Persistent thrombocytopenia predicts poor long-term survival in patients with antiphospholipid syndrome: a 38-year follow-up study.

OBJECTIVES To investigate the impact of thrombocytopenia on survival in patients with antiphospholipid syndrome (APS). METHODS Thrombocytopenia and other predictors of outcome were retrospectively evaluated in an antiphospholipid-antibody (aPL)-positive and APS cohort with 38-year follow-up (1980-2018). Thrombocytopenia was defined as < 150 × 109 platelets/l. Hazard ratios (HR) of mortality were calculated using Cox-regression models. RESULTS Among 114 patients, 64% had primary APS, 25% secondary APS, and 10% asymptomatic aPL. Mean follow-up was 19 (5-38) years. ANA (HR 1.8, p= 0.10, 95%CI 0.8-3.6), arterial thrombotic events (HR 7.0, p= 0.016, 95%CI 1.4-3.5), myocardial infarction (HR 8.3, p= 0.03, 95%CI 1.1-59), intracardiac thrombosis (HR 17, p= 0.04, 95%CI 1-279), and thrombocytopenia (HR 2.9, p= 0.004, 95%CI 1.4-6.1) were risk factors for all-cause mortality but in multivariate analysis only thrombocytopenia (HR 2.7, p= 0.01, 95%CI 1.3-6.0) remained significant. Persistent (HR 4.4, p= 0.001, 95%CI 2.1-9.2) and low-moderate thrombocytopenia (HR 2.8, p= 0.01, 95%CI 1.2-6.4) were associated with a significant increase in mortality compared with acute (HR 1.6, p= 0.40, 95%CI 0.5-5.3) and severe forms (HR 2.1, p= 0.30, 95%CI 0.5-9.2). APS patients with vs without thrombocytopenia were more frequently male (58% vs 24%, p= 0.001) with arterial thrombosis (55% vs 32%, p= 0.04), LA positivity (100% vs 87%, p= 0.04), type I aPL profile (89% vs 71%, p= 0.05), and anticoagulant treatment (89% vs 63%, p= 0.01). Thrombosis caused 13% of deaths in thrombocytopenic patients and 1% in those without (p= 0.01). CONCLUSION Thrombocytopenia is an aPL-related manifestation that identifies patients with severe disease phenotype and high thrombotic risk. Persistent low-moderate thrombocytopenia is associated with a reduced long-term survival.