Table 3. Multivariate analysis using a Cox proportional hazards model including the groups determined by the RPA and age.
| Group | Hazard Ratio | 95% CI | P value |
|---|---|---|---|
| 1 | Reference | ||
| 2 | 4.977 | 0.677 – 36.579 | 0.115 |
| 3 | 5.711 | 0.743 – 43.897 | 0.094 |
| 4 | 11.362 | 1.485 – 86.953 | 0.019 |
| 5 | 12.661 | 1.464 – 109.527 | 0.021 |
| 6 | 31.732 | 4.295 – 234.453 | 0.001 |
| Age ≥ 70 | 0.787 | 0.245 – 2.532 | 0.688 |
Note: Gleason score, pre-operation PSA, tumor margins, risk and pathologic stage were not retained by the model due to co-linearity with the recursive partitioning analysis (RPA) group variable. Multivariate analysis showed that the risk of groups 4, 5, 6 is higher than the control group (group 1).