Acute myocardial infarction in patients with atrial fibrillation with a CHA₂DS₂-VASc score of 0 or 1: A nationwide cohort study

Background The risk of acute myocardial infarction (AMI) in patients with atrial fibrillation (AF) with a CHA₂DS₂-VASc score of 0 (for men) or 1 (for women) has not been previously investigated. Objective The objective of the present study was to compare the risk of AMI in AF and non-AF subjects with a low (0 or 1) CHA₂DS₂-VASc score. Methods By using the National Health Insurance Research Database in Taiwan, we identified 7254 men with AF (with a CHA₂DS₂-VASc score of 0) and 4860 women with AF (with a CHA₂DS₂-VASc score of 1). For each study patient, 1 age-, sex-, and CHA₂DS₂-VASc score–matched subject without AF was randomly selected to constitute the control group (n = 12,114). The clinical end point was the occurrence of AMI. Results During a mean follow-up period of 5.7 ± 3.6 years, 258 patients (1.1%) suffered an AMI, with an annual incidence of 0.29% and 0.10% for patients with and without AF. AF was an independent risk factor of AMI, with an adjusted hazard ratio (HR) of 2.93 (95% confidence interval 2.21–3.87; P <.001). The risk of AMI was higher in men with AF than in women with AF, with a hazard ratio of 2.24 (95% confidence interval 1.61–3.11; P <.001) after adjustment for age and other comorbidities. Conclusion In patients with a CHA₂DS₂-VASc score of 0 or 1, AF was an independent risk factor of AMI. The risk of AMI was higher in men with AF than in women with AF. Cardiovascular risk prevention should be performed as part of the holistic management of AF to minimize the risks of AMI associated with AF.