Background and aims: We examined temporal trends and age-related differences in the prevalence of vascular diseases and in their association with ischemic stroke (IS) risk in patients with atrial fibrillation (AF).

Methods: The registry-based FinACAF study covered all patients with AF in Finland during 2007-2018. Incidence rate ratios (IRRs) of IS were computed with Poisson regression, and the interaction of vascular diseases with age and calendar year period was assessed.

Results: We identified 229,565 patients (50.0 % female; mean age 72.7 years) with incident AF. The overall prevalence of any vascular disease was 28.6 %, and the prevalence increased from 2007 to 2018, primarily among patients over 75 years. Overall, 5909 (2.6 %) patients experienced IS within the first year after AF diagnosis. Crude IS rate decreased continuously during the study period in both patients with and without vascular diseases, with the rates remaining consistently higher in patients with vascular diseases. Vascular diseases were independently associated with higher IS incidence among patients under 65 years (adjusted IRR with 95 % confidence interval 1.35 (1.10-1.66)), while among older patients, only peripheral artery disease was associated with IS, and other vascular conditions had no association with IS. No interactions between the calendar year period and vascular diseases with IS rate were observed.

Conclusions: The association between vascular diseases and IS has remained stable over time and vascular diseases were independently associated with higher incidence of IS particularly in patients with AF under the age of 65.