NOACs versus warfarin for stroke prevention in patients with AF: a systematic review and meta-analysis

Background: Warfarin has been the anticoagulant of choice for the prevention of ischaemic stroke in patients with atrial fibrillation (AF). Novel oral anticoagulants (NOACs) are increasingly used as an alternative. Objectives: The objective of this review was to evaluate the efficacy and safety of the NOACs versus warfarin in patients with AF. Search methods: Medline, EMBASE and grey literature search for all phase II and III randomised control trials. Data collection/analysis: Two authors independently reviewed abstracts and performed data extraction of eligible full-text articles. Revman V.5 was used for meta-analysis. Main results: 12 studies were identified with a total study population of 77 011. NOACs demonstrated a reduction in the composite of stroke or systemic embolic events OR 0.85 (95% CI 0.75 to 0.98), a 52% reduction in intracranial haemorrhage OR 0.48 (95% CI 0.40 to 0.57) and a 14% reduction in mortality OR 0.86 (0.82 to 0.91). The 30-day end of study switch to warfarin demonstrated an in increase in stroke or systemic embolic events OR 2.60 (95% CI 1.61 to 4.18) and an increase in major bleeding OR 2.19 (95% CI 1.42 to 3.36). Conclusions: NOACs are superior to warfarin for the prevention of the composite of stroke and systemic embolism in patients with AF and an additional risk factor for stroke. There is a significant reduction in intracranial haemorrhage, which drives the finding of significantly lower mortality. During the poststudy switch from NOACs to warfarin there is an excess of the composite of stroke and systemic embolism as well as major bleeding events, which may be of significance in clinical practice.