Delayed diagnosis of atrial fibrillation after first-ever stroke increases recurrent stroke risk: a 5-year nationwide follow-up study

Background: Delayed detection of atrial fibrillation (AF) is common in patients with stroke. However, it is not well known whether delayed identification of AF in patients with stroke affects the prognosis of patients. Aims: To evaluate the association between the timing of AF diagnosis after stroke and clinical outcomes. Methods: We identified a cohort of all patients admitted with a primary diagnosis of first-ever ischaemic stroke, which was categorised into three groups, namely, non-AF, AF presenting with stroke and delayed AF diagnosis groups. The study patients were individually followed for 5 years to evaluate the occurrence of recurrent stroke and death. Results: In total, 17 399 patients were hospitalised with first-ever ischemic stroke, of whom 16 261 constituted the non-AF group, 907 the AF presenting with stroke group and 231 the delayed AF diagnosis group. During the 5-year follow up, 2773 (17.1%), 175 (19.3%) and 68 (29.4%) patients in the non-AF, AF presenting with stroke and delayed AF diagnosis groups, respectively, were hospitalised for recurrent stroke. The delayed AF diagnosis group exhibited a 1.57-times higher risk of recurrent stroke than the AF presenting with stroke group, after adjustment for the CHA2DS2-VASc scores (adjusted hazard ratio (HR): 1.57; 95% confidence interval (CI) = 1.19–2.08; P = 0.002). In addition, delayed diagnosis of AF significantly increased the risk of recurrent stroke in men, but not in women, after adjustment for the CHA2DS2-VASc scores. Conclusion: Delayed diagnosis of AF after stroke increased the risk of recurrent stroke, particularly in men.