Association Between Relevant Co-Morbidities and Dementia in Patients With Atrial Fibrillation–A National Swedish Study

Background: The risk of dementia is increased in patients with atrial fibrillation (AF). Objective: To study relevant co-morbidities and incident dementia (vascular dementia, Alzheimers disease, other dementia and all dementia) in AF patients. Methods: All adults (n = 537,513) ≥45 years diagnosed with AF in hospitals in Sweden 1998–2012 were included. Cox regression was used to estimate hazard ratios (HR) with 95% CIs for association between co-morbidities, and incident dementia, after adjustment for age, residence place in Sweden, and socio-economic factors. Results: Totally 30,332 patients (5.6%) were diagnosed with dementia during the follow-up, with 14,097 men (4.9%) and 16,235 women (6.5%). After adjustments (HRs; 95% CI), hypertension was associated with lower risk of incident dementia (all types) in men (0.79; 0.76–0.82) and women (0.77; 0.74–0.79). Higher risk of dementia was seen in patients with stroke, diabetes, depression and anxiety. Lower risks of dementia were also seen in AF patients with concomitant coronary heart disease and congestive heart failure. Conclusions: The findings regarding incident dementia need to be interpreted with great caution, owing to possible “survival bias” or reversed causation. However, the lower associated risks of dementia associated with hypertension could possibly be explained by protective effects of certain antihypertensive drugs.