Table 3.
Accuracy of the Nomogram for estimating the risk of EPT birth after cerclage.
| Variable | Training cohort | Internal validation cohort | External validation cohort |
|---|---|---|---|
| C index | 0.82 (95%CI 0.77–0.88) | 0.80 (95%CI 0.72–0.88) | 0.79 (95%CI 0.68–0.90) |
| Sensitivity, % | 74.60 | 69.20 | 66.70 |
| Specificity, % | 72.00 | 71.10 | 74.20 |
| Positive predictive value, % | 35.58 | 43.35 | 41.67 |
| Negative predictive value, % | 93.19 | 87.84 | 88.97 |
| Positive likelihood ratio | 2.67 | 2.39 | 2.59 |
| Negative likelihood ratio | 0.35 | 0.43 | 0.45 |
EPT: extremely preterm.