Poor adherence to guideline recommendations among patients with atrial fibrillation and acute myocardial infarction

Abstract

Background: The prevalence of atrial fibrillation in patients with acute myocardial infarction is largely unknown. The aims of the present study were to assess the prevalence of atrial fibrillation in a nationwide cohort of patients with acute myocardial infarction, to assess the prescription of anticoagulation therapy, and to study the long-term outcomes. Design: A nationwide registry-based cohort study. Methods: All patients registered in the Norwegian Myocardial Infarction Registry between 2013 and 2016 were included and followed up through 2017. Stroke rates during follow-up were obtained through linkage with the Norwegian Patient Registry. Results: In total, 47,204 patients were registered in the Norwegian Myocardial Infarction Registry. Atrial fibrillation on admission was recorded in 5393 (11%) patients, and 2190 (5%) additional patients developed atrial fibrillation during their hospital stay. Only 45% of patients with atrial fibrillation on admission and CHA2DS2-VASc score ≥ 2 were treated with anticoagulation therapy prior to myocardial infarction, and 56% of patients with atrial fibrillation and CHA2DS2-VASc score ≥ 2 were prescribed anticoagulation therapy at discharge. Patients with myocardial infarction and atrial fibrillation had an increased risk of stroke or death during 822 (426, 1278) days of follow-up compared with patients without atrial fibrillation (multivariate adjusted hazard ratio 1.4, 95% confidence interval 1.3–1.4). Conclusions: Almost half of patients with atrial fibrillation and myocardial infarction were not prescribed the guideline recommended treatment with anticoagulation therapy at discharge, and their long-term risk of stroke and death was increased compared with patients without atrial fibrillation. Increased efforts to improve the treatment of patients with myocardial infarction and atrial fibrillation are needed.