OBJECTIVES: This study investigated the outcomes and management associated with stroke prevention treatments in patients with non-valvular atrial fibrillation (NVAF) in Europe. This analysis estimated persistence and adherence to treatment with VKA. METHODS: We conducted an observational retrospective cohort study of patients with NVAF in the Longitudinal Patient Database (CEGEDIM) in France, Italy, the UK, Spain and Germany .The analysis included patients >=18 years old, with AF diagnosis, treated with VKA and without rheumatic valvular disease or prosthetic valves. Patients had to be in the database for >=1 year before date of 1stvisit during inclusion period (May 2010/April 2012). We estimated persistence (time to VKA discontinuation) as the time from first prescription to last prescription before discontinuation, defining discontinuation as switch or absence of renewal  within 3 months, using the Kaplan-Meier method. We measured adherence to treatment by the Medication Possession Ratio (MPR) during the inclusion period. RESULTS: Median time to treatment discontinuation was 0.78 year in Germany (n=6,386), 1.00 year in Italy (n=8,774), 1.34 years in France (n=9,184), 1.99 years in Spain (n=7,526), and 1.92 years in the UK (n=7,731). Persistence at 5 years was 12% in Germany, 20% in Italy, 24% in France, 26% in Spain, and 25% in the UK. Concerning adherence the mean MPR was 0.54 in Spain, 0.56 in Italy, 0.57 in France, and 0.59 in Germany. There was insufficient data to estimate adherence in the UK. CONCLUSIONS: MPR >=0.80 is used to define good adherence. The results show adherence to treatment with VKA is low in the countries studied. Results were consistent across countries, which suggest that low adherence is not country specific. Low adherence to treatment with VKA can affect the maintenance of patients within recommended range of INR, and therefore may increase the risk of stroke.