Abstract: AIM: To evaluate the predictive performance of Warfarin Dose Calculator (WDC) based on Bayesian method, Warfarin Dosing and International Warfarin Pharmacogenetics Consortium (IWPC) Warfarin Dose Calculator based on Multiple Linear Regression (MLR) in the absence of warfarin related genotypes, in order to provide help for patients using warfarin in areas where there is unconditional warfarin related genotypes detection. METHODS: The predicted performance of each tool was evaluated by calculating the mean prediction error (MPE), root mean square error (RMSE) and the percentage of patients whose prediction error was within ±20% of the actual maintenance dose. All statistical analyses were performed by SPSS statistics 26.0 software. RESULTS: The Posteriori of the WDC had the lowest MPE, RMSE and highest percentage of patients whose prediction errors within ±20% of the actual maintenance dose. In addition, the predictive accuracy of the Priori and Posteriori of WDC is significantly higher than that of Warfarin Dosing and IWPC warfarin dose calculator. CONCLUSION: Among the three assistant tools for warfarin dose prediction, Warfarin Dose Calculator based on Bayesian method may be more suitable for warfarin dose prediction of patients in unconditional warfarin related genotypes detection area.

Key words: Warfarin, Bayesian method, multiple linear regression, dose prediction