Comparison of single 2000-microg dose treatment vs. sequential repeated-dose 500-microg treatments with nebulized budesonide in acute asthma exacerbations

Increased versus stable doses of inhaled corticosteroids for exacerbations of chronic asthma in adults and children

BACKGROUND

People with asthma may experience exacerbations, or 'attacks', during which their symptoms worsen and additional treatment is required. Written action plans sometimes advocate a short-term increase in the dose of inhaled corticosteroids (ICS) at the first sign of an exacerbation to reduce the severity of the attack and to prevent the need for oral steroids or hospital admission.

OBJECTIVES

To compare the clinical effectiveness and safety of increased versus stable doses of ICS as part of a patient-initiated action plan for the home management of exacerbations in children and adults with persistent asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register, which is derived from searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and CINAHL (Cumulative Index to Nursing and Allied Health Literature), and handsearched abstracts to 20 December 2021. We also searched major trial registries for ongoing trials.

SELECTION CRITERIA

We included parallel and cross-over randomised controlled trials (RCTs) that allocated people with persistent asthma to take a blinded inhaler in the event of an exacerbation which either increased their daily dose of ICS or kept it stable (placebo).

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed quality, and extracted data. We reassessed risk of bias for all studies at the result level using the revised risk of bias tool for RCTs (Risk of Bias 2), and employed the GRADE approach to assess our confidence in the synthesised effect estimates. The primary outcome was treatment failure, defined as the need for rescue oral steroids in the randomised population. Secondary outcomes were treatment failure in the subset who initiated the study inhaler (treated population), unscheduled physician visits, unscheduled acute care, emergency department or hospital visits, serious and non-serious adverse events, and duration of exacerbation.

MAIN RESULTS

This review update added a new study that increased the number of people in the primary analysis from 1520 to 1774, and incorporates the most up-to-date methods to assess the likely impact of bias within the meta-analyses. The updated review now includes nine RCTs (1923 participants; seven parallel and two cross-over) conducted in Europe, North America, and Australasia and published between 1998 and 2018. Five studies evaluated adult populations (n = 1247; ≥ 15 years), and four studies evaluated child or adolescent populations (n = 676; < 15 years). All study participants had mild to moderate asthma. Studies varied in the dose of maintenance ICS, age, fold increase of ICS in the event of an exacerbation, criteria for initiating the study inhaler, and allowed medications. Approximately 50% of randomised participants initiated the study inhaler (range 23% to 100%), and the included studies reported treatment failure in a variety of ways, meaning assumptions were required to permit the combining of data. Participants randomised to increase their ICS dose at the first signs of an exacerbation had similar odds of needing rescue oral corticosteroids to those randomised to a placebo inhaler (odds ratio (OR) 0.97, 95% confidence interval (CI) 0.76 to 1.25; 8 studies; 1774 participants; I2 = 0%; moderate quality evidence). We could draw no firm conclusions from subgroup analyses conducted to investigate the impact of age, time to treatment initiation, baseline dose, smoking history, and fold increase of ICS on the primary outcome. Results for the same outcome in the subset of participants who initiated the study inhaler were unchanged from the previous version, which provides a different point estimate with very low confidence due to heterogeneity, imprecision, and risk of bias (OR 0.84, 95% CI 0.54 to 1.30; 7 studies; 766 participants; I2 = 42%; random-effects model). Confidence was reduced due to risk of bias and assumptions that had to be made to include study data in the intention-to-treat and treated-population analyses. Sensitivity analyses that tested the impact of assumptions made for synthesis and to exclude cross-over studies, studies at overall high risk of bias, and those with commercial funding did not change our conclusions. Pooled effects for unscheduled physician visits, unscheduled acute care, emergency department or hospital visits, and duration of exacerbation made it very difficult to determine where the true effect may lie, and confidence was reduced by risk of bias. Point estimates for both serious and non-serious adverse events favoured keeping ICS stable, but imprecision and risk of bias due to missing data and outcome measurement and reporting reduced our confidence in the effects (serious adverse events: OR 1.69, 95% CI 0.77 to 3.71; 2 studies; 394 participants; I² = 0%; non-serious adverse events: OR 2.15, 95% CI 0.68 to 6.73; 2 studies; 142 participants; I² = 0%).

AUTHORS' CONCLUSIONS

Evidence from double-blind trials of adults and children with mild to moderate asthma suggests there is unlikely to be an important reduction in the need for oral steroids from increasing a patient's ICS dose at the first sign of an exacerbation. Other clinically important benefits and potential harms of increased doses of ICS compared with keeping the dose stable cannot be ruled out due to wide confidence intervals, risk of bias in the trials, and assumptions that had to be made for synthesis. Included studies conducted between 1998 and 2018 reflect evolving clinical practice and study methods, and the data do not support thorough investigation of effect modifiers such as baseline dose, fold increase, asthma severity and timing. The review does not include recent evidence from pragmatic, unblinded studies showing benefits of larger dose increases in those with poorly controlled asthma. A systematic review is warranted to examine the differences between the blinded and unblinded trials using robust methods for assessing risk of bias to present the most complete view of the evidence for decision makers.

Increased versus stable doses of inhaled corticosteroids for exacerbations of chronic asthma in adults and children

BACKGROUND

People with asthma may experience exacerbations or "attacks" during which their symptoms worsen and additional treatment is required. Written action plans may advocate doubling the dose of inhaled steroids in the early stages of an asthma exacerbation to reduce the severity of the attack and to prevent the need for oral steroids or hospital admission.

OBJECTIVES

To compare the clinical effectiveness and safety of increased versus stable doses of inhaled corticosteroids (ICS) as part of a patient-initiated action plan for home management of exacerbations in children and adults with persistent asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register, which is derived from searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) to March 2016. We handsearched respiratory journals and meeting abstracts.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared increased versus stable doses of ICS for home management of asthma exacerbations. We included studies of children or adults with persistent asthma who were receiving daily maintenance ICS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed quality and extracted data. We contacted authors of RCTs for additional information.

MAIN RESULTS

This review update added three new studies including 419 participants to the review. In total, we identified eight RCTs, most of which were at low risk of bias, involving 1669 participants with mild to moderate asthma. We included three paediatric (n = 422) and five adult (n = 1247) studies; six were parallel-group trials and two had a cross-over design. All but one study followed participants for six months to one year. Allowed maintenance doses of ICS varied in adult and paediatric studies, as did use of concomitant medications and doses of ICS initiated during exacerbations. Investigators gave participants a study inhaler containing additional ICS or placebo to be started as part of an action plan for treatment of exacerbations.The odds of treatment failure, defined as the need for oral corticosteroids, were not significantly reduced among those randomised to increased ICS compared with those taking their usual stable maintenance dose (odds ratio (OR) 0.89, 95% confidence interval (CI) 0.68 to 1.18; participants = 1520; studies = 7). When we analysed only people who actually took their study inhaler for an exacerbation, we found much variation between study results but the evidence did not show a significant benefit of increasing ICS dose (OR 0.84, 95% CI 0.54 to 1.30; participants = 766; studies = 7). The odds of having an unscheduled physician visit (OR 0.96, 95% CI 0.66 to 1.41; participants = 931; studies = 3) or acute visit (Peto OR 0.98, 95% CI 0.24 to 3.98; participants = 450; studies = 3) were not significantly reduced by an increased versus stable dose of ICS, and evidence was insufficient to permit assessment of impact on the duration of exacerbation; our ability to draw conclusions from these outcomes was limited by the number of studies reporting these events and by the number of events included in the analyses. The odds of serious events (OR 1.69, 95% CI 0.77 to 3.71; participants = 394; studies = 2) and non-serious events, such as oral irritation, headaches and changes in appetite (OR 2.15, 95% CI 0.68 to 6.73; participants = 142; studies = 2), were neither increased nor decreased significantly by increased versus stable doses of ICS during an exacerbation. Too few studies are available to allow firm conclusions on the basis of subgroup analyses conducted to investigate the impact of age, time to treatment initiation, doses used, smoking history and the fold increase of ICS on the magnitude of effect; yet, effect size appears similar in children and adults.

AUTHORS' CONCLUSIONS

Current evidence does not support increasing the dose of ICS as part of a self initiated action plan to treat exacerbations in adults and children with mild to moderate asthma. Increased ICS dose is not associated with a statistically significant reduction in the odds of requiring rescue oral corticosteroids for the exacerbation, or of having adverse events, compared with a stable ICS dose. Wide confidence intervals for several outcomes mean we cannot rule out possible benefits of this approach.

Effects of nebulized high-dose budesonide on moderate-to-severe acute exacerbation of asthma in children: a randomized, double-blind, placebo-controlled study

BACKGROUND AND OBJECTIVE

The efficacy of inhaled corticosteroids (ICS) in asthma exacerbation are yet to be clarified. The aim of this study was to investigate the efficacy of nebulized ICS in children with moderate-to-severe acute exacerbation of asthma in an emergency room setting in order to elucidate the potential use of ICS as the first-line therapy in the management of acute exacerbation of asthma.

METHODS

This was a prospective, randomized, double-blind, placebo-controlled study. Paediatric patients with moderate-to-severe acute exacerbation of asthma in emergency room were randomized to receive nebulized salbutamol and ipratropium bromide, with the addition of nebulized high-dose budesonide (BUD group, n = 60) or normal saline (control group, n = 58), three doses in the first hour.

RESULTS

The improvement in forced expiratory volume in 1 s was similar in both groups at 0 h after three doses of nebulization, but there was significantly further improvement at 1 and 2 h in the BUD group (0.095 ± 0.062 L and 0.100 ± 0.120 L, respectively) compared with the control group (0.059 ± 0.082 L and 0.021 ± 0.128 L, respectively), P = 0.013 and 0.001, respectively. Complete remission rate was significantly higher (84.7% vs 46.3%, P = 0.004) and need for oral corticosteroids was significantly lower (16.9% vs 46.3%, P = 0.011) in BUD group than in control group.

CONCLUSION

On the basis of nebulized short-acting bronchodilators, addition of nebulized high-dose budesonide resulted in clinical improvement in children with moderate-to-severe acute exacerbation of asthma, suggesting that nebulized high-dose ICS can be used as first-line therapy for non-life-threatening acute exacerbation of asthma in children.

Inhaled steroids for acute asthma following emergency department discharge

BACKGROUND

Patients with acute asthma treated in the emergency department (ED) are frequently treated with inhaled beta(2)-agonists and systemic corticosteroids after discharge. The use of inhaled corticosteroids (ICS) following discharge may also be beneficial in improving patient outcomes after acute asthma.

OBJECTIVES

To determine the effectiveness of ICS on outcomes in the treatment of acute asthma following discharge from the ED. To quantify the effectiveness of ICS therapy on acute asthma following ED discharge, when used in addition to, or as a substitute for, systemic corticosteroids.

SEARCH METHODS

Controlled clinical trials (CCTs) were identified from the Cochrane Airways Review Group register, which consists of systematic searches of EMBASE, MEDLINE and CINAHL databases supplemented by handsearching of respiratory journals and conference proceedings. In addition, primary authors and pharmaceutical companies were contacted to identify eligible studies. Bibliographies from included studies, known reviews and texts also were searched. The searches have been conducted up to September 2012

SELECTION CRITERIA

We included both randomised controlled trials (RCTs) and quasi-RCTs. Studies were included if patients were treated for acute asthma in the ED or its equivalent, and following ED discharge were treated with ICS therapy either in addition to, or as a substitute for, oral corticosteroids. Two review authors independently assessed articles for potential relevance, final inclusion and methodological quality.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two review authors, or confirmed by the study authors. Several authors and pharmaceutical companies provided unpublished data. The data were analysed using the Cochrane Review Manager software. Where appropriate, individual and pooled dichotomous outcomes were reported as odds ratios (OR) or relative risks (RR) with 95% confidence intervals (CIs). Where appropriate, individual and pooled continuous outcomes were reported as mean differences (MD) or standardized mean differences (SMD) with 95% CIs. The primary analysis employed a fixed effect model and heterogeneity is reported using I-squared (I(2)) statistics.

MAIN RESULTS

Twelve trials were eligible for inclusion. Three of these trials, involving a total of 909 patients, compared ICS plus systemic corticosteroids versus oral corticosteroid therapy alone. There was no demonstrated benefit of ICS therapy when used in addition to oral corticosteroid therapy in the trials. Relapses were reduced; however, this was not statistically significant with the addition of ICS therapy (OR 0.68; 95% CI 0.46 to 1.02; 3 studies; N = 909). In addition, no statistically significant differences were demonstrated between the two groups for relapses requiring admission, quality of life, symptom scores or adverse effects.Nine trials, involving a total of 1296 patients compared high-dose ICS therapy alone versus oral corticosteroid therapy alone after ED discharge. There were no significant differences demonstrated between ICS therapy alone versus oral corticosteroid therapy alone for relapse rates (OR 1.00; 95% CI 0.66 to 1.52; 4 studies; N = 684), admissions to hospital, or in the secondary outcomes of beta(2)-agonist use, symptoms or adverse events. However, the sample size was not adequate to exclude the possibility of either treatment being significantly inferior and people with severe asthma were excluded from these trials.

AUTHORS' CONCLUSIONS

There is insufficient evidence that ICS therapy provides additional benefit when used in combination with standard systemic corticosteroid therapy upon ED discharge for acute asthma. There is some evidence that high-dose ICS therapy alone may be as effective as oral corticosteroid therapy when used in mild asthmatics upon ED discharge; however, the confidence intervals were too wide to be confident of equal effectiveness. Further research is needed to clarify whether ICS therapy should be employed in acute asthma treatment following ED discharge. The review does not suggest any reason to stop usual treatment with ICS following ED discharge, even if a course of oral corticosteroids are prescribed.

Early use of inhaled corticosteroids in the emergency department treatment of acute asthma

BACKGROUND

Systemic corticosteroid therapy is central to the management of acute asthma. The use of inhaled corticosteroids (ICS) may also be beneficial in this setting.

OBJECTIVES

To determine the benefit of ICS for the treatment of patients with acute asthma managed in the emergency department (ED).

SEARCH METHODS

We identified controlled clinical trials from the Cochrane Airways Group specialised register of controlled trials. Bibliographies from included studies, known reviews, and texts also were searched. The latest search was September 2012.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs. Studies were included if patients presented to the ED or its equivalent with acute asthma, and were treated with ICS or placebo, in addition to standard therapy. Two review authors independently selected potentially relevant articles, and then independently selected articles for inclusion. Methodological quality was independently assessed by two review authors. There were three different types of studies that were included in this review: 1) studies comparing ICS vs. placebo, with no systemic corticosteroids given to either treatment group, 2) studies comparing ICS vs. placebo, with systemic corticosteroids given to both treatment groups, and 3) studies comparing ICS alone versus systemic corticosteroids. For the analysis, the first two types of studies were included as separate subgroups in the primary analysis (ICS vs. placebo), while the third type of study was included in the secondary analysis (ICS vs. systemic corticosteroid).

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two review authors if the authors were unable to verify the validity of extracted information. Missing data were obtained from the authors or calculated from other data presented in the paper. Where appropriate, individual and pooled dichotomous outcomes were reported as odds ratios (OR) with 95% confidence intervals (CIs). Where appropriate, individual and pooled continuous outcomes were reported as mean differences (MD) or standardized mean differences (SMD) with 95% CIs. The primary analysis employed a fixed-effect model and a random-effects model was used for sensitivity analysis. Heterogeneity is reported using I-squared (I(2)) statistics.

MAIN RESULTS

Twenty trials were selected for inclusion in the primary analysis (13 paediatric, seven adult), with a total number of 1403 patients. Patients treated with ICS were less likely to be admitted to hospital (OR 0.44; 95% CI 0.31 to 0.62; 12 studies; 960 patients) and heterogeneity (I(2) = 27%) was modest. This represents a reduction from 32 to 17 hospital admissions per 100 patients treated with ICS in comparison with placebo. Subgroup analysis of hospital admissions based on concomitant systemic corticosteroid use revealed that both subgroups indicated benefit from ICS in reducing hospital admissions (ICS and systemic corticosteroid versus systemic corticosteroid: OR 0.54; 95% CI 0.36 to 0.81; 5 studies; N = 433; ICS versus placebo: OR 0.27; 95% CI 0.14 to 0.52; 7 studies; N = 527). However, there was moderate heterogeneity in the subgroup using ICS in addition to systemic steroids (I(2) = 52%). Patients receiving ICS demonstrated small, significant improvements in peak expiratory flow (PEF: MD 7%; 95% CI 3% to 11%) and forced expiratory volume in one second (FEV(1): MD 6%; 95% CI 2% to 10%) at three to four hours post treatment). Only a small number of studies reported these outcomes such that they could be included in the meta-analysis and most of the studies in this comparison did not administer systemic corticosteroids to either treatment group. There was no evidence of significant adverse effects from ICS treatment with regard to tremor or nausea and vomiting. In the secondary analysis of studies comparing ICS alone versus systemic corticosteroid alone, heterogeneity among the studies complicated pooling of data or drawing reliable conclusions.

AUTHORS' CONCLUSIONS

ICS therapy reduces hospital admissions in patients with acute asthma who are not treated with oral or intravenous corticosteroids. They may also reduce admissions when they are used in addition to systemic corticosteroids; however, the most recent evidence is conflicting. There is insufficient evidence that ICS therapy results in clinically important changes in pulmonary function or clinical scores when used in acute asthma in addition to systemic corticosteroids. Also, there is insufficient evidence that ICS therapy can be used in place of systemic corticosteroid therapy when treating acute asthma. Further research is needed to clarify the most appropriate drug dosage and delivery device, and to define which patients are most likely to benefit from ICS therapy. Use of similar measures and reporting methods of lung function, and a common, validated, clinical score would be helpful in future versions of this meta-analysis.

Management of severe asthma exacerbation in children

BACKGROUND

Asthma is a common disease in children and acute severe asthma exacerbation can be life-threatening. This article aims to review recent advances in understanding of risk factors, pathophysiology, diagnosis and treatment of severe asthma exacerbation in children.

DATA SOURCES

Articles concerning severe asthma exacerbation in children were retrieved from PubMed. Literatures were searched with MeSH words "asthma", "children", "severe asthma exacerbation" and relevant cross references.

RESULTS

Severe asthma exacerbation in children requires aggressive treatments with β2-agonists, anticholinergics, and corticosteroids. Early initiation of inhaled β-agonists and systemic use of steroids are recommended. Other agents such as magnesium and aminophylline have some therapeutic benefits. When intubation and mechanical ventilation are needed, low tidal volume, controlled hypoventilation with lower-than-traditional respiratory rates and permissive hypercapnia can be applied.

CONCLUSIONS

Researchers should continue to detect the risk factors, pathophysiology, diagnosis and treatment of severe asthma exacerbation in children. More studies especially randomized controlled trials are required to evaluate the efficacy and safety of standard and new therapies.

Genome Wide Association Study to predict severe asthma exacerbations in children using random forests classifiers

BACKGROUND

Personalized health-care promises tailored health-care solutions to individual patients based on their genetic background and/or environmental exposure history. To date, disease prediction has been based on a few environmental factors and/or single nucleotide polymorphisms (SNPs), while complex diseases are usually affected by many genetic and environmental factors with each factor contributing a small portion to the outcome. We hypothesized that the use of random forests classifiers to select SNPs would result in an improved predictive model of asthma exacerbations. We tested this hypothesis in a population of childhood asthmatics.

METHODS

In this study, using emergency room visits or hospitalizations as the definition of a severe asthma exacerbation, we first identified a list of top Genome Wide Association Study (GWAS) SNPs ranked by Random Forests (RF) importance score for the CAMP (Childhood Asthma Management Program) population of 127 exacerbation cases and 290 non-exacerbation controls. We predict severe asthma exacerbations using the top 10 to 320 SNPs together with age, sex, pre-bronchodilator FEV1 percentage predicted, and treatment group.

RESULTS

Testing in an independent set of the CAMP population shows that severe asthma exacerbations can be predicted with an Area Under the Curve (AUC)=0.66 with 160-320 SNPs in comparison to an AUC score of 0.57 with 10 SNPs. Using the clinical traits alone yielded AUC score of 0.54, suggesting the phenotype is affected by genetic as well as environmental factors.

CONCLUSIONS

Our study shows that a random forests algorithm can effectively extract and use the information contained in a small number of samples. Random forests, and other machine learning tools, can be used with GWAS studies to integrate large numbers of predictors simultaneously.

Increased versus stable doses of inhaled corticosteroids for exacerbations of chronic asthma in adults and children

BACKGROUND

Written action plans providing guidance in the early treatment of asthma exacerbations have traditionally advocated doubling of inhaled corticosteroids (ICS) as one of the first steps in treatment.

OBJECTIVES

To compare the clinical effectiveness of increasing the dose of ICS versus keeping the usual maintenance dose as part of a patient-initiated action plan at the onset of asthma exacerbations.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register (last search October 2009) which is derived from searches of CENTRAL, MEDLINE, EMBASE and CINAHL, as well as handsearched respiratory journals and meeting abstracts.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared the strategy of increasing the daily dose of ICS to continuing the same ICS dose in the home management of asthma exacerbations in children or adults with persistent asthma on daily maintenance ICS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed quality and extracted data. We contacted authors of RCTs for additional information.

MAIN RESULTS

Five RCTs (four parallel-group and one cross-over) involving a total of 1250 patients (28 children and 1222 adults) with mild to moderate asthma were included. The mean daily baseline ICS dose was 555 mcg (range 200 mcg to 795 mcg) and the mean daily ICS dose achieved following increase was 1520 mcg (range 1000 mcg to 2075 mcg), in CFC beclomethasone dipropionate equivalents. Three parallel-group studies in adults (two doubling and one quadrupling; mean achieved daily dose of 1695 mcg with a range of 1420 to 2075 mcg), involving 1080 patients contributed data to the primary outcome. There was no significant reduction in the need for rescue oral corticosteroids when patients were randomised to the increased ICS compared to stable maintenance dose groups (OR 0.85, 95% CI 0.58 to 1.26). There was no significant difference in the overall risk of non-serious adverse events associated with the increased ICS dose strategy, but the wide confidence interval prevents a firm conclusion. No serious adverse events were reported.

AUTHORS' CONCLUSIONS

There is very little evidence from trials in children. In adults with asthma on daily maintenance ICS, a self-initiated ICS increase to 1000 to 2000 mcg/day at the onset of an exacerbation is not associated with a statistically significant reduction in the risk of exacerbations requiring rescue oral corticosteroids. More research is needed to assess the effectiveness of increased ICS doses at the onset of asthma exacerbations (particularly in children).

Increased versus stable doses of inhaled corticosteroids for exacerbations of chronic asthma in adults and children

BACKGROUND

Written action plans providing guidance in the early treatment of asthma exacerbations have traditionally advocated doubling of inhaled corticosteroids (ICS) as one of the first steps in treatment.

OBJECTIVES

To compare the clinical effectiveness of increasing the dose of ICS versus keeping the usual maintenance dose as part of a patient-initiated action plan at the onset of asthma exacerbations.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register (last search October 2009) which is derived from searches of CENTRAL, MEDLINE, EMBASE and CINAHL, as well as handsearched respiratory journals and meeting abstracts.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared the strategy of increasing the daily dose of ICS to continuing the same ICS dose in the home management of asthma exacerbations in children or adults with persistent asthma on daily maintenance ICS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed quality and extracted data. We contacted authors of RCTs for additional information.

MAIN RESULTS

Five RCTs (four parallel-group and one cross-over) involving a total of 1250 patients (28 children and 1222 adults) with mild to moderate asthma were included. The mean daily baseline ICS dose was 555 mg (range 200 mg to 795 mg) and the mean daily ICS dose achieved following increase was 1520 mg (range 1000 mg to 2075 mg), in CFC beclomethasone dipropionate equivalents. Three parallel-group studies in adults (two doubling and one quadrupling; mean achieved daily dose of 1695 mg with a range of 1420 to 2075 mg), involving 1080 patients contributed data to the primary outcome. There was no significant reduction in the need for rescue oral corticosteroids when patients were randomised to the increased ICS compared to stable maintenance dose groups (OR 0.85, 95% CI 0.58 to 1.26). There was no significant difference in the overall risk of non-serious adverse events associated with the increased ICS dose strategy, but the wide confidence interval prevents a firm conclusion. No serious adverse events were reported.

AUTHORS' CONCLUSIONS

There is very little evidence from trials in children. In adults with asthma on daily maintenance ICS, a self-initiated ICS increase to 1000 to 2000 mcg/day at the onset of an exacerbation is not associated with a statistically significant reduction in the risk of exacerbations requiring rescue oral corticosteroids. More research is needed to assess the effectiveness of increased ICS doses at the onset of asthma exacerbations (particularly in children).

Rescue treatment in asthma. More than as-needed bronchodilation

International guidelines recommend the use of rapid-onset inhaled beta(2)-agonists alone for symptom relief in all asthmatic patients. However, recent clinical trials have shown that the "as-required," or PRN, use of inhaled combinations of a corticosteroid and a rapid-onset beta(2)-agonist provides clinical advantages over the traditional PRN inhaled rapid-onset beta(2)-agonists alone in patients with different degrees of asthma severity. Asthma symptoms are associated not only with bronchoconstriction but also with increased airway inflammation. Inhaled beta(2)-agonists have a rapid onset of bronchodilator action that is mainly mediated by a relaxing effect on airway smooth muscle. Inhaled corticosteroids also have rapid clinical effects that can suppress lower airway inflammation, and there is a rapid synergistic potentiation of the antiinflammatory effect of corticosteroids and of the bronchodilatory action of beta(2)-agonists when the two drugs are given simultaneously. On the basis of this emerging evidence, we propose that the current rescue use of rapid-onset inhaled beta(2)-agonists alone should now be replaced by an inhaled rapid-acting beta(2)-agonist combined with a corticosteroid as preferred PRN strategy. We conclude with a call for clinical trials aimed to test the superiority of this approach in all degrees of asthma severity in a real-world setting in addition to any of the regular treatments recommended by international guidelines. In the future it might even be possible to control asthma entirely with PRN combination inhalers without maintenance therapy, at least in patients with less severe disease.