Non-valvular atrial fibrillation and cognitive decline: a longitudinal cohort study

OBJECTIVES: non-valvular atrial fibrillation (NVAF) is an established risk factor for thromboembolism and stroke. Small cross-sectional studies suggest associations between NVAF, silent cerebral infarction and decreased cognitive function. We compared change in cognitive function between patients with recent onset NVAF and controls 12 and 36 months after baseline assessment, and examined the impact of anti-thrombotic therapy. DESIGN: prospective longitudinal cohort study with follow-up at 12 and 36 months. SETTING: Sunderland and South Tyneside, North East of England. Participants: community-dwelling men and women aged over 60 with recently identified NVAF or in sinus rhythm, matched for age, sex and general practice (N = 362, 174 NVAF, 188 sinus rhythm). Participants were stratified for use of anti-thrombotic therapy. MEASUREMENTS: assessment included stroke risk factors and a comprehensive battery of neuropsychological tests. RESULTS: at 3 years, 74 cases and 86 controls remained, giving an attrition rate for cases (59%) versus controls (52%); p = 0.15. Analysis of change in cognitive function between baseline and follow-up at 12 and 36 months revealed no clinically important differences between cases and controls, nor between subgroups on aspirin, warfarin or neither. Age and other confounders did not influence the results. CONCLUSIONS: there was no association between overall cognitive decline and NVAF after 3 years' follow-up, nor any apparent effect of anti-thrombotic therapy. This is consistent with our baseline results, but conflicts with previous studies. Cognitive decline is probably multifactorial and any influence of NVAF was not identified in this study.