Overview
Thrombocytopenia is common in antiphospholipid syndrome (APS) and is now included in the 2023 ACR/EULAR APS criteria as an important non criteria/hematologic feature. Persistent or low-moderate thrombocytopenia independently predicts reduced long-term survival in APS, with hazard ratios for mortality around 2.7-4.4, and is associated with a severe disease phenotype and thrombotic deaths.
Description
Thrombocytopenia also independently predicts recurrent thrombosis, pregnancy morbidity, and severe extra criteria events in primary APS, correlates with higher damage indices and thrombotic/neurological involvement, and is enriched in high-risk thrombotic APS clusters with poorer prognosis. Existing studies treat thrombocytopenia as a static exposure (present/absent, baseline level). The prognostic value of longitudinal platelet trajectories (persistent vs intermittent vs transient vs absent thrombocytopenia) for global clinical severity and survival has not been systematically evaluated.
Eligibility
Inclusion Criteria:
- Age ≥18 years.
- Definite APS by Sydney criteria (thrombotic and/or obstetric) with persistent aPL positivity.
- ≥3 documented platelet counts over ≥12 months before inclusion (to allow trajectory modeling)
Exclusion Criteria:
- Thrombocytopenia clearly attributable to non APS causes (e.g., chemotherapy, myelodysplastic syndromes, cirrhosis, HIV).
- Concomitant conditions strongly affecting survival independent of APS (e.g., metastatic cancer), at investigator discretion
