Table 3.

MAFs and variation in warfarin dose explained (R²) by individual VKORC1 SNPs among Asians, blacks, and whites

SNP	No. of participants*	MAF, %	Univariate R2, %	Multivariable R2, %†
−1639G>A
Asian	641	91.03	18.4	26.7
Black	368	10.05	4.2	26.3
White	681	37.81	22.5	48.5
1173C>T
Asian	641	91.03	18.4	26.7
Black	368	10.19	4.5	26.2
White	681	37.81	22.8	48.9
1542G>C
Asian	641	91.03	18.4	26.7
Black	368	26.36	0.2	23.0
White	681	38.33	22.4	48.3
2255C>T
Asian	641	91.03	18.4	26.7
Black	368	21.33	2.6	24.7
White	681	37.89	22.5	48.4

Model parameters are estimated on the square root of warfarin dose, and the resulting R² value is calculated by squaring the correlation between the retransformed predicted dose and observed dose.

SNP indicates single nucleotide polymorphism; and MAF, frequency of the minor allele.

^*Participants with genotype information on all 4 VKORC1 SNPs.

^†Restricted to 1638 participants (619 Asian, 354 blacks, and 665 whites) with genotype information on all 4 VKORC1 SNPs and complete data on age, height, weight, CYP2C9 enzyme inducer status, and amiodarone status.