Clinical and Safety Outcomes of Oral Antithrombotics for Stroke Prevention in Atrial Fibrillation: A Systematic Review and Network Meta-analysis

Abstract Introduction Novel oral anticoagulants (NOACs) expanded the options for stroke prevention in atrial fibrillation (AF). Earlier studies comparing their relative effectiveness and safety typically do not incorporate age-related differences or postmarketing studies. This study aimed to summarize and compare clinical and safety outcomes of oral antithrombotics for stroke prevention in AF in younger (65–74 years) and older (≥75 years) elderly. Methods We searched PubMed, Embase, and The Cochrane Library from inception through May 1, 2015, for randomized and nonrandomized studies comparing NOACs, warfarin, and aspirin in elderly with AF. Stroke and systemic embolism (SSE) and major bleeding (MB) are the main outcomes. We also studied secondary outcomes of ischemic stroke, all-cause mortality, intracranial bleeding, and gastrointestinal bleeding. Results Of 5255 publications identified, 25 randomized controlled trials and 24 nonrandomized studies of 897,748 patients were included. NOACs reduced the risk of SSE compared with warfarin (rate ratios [RRs] range from 0.78–0.82). Relative to SSE, NOACs demonstrated a smaller benefit for ischemic stroke (dabigatran 110 mg, RR 1.08; edoxaban, 1.00; apixaban, 0.99). On the contrary, aspirin was associated with a significantly higher risk of SSE, ischemic stroke, and mortality than warfarin or NOACs (RR > 1), particularly in older elderly. Regarding safety, medium-dose aspirin (100–300 mg daily) and aspirin/clopidogrel combination showed an increased risk of MB compared with warfarin (RR 1.17 and 1.15, respectively), as per dabigatran 150 mg and rivaroxaban in older elderly (RR 1.17 and 1.12, respectively). Among the NOACs, dabigatran 150 mg conferred greater gastrointestinal bleeding risk compared with warfarin (RR 1.51), whereas rivaroxaban (RR 0.73) demonstrated less benefit of reduced intracranial bleeding than other NOACs (RRs range 0.39–0.46). Conclusions Lower rates of SSE and intracranial bleeding were observed with the NOACs compared with warfarin. Dabigatran 150 mg and rivaroxaban were associated with higher rates of MB in older elderly.