The populations included in the randomized controlled clinical trials and observational studies were different. The effectiveness and safety of rivaroxaban for stroke prevention in patients with atrial fibrillation (AF) varied among studies. This study aimed to estimate the real-world outcomes of rivaroxaban in patients with AF accurately. A discrete event simulation (DES) was used to predict the counterfactual results of the ROCKET AF study. The hypothetical cohorts of patients were generated using Monte Carlo simulation according to the baseline covariate distributions that matched the marginal distribution of covariates reported in the ROCKET AF and three observational studies. The DES model structure was constructed based on a priori knowledge about disease progression and possible outcomes of patients with AF. The DES model accurately replicated the overall results of the ROCKET AF study. Both predicted stroke/systematic embolism (SE) and major bleeding rates were lower in the three observational studies than in the simulated ROCKET AF study. The risk difference of stroke/SE and major bleeding was not significant among the predicted outcomes of the three observational studies. Although some differences existed in the absolute rates of stroke/SE and major bleeding between observed and simulated studies, the results confirmed that rivaroxaban was noninferior to warfarin for the prevention of stroke/systematic embolism with no significance in the risk of major bleeding in large AF populations, which was similar to the results of ROCKET AF.