Liver Transplant Patients with High Preoperative Serum Bilirubin Levels Are at Increased Risk of Postoperative Delirium: A Retrospective Study

Postoperative delirium is a common complication after liver transplantation (LT). A high model for end-stage liver disease (MELD) score is an independent risk factor for postoperative delirium, but it is unclear which of the components of this score are risk indicators. The aim of this study was to analyze the incidence of postoperative delirium according to the preoperative serum bilirubin level, a component of the MELD score, in patients who underwent LT. The medical records of 325 patients who underwent LT from January 2010 to February 2019 at a single university hospital were retrospectively reviewed. The patients were divided into two groups: those who experienced postoperative delirium (Delirium group, n = 69) and those who did not (Control group, n = 256). Data on the patients' demographic characteristics, perioperative management, and postoperative complications were collected. Mean preoperative bilirubin level was higher in the Delirium group than in the Control group (p < 0.0001). In the Delirium group, 54 (78.26%) patients had preoperative bilirubin levels above 3.5 mg/dL. In the multivariate analysis, preoperative bilirubin above 3.5 mg/dL was associated with postoperative delirium (p = 0.002). Therefore, preoperative hyperbilirubinemia is an independent risk factor for postoperative delirium.