In Reply We thank Chen and colleagues for their interest in our work1 and are pleased that our report triggers debate about the optimal treatment of atrial fibrillation (AF) to prevent dementia, in addition to stroke and other thromboembolic complications of AF.
The main concerns that Chen et al express in their letter relate to uncertainty about the type of anticoagulant treatment and treatment adverse effects in our study. The first large phase 3 trials that compared novel oral anticoagulants with warfarin for thromboprophylaxis in AF appeared in late 2009 (RE-LY for dabigatran) and in 2011 (ARISTOTLE for apixaban and ROCKET-AF for rivaroxaban). As follow-up in our study lasted until February 2010, essentially all patients treated with anticoagulants in our study were prescribed coumarin derivatives, rather than novel oral anticoagulants. Consequently, differences in types of anticoagulants are unlikely to have influenced our findings. Despite proven efficacy of preventive treatment in younger as well as elderly patients,2 AF remains largely undertreated for the prevention of stroke.3,4 Of all patients diagnosed as having AF during follow-up in our study, 57.9% started anticoagulant treatment during the course of the study. We did not specifically assess for adverse effects. However, as we observed associations of exposure time both in users and in nonusers of anticoagulants, these do not appear explicable by bias due to treatment adverse effects.
Wolters FJ, de Bruijn RFAG, Ikram MA. Potential Association Between Atrial Fibrillation and Dementia—Reply. JAMA Neurol. 2016;73(5):607-608. doi:10.1001/jamaneurol.2015.5069