PB0390 - Outcome and incidence of major bleeding in older patients with venous thromboembolism - a 10-year retrospective review

Background: Older patients anticoagulated for venous thromboembolism (VTE) is at increased risk of major bleeding. There is limited real-world data about bleeding complications in this vulnerable cohort.

Aims: To review the risk of major bleeding (MB) in older patients anticoagulated for VTE at a tertiary hospital.

Methods: Retrospective review of patients 75 years-old anticoagulated for a new diagnosis of VTE from December 2010 to December 2020. Patients with active malignancy at time of VTE diagnosis were excluded. Competing risk analysis was performed, with MB (defined as per ISTH-SSC criteria) as the endpoint and death as the competing risk. Patients without MB were censored at the time of last follow-up or death.

Results: 662 patients (median age 82 years, 36.7% male) were identified. The most common anticoagulants included warfarin (n=347; 48.1%), direct oral anticoagulants (DOAC) (n=210; 29.1%) and enoxaparin (n=101; 14.0%) (Table 1). The mean Charlson Comorbidity Index (CCI) was >5, indicating serious comorbid conditions. Enoxaparin patients were older and more likely on concurrent antiplatelets.

Over a total follow-up of 770.1 patient-years (PY), there were 54 MB events (7.01/100PY) including 17 gastrointestinal and 13 intracranial bleeds. There were 13 (24.1%) bleeding-related mortality. MB rates were 35.9/100PY for enoxaparin, 6.0/100PY for DOAC and 4.4/100PY for warfarin. No significant differences for bleeding rates between patients on DOAC and warfarin were found (Figure 1). MB was more likely in to occur in patients on enoxaparin vs DOAC (sub-hazard ratio (SHR) 3.99, 95%CI 1.8-8.8, p=0.001).

Conclusion(s): Major bleeding was not uncommon (7/100PY) in older patients being anticoagulated for VTE, with a substantial risk of death. Comparable between DOACs and warfarin, the highest risk was seen with enoxaparin use, which may be attributable to higher predisposed bleeding risk (eg post-surgery, frailer). Careful considerations should be made when weighing up the management of older patients with VTE.