Efficacy and safety of direct oral anticoagulants for intermediate stroke risk in patients with atrial fibrillation (SINGLE-AF): Study design and protocol

Background The optimal antithrombotic strategy for patients with atrial fibrillation (AF) with intermediate stroke risk (CHA₂DS₂-VASc score of 1 [in males] and 2 [in females]) is uncertain. Although current guidelines provide class IIa recommendations for oral anticoagulant (OAC) treatment in the population, no randomized trials have addressed this therapeutic question. Objective This study aimed to conduct a randomized clinical trial evaluating the safety and efficacy of OAC therapy compared with no OAC therapy in patients with AF at intermediate stroke risk. Methods The Efficacy and Safety of Nonvitamin K Antagonist Oral Anticoagulants for Intermediate Stroke Risk in Patients With Atrial Fibrillation trial is an investigator-initiated, multicenter, open-label, superiority, randomized trial with blinded outcome assessment, enrolling 1800 patients with AF who have 1 nongender stroke risk factor, as indicated by their CHA₂DS₂-VASc score scoring 1 (in males) and 2 (in females). Eligible patients will be randomized to receive either OAC therapy with direct OACs (apixaban or rivaroxaban) or no OAC therapy. Results The primary endpoint is a composite of stroke, systemic embolism, major bleeding as defined by the International Society on Thrombosis and Hemostasis criteria, and cardiovascular death, assessed at 2 years after randomization. We hypothesized that OAC therapy would be superior to no OAC therapy for the net composite outcome among patients with AF. Conclusion The Efficacy and Safety of Nonvitamin K Antagonist Oral Anticoagulants for Intermediate Stroke Risk in Patients With Atrial Fibrillation trial will evaluate the efficacy and safety of OAC therapy vs no OAC in patients with AF with a single nongender stroke risk factor, aiming to provide evidence to guide anticoagulation strategies in those with intermediate stroke risk.