Rivaroxaban Plus Aspirin Versus Aspirin in Relation to Vascular Risk in the COMPASS Trial

Abstract

Background: The COMPASS (Cardiovascular Outcomes for People Using Anticoagulation Strategies) trial showed that the combination of low-dose rivaroxaban and aspirin reduced major vascular events in patients with stable vascular disease. Objectives: The purpose of this study was to identify subsets of patients at higher risk of recurrent vascular events, which may help focus the use of rivaroxaban and aspirin therapy. Methods: COMPASS patients with vascular disease were risk stratified using 2 methods: the REACH (REduction of Atherothrombosis for Continued Health) atherothrombosis risk score and CART (Classification and Regression Tree) analysis. The absolute risk differences for rivaroxaban with aspirin were compared to aspirin alone over 30 months for the composite of cardiovascular death, myocardial infarction, stroke, acute limb ischemia, or vascular amputation; for severe bleeding; and for the net clinical benefit. Results: High-risk patients using the REACH score were those with 2 or more vascular beds affected, history of heart failure (HF), or renal insufficiency, and by CART analysis were those with ≥2 vascular beds affected, history of HF, or diabetes. Rivaroxaban and aspirin combination reduced the serious vascular event incidence by 25% (4.48% vs. 5.95%, hazard ratio: 0.75; 95% confidence interval: 0.66 to 0.85), equivalent to 23 events prevented per 1,000 patients treated for 30 months, at the cost of a nonsignificant 34% increase in severe bleeding (1.34; 95% confidence interval: 0.95 to 1.88), or 2 events caused per 1,000 patients treated. Among patients with ≥1 high-risk feature identified from the CART analysis, rivaroxaban and aspirin prevented 33 serious vascular events, whereas in lower-risk patients, rivaroxaban and aspirin treatment led to the avoidance of 10 events per 1,000 patients treated for 30 months. Conclusions: In patients with vascular disease, further risk stratification can identify higher-risk patients (≥2 vascular beds affected, HF, renal insufficiency, or diabetes). The net clinical benefit remains favorable for most patients treated with rivaroxaban and aspirin compared with aspirin.