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 APS.

METHODS: Thrombocytopenia and other predictors of outcome were retrospectively evaluated in an 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 (range 5-38) years. ANA [hazard ratio (HR) 1.8, 95% CI 0.8, 3.6, P = 0.10], arterial thrombotic events (HR 7.0, 95% CI 1.4, 3.5, P = 0.016), myocardial infarction (HR 8.3, 95% CI 1.1, 59, P = 0.03), intracardiac thrombosis (HR 17, 95% CI 1, 279, P = 0.04) and thrombocytopenia (HR 2.9, 95% CI 1.4, 6.1, P = 0.004) were risk factors for all-cause mortality, but in multivariate analysis only thrombocytopenia (HR 2.7, 95% CI 1.3, 6.0, P = 0.01) remained significant. Persistent (HR 4.4, 95% CI 2.1, 9.2, P = 0.001) and low-moderate thrombocytopenia (HR 2.8, 95% CI 1.2, 6.4, P = 0.01) were associated with a significant increase in mortality compared with acute (HR 1.6, 95% CI 0.5, 5.3, P = 0.40) and severe (HR 2.1, 95% CI 0.5, 9.2, P = 0.30) forms. 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.