Model validation of EASIX-PRE as predictor of ICU admission. (A) Multivariate model. The prediction error of EASIX-PRE (red curve) developed in the study cohort was computed for the entire follow-up and compared with the prediction error of the reference value (black curve). A lower prediction error curve in the model including EASIX (red curve) supports the usefulness of EASIX for predicting prognosis. (B) Time-dependent concordance indices for ICU admission. The highest concordance index is found in the model that includes EASIX-PRE (red; multivariable). A concordance index of 0.5 (dotted line) implies random concordance. A concordance index >0.6 is regarded as acceptable. The concordance index found in our analysis was >0.7. AUC, area under the curve.