Baseline characteristics and outcomes of extended oral anticoagulant treatment in patients with venous thrombosis: a retrospective cohort study in France

Abstract

Abstract Background Guidelines recommend anticoagulant (AC) extended treatment for patients with unprovoked VTE or VTE provoked by permanent risk factors (ESC 2019, CHEST 2021). A recent observational study has shown that apixaban extended treatment (>6 months) vs no extended treatment in patients with venous thromboembolism (VTE), regardless of risk factors, is associated with decreased risk of recurrent VTE (rVTE), with no increase in major bleeding. A better safety profile for patients receiving apixaban vs those receiving vitamin K antagonists (VKAs) was also observed. Purpose To describe characteristics of patients with VTE receiving AC extended treatment (>6months) vs those receiving acute treatment only (<6 months). Outcomes among patients receiving extended treatment with apixaban and VKAs were also reported. Methods The presence of risk factors were assessed in a nationwide retrospective cohort study of AC treatment-naïve adult patients (identified via the French national health data system: SNDS) with VTE, who were prescribed VKAs or apixaban from 2013 to 2018. Descriptive statistics for patients receiving AC extended treatment vs those receiving only acute treatment are presented. Risk of bleeding (based on principal diagnoses of hospital stays), rVTE (based on principal diagnosis of hospital stays and specified procedures), and all-cause mortality were assessed 18 months following the initiation of extended treatment using inverse probability treatment weighted (IPTW) analysis to balance baseline socio-demographic and clinical characteristics. Results 21,215 VTE patients who initiated AC treatment were included: 10,775 VKAs (41.5% acute vs 58.5% extended treatment) and 10,440 apixaban (44.5% acute vs and 55.5% extended treatment). A higher proportion of apixaban and VKA patients with permanent risk factors (apixaban: 57.7%; VKAs: 57.7%) or unprovoked VTE (apixaban: 56.8%; VKAs: 59.7%) received extended treatment vs acute treatment only. Table 1 shows the adverse clinical outcomes assessed during extended treatment in IPTW balanced cohorts. Compared to patients treated with VKAs (n=6151), patients treated with apixaban (n=5682) had lower rates of rVTE (1.89 vs 2.84 per 100 person-years), bleeding (1.11 vs 1.69 per 100 person-years) and all-cause mortality (2.70 vs 6.74 per 100 person-years). Conclusions A slightly higher proportions of patients with permanent VTE risk factors and unprovoked VTE received extended treatment compared to acute treatment. Consistent with guidelines, there persists a need to increase these rates when clinically indicated to improve patient outcomes. Clinical event rates were numerically lower for apixaban compared to VKAs, which suggests clinical benefit for apixaban. However, more robust confirmatory analyses are required.