The National Clinical Database Risk Calculator and the 5‐Item Modified Frailty Index Predict the Development of Postoperative Delirium After Surgery for Hepatocellular Carcinoma

ABSTRACT Aim Postoperative delirium in elderly patients is a critical clinical issue because of its adverse effect on recovery and prognosis. The National Clinical Database (NCD) Risk Calculator, a clinical tool developed in Japan, is widely used to predict various postoperative complications, including delirium. In this study, we aimed to develop a more accurate delirium prediction model by integrating the NCD Risk Calculator with additional clinical indicators. Methods This study included 106 patients who underwent segmentectomy or more extensive procedures for hepatocellular carcinoma between 2013 and 2023. The training cohort comprised patients treated between 2013 and 2017, and those treated afterward formed the validation cohort. In the training cohort, we assessed the NCD Risk Calculator and additional indices for the favorable‐risk group, and validated the best‐performing index in combination with the NCD Risk Calculator. Results Using the median predicted risk (6.4%) as a threshold, the adverse‐risk group had a significantly higher incidence of delirium than the favorable‐risk group ( p < 0.01). Among several indices, the 5‐Item Modified Frailty Index (mFI‐5) showed the strongest association with delirium (AUC 0.76, p < 0.01). Patients classified as high‐risk by both the NCD Risk Calculator and mFI‐5 had significantly higher delirium incidence in the training ( p < 0.01) and validation ( p = 0.05) cohorts. Multivariate analysis identified high‐risk status as an independent predictor of postoperative delirium ( p < 0.01). Conclusion The combination of the NCD Risk Calculator and mFI‐5 enhances predictive accuracy and serves as a reliable tool for assessing delirium risk in older patients.