The aim of FINACAF study is to evaluate the incidence and risk of stroke, systemic thromboembolic events, myocardial infarction, major bleeding events, and mortality in relation to different attitudes regarding stroke prevention treatment among AF patients.

The study with cohort design is conducted as a nationwide retrospective register-based linkage study using data obtained from the Finnish health care registers.

Atrial fibrillation (AF) is the most common sustained arrhythmia, its prevalence increases with age, and it presents with a wide spectrum of symptoms and severity. It has been estimated that number of AF patients is about 150 000 in Finland, and this number will be increased at least two-fold until year 2050.

The aim of this study is to evaluate the incidence and risk of stroke, systemic thromboembolic events, myocardial infarction, major bleeding events, and mortality in relation to different attitudes regarding stroke prevention treatment among AF patients.

An important part of the study is also the assessment of cost effectiveness of different OAC therapies. The risks mentioned above are separately evaluated with different management levels of warfarin therapy as well as with different NOACs and in patients without OAC treatment. The study population is also characterized according to co-morbidity, interactive medications and antiarhythmic drugs in use.

The study with cohort design is conducted as a nationwide retrospective register-based linkage study using data obtained from the Finnish health care registers. The study cohort consists of patients from six hospital district areas having a diagnosis of AF. The catchment population of these six districts is about 3.5 million; 64 % of the total Finnish population 5.5 million.

The study is register-based and patients will not be contacted in any phase of the study. Thus, no patient consents will be needed according to Finnish legislation. All patient data handled by the researchers will anonymous, ensuring full data protection of the patients.

Inclusion Criteria:

Subject has an International Classification of Diseases (ICD-10 version 10) diagnosis code I48 for AF during 1.1.2004-31.12.2018 in any of the used registries

Exclusion Criteria:

• No ICD-10 I48 diagnose in any of the study registries.
• Subjects with age below 18 years at index date
• Patients with permanent residence in Finland less than 12 months prior to index date.

The study population consists of all AF patients of the study region (Six pre-selected hospital districts with laboratory data available) during 1.1.2004-31.06.2018, including newly diagnosed patients with ICD-10 I48 diagnose code.