Comparative Outcomes of Apixaban and Acenocoumarol in Advanced Chronic Kidney Disease and Atrial Fibrillation: A Retrospective Observational Study

Background: Anticoagulation in patients with advanced chronic kidney disease (CKD) and atrial fibrillation (AF) remains challenging due to the concurrent risks of thrombosis and bleeding driven by endothelial dysfunction, uremic inflammation, and impaired hemostasis. Evidence comparing vitamin K antagonists (VKAs) with direct oral anticoagulants (NOACs) in this high-risk population, particularly in dialysis, is still limited. Methods: We conducted a single-center, retrospective observational study including 93 patients with CKD stages 4–5 and AF treated between January 2021 and February 2025. Fifty patients received apixaban (2.5–5 mg twice daily), and forty-three received acenocoumarol with a target INR of 2.0–3.0. Thirty-eight patients (41%) were on maintenance hemodialysis. Demographics, comorbidities, and risk scores (CHA2DS2-VASc and HAS-BLED) were analyzed. Bleeding events were classified per ISTH criteria. Statistical comparisons used t-tests and χ2 tests, with p < 0.05 considered significant. Results: The mean age was 67.8 ± 9.1 years, and 51.6% were male. Major bleeding occurred in 9.7%, minor in 15.8%, and overdose-related bleeding in 10.0% of patients. The overall bleeding rate was significantly lower in the apixaban group (16.0%) than in the acenocoumarol group (53.5%; p = 0.01). No thromboembolic events were observed in either group. Dialysis patients had higher bleeding rates overall (13.2% vs. 7.4%), mainly among those on VKAs. The HAS-BLED score moderately correlated with bleeding incidence (r = 0.43, p < 0.01). Conclusions: Apixaban provided comparable thromboembolic protection with significantly fewer bleeding events than acenocoumarol, including in patients on dialysis. These findings support apixaban as a safer and more practical anticoagulant option in advanced CKD, consistent with its limited renal clearance and reduced influence on the inflammation–coagulation axis. Further multicenter prospective studies are warranted to validate these real-world results.