Twenty-four RCTs were identified, but data were reported only for the 21 RCTs with a Jadad score of at least 3 (n=52,748 participants, range 75 to 18,113). Mean follow-up ranged from 10 to 42 months.
Compared to placebo, 150mg dabigatran etexilate significantly reduced the risk of all stroke by 75% (RR 0.25, 95% CI 0.12 to 0.51), ischaemic stroke by 77% (RR 0.23, 95% CI 0.14 to 0.38), systemic embolism by 83% (RR 0.17, 95% CI 0.05 to 0.50) and mortality by 36% (RR 0.64, 95% CI 0.45 to 0.91). There were no significant differences for extracranial haemorrhage or acute myocardial infarction.
Compared to aspirin monotherapy, 150mg dabigatran etexilate significantly reduced the risk of all stroke by 63% (RR 0.37, 95% CI 0.20 to 0.69) and ischaemic stroke by 52% (RR 0.48, 95% CI 0.27 to 0.84). There were no significant differences for the other outcomes.
Compared to aspirin plus clopidogrel, 150mg dabigatran etexilate significantly reduced the risk of all stroke by 61% (RR 0.39, 95% CI 0.21 to 0.72), ischaemic stroke by 63% (RR 0.37, 95% CI 0.23 to 0.61) and systemic embolism by 79% (RR 0.21, 95% CI 0.07 to 0.61). There were no significant differences for the other outcomes.
Compared to adjusted dose vitamin K antagonists, 150mg dabigatran etexilate significantly reduced the risk of any stroke by 35% (RR 0.65, 95% CI 0.45 to 0.94). There were no significant differences for the other outcomes.
Compared to placebo, 110mg dabigatran etexilate significantly reduced the risk of all stroke by 65% (RR 0.35, 95% CI 0.17 to 0.71), ischaemic stroke by 67% (RR 0.33, 95% CI 0.21 to 0.54), systemic embolism by 81% (RR 0.19, 95% CI 0.06 to 0.57) and mortality by 34% (RR 0.66, 95% CI 0.47 to 0.93).
Compared to aspirin monotherapy, 110mg dabigatran etexilate significantly reduced the risk of all stroke by 48% (RR 0.52, 95% CI 0.28 to 0.96).
Compared to aspirin plus clopidogrel, 110mg dabigatran etexilate significantly reduced the risk of ischaemic stroke by 46% (RR 0.54, 95% CI 0.33 to 0.87), systemic embolism by 76% (RR 0.24, 95% CI 0.08 to 0.70) and all stroke by 45% (RR 0.55, 95% CI 0.30 to 1.00; borderline significance).
Compared to adjusted dose vitamin K antagonists, 110mg dabigatran etexilate significantly reduced the risk of intracranial haemorrhage by 67% (RR 0.33, 95% CI 0.15 to 0.72). There were no significant differences for other outcomes.
Numbers needed to treat and data for the numbers of trial arms for each treatment by outcome were reported. Results for the sensitivity analyses were reported in an online appendix, which changed the significance of some results, especially for 110 mg dabigatran etexilate and particularly when the ACTIVE trial was included in analyses.