Severe thrombocytopenia in antiphospholipid syndrome: a retrospective study of 432 patients

INTRODUCTION: Antiphospholipid syndrome (APS) is an autoimmune disease characterised by obstetric morbidity and recurrent venous and/or arterial thrombosis. It is frequently associated with systemic lupus erythematosus, and thrombocytopenia is a common manifestation. This study aimed to compare patients with APS, with and without thrombocytopenia, and to describe management and outcomes of severe thrombocytopenia. METHODS: We performed a retrospective single-centre study that included 432 patients with APS. Patients were divided into three groups according to the platelet count nadir: severe thrombocytopenia (< 50 G/L), moderate thrombocytopenia (between 50 and 130 G/L) and no thrombocytopenia (≥ 130 G/L). RESULTS: 142 patients developed thrombocytopenia during follow-up (32.9%): 57 (13%) had severe thrombocytopenia (< 50 G/L) and 85 (19.4%) had moderate thrombocytopenia (50-130 G/L). Patients with thrombocytopenia more frequently experienced thrombotic manifestations, including lower limb deep vein thrombosis (49% vs 37%, p=0.014), coronary thrombosis (15% vs 6.6%, p=0.006) and catastrophic antiphospholipid syndrome (CAPS) (27% vs 2.1%, p