Fig. 1From: Comparing stroke prevention therapy of direct oral anticoagulants and vitamin K antagonists in patients with atrial fibrillation: a nationwide retrospective observational studyDefinition of the study population. AF, atrial fibrillation; OAC, oral anticoagulant; VKA, vitamin K antagonist; DOAC, direct OAC; for final patient numbers of all study populations, see Table 2Back to article page