Atrial Fibrillation (AF) is associated with a substantial part of ischemic strokes (IS). CHA₂DS₂-VASc score is able to identify patients at higher risk of AF following IS among patients without known AF.

We aimed to find other independent predictive factors related to AF occurrence after IS.

This French longitudinal cohort study was based on the national database covering hospital care from 2009 to 2012 for the entire population.

Of 336,291 patients with IS from 2009 to 2012, 240,459 (71.5%) did not have AF at baseline. A total of 14,095 (5.9%) of these patients were diagnosed as having AF during a follow-up of 7.9±11.5 months (incidence rate 8.9 per 100 person-years). Beyond CHA₂DS₂-VASc score, newly found independent predictors of subsequent diagnosis of AF were coronary artery disease (HR 1.22, 95% CI 1.15–1.28), abnormal renal function (HR 1.12, 95% CI 1.07–1.17), anaemia (HR 1.10, 95% CI 1.06–1.15), lung disease (HR 1.14, 95% CI 1.09–1.18), PM-ICD implantation (HR 1.56, 95% CI 1.48–1.64) and valvular disease (HR 1.44, 95% CI 1.37–1.51). From these results, we developed a new score with better predictive ability (C statistics 0.756 95%CI 0.754–0.757) for identifying patients at higher risk of incident AF following IS than CHA₂DS₂-VASc score (0.703 95%CI 0.701–0.704, p<0.0001 for comparison with De Long test) and Framingham score (0.698 95%CI 0.697–0.700, P<0.0001 for De Long test).

New risk factors, particularly a history of coronary artery disease, pacemaker/ICD implantation, valvular disease and kidney disease, anaemia or chronic lung disease were associated with AF onset after IS. These finding helped us to build a new risk score identifying patients at higher risk of incident (or previously unknown) AF following IS with better predictive ability than previously described scores.