Table 2.
Multivariable analysis of PFS in the unadjusted and IPTW-adjusted study populations
| Variable | Before IPTW adjustment |
After IPTW adjustment |
||||
|---|---|---|---|---|---|---|
| HR | 95% CI | P value | Weighted HR | 95% CI | P value | |
| Sex | ||||||
| Male | Reference | Reference | ||||
| Female | 0.66 | 0.33-1.32 | 0.24 | 0.81 | 0.41-1.61 | 0.56 |
| Drinking | ||||||
| No | Reference | Reference | ||||
| Yes | 1.39 | 0.77-2.53 | 0.27 | 1.23 | 0.68-2.23 | 0.50 |
| Liver metastases | ||||||
| No | Reference | Reference | ||||
| Yes | 1.50 | 0.95-2.37 | 0.08 | 1.34 | 0.79-2.30 | 0.27 |
| No. of metastatic lesions | ||||||
| ≤5 | Reference | Reference | ||||
| >5 | 1.22 | 0.76-1.96 | 0.42 | 1.42 | 0.81-2.51 | 0.22 |
| EBV DNA4-6 cycles | ||||||
| Undetectable | Reference | Reference | ||||
| Detectablea | 2.49 | 1.53-4.06 | <0.001 | 2.19 | 1.22-3.92 | 0.008 |
| LRRT | ||||||
| No | Reference | Reference | ||||
| Yes | 0.51 | 0.32-0.80 | 0.03 | 0.58 | 0.34-0.99 | 0.04 |
CI, confidence interval; EBV, Epstein–Barr virus; HR, hazard ratio; IPTW, inverse probability of treatment weighting; LRRT, locoregional radiotherapy; PFS, progression-free survival.
a
Detectable values (for all four centers), 0 copies/ml.