Adherence to anticoagulant treatment with apixaban and rivaroxaban in a real-world setting

Low adherence to cardiovascular medications is often difficult to monitor and is associated with adverse outcomes. We investigated whether there is a difference between the estimated adherence (EA) of the two-dosed regimens of apixaban (A) and the one-dosed regimen of rivaroxaban (R) for stroke prophylaxis in patients with non-valvular atrial fibrillation (AF). This is a retrospective cohort study of AF patients referred to a well-structured nurse-based AF unit for the initiation of anticoagulation therapy. The adherence data was extracted from the Swedish national prescribed drug register. EA was calculated by dividing the number of daily doses dispensed from the prescription that occurred closest after 3 months from the first dispensed prescription of the respective agent until (but excluding) the last refill by the number of days in the interval. The study included 123 patients on A and 227 patients on R with a 12-month follow-up period. There were no significant demographic differences between the two patient groups except for previous vitamin K antagonist treatment, in the A patient group (n = 29, 24%) and in the R (n = 31, 14%), p = 0.025. The mean ± SD of EA after 3 months was high for both A 97 ± 7 (n = 112) and R 97 ± 9 (n = 197) p = 0.97. The EA ≥ 80% was for A 97% (n = 109) and for R 96% (n = 189) p = 0.43. The two dosed regimens of apixaban and the one dosed regimen of rivaroxaban showed similar high estimated adherence when administered for stroke prophylaxis in patients with AF in a well-structured nurse-based AF clinic.