Rivaroxaban, an oral factor Xa inhibitor, has been proven to be non inferior to warfarin in the ROCKET AF trial. An important consideration is the risk benefit in the elderly population who are susceptible to various anticoagulation associated complications. A recent article compared the safety and efficacy between rivaroxaban and warfarin in patients >75 vs those <75 years (1).

In this international, double blind, double dummy, event driven study, 14,264 patients were followed over a period of 707 days with median treatment duration of 590 days. These patients were randomized to receive either warfarin or dose adjusted rivaroxaban. The study population consisted of 6229 (44%) patients over 75 years old with a CHADS2 score of 3.7.Patients under 75 years of age had a mean CHADS2 score of 3.3. A standardized stroke questionnaire was used to detect the primary endpoints of stroke and systemic embolism and detailed inclusion and exclusion criteria were described. For all analysis, a p value of <0.05 was considered significant.

The overall incidence of stroke/systemic embolism was significantly higher in older patients when compared to the younger patients (2.57% vs. 2.05%/100 patient-years, p=0.0068). In elderly patients, there was a trend towards decreased risk with rivaroxaban ( 2.29% vs 2.85% warfarin per 100 patient-years, hazard ratio [HR] 0.80, 95% confidence interval (CI) 0.63–1.02). However in younger patients, there was no significant difference between rivaroxaban and warfarin (2.00% vs. 2.10%/100 patient-years; HR 0.95, 95% CI 0.76–1.19). Major bleeding was higher in older patients (4.63 vs 2.74/100 patient years, p <0.0001). There was no increased risk of major bleeding with rivaroxaban compared to warfarin in elderly as well as younger patients(>75 years 4.86% rivaroxaban vs. 4.40% warfarin per 100 patient-years; HR 1.11, 95% CI 0.92– 1.34; <75 years 2.69% vs. 2.79%/100 patient-years; HR 0.96, 95% CI 0.78–1.19). Rivaroxaban increased the risk of combined endpoint of major and clinically relevant non-major bleeding in elderly patients (HR: 1.13, 95% CI 1.02–1.25), where as in younger patients, the risk was similar (HR 0.93, 95% CI 0.84–1.04). While the risk of intracranial bleeding was lower with rivaroxaban in younger patients HR 0.54, 95% CI 0.33–0.89), there was no significant difference in older patients (HR 0.80, 95% CI 0.50–1.28).

Conclusion:In summary, this study showed that rivaroxaban is non-inferior to warfarin for elderly non-valvular AF patients. Rivaroxaban increased the risk of clinically relevant non-major bleeding. Conversely it decreased the risk of intracranial bleeding. However, it is important to note that anti-coagulation management is much simplified by rivaroxaban. Therefore rivaroxaban can be considered as an alternative for stroke prevention in the elderly population with non valvular atrial fibrillation.

Reference:

1. Halperin JL, Hankey GJ, Wojdyla DM et al. Efficacy and Safety of Rivaroxaban Compared With Warfarin Among Elderly Patients With Nonvalvular Atrial Fibrillation in the Rivaroxaban Once Daily, Oral, Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF). Circulation 2014;130:138-46.