Clinical Characteristics Associated With Ischaemic Stroke and Transient Ischaemic Attack Among Non-Anticoagulated Patients With Atrial Fibrillation

Abstract

aim: We aimed to examine clinical characteristics associated with ischaemic stroke (IS) or transient ischaemic attack (TIA) among non-anticoagulated patients with atrial fibrillation (AF). methods: We conducted a case–control study restricted to adults with non-valvular AF who were not treated with oral anticoagulation. Incident IS/TIA cases were identified from the Auckland Regional Community Stroke (ARCOS) V study (1 September 2020–31 August 2021). Controls were patients hospitalised with AF prior to 1 September 2020 who remained IS/TIA-free through follow-up and were identified from the National Minimum Dataset. Demographics, comorbidities, body mass index and AF phenotype were ascertained from clinical records. Multivariable logistic regression was used to estimate adjusted odds ratios (aORs), with stabilised inverse probability weighting (IPW) performed as a sensitivity analysis. results: Among 593 non-anticoagulated AF patients, 121 experienced IS/TIA. Cases were older, more often female, and had a higher comorbidity burden. Persistent/permanent AF was strongly associated with IS/TIA compared with paroxysmal AF (aOR 5.32 [95% confidence interval (CI) 3.20–8.82]), with partial attenuation after IPW (aOR 4.41 [95% CI 2.72–7.12]). Female sex was also associated with higher odds of IS/TIA (aOR 1.78 [95% CI 1.08–2.94]), and this association remained after IPW. conclusion: Among non-anticoagulated patients with AF, IS/TIA risk is concentrated within identifiable high-risk phenotypes, highlighting missed opportunities for stroke prevention in routine clinical practice.