Identifying Additional Risk Factors for Thrombosis and Pregnancy Morbidities Among Antiphospholipid Antibodies Carriers

The evaluation of thrombotic and pregnancy risks associated with antiphospholipid antibodies (aPL)in individual patients without antiphospholipid syndrome (APS) clinical manifestation is challenging. Our aim is to identify additional risk factors or potential candidate “second hits” for APS clinical events in a large cohort of ethnically diverse aPL-positive patients. We included 219 consecutive aPL-positive patients who attended clinic at our institution. All patients had at least 1 persistent high titer (≥99 percentiles) aPL. Independent risk factors for thrombosis and pregnancy morbidities among patients with positive aPL were evaluated. When assessing risk factors associated with pregnancy morbidities, only female controls of reproductive age (age ≤45) were used. Pearson χ² analysis and multivariable logistic regression were used to evaluate correlation between different risk factors and clinical manifestations. Of the 219 aPL-positive patients, 120 (54.8%) patients had criteria APS clinical manifestations and 99 patients did not. A total of 46.1% were Caucasian, 26.4% of African descent, 16.9% Hispanic, 1.8% Asian, and 8.7% were unspecified. Among traditional risk factors and signs of endothelial injury, only hypertension demonstrated an independent association with arterial thrombosis (odds ratio [OR] = 3.826, 95% confidence interval [CI]: 1.597-9.167, P =.0026), and lupus anticoagulant (LA) demonstrated an independent association with venous thrombosis (OR = 3.308, 95% CI: 1.544-7.085, P =.0021). None of the evaluated risk factors demonstrated a significant association with pregnancy morbidity. Hypertension is a potential predictor of arterial thrombosis and the presence of LA is a potential predictor of venous thrombosis in aPL-positive patients.