Outcomes in patients with ischemic stroke and newly diagnosed atrial fibrillation after stroke

ABSTRACT BACKGROUND The clinical characteristics and long-term outcomes of patients with ischemic stroke (IS) and newly diagnosed atrial fibrillation after stroke (NAF) have not been clearly established. Previous studies evaluating patients with NAF were limited by the low prescription rates of anticoagulants and short follow-up periods. METHODS Consecutive patients hospitalized for IS between 2014 and 2017 were identified from a National Health Insurance Research Database. The included patients were categorized into three groups: (1) known diagnosis of AF (KAF) before the index stroke, (2) NAF, and (3) without AF (non-AF). Univariable and multivariable Cox regression analyses were performed to estimate the hazard ratio (HR) for independent variables and recurrent IS, hemorrhagic stroke, or death. RESULTS We identified 158,909 patients with IS of whom 16,699 (10.5%) had KAF and 7,826 (4.9%) had NAF. The patients with NAF were younger, more often male, and had lower CHA 2 DS 2 -VASc scores (3.8 ± 1.9 versus 4.9 ± 1.8, p < 0.001) than the patients with KAF. Anticoagulant treatment significantly reduced the risks of all outcomes. Compared with NAF, KAF was associated with lower risks of recurrent IS [hazard ratio (HR): 0.91, 95% confidence interval (CI): 0.86–0.97, p < 0.01] and hemorrhagic stroke (HR: 0.88, 95% CI: 0.79–0.99, p < 0.01) and a higher risk of all-cause mortality (HR: 1.11, 95% CI: 1.07–1.16, p < 0.001). The risks of all three outcomes were significantly higher for both NAF and KAF than for non-AF. CONCLUSIONS The risks of recurrent IS and hemorrhagic stroke were higher and of all-cause mortality was lower for patients with NAF than with KAF. Anticoagulant therapy significantly reduced the risks of recurrent IS, hemorrhagic stroke, and all-cause mortality.