FIG 1.

The framework used for model development and validation. An nCV approach was used to generate 300 promising models, from which one model was selected and locked. The final model was validated by an external data set. The model accessed the features only, generated risk scores, and sent them for comparison with the actual outcome. The performance was evaluated using the area under the receiver operating characteristics curve and the discrimination c-index for survival analysis. This study represents a TRIPOD type 3 analysis. nCV, nested cross-validation; ROC, receiver operating characteristic curve.