Clinical Predictors Associated With Warfarin Sensitivity.

Abstract

Our study aimed to identify predictors of warfarin sensitivity like demographic, clinical, and genetic data from a previously collected cohort of patients (n = 4272) with a stable warfarin dose who were able to achieve an observed international normalized ratio of 2-3. Predictors of warfarin sensitivity (dose ≤21 mg/wk) were identified using a 2-stage approach. First, bivariate analysis, using analysis of variance for continuous variables and χ test for categorical variables, was performed to identify possible predictors of warfarin sensitivity (P < 0.05). Second, logistic regression with backward stepwise selection was then performed using predictors identified in bivariate analysis step to produce final model containing independent predictors at P < 0.05. Increased warfarin sensitivity was associated with increased age; CYP2C9 genotypes 2/3, 1/3, and 3/3; VKORC1 genotypes AA and AG; and amiodarone use. Decreased warfarin sensitivity (ie, weekly warfarin dose of >21 mg) was associated with increased height, increased weight, having diabetes mellitus, VKORC1 genotype GG, and CYP2C9 genotype 1/1. In conclusion, we identified patients' characteristics associated with warfarin sensitivity. This project is expected to improve patient care by identifying patients who need a low warfarin dose before warfarin administration. Early identification of this subset of patients helps minimize the incidence of bleeding.