A Match Made Unequal: Impact of Oral Anticoagulants on Stroke Outcomes Following Propensity Score Matching

Background/Objectives: Oral anticoagulants (OACs) are commonly used for stroke prevention in patients with atrial fibrillation (AF), but their impact on long-term outcomes following acute ischemic stroke (AIS) remains uncertain. This study evaluated whether prior anticoagulation influences functional outcomes and mortality in AIS patients. Methods: A total of 914 patients admitted to the Department of Neurology, University of Pécs, following an AIS from January 2023 to September 2024, were retrospectively reviewed. Patients were categorized into an anticoagulated group (OAC use, n=153) and a non-anticoagulated group (Non-OAC use, n=761). Caliper-matched propensity score matching (PSM) was performed to balance confounding factors, including age, sex, history of hypertension or diabetes mellitus, stroke severity at 72 hours (assessed by National Institutes of Health Stroke Scale [NIHSS] score) and pre-stroke disability (based on pre-morbidity modified Rankin Scale [pre-mRS] score). Analyses were conducted on two key outcomes: 90-day mRS (modified Rankin Scale) scores and mortality. Results: After matching, 276 patients were analyzed for functional outcomes and 306 for mortality. Anticoagulated patients were 2.26 times more likely to have an unfavorable functional outcome (90-day mRS >2) compared to non-anticoagulated patients (p=0.043). No significant difference in mortality (mRS = 6) was observed between the groups (p=0.307). Advanced age and higher 72h-NIHSS scores were significant predictors of poor functional outcomes, regardless of anticoagulation status. Conclusions: Prior anticoagulation in AIS patients was associated with an unfavorable functional outcome without reducing mortality. While OACs remain essential for stroke prevention in AF patients, these findings suggest that the benefit of stroke prevention must be weighed against the risk of increased long-term disability following AIS.