PB0982 - Prediction of Anticoagulant-Related Bleeding in Patients with Cancer-associated Thrombosis

Background: Patients with cancer-associated thrombosis (CAT) have a high risk of recurrent venous thromboembolism as well as anticoagulant-related major bleeding.

Aims: We aimed to evaluate the association candidate traditional and cancer-specific risk factors with anticoagulant-related bleeding in a large cohort of patients with CAT.

Methods: We identified patients diagnosed with CAT with a new prescription for anticoagulant therapy between 2012 and 2020 in the US Veterans Administration database. Patients with outpatient prescriptions for anticoagulation within the six months preceding CAT were excluded. Using the methods of Fine and Gray, we assessed the association between candidate risk factors and clinically significant anticoagulant-related bleeding. Anticoagulant related bleeding was identified using previously validated international classification of disease coding, with position dependent on site of bleed.

Results: We identified a cohort of 11,731 patients with CAT. The most common malignancies included lung (23%), gastrointestinal (14%), and prostate (11%). Most patients received anticoagulant therapy with LMWH (47.7%), followed by DOACs (26.8%), VKAs (24.5%), and fondaparinux (1%).
The 12-month cumulative incidence of bleeding in the cohort was 9.5% (CI 8.9-10.1). The most frequent sites of clinically significant bleeding included gastrointestinal tract (57.2%), genitourinary tract (excluding microscopic) (20.2%), and intracranial hemorrhage (10.4%).
Candidate variables were included in the multivariable model if significantly associated with risk of clinically significant bleeding (p < 0.05) and/or p < 0.20 and findings consistent with prior literature. Variables were removed from the model via backward elimination until all remaining variables had a p value of significance (p < 0.05) and/or a p < 0.20 with findings consistent with prior literature. Full results of the analysis are in Table 1.

Conclusion(s): Our study found that many traditional and cancer-specific variables are associated with the risk of anticoagulant-related bleeding in patients with cancer. Efforts to develop a risk model based on these findings are underway.