Evidence
This page contains a snapshot of featured content which highlights evidence addressing key clinical questions including areas of uncertainty. Please see the main topic reference list for details of all sources underpinning this topic.
BMJ Best Practice evidence tables
Evidence tables provide easily navigated layers of evidence in the context of specific clinical questions, using GRADE and a BMJ Best Practice Effectiveness rating. Follow the links at the bottom of the table, which go to the related evidence score in the main topic text, providing additional context for the clinical question. Find out more about our evidence tables.
This table is a summary of the analysis reported in a Cochrane Clinical Answer that focuses on the above important clinical question.
Confidence in the evidence is high or moderate to high where GRADE has been performed and the intervention is more effective/beneficial than the comparison for key outcomes.
Population: People attending the emergency department due to an acute exacerbation of asthma
Intervention: Intravenous magnesium sulfate
Comparison: Placebo or no magnesium sulfate
| Outcome | Effectiveness (BMJ rating)? | Confidence in evidence (GRADE)? |
|---|---|---|
Hospital admission | Favours intervention | High |
Intensive care unit (ICU) admission | No statistically significant difference | Low |
High-dependency unit admission | No statistically significant difference | Low |
Lung function (time lapse after treatment unclear): Forced Expiratory Volume FEV1 (% predicted); Peak Expiratory Flow (PEF) (% predicted) | Favours intervention | High |
Lung function (time lapse after treatment unclear): PEF (L/min) | Favours intervention | Moderate |
Duration of emergency department treatment | No statistically significant difference | Low |
Duration of hospital stay | No statistically significant difference | Low |
Readmission (within 7 or 30 days) | No statistically significant difference | Moderate |
Adverse events | See note ᵃ | GRADE assessment not performed for this outcome |
Note The Cochrane review which this Cochrane Clinical Answer (CCA) is based upon notes that variations in the methodology of included trials affected the reviewer's ability to assess whether the severity of the exacerbation, or additional co‐medications, altered the treatment effect of intravenous magnesium sulfate. ᵃ The CCA notes that differences in the definition of asthma exacerbation and dosing of magnesium sulfate between trials affected the incidence of adverse events seen. The most common adverse events reported were flushing, fatigue, nausea, and headache. See the CCA for more details.
This evidence table is related to the following section/s:
Cochrane Clinical Answers
Cochrane Clinical Answers (CCAs) provide a readable, digestible, clinically focused entry point to rigorous research from Cochrane systematic reviews. They are designed to be actionable and to inform decision making at the point of care and have been added to relevant sections of the main Best Practice text.
- What are the effects of intravenous (IV) magnesium sulfate (MgSO4) for people with acute exacerbation of asthma attending the emergency department?
- How does increased doses of inhaled corticosteroids compare with stable doses for treating exacerbations of chronic asthma?
- Is there randomized controlled trial evidence to support the use of oral leukotriene receptor antagonists in addition to usual care in adults with acute asthma?
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