European Headache Federation (EHF) critical re-appraisal and meta-analysis of oral drugs in migraine prevention—part 1: amitriptyline

Table 2 Amitriptyline compared to placebo for migraine prophylaxis

Patient or population: migraine Intervention: prophylaxis with amitriptyline Comparison: placebo
Outcomes	№ of participants (studies)	Certainty of the evidence (GRADE)	Relative effect (95% CI)	Anticipated absolute effects^a
Outcomes	№ of participants (studies)	Certainty of the evidence (GRADE)	Relative effect (95% CI)	Risk with placebo	Risk difference with Amitriptyline
50% or more reduction in monthly migraine days	389 (3 RCTs)	Moderate (downgraded due to risk of bias)	RR 1.60 (1.17 to 2.19)	275 per 1,000	165 more per 1,000 (47 more to 327 more)
Monthly migraine days	118 (1 RCT)	High	-	NA	MD 1.2 migraine days fewer (2.1 fewer to 0.3 fewer)
Adverse events leading to discontinuation	507 (2 RCTs)	Moderate (downgraded due to risk of bias)	RD 0.05 (0.01 to 0.10)	0 per 1,000	50 more per 1,000 (10 more to 100 more)

CI confidence interval, MD mean difference, RR risk ratio, RD Risk difference
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
^aThe 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)

ISSN: 1129-2377