BackgroundReduced dose anticoagulant therapy for the extended treatment of cancer-associated venous thromboembolism (VTE) has been used to avoid bleeding. However, it may increase the risk of recurrent VTE. AimsTo study the rate of recurrent VTE and bleeding complications in Thai patients with cancer-associated VTE who were treated with full-dose or reduced-dose anticoagulants. MethodsA retrospective cohort study was conducted in a single-center academic hospital. Electronic medical records were reviewed from 2016-2023. Patients with cancer-associated VTE who received anticoagulants for at least 3 months were evaluated. Reduced-dose anticoagulant was defined as a dose that was lower than the recommended standard dosage. The primary outcome was recurrent VTE. The secondary outcomes were major bleeding and clinically relevant non-major bleeding. ResultsA total of 229 patients were included. The median age was 65 years (interquartile range [IQR] 54-72). In the reduced-dose group, age and history of previous bleeding were higher than in the full-dose group. There were 169 (74%) patients and 60 (26%) patients who received full- and reduced-dose anticoagulants. The median time to reduce the dose was 3.6 months ([IQR] 0.7 – 5.5). Of a total of 7 (3.1%) recurrent VTE, 4 (2.4%) occurred in the full-dose and 3 (5.0%) in the reduced-dose groups (p=0.4), respectively. The median time to recurrent VTE was 7.2 months ([IQR] 3.5-12.4). There were 8 (3.5%) bleeding events, 7 (4.1%) and 1 (1.7%) in the full and reduced-dose anticoagulant groups (p=0.35), respectively. The median follow-up time was 1.5 years (IQR 1-3.1). ConclusionOlder age and a history of previous bleeding were associated with the use of reduced-dose anticoagulants. Patients with cancer-associated VTE receiving reduced-dose anticoagulants had a numerically higher risk of recurrent VTE and lower bleeding outcomes compared with those receiving full-dose anticoagulants.
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