Comparative Risk of Clinically Significant Bleeding In Patients with Atrial Fibrillation Receiving Factor Xa Inhibitors versus Vitamin K Antagonists: A Case-Control Study

Abstract

Background: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with an important risk of thromboembolic event. The mainstay of stroke prevention in these patients is oral anticoagulation. Bleeding is the most important side effect of anticoagulant treatment and comparative safety information from clinical practice in Pakistan is scarce.

Objective: To assess differences in clinically significant bleeding risk in patients with AF who are treated with Factor Xa inhibitors compared with those treated with vitamin K antagonists.

Methods: This was a retrospective case-control study in the Department of Medicine, SIMS Hospital and Research Centre, which was conducted for 6 months after ethical clearance. Study patients consisted of those with documented AF on OAC. The cases were those patients who developed clinically significant bleeding, and the controls were anti-coagulated patients without bleeding, in 1:2 ratios. Analysis of data was done through SPSS version 26. Odds ratios and 95% confidence intervals were computed and a multivariable logistic regression was performed to adjust for confounders.

Results: 300 patients (100 cases and 200 controls) were included. Factor Xa inhibitors had a significantly lower rate of bleeding than did vitamin K antagonists (OR 0.58, 95% CI 0.35-0.95, p=0.03). Advanced age (OR 1.85), chronic kidney disease (OR 2.21), concomitant antiplatelet use (OR 2.67) and HAS-BLED score > 3 (OR 3.12) were independent predictors of bleeding.

Conclusion: Factor Xa inhibitors have demonstrated a reduced risk of clinically important bleeding over VKA in patients with AF. To reduce bleeding complications risk stratification with HAS-BLED score and careful selection of patients are crucial.