Table 3.
The discriminatory ability of the nomogram model vs. AJCC stage.
| C-index (95% CI) |
AUC (95% CI) |
△C-index (P value) |
NRI (P value) |
IDI (P value) |
|
|---|---|---|---|---|---|
| TC Nomogram |
0.622 (0.591-0.654) |
0.709 (0.661-0.758) |
– | – | – |
| TC AJCC stage |
0.580 (0.548-0.612) |
0.654 (0.605-0.703) |
– | – | – |
| VC Nomogram |
0.713 (0.656-0.771) |
0.739 (0.655-0.823) |
– | – | – |
| VC AJCC stage |
0.659 (0.602-0.716) |
0.689 (0.605-0.773) |
– | – | – |
| TC Nomogram vs. AJCC stage | – | – | 0.057 P <.001 |
26.6% P <.001 |
6.4% P <.001 |
| VC Nomogram vs. AJCC stage | – | – | 0.054 P = 0.020 |
23.9% P = 0.040 |
7.6% P <.001 |
TC, training cohort; VC, validation cohort; C-index, concordance index; CI, confidence interval; NRI, net reclassification index; IDI, integrated discrimination improvement.
NRI or IDI>0 indicate positive improvement, suggesting that the nomogram model achieved better prediction ability than AJCC stage. NRI or IDI<0 indicate diminished improvement, and the nomogram model’s prediction ability was less than that of the AJCC stage. NRI or IDI = 0 indicate that the nomogram model did not change.