Non-valvular atrial fibrillation (NVAF) is associated with an increased risk of dementia. Thus, we assessed whether the use of OACs may decrease the risk of dementia in this population.
Using the Clinical Practice Research Datalink, a UK primary care database, we formed a cohort of all patients aged 50 years or more, with an incident diagnosis of NVAF (cohort entry) between 1988 and 2017 and no prior OAC use, with follow-up until 2019. Patients were considered unexposed until six months after their first OAC prescription and exposed thereafter until the end of follow-up. We used time-dependent Cox regression to estimate adjusted HRs with 95% CIs for dementia associated with OAC use, compared with non-use.
The cohort included 142,227 NVAF patients, with 8,023 cases of dementia over a mean follow-up of 4.7 years (incidence rate 12.1; 95% CI: 11.9-12.4 per 1,000 person-years). OAC use decreased the risk of dementia (HR: 0.90; 95% CI: 0.85-0.94), compared with non-use. A restricted cubic spline also suggested a decreased risk of dementia, reaching a low at approximately 1.5 years of cumulative OAC use and stabilizing thereafter. Moreover, OAC use decreased the risk in patients aged ≥75 years (HR: 0.84; 95% CI: 0.80-0.89), but not in those younger. The decrease in risk did not vary according to sex.
In patients with incident NVAF, OAC use decreased the risk of dementia, evident after 1-2 years of OAC use.
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