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

Rethinking the use of direct oral anticoagulants for secondary thromboprophylaxis in patients with thrombotic antiphospholipid syndrome

Patients with thrombotic antiphospholipid syndrome (APS) are at high risk for recurrent thrombosis, and indefinite anticoagulation is recommended. Patients with APS merit indefinite anticoagulation, and vitamin K antagonists (VKAs) have historically been the standard treatment. Direct oral anticoagulants (DOACs) present an appealing alternative to VKAs. Due to their pharmacokinetic and pharmacodynamic characteristics, DOACs offer advantages over VKAs, namely the lack of need for laboratory monitoring, the usage of a fixed dosage, and the absence of significant interaction with dietary components and drugs. The efficacy and safety of DOACs in patients with APS have been studied in four phase II/III clinical trials (three with rivaroxaban and one with apixaban). These studies showed DOACs' inferiority compared to VKAs in preventing recurrent thrombosis. Recurrence was significantly greater in patients with arterial thrombotic events and a triple positivity for antiphospholipid antibodies. No differences were observed in the incidence of venous thromboembolism between both groups. Major bleeding was similar in patients treated with DOACs or VKAs. Several observational studies have reported similar results. This review aims to analyse the existing evidence on the efficacy and safety of DOACs for secondary prevention in patients with APS.

Bleeding Outcomes of Direct Oral Anticoagulants and Vitamin K Antagonists for Acute Venous Thromboembolism: A Cross-Sectional Study

BACKGROUND

Venous thromboembolism (VTE) is a widespread and significant cause of morbidity and mortality on a global scale. The primary objective of this cross-sectional study is to examine the impact of anticoagulant therapy on major organ hemorrhage events in patients diagnosed with acute venous thromboembolism (VTE). Specifically, this research compares the effects of vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs).

MATERIALS AND METHODS

This retrospective observational study examined the medical records of 46 patients who had been diagnosed with VTE and were receiving treatment with DOACs or VKAs. The documentation of patient characteristics encompassed demographic information, comorbidities, and treatment particulars. Within 30 days of hospital admission, the incidence of significant organ bleeding events, with an emphasis on gastrointestinal and intracranial hemorrhage, was the primary outcome evaluated.

RESULTS

Overall, 46 patients with VTE who were treated with oral anticoagulation therapy participated in the study. Twenty-four and 22 patients were administered VKAs and DOACs, respectively. The similarity in baseline characteristics between the DOAC and VKA groups ensured that the analyses were well-matched. The examination of bleeding sites unveiled subtle variations, as the DOAC group exhibited a progressive increase in the incidence of intracranial bleeding (12, 55.5%), while the VKA group demonstrated a surge in upper gastrointestinal bleeding (12, 50%) as well. While lacking statistical significance, these observed patterns are consistent with prior research that indicates that DOACs may have a lower risk of catastrophic hemorrhage in comparison to VKAs. The overall in-hospital mortality rate for patients treated with VKA was 33.3% (n=8), while that treated with DOAC was 18.2% (n=4). These differences did not reach statistical significance (P>0.05). In a similar vein, the evaluation of mortality associated with hemorrhage revealed six (25%) in the group receiving VKA and three (13.6%) in the group receiving DOAC; the P value was not statistically significant (P>0.05).

CONCLUSIONS

This study contributes valuable insights into bleeding outcomes associated with anticoagulant therapy for acute VTE. The nuanced differences in bleeding patterns highlight the complexity of anticoagulant selection, emphasizing the importance of considering bleeding site considerations. The comparable mortality rates support existing evidence regarding the favorable safety profile of DOACs.

Therapy with direct oral anticoagulants for secondary prevention of thromboembolic events in the antiphospholipid syndrome: a systematic review and meta-analysis of randomised trials

OBJECTIVE

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterised by venous thrombosis (VT) or arterial thrombosis (AT) and/or pregnancy morbidity and the presence of antiphospholipid antibodies. Direct oral anticoagulants (DOACs) hold several advantages to vitamin K antagonists (VKAs) for prevention of thrombosis and we wish to evaluate DOACs compared with VKAs in secondary prevention of thromboembolic events in patients with APS.

METHODS

We conducted searches of the published literature using relevant data sources (MEDLINE, Embase and Cochrane CENTRAL), and of trial registers for unpublished data and ongoing trials. We included randomised trials examining individuals >18 years with APS classified according to the criteria valid when the trial was carried out. Randomised controlled trials had to examine any DOAC agent compared with any comparable drug. We tabulated all occurrences of events from all eligible randomised trials. Due to few events, ORs and 95% CIs were calculated using the Peto method.

RESULTS

5 randomised trials comprising 624 patients met the predefined eligibility criteria. The primary outcome measure was new thrombotic events, a composite endpoint of any VT or AT, during the VKA-controlled phase of treatment. According to the I2 inconsistency index, there was evidence of statistical heterogeneity across the studies (I2=60%). Across trials, 29 and 10 thrombotic events were observed in 305 and 319 patients with APS treated with DOAC and VKA, respectively, corresponding to a combined Peto OR of 3.01 (95% CI 1.56 to 5.78, p=0.001). There was a significantly increased risk of AT while treated with DOACs compared with VKA (OR 5.5 (2.5, 12.1) p<0.0001), but no difference in the risk of VT (p=0.87). We found no significant difference in risk of bleeding.

CONCLUSIONS

DOACs were associated with a significant increase in the risk of a new thrombotic event, especially AT, favouring standard prophylaxis with warfarin.

PROSPERO REGISTRATION NUMBER

CRD42019126720.