Table 4.
ITPA Variants and ITPase Deficiency Are Associated With Reduction in Week 4 Hb Level
| Estimate | Standard error |
P value | Adjusted estimatea |
Standard error |
Adjusted P valuea |
|
|---|---|---|---|---|---|---|
| ITPA variantb | ||||||
| rs1127354 | −1.64 | 0.21 | 3.12 × 10−13 | −1.77 | 0.21 | 1.53 × 10−15 |
| rs7270101 | −0.63 | 0.19 | 1.28 × 10−3 | −0.83 | 0.18 | 4.22 × 10−6 |
| ITPase deficiency variable | −0.89 | 0.09 | 2.35 × 10−18 |
NOTE. ITPA variants were strongly and independently associated with protection from quantitative Hb reduction at week 4 of therapy in multivariable linear regression analyses. The composite ITPase deficiency variable was more strongly associated with protection from week 4 quantitative Hb reduction than either individual ITPA variant in a multivariable linear regression model.
Adjusted estimates and P values were calculated in models in which the other functional variant was already included.
Covariables rs1127354 and/or rs7270101, or ITPase defciency variable, plus ethnicity (white vs black), age (years), sex, baseline Hb level (g/dL), baseline creatinine level (mg/dL), METAVIR F3–4 vs F0–2, and RBV starting dose (mg/kg) were considered. Backward selection was used to remove variables from the model. A P value of .05 was used to remove variables from the final model.