Fig. (1) Receiver-operating characteristic curves (ROC) of elevated serum urea levels at admission (alone and in combination with other factors) for predicting the all-cause in-hospital mortality in older patients with hip fracture. A (solid line), ROC curve based on data from the full model (8 on admission independent risk factors plus HPIR vs. 0 risk factors); B, ROC curve based on combination of urea>7.5mmol/L and albumin <33g/L; C, ROC curve based on combination of urea>7.5mmol/L and GGT/ALT>2.5; D, ROC curve based on urea>10.0mmol/L and E, ROC curve based on urea>7.5mmol/L. Abbreviations: AUC, area under receiver operating characteristic curve; CI, confidence interval; HPIR, high postoperative inflammatory response; U7.5, serum urea>7.5mmol/L; Alb, serum albumin<33g/L; G/A, gamma-glutamyl transferase/alanine aminotransferase ratio (GGT/ALT); U10.0, serum urea>10.0mmol/L.