Model Derivation cohort Validation cohort Model AUROc (95% CI) Brier score AUROc (95% CI) Brier score 4C Mortality Score 0.786 (0.781 to 0.790) 0.170 0.767 (0.760 to 0.773) 0.171 Machine learning comparison* 0.796 (0.786 to 0.807) 0.191 0.779 (0.772 to 0.785) 0.197