A nomogram was developed using MIMIC-IV (4,478 DN patients) to predict 30-365 day mortality. LASSO-Cox selected 14 predictors (AUC>0.81). SHAP enhanced interpretability. External validation in elCU-CRD (n=866) gave AUC=0.668, acceptable calibration, net clinical benefit. The tool supports bedside risk stratification and individualized decisions.