P3580Which factors influence the choice of a non-vitamin K oral anticoagulant over warfarin for stroke prevention among atrial fibrillation patients? Insights from the prospective SPRINT-AF registry

Abstract

Background/Introduction: In randomized controlled trials, non-vitamin K oral anticoagulants (NOAC) are at least as safe and efficacious as warfarin among atrial fibrillation (AF) patients who are at increased risk for stroke. Whether these findings are translated in real-world clinical practice is less well-defined. Purpose: We examined potential factors (clinical, preference-based, and secular) which may influence the selection of NOAC agents vs. warfarin in real-world practice. Methods: Phase-II of the Stroke Prevention and Rhythm INTerventions in Atrial Fibrillation (SPRINT-AF) registry prospectively enrolled 2,499 patients with nonvalvular AF at 132 community -based practices in Canada (from November 2013 to March 2016). Here, we report on data from the first 2,215 patients enrolled. Multivariable logistic regression was performed to identify factors associated with use of NOAC vs. warfarin. Statistical measures of association were reported with risk ratios (RR) and their 95% confidence intervals (CI). Patient satisfaction with OAC use was measured with a validated treatment-specific instrument, the Anti- Clot Treatment Scale (ACTS). The ACTS consists of 2 domains: Treatment burden (range: 12-60) and Treatment benefit (range: 3-15). Higher scores denote lower treatment burden and greater treatment benefit, as reported by the patient. Results: At the baseline visit, there were 1,240 (69%) patients who were treated with a NOAC agent and 550 patients who were treated with warfarin at baseline. The baseline demographics were similar between both groups of patients. Compared to those treated with NOAC, patients treated with warfarin were older (76.2±9.1 vs. 74.0±9.7 years, p<0.001), more likely to have heart failure (HF) (19.1% vs. 12.0%, p<0.001), and had higher CHA2DS2-VASc scores (3.7±1.6 vs. 3.4±1.5, p<0.001). Patients treated with NOAC agents reported slightly lower treatment burden relative to those treated with warfarin (ACTS burden score: 58.0 (IQR 55.0, 60.0) vs. 57.0 (IQR 53.0, 59.0), p<0.001). Both groups reported similar treatment benefits scores (ACTS benefit score: 12.0 (IQR 9.0, 14.0) vs. 12.0 (IQR 9.0, 13.0), p=0.05). After adjustment of baseline factors with multivariable logistic regression, physician-perceived factors (superior efficacy, lower bleeding risk), patient-perceived factors (better side effect profile), and ease of dosing favoured the use of NOAC over warfarin. On the other hand, lower cost, older age, and a history of HF were associated with use of warfarin over NOAC (Figure). Conclusions: In real-world clinical practice, preference-based factors and cost appear to be strong determinants of whether a NOAC agent or warfarin is prescribed for AF-related stroke prevention. (Table Presented).