Figure 2.

LOS cut-off value associated with increasing risk of death in ROC analysis. (n = 1638 patients/108 died). Legend: sensitivity (True Positive Rate), 1-specificity (False Positive Rate); scale is in decimals of sensitivity and specificity; interval every 0.2, i.e. 20%; green line—optimum cut-off point (max. Youden’s index = 0.22, cut-off point: 5), blue line—ROC curve with AUC 0.567, 95%CI 0.498–0.637, SE 0.035, p = 0.0568, red line—classification due to chance with AUC 0.5. Abbreviations: ROC—receiver operating characteristic, AUC—area under the curve, SE—standard error, LOS—length of stay. Method: AUC, ROC and SE analyzes performed according to Hanley and McNeil¹⁰.