Table 4 Cox regression analysis for risk stratification of nomograms in the training and validation sets

Training set

 Low risk

83.18

42.82

31.12

31.43

Reference

 Moderate risk

63.24

18.77

11.59

15.70

1.974(1.723–2.263)

< 0.001

 High risk

32.75

8.19

5.04

8.83

3.798(3.126–4.614)

< 0.001

Validation set

 Low risk

76.75

29.71

21.91

22.57

Reference

 Moderate risk

56.30

12.94

8.36

13.23

1.785(1.488–2.141)

< 0.001

 High risk

26.36

6.59

4.71

7.97

3.154(2.455–4.050)

< 0.001