An analysis of the prospective, real-world, Prevention of thromboembolic events–European Registry in Atrial Fibrillation (PREFER in AF) registry demonstrated, in a cohort of anticoagulated patients with AF—the large majority being on vitamin K antagonist anticoagulants (VKAs)—that the sole presence of diabetes not requiring insulin did not imply a higher risk of stroke or systemic embolism [5]; conversely, insulin-requiring diabetes mostly, if not exclusively, contributed to the overall increase of thromboembolic risk [5]. This evidence concerns the gene INS and Stroke.