P124 | INCIDENCE AND PREDICTIVE FACTORS FOR THROMBOEMBOLIC EVENTS IN AUTOIMMUNE HEMOLYTIC ANEMIA: A SINGLE-CENTER EXPERIENCE

An increased risk of thromboembolic events (TEEs) has been observed in autoimmune hemolytic anemia (AIHA), data on subtype-specific risk and predictive factors remain limited. We conducted a retrospective analysis of 133 patients (pts) followed for AIHA at our Institution between 2015 and 2025. The diagnosis was verified based on Direct Antiglobuline Test (DAT) status and hemolytic markers, including lactate dehydrogenase (LDH), reticulocyte count and total and indirect bilirubin. Thrombotic and infective events occurrence, treatment lines for AIHA and cardiovascular risk factors (CVRF, according to ESC 2021 guidelines) were evaluated. Most pts had warm AIHA (wAIHA, IgG: n=56, 42.1% and IgG+C3d: n=27, 20.3%) and were female (n=86, 64.7%). Secondary AIHA made up nearly half of the cohort (n=58, 43.6%). Median age at diagnosis was 68.2 (22.2-89) years. Median number of treatment lines was 2 (0-7). In 11 pts (8.2%), TEEs occurred before AIHA diagnosis. Overall, 44 (33.1%) pts presented >2 CVRF. Over a median follow-up of 48.5 (1.7-657) months, TEEs were observed in 15.8% (n=21) pts, with no significative differences by demographic and disease characteristics (Table1). Venous thromboembolism, particularly deep vein thrombosis and pulmonary embolism, represented the majority of events (n=13, 61.9%). The median time from AIHA diagnosis to thrombotic event was 5.49 (0-95.2) months. At the time of thrombosis, 71.4% (n=15) pts had active hemolysis, 61.9% (n=13) were receiving treatment for AIHA, and 80.9% (n=17) required hospitalization. Although no thrombosis-related deaths were recorded, all-causes mortality was significantly higher in the TEE group (38.1% vs 14.3%, p=0.009). Univariate analysis identified previous TEE (OR 8.56, 95% CI 2.32–31.53; p=0.001), history of severe infections (OR 3.46, 95% CI 1.33–9.04; p=0.01), and >2 CVRF (OR 2.63, 95% CI 1.02–6.79; p=0.04) as significantly associated with increased thrombotic risk. In multivariate analysis, only previous TEE remained an independent predictor (OR 5.81, 95% CI 1.43–23.63; p=0.01). Our findings confirm a substantial thrombotic risk across AIHA subtypes, mainly in the early disease phase and among patients with active hemolysis or prior thrombotic history. Routine thrombotic risk assessment and consideration of preventive strategies may be warranted, although further prospective studies are needed.