Impact of Anemia on Clinical Outcomes in Atrial Fibrillation Patients on Oral Anticoagulants: A Prognostic Meta-Analysis

Background: Anemia is frequently observed as a comorbidity in atrial fibrillation (AF), especially in elderly patients and in those on anticoagulation. This has been associated with poor clinical outcomes. We aim to investigate the impact of anemia on clinical outcomes in patients with AF on oral anticoagulation.

Methods: We comprehensively searched PubMed, WOS, SCOPUS, EMBASE, and CENTRAL through March 2024 and conducted a prognostic systematic review and meta-analysis. All analyses were performed using R V. 4.3.1. This meta-analysis was registered at PROSPERO (CRD42024556023).

Results: We included 23 studies comprising 286,781 patients for analysis. Anemia had a significant association with an 84% increase in risk of major bleeding (HR: 1.84 with 95% CI [1.59, 2.13], p < 0.01), a 32% increase in the risk of intracranial hemorrhage (HR: 1.32 with 95% CI [1.10, 1.58], p < 0.01), a 98% increase in the risk of gastrointestinal bleeding (HR: 1.98 with 95% CI [1.67, 2.35], p < 0.01), and a 91% increase in the risk of all-cause mortality (HR: 1.91 with 95% CI [1.46, 2.51], p < 0.01). However, the impact of anemia did not significantly affect the risk of stroke, transient ischemic stroke (TIA), or systemic embolism (HR: 1.07 with 95% CI [0.93, 1.22], p = 0.36).

Conclusion: Anemia was significantly associated with an increased risk of major bleeding, intracranial hemorrhage, gastrointestinal bleeding, and all-cause mortality. However, anemia did not significantly impact stroke, TIA, or systemic embolism.