Abstract 15864: Effectiveness and Safety of Standard and Reduced Doses of Dabigatran versus Rivaroxaban in Non-Valvular Atrial Fibrillation: A Cohort Study in the French Nationwide Claims Database SNDS.

Introduction: Dabigatran (D) and rivaroxaban (R) showed a better benefit-risk than VKA for stroke prevention in non-valvular atrial fibrillation (NVAF), but no randomized trial has compared D to R. Objectives: The objective was to compare the 2-year risk of major events in real-life use for NVAF in new users of standard doses (D150mg vs R20mg) and reduced doses (D110mg vs R15mg). Methods: Cohorts of D or R new users for NVAF in 2013 identified and followed 2 years in the SNDS French nationwide claims database. NVAF was defined from long-term disease registration, hospitalisation diagnosis or procedure for atrial fibrillation, without valvular disease (3-year history). D and R patients were 1:1 matched according to dose, on gender, age, drug start date and high-dimensional propensity scores (hdPS) including individual risk factors from CHA2DS2-VASc and HAS-BLED scores. Hazard ratios (HR) [95% confidence interval] were estimated on-treatment, using Cox proportional hazard risk or Fine and Gray models. Results: From the 10,847 D150, 15,532 D110, 18,829 R20 and 11,195 R15 new users for NVAF in 2013, 8,290 D150/R20 per arm, and 7,639 D110/R15 per arm were matched, i.e. 76% and 68% of the smallest group (D150 and R15 groups), respectively, with all standardized differences <0.1, most <0.02, and a good overlap of hdPS distributions. Patients on standard dose were younger than those with reduced dose (mean 66.9 and 80.4 years, respectively), with fewer stroke and bleeding risk factors (58.9% and 94.0% CHA2DS2-VASc > 2, 15.6% and 34,0% HAS-BLED ≥ 3, respectively). The D vs R HR for clinically relevant bleeding was 0.55 [0.43-0.70] for standard dose and 0.77 [0.64-0.92] for reduced dose, and respectively 0.92 [0.67-1.26] and 0.73 [0.56-0.94] for stroke and systemic embolism, 0.93 [0.66-1.29] and 0.95 [0.71-1.26] for acute coronary syndrome, 0.84 [0.65-1.11] and 0.95 [0.83-1.09] for death, and 0.74 [0.64-0.86] and 0.88 [0.79-0.97] for the composite of the 4 major events. Conclusions: This nationwide study shows that in a real-world setting, standard and reduced doses of dabigatran or rivaroxaban were not given to the same new users for NVAF, but in both doses there was a better benefit-risk for dabigatran than for rivaroxaban. [ABSTRACT FROM AUTHOR]