Summary of findings for the main comparison. MgSO4 + SABA + ipratropium compared to SABA + ipratropium in the treatment of acute asthma.
| MgSO₄+ SABA + ipratropium compared to SABA + ipratropium in the treatment of acute asthma | ||||||
| Patient or population: adults and children with acute exacerbation of asthma Setting: emergency department/inpatient Intervention: MgSO₄ + SABA + ipratropium Comparison: SABA + ipratropium | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with SABA + ipratropium | Risk with MgSO4 + SABA + ipratropium | |||||
| Pulmonary function (% predicted FEV1) (90 to 120 minutes) |
The mean pulmonary function (% predicted FEV1) was 65% | % predicted FEV1 was 3.28% higher (1.06 higher to 5.49 higher) | ‐ | 120 (2 RCTs) | ⊕⊝⊝⊝ VERY LOW 1 2 3 | Outcome measured at 90 mins in 1 study and 120 mins in the other. 1 study (Gaur 2008) has reported much smaller standard deviations and contributes almost 90% of analysis weight |
| Pulmonary function % predicted PEF (60 minutes) |
The mean pulmonary function % predicted PEF was 50.45% | % predicted PEF was 0.05 higher (2.33 lower to 2.42 higher) | ‐ | 636 (2 RCTs) | ⊕⊕⊕⊝ MODERATE 2 4 5 | Both studies in adults Mean control group % predicted PEF was 36% in 1 study and 64.9% in the other |
| Clinical severity scores (60 minutes) |
The mean dyspnoea VAS was 31.8; the mean Yung ASS was 4.95 | SMD 0.01 higher (0.11 lower to 0.12 higher) | ‐ | 1130 (2 RCTs) | ⊕⊕⊝⊝ LOW 2 6 | 1 study reported Yung ASS and the other change in dyspnoea VAS |
| Admission at first presentation | 819 per 1000 | 778 per 1000 (745 to 819) | RR 0.95 (0.91 to 1.00) | 1308 (4 RCTs) | ⊕⊕⊕⊝ MODERATE 7 8 9 | Adults vs children test for subgroup difference: P = 0.72, I² = 0% |
| Readmission (7 to 30 days) |
26 per 1000 | 46 per 1000 (22 to 100) | RR 1.80 (0.84 to 3.87) | 750 (2 RCTs) | ⊕⊕⊝⊝ LOW 10 | Outcome measured at 7 days in 1 study and 30 days in the other. |
| Serious adverse events (during admission) | 43 per 1000 | Not estimable. See comment. | ‐ | 557 (2 RCTs) | ⊕⊕⊕⊝ MODERATE 11 | Risk difference: −0.03 (95% CI −0.06 to 0.00) Adults vs children test for subgroup difference: P = 0.39, I² = 0% Goodacre 2013 also reported participants with 1 or more SAE within 30 days: 35/332 in the MgSO₄ group and 28/358 in the placebo group (RD: 0.03; 95% CI −0.02 to 0.07) |
| Any adverse event (during admission) | 144 per 1000 | Not estimable. See comment. | ‐ | 1197 (2 RCTs) | ⊕⊕⊕⊕ HIGH | Risk Difference: 0.01 (95% CI −0.03 to 0.05) Adults vs children test for subgroup difference: P = 0.34, I² = 0% Goodacre 2013 also reported participants with 1 or more adverse event within 30 days: 52/332 in the MgSO₄ group and 36/358 in the placebo group (OR 1.66, 95% CI 1.05 to 2.62) |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). ASS: asthma severity score; CI: Confidence interval; RD: risk difference; RR: Risk ratio; OR: Odds ratio; VAS: visual analogue scale | ||||||
| GRADE Working Group grades of evidence High quality: We are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: We are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low quality: Our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect Very low quality: We have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect | ||||||
1 One study contributing most of weight at unclear risk of bias in multiple domains (−1 study limitations)
2 I² > 50% (−1 inconsistency)
3 Studies equal size but one study contributes almost 90% of weight to analysis due to much smaller standard deviations. Result no longer significant if random‐effects model applied (−1 imprecision)
4 Although one study at unclear risk of bias in several domains, the larger study, which contributes vast majority of weight to analysis, if of high methodological quality (no downgrade)
5 Although confidence interval includes no difference, they are sufficiently tight to effectively rule out an important between‐group difference (no downgrade)
6 Confidence intervals include both harm and benefit of intervention (−1 imprecision)
7 Although two of the studies at unclear risk of bias in several domains the two large studies contributing nearly 95% of weight in analysis are both of high methodological quality (no downgrade)
8 Although the I² = 52%, the two large studies contributing to this analysis show consistent results (no downgrade)
9 Confidence intervals include no difference (−1 imprecision)
10 Confidence intervals include no difference and appreciable harm or benefit of the intervention (−2 imprecision)
11 Events rare and confidence intervals include no difference (−1 imprecision)