Lupus Anticoagulant Positivity as a Risk Marker for Hemolytic Anemia in Patients with APS

Background and Objectives: Thrombocytopenia and hemolytic anemia are common but non-criteria manifestations of antiphospholipid syndrome (APS). However, their relationship with specific immunological profiles remains poorly characterized. This study aimed to evaluate these hematologic manifestations and identify their serological associations in patients with APS. Materials and Methods: We retrospectively reviewed 346 patients diagnosed with APS. Demographic, clinical, and laboratory characteristics were analyzed. Logistic regression was used to identify risk factors associated with hemolytic anemia. Results: The mean age was 47.1 ± 13.1 years, and 71.7% were female. Thrombocytopenia was present in 34.5%, and hemolytic anemia in 16.5% of patients. Lupus anticoagulant (LAC) was the most common antibody (66.8%). In univariate analysis, hemolytic anemia was significantly associated with LAC positivity (OR 4.216, 95% CI: 2.326-7.640, p < 0.001), anticardiolipin IgG (OR 7.170, p = 0.007), triple positivity (OR 3.638, p = 0.002), and diabetes mellitus (OR 2.084, p = 0.007). DIAPS showed a protective trend (OR 0.547, p = 0.002). In multivariate analysis, only LAC remained an independent risk factor for hemolytic anemia (adjusted OR 3.557, 95% CI: 1.355-9.335, p = 0.003). Conclusions: LAC positivity is an independent predictor of hemolytic anemia in APS. These findings suggest a distinct immunologic profile among patients with hematologic involvement and highlight the need for further investigation into non-criteria manifestations.