Direct oral anticoagulants versus vitamin K antagonists in patients with antiphospholipid syndrome: systematic review and meta-analysis

BACKGROUND: Despite vitamin K antagonists (VKA) being the gold standard in the prevention of thromboembolic events in antiphospholipid syndrome (APS), non-vitamin K antagonists oral anticoagulants/direct oral anticoagulants (DOACs) have been used off-label. OBJECTIVE: We aimed to perform a systematic review comparing DOACs to VKA regarding prevention of thromboembolic events, occurrence of bleeding events and mortality in patients with APS. METHODS: An electronic database search was performed through MEDLINE, CENTRAL and Web of Science. After data extraction, we pooled the results using risk ratio (RR) and 95% CI. Heterogeneity was assessed using the I². The outcomes considered were all thromboembolic events as primary, and major bleeding, all bleeding events and mortality as secondary. Evidence confidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation methodology. RESULTS: We included 7 studies and a total of 835 patients for analyses. Thromboembolic events were significantly increased in DOACs arm, compared with VKA-RR 1.69, 95% CI 1.09 to 2.62, I²-24%, n=719, 6 studies. In studies using exclusively rivaroxaban, which was the most representative drug in all included studies, the thromboembolic risk was increased threefold (RR 3.36, 95% CI 1.53 to 7.37). The risks of major bleeding, all bleeding events and mortality were not significantly different from control arm. The grade of certainty of our results is very low. CONCLUSIONS: Current evidence suggests DOACs use, particularly rivaroxaban, among patients with APS, is less effective than VKA since it is associated with 69% increased risk of thromboembolic events. TRIAL REGISTRATION NUMBER: CRD42020216178.