Summary of findings 1. Beta‐blockers compared to placebo for prophylaxis of vestibular migraine.
| Beta‐blockers compared to placebo for prophylaxis of vestibular migraine | ||||||
| Patient or population: people with vestibular migraine Setting: outpatients Intervention: beta‐blockers Comparison: placebo | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with placebo | Risk with beta‐blockers | |||||
| Improvement in vertigo | This outcome was not reported. | |||||
| Change in vertigo frequency Assessed with: number of vertigo attacks per month Follow‐up: range 3 months to 6 months |
The mean vertigo frequency was 3.78 attacks per month | MD 0.3 attacks per month lower (1.83 lower to 1.23 higher) | — | 114 (1 RCT) | ⊕⊕⊝⊝ Low1,2 | Beta‐blockers may result in little or no difference in the number of vertigo attacks at 3 to 6 months. |
| Serious adverse events | Study population | RR 0.63 (0.24 to 1.67) | 121 (1 RCT) | ⊕⊝⊝⊝ Very low1,2,3 | The evidence is very uncertain as to whether beta‐blockers result in a change in the likelihood of serious adverse events. | |
| 153 per 1000 | 96 per 1000 (37 to 255) | |||||
| *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). CI: confidence interval; MD: mean difference; RCT: randomised controlled trial; RR: risk ratio | ||||||
| GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: 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 certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. | ||||||
1Risk of attrition bias due to substantial dropout over the course of the study.
2Optimal information size was not reached (taken as < 400 participants for continuous outcomes or < 300 events for dichotomous outcomes, as a rule of thumb).
3Wide confidence interval, which includes both the potential for considerable harm and potential benefit from the intervention.