Metabolic syndrome and ischaemic stroke in non-anticoagulated atrial fibrillation with low CHA2DS2-VASc scores

Objective Conflicting results have been reported on whether metabolic syndrome (MetS) confers an increased risk of ischaemic stroke in atrial fibrillation (AF). We investigated the risk of ischaemic stroke according to MetS in patients with AF who are not indicated for oral anticoagulants. Methods A total of 76 015 oral anticoagulant-naïve patients with AF with low Congestive Heart Failure, Hypertension, Age ≥75 years (Doubled), Diabetes Mellitus, Stroke (Doubled), Vascular Disease, Age 65–74 years, Sex Category (Female) (CHA 2 DS 2 -VASc) score (0 and 1) were included from the National Health Information Database. The risk of ischaemic stroke was evaluated according to MetS, the number of MetS components (metabolic burden), and individual metabolic components defined by health examination data within 2 years of AF diagnosis. Results MetS was prevalent among 21 570 (28.4%) of the entire study population (mean age 49.8±11.1 years, mean CHA 2 DS 2 -VASc score 0.7±0.5). During a mean follow-up of 5.1 years, ischaemic stroke occurred in 1395 (1.84%) patients. MetS was associated with a higher risk of ischaemic stroke (adjusted HR (aHR) 1.19, 95% CI 1.06 to 1.33, p=0.002). Patients with the highest number of MetS components (4 or 5) showed the greatest aHR of 1.38 (95% CI 1.13 to 1.69), whereas those with a single component had a marginal risk of ischaemic stroke (aHR 1.17, 95% CI 0.97 to 1.40). Elevated blood pressure and increased waist circumference were independent components associated with 1.48-fold and 1.15-fold higher risks of ischaemic stroke, respectively. Conclusion Among AF patients with CHA 2 DS 2 -VASc scores of 0 and 1 with no anticoagulation, MetS is associated with an increased risk of ischaemic stroke. Given the linear incremental association between metabolic burden and ischaemic stroke, the integrated management of metabolic derangements in AF is required.