Background: Hepatic resection often results in delirium in preoperatively self-sufficient elderly people. The association of frailty with postoperative delirium remains unclear, and preoperative risk assessment, including frailty, of postoperative delirium has not been established.

Methods: This prospective multicenter study included 295 independently living patients aged ≥ 65 years scheduled for initial hepatic resection. All patients answered the phenotypic frailty index Kihon Checklist, which is a self-reporting list of 25 questions, within a week before surgery. The risk factors for postoperative delirium were investigated. Patients who scored ≥ 4 in the Intensive Care Delirium Screening Checklist were designated as having postoperative delirium.

Results: Delirium developed after liver resection in 22 of 295 patients (7.5%). Total Kihon Checklist score (≥ 6 points), age (≥ 75 years), and serum albumin concentration (≤ 3.7 g/dL) were the independent risk factors for postoperative delirium. The proportion of patients with postoperative delirium was 0% in those with no applicable risk factors, 3.2% in those with one applicable risk factor, 12.0% in those with two applicable risk factors, and 40.9% in those with all three factors (p < 0.001). The area under the receiver operating characteristic curve for this risk assessment for predicting postoperative delirium was 0.842.

Conclusion: The use of these three factors for preoperative risk assessment may be effective in predicting and preparing for delirium after hepatic resection in elderly patients.