Rivaroxaban en prévention prolongée de la MTEV chez les patients de plus de 75 ans avec affection médicale aigüe.

Background: Although older patients are at increased risk for venous thromboembolism (VTE), thromboprophylaxis is underutilized because of bleeding concerns. The MARINER trial evaluated whether rivaroxaban reduced symptomatic post-discharge VTE in acutely ill medical patients. We hypothesized that rivaroxaban would have a favorable benefit/risk profile in patients ≥75 years of age.

Methods: Patients were randomized in a double-blind manner at hospital discharge to rivaroxaban (10mg/day for creatinine clearance ≥50 ml/min; 7.5mg/day for ≥30-<50ml/min) or placebo for 45 days. Using a Cox proportional hazard model including treatment as a covariate, we compared the risk of the primary efficacy outcome (symptomatic VTE plus VTE-related death in the intention-to-treat population) and safety outcome (ISTH major bleeding in the safety population) in the prespecified subgroups of patients ≥ and <75 years of age.

Results: The primary event rate in patients ≥75 years of age was 2-fold higher than that in those <75. The incidence of the primary efficacy outcomes in both age groups was numerically lower with rivaroxaban than with placebo (≥75: 1.2% and 1.6%, HR 0.73 95% CI 0.43, 1.22; <75 0.6% and 0.8%, HR 0.78 95% CI 0.46, 1.32; interaction p-value for age group=0.85). The incidence of major bleeding was low and similar in the two age and treatment groups (interaction p-value for age group=0.35).

Limitations: Subgroup analysis.

Conclusion: Symptomatic VTE and VTE-related death occur frequently in older patients with acute medical illness. The benefit/risk profile of rivaroxaban in patients ≥75 years of age appears consistent with that observed in the general population.