The Walter Index combined with delirium alone showed an optimism-corrected AUC of 0.723 (95% CI, 0.702-0.749); adding only frailty yielded an AUC of 0.713 (95% CI, 0.690-0.736), and adding only CRP level yielded an AUC of 0.716 (95% CI, 0.694-0.743) (Table 3). Here, CRP is linked to delirium.