Table 3.
Unadjusted and adjusted hazard ratios for time to maintenance dose for genetic factors, stratified by race.
| Gene/allele (N = 358)a | African American | No. of variants | N (%) | N (%) Reaching Maintenance Doseb | Unadjustedc | Adjustedc,f | ||
|---|---|---|---|---|---|---|---|---|
| Hazard Ratiod | Pinteractione | Hazard Ratiod | Pinteractione | |||||
| VKORC1 | No | ≥1 | 127 (64) | 97 (76) | 1.09 (0.81, 1.46) | 0.42 | 1.31 (0.93, 1.85) | 0.85 |
| 0 | 72 (36) | 59 (82) | — | — | ||||
| Yes | ≥1 | 32 (20) | 22 (69) | 1.41 (0.78, 2.54) | 1.40 (0.71, 2.77) | |||
| 0 | 127 (80) | 89 (70) | — | — | ||||
|
| ||||||||
| CYP2C9 | No | ≥1 | 72 (38) | 58 (81) | 0.97 (0.69, 1.36) | 0.99 | 1.05 (0.73, 1.52) | 0.49 |
| 0 | 120 (62) | 93 (78) | — | — | ||||
| Yes | ≥1 | 12 (8) | 8 (67) | 0.96 (0.53, 1.73) | 0.68 (0.35, 1.35) | |||
| 0 | 143 (92) | 99 (69) | — | — | ||||
|
| ||||||||
| APOE ε2 | No | ≥1 | 28 (14) | 20 (71) | 1.08 (0.68, 1.73) | 0.93 | 0.91 (0.52, 1.58) | 0.46 |
| 0 | 168 (86) | 134 (80) | — | — | ||||
| Yes | ≥1 | 36 (23) | 25 (69) | 1.11 (0.62, 2.01) | 1.21 (0.61, 2.40) | |||
| 0 | 121 (77) | 85 (70) | — | — | ||||
|
| ||||||||
| APOE ε4 | No | ≥1 | 45 (23) | 37 (82) | 1.01 (0.71, 1.44) | 0.93 | 0.97 (0.67, 1.42) | 0.92 |
| 0 | 151 (77) | 117 (77) | — | — | ||||
| Yes | ≥1 | 60 (38) | 43 (72) | 1.03 (0.57, 1.86) | 1.00 (0.51, 1.98) | |||
| 0 | 97 (62) | 67 (69) | — | — | ||||
Both unadjusted and adjusted results are from the same complete-case dataset to improve comparability.
Individuals who failed to reach maintenance dose by the end of the study were considered censored.
All models are stratified by anticoagulation clinic site.
Hazard ratios and confidence intervals are based on the mean and variance from 1,000 bootstrap replications. Hazard ratios less than 1 indicate longer time to maintenance dose; hazard ratios greater than 1 indicate shorter time to maintenance dose.
P-values for interactions are based on the Wald test using the mean and variance of interaction terms from 1,000 bootstrap replications.
Adjusted for all baseline factors shown in Table 2.
P < 0.05