Aim: To examine inter-national and regional variations in persistence of oral anticoagulation (OAC) therapy and incidence of clinical outcomes and mortality, among patients with incident atrial fibrillation (AF) in the Nordic countries.

Methods: We conducted a registry-based multinational cohort study of OAC-naïve patients diagnosed with AF that redeemed at least one prescription of OAC after AF in Denmark (N = 25 585), Sweden (N = 59 455), Norway (N = 40 046) and Finland (N = 22 415). Persistence was dispensing at least one prescription of OAC from Day 365 after the first prescription and 90 days forward.

Results: Persistence was 73.6% (95% confidence interval 73.0-74.1) in Denmark, 71.1% (70.7-71.4) in Sweden, 89.3% (88.2-90.1) in Norway and 68.6% (68.0-69.3) in Finland. One-year risk of ischemic stroke varied between 2.0% (1.8-2.1) in Norway and 1.5% (1.4-1.6) in Sweden and 1.5% (1.3-1.6) in Finland. One-year risk of major bleeding other than intracranial bleeding varied between 2.1% (1.9-2.2) in Norway and 5.9% (5.6-6.2) in Denmark. One-year mortality risk varied between 9.3% (8.9-9.6) in Denmark and 4.2% (4.0-4.4) in Norway.

Conclusion: In OAC-naïve patients with incident AF, persistence of OAC therapy and clinical outcomes vary across Denmark, Sweden, Norway and Finland. Initiation of real-time efforts are warranted to ensure uniform high-quality care across nations and regions.