Risk of death, thrombotic and hemorrhagic events in anticoagulated patients with atrial fibrillation and systemic autoimmune diseases: an analysis from a global federated dataset

Background: Growing evidence showing that systemic autoimmune diseases (SADs) are associated with a high risk of atrial fibrillation (AF). However, the impact of SAD on the clinical course of AF patients is largely unknown. Methods: Retrospective cohort study within a federated healthcare network (TriNetX). Using ICD codes, AF patients on anticoagulant therapy were categorized according to the presence of SAD (M32: Systemic Lupus Erythematosus (SLE); M33: Dermato-polymyositis (DMP); M34: Systemic Sclerosis (SSc); M35: Sjogren syndrome). The primary outcomes were the 5-year risks of (1) all-cause death, (2) thrombotic events (ischemic stroke, acute myocardial infarction, deep vein thrombosis, and pulmonary embolism), and (3) bleeding (intracranial (ICH) and gastrointestinal (GI)). Secondary outcomes were each component of the primary outcomes. Cox regression analysis after propensity score matching (PSM) was used to estimate hazard ratio (HR) and 95% confidence interval (95%CI). Results: We identified 16,098 AF patients with SAD (68.2 ± 13.4 years; 71.0% female) and 828,772 AF controls (70.7 ± 12.9 years, 41.1% females). After PSM, AF patients with SAD were associated with a higher risk of all-cause death (HR 1.13, 95%CI 1.09-1.71), thrombotic events (HR 1.37, 95%CI 1.32-1.43), and hemorrhagic events (HR 1.41, 95%CI 1.33-1.50) compared to AF controls without SAD. The highest risk of all-cause death and GI bleeding was associated with SSc, while the highest risk of thrombotic events and ICH was associated with SLE. Conclusion: AF patients with SAD are associated with a high risk of all-cause death, thrombotic, and hemorrhagic events. These patients merit careful follow-up and integrated care management to improve their prognosis.