An Italian cartography of VEXAS‐related thrombosis

Thrombotic events (TEs) occur in up to 40% of patients with vacuoles, E1 enzyme, X‐linked, autoinflammatory, and somatic (VEXAS) syndrome, but data on its clinical‐genomics features and anticoagulation strategies are limited. To gain more insight into this, we conducted a two‐step study evaluating the prevalence and outcome of TE in VEXAS. First, among 1086 patients followed for TEs, 198 were men aged >40 years with unprovoked thrombosis and no known thrombophilia; 21 also had at least one VEXAS‐compatible feature and underwent UBA1 exon 3 testing. No UBA1 mutation was detected in these 21 patients. Next, we leveraged our Italian VEXAS network, and we accrued 87 molecularly confirmed Italian VEXAS cases (median age 70 years). Any history of TE was documented in 43/87 patients (49%), deep vein thrombosis being the most common (71%). Because follow‐up varied, incident thrombosis was analyzed using a time‐to‐first‐event framework from molecular VEXAS diagnosis, with death without prior TE treated as a competing event. Among 49 patients without prior/concomitant TE, five developed incident post‐diagnosis TE; the 24‐month cumulative incidence was 18.3%. Thrombophilia testing revealed a 15% co‐occurrence, including heterozygous Factor V Leiden, Factor II G20210A, and anti‐cardiolipin antibodies. Treatments comprised direct oral anticoagulants (DOACs) (51%), low molecular weight heparin (LMWH) (28%), Fondaparinux (14%), and vitamin K antagonists (AVKs) (7%). Notably, 27% experienced multiple TEs, of which 22% occurring despite anticoagulation during disease flares. Our findings provide an updated cartography of VEXAS‐related TE, suggesting early screening for thrombophilia in these patients to inform both personalized anticoagulation and disease‐control strategies.