Comparison of goodness of fit (R²) among 4 models for each of the 3 outcome variables. (A) Time to INR ≥ the lower limit of therapeutic range. (B) Time to INR > 4. (C) Early stable warfarin dose. In each panel, the first bar (□) represents the baseline model (including age, ethnicity, sex, amiodarone use, target INR, and cumulative warfarin dose); second bar (), the baseline model + VKORC1 / CYP2C9 genotypes; the third bar (), the baseline model + early INR values; fourth bar (■), the full model. The difference between the last 2 bars (■ and ) in each panel represents the contribution of genotypes after adjustment for baseline covariates and INR_early.