhaled beta-agonists early in the ED treatment. "Continuous" nebulisation was defined as truly continuous aerosol delivery of beta-agonist medication (e.g., using a commercially available large-volume nebuliser, or a small-volume nebuliser with infusion pump) or sufficiently frequent nebulisations that medication delivery was effectively continuous (i.e., 1 nebulisation every 15 minutes or > 4 nebulisations per hour). Studies also needed to report either pulmonary function or admission results. Two reviewers independently selected potentially relevant articles and two additional reviewers independently selected articles for inclusion. Methodological quality was independently assessed by two reviewers.

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 using the Cochrane Review Manager (Version 4.1). Relative risks (RR), weighted mean differences (WMD) and standardized mean differences (SMD) are reported with corresponding 95% confidence intervals (CI); both peak expiratory flow rates (PEFR) and forced expiratory volume in one second (FEV-1) data are reported.

MAIN RESULTS

165 trials were reviewed and eight were included; a total of 461 patients have been studied (229 with CBA; 232 with intermittent beta-agonists). Overall, admission to hospital was reduced with CBA compared to intermittent beta-agonists (RR: 0.68; 95% CI: 0.5 to 0.9); patients with severe airway obstruction at presentation appeared to benefit most from this intervention (RR: 0.64; 95% CI: 0.5 to 0.9). Patients receiving CBA demonstrated small but statistically significant improvements in pulmonary function tests when all studies were pooled. Patients receiving CBA had greater improvements in % predicted FEV-1 (SMD: 0.3; 95% CI: 0.03 to 0.5) and PEFR (SMD: 0.33; 95% CI: 0.1 to 0.5); this effect was observed by 2-3 hours. Continuous treatment was generally well tolerated, with no clinically important differences observed in pulse rate (WMD: -2.87; 95% CI: -6.0 to 0.3) or blood pressure (WMD: -1.75; 95% CI: -5.6 to 2.1) between the treatment groups. Tremor was equally common in both groups (OR: 0.81; 95% CI: 0.5 to 1.3) and potassium concentration was unchanged (WMD: 0.02; 95% CI: -0.2 to 0.2).

REVIEWER'S CONCLUSIONS

Current evidence supports the use of CBA in patients with severe acute asthma who present to the emergency department to increase their pulmonary functions and reduce hospitalisation. Moreover, CBA treatment appears to be safe and well tolerated in patients who receive it.