Association of CYP2C9 variants with PHT maintenance dose
| Model | Independent Variables | Beta Coefficient | Adjusted R2 | F | p-Value |
|---|---|---|---|---|---|
| 1 | CYP2C9*2 | −44.6 | 0.113 | 3.44 | 0.004 |
| 2 | CYP2C9*3 | −89.0 | 0.143 | 4.20 | 6.71 × 10−5 |
| 3 | CYP2C9*1B | −21.7 | 0.080 | 2.66 | 0.121 |
| 4 | CYP2C9*2 + | −45.2 | 0.186 | 4.94 | 3.09 × 10−6 |
| CYP2C9*3 | −89.6 | ||||
| 5 | CYP2C9*2 + | −105.4 | 0.230 | 5.67 | 1.11 × 10−7 |
| CYP2C9*3 + | −52.6 | ||||
| CYP2C9*1B | −42.2 | ||||
| 6 | TBW + | 2.52 | 0.371 | 5.06 | 2.70 × 10−5 |
| CYP2C9*2 + | −47.9 | ||||
| CYP2C9*3 + | −93.2 | ||||
| 7 | TBW + | 2.29 | 0.471 | 6.59 | 5.4 × 10−7 |
| CYP2C9*2 + | −65.5 | ||||
| CYP2C9*3 + | −121 | ||||
| CYP2C9*1B | −66.4 |
Effects of CYP2C9 alleles on PHT dose were estimated by linear regression in a multivariate model including gender and ancestry estimated according to a principal components method (EIGENSTRAT). The test sample included n = 173 patients with epilepsy receiving maintenance PHT therapy, except for models 6 and 7 which included only a subset of n = 70 patients with known body weight at the time of PHT maintenance therapy.