Impact of age, comorbidity, and polypharmacy on the efficacy and safety of edoxaban for the treatment of venous thromboembolism: An analysis of the randomized, double-blind Hokusai-VTE trial

Background Many patients with venous thromboembolism (VTE) are elderly, have multiple comorbidities and take several concomitant medications. Physicians may prefer warfarin over direct oral anticoagulants (DOACs) in such patients because comparative data are lacking. This analysis was designed to determine the effects of advanced age, comorbidities, and polypharmacy on the efficacy and safety of edoxaban and warfarin in patients with VTE. Methods Using data from the Hokusai-VTE study, we report rates of recurrent VTE and of clinically relevant bleeding by age category (< 65, 65–75, and ≥ 75; < 80 versus ≥ 80 years), and by number of comorbidities (0, 1–2, > 2) and concomitant medications (< 3, 3–5, > 5). Hazard ratios (HR) and corresponding 95% confidence intervals (CI) for edoxaban versus warfarin were determined and Kaplan-Meier methodology was used to construct time-to-event curves. At 3 months, pre- and postdose levels of edoxaban were measured using mass spectrometry. For warfarin-treated patients, the time in therapeutic range was calculated. The study was approved by institutional review boards; informed consent was obtained. Results Recurrent VTE increased with advanced age, multiple comorbidities, and polypharmacy in warfarin-treated patients but not with edoxaban. Edoxaban was more effective than warfarin in patients ≥ 75 years of age and in those with multiple comorbidities. In the 517 patients over 80 years of age, recurrent VTE occurred in 2.8% given edoxaban and in 5.7% given warfarin (HR 0.51, 95% CI 0.21–1.24). Bleeding increased with age, comorbidity, and polypharmacy regardless of treatment, but the relative safety of edoxaban versus well-managed warfarin was maintained. Age, comorbidity, and polypharmacy did not impact edoxaban concentrations. Conclusions These data suggest that a once-daily fixed dose of edoxaban is more effective and at least as safe as warfarin in high-risk VTE patients identified by older age, more comorbidities, and polypharmacy. Clinical trial registration: NCT00986154