Oral anticoagulants and cognitive disease progression in atrial fibrillation

Background Atrial fibrillation (AF) is associated with cognitive decline and dementia. Use of oral anticoagulant (OAC) medications has been reported to offer a lower risk of dementia, but whether differences exist in risk of cognitive decline between types of OAC agents is unclear. Purpose We explored whether the progression from normal cognition to mild cognitive impairment (MCI) or MCI to dementia differs between adults with AF on warfarin versus non-Vitamin K inhibitors (NOACs) in the National Alzheimer’s Coordinating Center (NACC) clinical case series. Methods Data freeze/extraction of NACC data (N= 48,605) took place June 2023. The presence of AF was derived using both clinician-reported health information and self-reported medical history. Subjects with AF who reported use of OACs, had normal cognition and no history of stroke at baseline, and had at least one follow-up visit were included. OAC usage was calculated based on follow-up time and reported OAC use in previous visits. Continuation ratio models (with subject-specific random intercepts) were used to examine the association between OAC type and cognitive diagnosis controlling for cognitive diagnosis from previous visit. Interactions with sex were examined in all models. Results Among 1,475 eligible participants, 478 reported taking OACs including either warfarin (N=396) or NOACs (N=82) at baseline (mean age 79 years, 51% females, 84% White). Individuals on NOACs were either on dabigatran (N=24, 29%) or rivaroxaban (N=58, 71%). The median follow-up time was 4 (interquartile range 2-7) years. About 63% continued using either warfarin or NOACs, 44% switched from warfarin to NOACs, and 2% switched from NOACs to warfarin. After adjusting for age, sex, education, race, hypertension, diabetes, hyperlipidemia, smoking history, and depression in the past two years, no significant association was found between OAC type and cognitive decline (p=0.14). Conclusions In this study of older patients with AF on OACs, we found similar risks of cognitive decline between those on NOACs or warfarin. Future studies should consider effects of patient age, provider prescribing practices, and OAC adherence on this risk.