The cases were more likely to have higher proportions of ever use of DPP-4 inhibitors, ever use of other anti-diabetic medications, alcohol-related disease, atrial fibrillation, chronic kidney disease, coronary artery disease, hyperlipidemia, and hypertension than the matched controls, with statistical significance (Chi-square test, P < 0.05, for all). This evidence concerns the gene DPP4 and atrial fibrillation.