Risk of cognitive impairment with non-vitamin K antagonist oral anticoagulants in atrial fibrillation Protocol for a systemic review of randomized controlled trials and real-world studies

Background: The association between use of non-vitamin K antagonist oral anticoagulants (NOACs) with cognitive impairment in atrial fibrillation (AF) remains unknown. Methods: An electronic search of Medline, Embase, Cochrane Library databases and ClinicalTrials.gov Website will be performed for randomized controlled trials (RCTs) that reported cognitive impairment events and observational nationwide database studies that reported adjusted hazard ratio (HR) in AF patients with NOACs. The primacy outcome will be a composite of any forms of cognitive impairment. HRs and their 95% confidence intervals (95% CI) will be calculated by using fixed-and random-effects models. Subgroup analyses will be undertaken based on individual NOACs, study types and follow-up duration. Results: This study will provide evidence of the association between use of NOACs and risk of cognitive impairment in patients with AF by pooling the results of RCTs and real-world studies. Conclusions: The results will bring about vigorous evidence in this topic and provide optimal anticoagulation strategy in AF patients at high risk of cognitive disorder.