Effectiveness and Safety of Apixaban Versus Warfarin Among Older Patients with Venous Thromboembolism with Different Demographics and Socioeconomic Status

Introduction Impact of demographics and socioeconomic status (SES) on anticoagulant treatment outcomes among patients with venous thromboembolism (VTE) is not well understood. This study evaluated risks of recurrent VTE, major bleeding (MB), and clinically relevant non-major bleeding (CRNMB) among older patients with VTE initiating apixaban or warfarin stratified by demographics and SES. Methods Adult patients (≥ 65 years) who initiated apixaban or warfarin after a VTE event were selected from the US CMS Medicare database (September 2014–December 2017). Stabilized inverse probability treatment weighting (IPTW) was used to balance patient characteristics between treatment cohorts. Patients were stratified by age, gender, race, and SES. For each subgroup, Cox proportional hazard models were used to evaluate if there was a significant interaction (p \u3c 0.10) between treatment and subgroup for recurrent VTE, MB, and CRNMB. Results In total, 22,135 apixaban and 45,840 warfarin patients with VTE were included. Post-IPTW, patient characteristics were balanced between treatment cohorts. In older patients, apixaban treatment was associated with significantly lower risks of recurrent VTE (hazard ratio [HR] 0.64; 95% confidence interval [CI] 0.52–0.79), MB (HR 0.65; 95% CI 0.57–0.75), and CRNMB (HR 0.79; 95% CI 0.75–0.85) versus warfarin. When stratified by demographics and SES, higher incidence rates of recurrent VTE, MB, and CRNMB were observed for black vs white patients and patients with lower vs higher SES. Comparison of apixaban with warfarin by different demographic and SES subgroups showed generally consistent results as the overall analysis. For most subgroups, no significant interaction was observed between treatment and subgroup strata for recurrent VTE, MB, and CRNMB. Conclusion Among older patients with VTE initiating apixaban or warfarin, higher rates of recurrent VTE and bleeding were observed in black patients and patients with lower SES. Apixaban had a lower risk of recurrent VTE, MB, and CRNMB compared to warfarin. Analyses of demographic and SES subgroups showed consistent findings

Effectiveness and Safety of Apixaban vs Warfarin in Patients with Venous Thromboembolism with Risk Factors for Bleeding or for Recurrences

Introduction Patients at increased risk of bleeding and recurrent VTE who develop venous thromboembolism (VTE) present challenges for clinical management. This study evaluated the effectiveness and safety of apixaban vs warfarin in patients with VTE who have risk factors for bleeding or recurrences. Methods Adult patients with VTE initiating apixaban or warfarin were identified from five claims databases. Stabilized inverse probability treatment weighting (IPTW) was used to balance characteristics between cohorts for the main analysis. Subgroup interaction analyses were conducted to evaluate treatment effects among patients with and without each of the conditions that increased the risk of bleeding (thrombocytopenia and history of bleed) or recurrent VTE (thrombophilia, chronic liver disease, and immune-mediated disorders). Results A total of 94,333 warfarin and 60,786 apixaban patients with VTE met selection criteria. After IPTW, all patient characteristics were balanced between cohorts. Apixaban (vs warfarin) patients were at lower risk of recurrent VTE (HR [95% confidence interval (CI) 0.72 [0.67–0.78]), major bleeding (MB) (HR [95% CI] 0.70 [0.64–0.76]), and clinically relevant non-major (CRNM) bleeding (HR [95% CI] 0.83 [0.80–0.86]). Subgroup analyses showed generally consistent findings with the overall analysis. For most subgroup analyses, there were no significant interactions between treatment and subgroup strata on VTE, MB and CRNM bleeding. Conclusion Patients with prescription fills for apixaban had lower risk of recurrent VTE, MB, and CRNM bleeding compared with warfarin patients. Treatment effects of apixaban vs warfarin were generally consistent across subgroups of patients at increased risk of bleeding/recurrences

Effectiveness and safety of apixaban vs warfarin among venous thromboembolism patients at high-risk of bleeding

This study evaluated effectiveness and safety of apixaban versus warfarin among venous thromboembolism patients at high-risk of bleeding (defined as having at least one of the following bleeding risk factors: ≥75 years; used antiplatelet, NSAIDs, or corticosteroids; had prior gastrointestinal bleeding or gastrointestinal-related conditions; late stage chronic kidney disease). Adult venous thromboembolism patients initiating apixaban or warfarin with ≥1 bleeding risk factor were identified from Medicare and four commercial claims databases in the United States. To balance characteristics between apixaban and warfarin patients, stabilized inverse probability treatment weighting was conducted. Cox proportional hazards models were used to estimate the risk of recurrent venous thromboembolism, major bleeding, and clinically relevant non-major bleeding. In total, 88,281 patients were identified. After inverse probability treatment weighting, the baseline patient characteristics were well-balanced between the two cohorts. Among venous thromboembolism patients at high-risk of bleeding, apixaban was associated with significantly lower risk of recurrent venous thromboembolism, major bleeding and clinically relevant non-major bleeding. No significant interactions were observed between treatment and number of risk factors on major bleeding and clinically relevant non-major bleeding or between treatment and type of bleeding risk factors on any of the outcomes. In conclusion, apixaban was associated with significantly lower risk of recurrent venous thromboembolism and bleeding among venous thromboembolism patients at high-risk of bleeding. Effects were generally consistent across subgroups of patients with different number or type of bleeding risk factors

Risk of recurrent VTE, major bleeding, and CRNM bleeding for apixaban vs. warfarin among VTE patients at a high risk of bleeding stratified by number of risk factors and type of risk factors.

Risk of recurrent VTE, major bleeding, and CRNM bleeding for apixaban vs. warfarin among VTE patients at a high risk of bleeding stratified by number of risk factors and type of risk factors.</p

Post-IPTW descriptive baseline characteristics among VTE patients at a high risk of bleeding stratified by type of risk factor.

(DOCX)</p

Risk of recurrent VTE, major bleeding, and CRNM bleeding for apixaban vs. warfarin among VTE patients at a high risk of bleeding.

Risk of recurrent VTE, major bleeding, and CRNM bleeding for apixaban vs. warfarin among VTE patients at a high risk of bleeding.</p

Descriptive pre- and post-IPTW baseline characteristics among VTE patients at a high risk of bleeding that initiated apixaban vs warfarin.

Descriptive pre- and post-IPTW baseline characteristics among VTE patients at a high risk of bleeding that initiated apixaban vs warfarin.</p

Inclusion criteria.

VTE: venous thromboembolism.</p

Post-IPTW descriptive baseline characteristics among VTE patients at a high risk of bleeding stratified by number of risk factors.

(DOCX)</p