The relationship between blood parameters and gastrointestinal bleeding in atrial fibrillation patients using oral anticoagulants presenting to the emergency department

Objective: Atrial fibrillation (AF) is a common cardiac arrhythmia, with increasing prevalence among older populations. Management strategies include rate control, rhythm control, and anticoagulant therapy to reduce thromboembolic risk. However, anticoagulants may lead to serious complications such as gastrointestinal (GI) bleeding. Current risk stratification tools (e.g., HAS-BLED, CHA₂DS₂-VASc) are used to predict bleeding and thromboembolic events, but their performance may vary due to patient-specific factors. Recent studies have highlighted the prognostic value of novel systemic inflammation markers in risk prediction. This study aims to investigate easily calculable emergency department biomarkers to anticipate GI bleeding complications in anticoagulated AF patients. Materials and Methods: This study included AF patients on anticoagulant therapy who presented with GI bleeding to the Emergency Department of Balıkesir University Health Practice and Research Hospital between 01/01/2018 and 31/12/2023. The control group comprised AF patients on anticoagulants without GI bleeding. Demographic data, comorbidities, stroke/bleeding risk scores, and systemic inflammation parameters (uric acid/albumin ratio, platelet-to-lymphocyte ratio [PLR], neutrophil-to-lymphocyte ratio [NLR], systemic immune-inflammation [SII] index) were compared. Statistical analyses were performed using SPSS version 20.0 (IBM Inc., Chicago, Illinois, USA). Results: Among novel oral anticoagulant (NOAC) users, all inflammatory markers differed significantly between groups. The case group exhibited statistically higher uric acid/albumin ratio, PLR, NLR, and SII index (p<0.05). In warfarin users, only the uric acid/albumin ratio was significant. Hypolipidemia and elevated uric acid were associated with bleeding risk in the NOAC group, while hypoalbuminemia and elevated urea were prominent in warfarin users. HAS-BLED scores were significantly higher in bleeding patients across both cohorts (p<0.05), whereas CHA₂DS₂-VASc scores were uniformly elevated without significant intergroup differences. Notably, NOAC controls showed elevated liver and kidney function parameters (p<0.05). Conclusion: In AF patients, GI bleeding risk correlates with HAS-BLED scores, elevated INR, hypocholesterolemia, hypoalbuminemia, and uric acid/albumin ratios. The significance of NLR, PLR, and SII in NOAC users suggests potential immunomodulatory effects of these agents. For warfarin users, strict INR monitoring remains critical. Paradoxical renal parameters (low creatinine/high GFR) may reflect dose optimization and close follow-up. Despite retrospective design and sample limitations, this study underscores the need for multidisciplinary risk assessment incorporating biomarkers and inflammatory indices. Personalized anticoagulation strategies are pivotal in reducing morbidity and mortality. Keywords: Emergency Department, Gastrointestinal Bleeding, Atrial Fibrillation, Inflammatory Indices