Age threshold for anticoagulation in patients with atrial fibrillation: A Swedish nationwide observational study.

BACKGROUND There is controversy as to whether patients with atrial fibrillation (AF) and perceived low risk of cerebral infarction should be treated with anticoagulants, especially at what age a cut-off treatment might be indicated. METHOD We performed a retrospective, nationwide cohort study based on the Swedish National Patient Register and the Prescribed Drugs Register. Patients with a diagnosis of AF between July 1, 2005, and December 31, 2014, were included and divided into age categories (<55, 55-59, 60-64 and 65-74 years) and CHA2DS2-VA score of 0 and 1. Incidence rates (IR) of cerebral infarction and cerebral bleeding were calculated. Associations between outcomes from anticoagulant therapy and no therapy were calculated with Cox regression and given as hazard ratios (HR) with 95% confidence intervals (CI). RESULTS The analyzed cohort consisted of 294,470 patients. All age categories older than 55 years on anticoagulants had lower IR and HR for cerebral infarction compared to patients off anticoagulants, from HR 0.72, 95% CI (0.54-0.96) for patients 55-59 years with 0 points according to the CHA2DS2-VA score, to HR 0.37, 95% CI (0.33-0.42) for patients 65-74 years with 1 point. Anticoagulant therapy was associated to an increased risk of cerebral bleeding in three of seven categories, <55 years with 0 point, 55-59 years with 1 point, and 65-74 years with 1 point. CONCLUSION Anticoagulant therapy in patients with AF and age 55 years and older may be considered even if the patient has no other known risk factors for cerebral infarction.