Anticoagulants/administration & dosage; Atrial Fibrillation/drug therapy; Pyridines/administration & dosage; Stroke/epidemiology; Thiazoles/administration & dosage; Administration, Oral; Adult; Anemia/epidemiology; Anemia/etiology; Anticoagulants/adverse effects; Atrial Fibrillation/complications; Dabigatran/administration & dosage; Dabigatran/adverse effects; Female; Gastrointestinal Hemorrhage/chemically induced; Gastrointestinal Hemorrhage/complications; Gastrointestinal Hemorrhage/epidemiology; Humans; Meta-Analysis as Topic; Observational Studies as Topic; Pyrazoles/administration & dosage; Pyrazoles/adverse effects; Pyridines/adverse effects; Pyridones/administration & dosage; Pyridones/adverse effects; Randomized Controlled Trials as Topic; Rivaroxaban/administration & dosage; Rivaroxaban/adverse effects; Stroke/etiology; Stroke/prevention & control; Thiazoles/adverse effects; Treatment Outcome; Warfarin/administration & dosage; Warfarin/adverse effects