Multiple linear regression analysis for first stable warfarin dose,* including early and week 1 INR values
| Covariate . | Including early INR values (days 4-6) . | Including late INR values (days 7-9) . | ||||
|---|---|---|---|---|---|---|
| β-coefficient . | 95% CI . | P . | β-coefficient . | 95% CI . | P . | |
| Age | −0.03 | −0.05 to −0.01 | .007 | −0.02 | −0.05 to 0.01 | .16 |
| Male sex | 0.42 | −0.18 to 1.02 | .17 | 0.34 | −0.46 to 1.14 | .40 |
| White ethnicity | 0.57 | −0.52 to 1.67 | .30 | −0.12 | −1.46 to 1.21 | .86 |
| Target INR | 1.05 | −0.92 to 3.03 | .29 | 2.16 | −0.31 to 4.63 | .09 |
| Amiodarone use | −0.92 | −1.72 to −0.13 | .023 | −0.46 | −1.55 to 0.63 | .40 |
| Cumulative warfarin dose† | 0.03 | −0.04 to 0.09 | .42 | 0.07 | 0.01 to 0.12 | .013 |
| INR values | ||||||
| INRearly | −1.29 | −1.79 to −0.80 | < .001 | NA | NA | NA |
| INRweek1 | NA | NA | NA | −1.21 | −1.70 to −0.73 | < .001 |
| VKORC1 A haplotype | −0.71 | −1.19 to −0.23 | .004 | −0.35 | −1.02 to 0.32 | .30 |
| CYP2C9 dose−reducing variant | −0.87 | −1.42 to −0.32 | .002 | −0.65 | −1.39 to 0.08 | .08 |
| Covariate . | Including early INR values (days 4-6) . | Including late INR values (days 7-9) . | ||||
|---|---|---|---|---|---|---|
| β-coefficient . | 95% CI . | P . | β-coefficient . | 95% CI . | P . | |
| Age | −0.03 | −0.05 to −0.01 | .007 | −0.02 | −0.05 to 0.01 | .16 |
| Male sex | 0.42 | −0.18 to 1.02 | .17 | 0.34 | −0.46 to 1.14 | .40 |
| White ethnicity | 0.57 | −0.52 to 1.67 | .30 | −0.12 | −1.46 to 1.21 | .86 |
| Target INR | 1.05 | −0.92 to 3.03 | .29 | 2.16 | −0.31 to 4.63 | .09 |
| Amiodarone use | −0.92 | −1.72 to −0.13 | .023 | −0.46 | −1.55 to 0.63 | .40 |
| Cumulative warfarin dose† | 0.03 | −0.04 to 0.09 | .42 | 0.07 | 0.01 to 0.12 | .013 |
| INR values | ||||||
| INRearly | −1.29 | −1.79 to −0.80 | < .001 | NA | NA | NA |
| INRweek1 | NA | NA | NA | −1.21 | −1.70 to −0.73 | < .001 |
| VKORC1 A haplotype | −0.71 | −1.19 to −0.23 | .004 | −0.35 | −1.02 to 0.32 | .30 |
| CYP2C9 dose−reducing variant | −0.87 | −1.42 to −0.32 | .002 | −0.65 | −1.39 to 0.08 | .08 |
NA indicates not applicable; INRearly, INR on days 4, 5, and 6 in 162, 27, and 25 patients, respectively; INRweek1, INR on days 7, 8, and 9 in 63, 34, and 48 patients, respectively.
First stable dose was defined as the first unchanged daily dose given for more than or equal to 7 days that yielded an INR value within the therapeutic range.
In each patient, cumulative dose was calculated up to the day preceding the respective INR used in the analysis.