Key messages

• Dexamethasone may be equally effective as other corticosteroids in reducing hospitalizations, and revisit to emergency services or unscheduled medical consultations in children with acute asthma exacerbations, but the certainty of the evidence is low.
• Dexamethasone, in comparison with others corticoids, probably have less adverse effects (vomiting) in children. 

What is the evidence.
See evidence matrix  in Epistemonikos later

We found six systematic reviews [1],[2],[3],[4],[5],[6] including 10 primary studies relevant to the question of interest, reported in 13 references [7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19]. All of them correspond to randomized controlled trials. Two trials [15],[16] were not considered for this summary since they evaluated adult population.

What types of patients were included

Regarding the definition of asthma, the different trials used different inclusion criteria: Three trials [7],[8],[19] required a history of  clinical episode of wheezing, two trials [12],[17] history of two or more episodes of wheezing, three trials [11],[13],[14] used as inclusion criteria "history of previous asthma".

Regarding to age, eight trials [7],[8],[11],[12],[13],[14],[17],[19] focused on pediatric population; six trials with an age range between 2 to 18 years [7],[8],[12],[14],[17],[19], one trial [11] between 1.5 to 7 years and one [13] between 0.5 to seven years. 

The inclusion criteria were mild or moderate acute asthma exacerbation in four trials [7],[11],[13],[14], moderate acute asthma exacerbation in one [19], three trials [8],[12],[17] excluded patients with severity factors, either life-threatening exacerbation [8], need of intubation [17], or previous history of severe acute asthma exacerbation/need of intubation [12].

Five trials excluded patients who had received corticosteroids in the last four weeks [8],[11],[12],[14], [17], two trials excluded children who received corticosteroids in the last two weeks [7],[13] and in one trial [19] this information could not be obtained from any systematic review.

Six trials [7],[8],[11],[12],[14],[17] excluded patients with some chronic comorbidity, one trial [13] did not exclude for this reason, and this information could not be obtained from any systematic review for one trial [19]

Other exclusion criteria were exposure to tuberculosis [8], [11], chickenpox [7],[8],[11],[12] and infection by respiratory syncytial virus [8],[13].

One trial [11] excluded patients who presented two episodes of vomiting during emergency consultation after administration of dexamethasone.

What types of interventions were included

Regarding the intervention group:

All of the trials used dexamethasone.

It was administered orally in four trials [7],[8],[12],[17], intramuscular in three [11],[13],[14], and nebulized in one [19].

The dose ranged from 0.3 mg/kg/day to 1.7 mg/kg/day.

In five trials the treatment lasted one day [7],[8],[11], [13],[14], in two trials [12],[17] it lasted two days, and we were not able to obtain this information for one trial [19].
 

Regarding the control group:

Three trials [7],[8],[11] compared against prednisolone and five trials [12],[13],[14],[17],[19] against prednisone.

The comparison was administered orally in all of the trials.

The dose varied between 1-2 mg/kg/day.

The duration of treatment was 3 to 5 days, except for one trial [14] that lasted two days. We could not obtain this information for another trial [19].

What types of outcomes
were measured

The outcomes were pooled by the systematic reviews as follows:

• Hospitalization at first consultation.
• Relapse, defined as revisit to doctor or emergency service
• Admission during relapse
• Asthma symptoms measured on PIS scale (Pulmonary Index Score), PSAS (Patient Self-Assessment Score) or PRAM (Paediatric Respiratory Assessment Measure)
• Adverse effect: vomiting
• Severe adverse effects
• Time to complete recovery

To whom this evidence does and does not apply

• The evidence presented in this summary only applies to children.
• None of the trials included severe acute asthma exacerbation. However, in absence of direct evidence, it is reasonable to extrapolate these findings to this group.

• We selected for this summary the outcomes hospitalization at first consultation, relapse and adverse effects (vomiting), since they are the critical outcomes for decision-making on this question. This selection is based on the opinion of the authors of this summary, but it generally agrees with the outcomes mentioned by the systematic reviews identified.
• In addition, a search in the database of the COMET Initiative (Core Outcome Measure in Effectiveness Trial Initiative) returned a study [20] interviewing 15 participants, including doctors, physiotherapists and patients (adults, parents and adolescents), which prioritized avoiding hospitalization, relapse, visit to emergency service or doctor, quality of life and number of days of exacerbation, and giving less weight to the adverse effects. However, both quality of life and number of days of exacerbation were only considered by one review [5] which reported the percentage of patients fully recovered at day three.
• It should be noted that most systematic reviews defined relapse as revisit to doctor or emergency service, but we selected the latter because not all revisits correspond to relapses and there is no consensus on the definition of relapse.
• Also, we preferred to use the outcome hospitalization at first consultation instead of hospitalization at relapse, because the second outcome is a subset of the outcome revisit to doctor or emergency service. On the other hand, a reduction in revisits to doctor or emergency service would decrease the number of hospitalizations. However, including admission during relapse does not make any difference in the conclusions of this summary. 

• Regarding the risk/benefit balance, it favors dexamethasone because it has similar benefits but less adverse effects. However, it is important to recognize the certainty of the evidence about the benefits is low.

• Based on the results presented in this summary, most doctors and patients should lean in favor of the use of dexamethasone, mainly because of the reduced risk of vomiting.
• However, some clinicians might prefer the more traditional approach in absense of higher-certainty evidence. On the other hand, a shorter treatment (i.e. 1 or 2 doses of dexamethasone versus 1 to 5 days) could generate insecurity in some parents, even though this is not directly reflected in a higher rate of revisit, as we show in the summary of findings.

• Administration of dexamethasone requires only 1 or 2 doses, so decreasing adverse effects and reducing costs. 

Differences between this summary and other sources

• The conclusions of this summary coincide with those of the systematic reviews identified, with slight differences in the appreciation of the certainty of the evidence.
• This summary partially agrees with the main international guidelines; the GINA 2016 guideline [21] recommends the use of dexamethasone in mild and moderate acute asthma exacerbation, the GEMA guideline [22] does not mention dexamethasone, and the British guideline on the management of asthma [23] states there is still insufficient evidence to support the use of dexamethasone in acute asthma exacerbation.
• It should be emphasized these guidelines incorporate a low proportion of the evidence analyzed in this summary.

• The probability that future research will change the conclusions of this summary is high for the benefits and low for the adverse effects due to the certainty of the existing evidence.
• We identified four ongoing randomized trials answering the question of this summary [24],[25],[26],[27] in the International Clinical Trials Registry Platform of the World Health Organization (WHO), which could improve the certainty of the existing evidence.