The aim of the present registry is to characterize and follow patients prospectively and retrospectively with renal impairment who have been prescribed apixaban for the prevention of stroke in atrial fibrillation, with a comparison to the characteristics and outcomes associated with warfarin therapy in this population.

Current guidelines for the management of patients with atrial fibrillation (AF) recommend the use of novel oral anticoagulants (NOACs) in patients with non-valvular AF .Renal dysfunction has been shown to be an independent predictor of stroke or systemic emboli, but the risk of bleeding with conventional warfarin therapy is also significantly increased.Prevalence of renal dysfunction in patients with atrial fibrillation is high, with approximately 60% of patients having an estimated glomerular filtration rate (eGFR) of ≤ 60 ml/min/BSA [6].NOACs undergoing significant renal secretion such as dabigatran are not recommended for patients with severe renal impairment, and dose adjustment are indicated for patients with milder degrees of renal dysfunction.However, real-world information regarding the usage and outcomes associated with NOAC therapy in patients with renal dysfunction are limited. The investigators plan to prospectively and retrospectively collect data regarding the clinical settings, characteristics, and outcomes of patients with renal dysfunction who have been prescribed apixaban in Israel, using a multicenter secure web-based registry.

Inclusion Criteria:

• Patients with renal dysfunction (eGFR <60 ml\min\BSA) who have an indication for treatment with an novel oral anticoagulant agent or VKA
• Patients prescribed apixaban or warfarin at the enrollment center (patients enrolled in a 2:1 ratio)

Exclusion Criteria:

• Valvular AF or presence prosthetic valve
• Dialysis patients
• Contraindications NOACs
• Hepatic dysfunction
• Cognitive impairment
• Clinical necessity to continue administration of potent inhibitors of both CYP3A4 and P-gp - including azole- antimycotics (e.g. ketoconazole, itraconazole) and HIV protease inhibitors (e.g. ritonavir)

patients prospectively and retropectively with renal impairment who have been prescribed apixaban for the prevention of stroke in atrial fibrillation, with a comparison to the characteristics and outcomes associated with warfarin therapy in this population