Table 3 Univariate Cox regression analysis for PTC recurrence in the training and testing patient sets
| Â | Training set | Â | Testing set | Â |
|---|---|---|---|---|
Factor | HR(95% CI) | p | HR(95% CI) | p |
All patients | 414 | Â | 609 | Â |
Age (years) | Â | 0.622 | Â | 0.753 |
  ≤45 | 1 (reference) |  | 1 (reference) |  |
  >45 | 0.982 (0.457 to 1.452) |  | 0.872(0.562 to 1.654) |  |
Age (years) | Â | 0.672 | Â | 0.261 |
  ≤55 | 1 (reference) |  | 1 (reference) |  |
  >55 | 1.524 (0.782 to 2.281) |  | 1.622 (0.891 to 2.462) |  |
Gender | Â | 0.321 | Â | 0.271 |
  Female | 1 (reference) |  | 1 (reference) |  |
  Male | 1.451 (0.661 to 2.992) |  | 1.652 (0.842 to 2.721) |  |
Postoperative RAI | Â | 0.172 | Â | 0.283 |
  Yes | 1 (reference) |  | 1 (reference) |  |
  No | 0.872 (0.521 to 1.726) |  | 0.982 (0.475 to 2.228) |  |
Race | Â | 0.372 | Â | 0.208 |
  Han | 1 (reference) |  | 1 (reference) |  |
  Other | 1.211 (0.872 to 1.872) |  | 1.253 (0.772 to 2.011) |  |
BRAF mutation | Â | 0.382 | Â | 0.229 |
  Positive | 1 (reference) |  | 1 (reference) |  |
  Negative | 0.871 (0.622 to 1.263) |  | 0.982 (0.821 to 1.461) |  |
T classification | Â | 0.021 | Â | 0.008 |
 T1-2 | 1 (reference) |  | 1 (reference) |  |
 T3-4 | 3.261 (1.271 to 5.653) |  | 3.876 (1.532 to 6.211) |  |
PTC nodule number | Â | 0.152 | Â | 0.102 |
  Single | 1 (reference) |  | 1 (reference) |  |
  Multiple | 1.933 (0.891 to 2.901) |  | 2.011 (0.902 to 3.110) |  |
N classification | Â | 0.048 | Â | 0.041 |
  N0 | 1 (reference) |  | 1 (reference) |  |
  N1 | 1.502 (1.029 to 2.893) |  | 1.462 (1.081 to 3.011) |  |
M classification | Â | <0.001 | Â | <0.001 |
  M0 | 1 (reference) |  | 1 (reference) |  |
  M1 | 8.662 (3.092 to 16.223) |  | 9.920 (3.825 to 21.273) |  |
Serum fibrinogen levels | Â | 0.012 | Â | 0.007 |
  Low | 1 (reference) |  | 1 (reference) |  |
  High | 3.457 (2.203 to 6.782) |  | 4.228(2.102 to 7.541) |  |