The Impact of Preoperative Hepatic Impairment on the Development of Postoperative Delirium: A Systematic Review and Meta-Analysis.

Postoperative delirium (POD) is one of the most common psychiatric and neurologic complications experienced by patients undergoing general anesthesia. While it is widely hypothesized that hepatic impairment is associated with POD, the increased risk that various forms of preoperative hepatic impairment contribute to the development of POD is not well defined in the literature. A database search was performed on Embase, Web of Science, and MEDLINE-PubMed searching for articles containing keywords regarding the association between hepatic impairment and POD, ultimately yielding 34 studies for inclusion. Adjusted odds ratios (ORs) were extracted, with two-sided p-values <0.05 deemed significant. A total of 12,089 patients were included in this review, of which 2,663 developed POD (overall incidence of 22.03%). Inverse variance random-effects meta-analysis reveals that history of alcohol consumption (OR: 2.59, 1.85 - 3.64, p<0.0001), history of hepatic encephalopathy (OR: 3.42, 2.25 - 5.19, p<0.0001), and a MELD (Model for End-Stage Liver Disease) score ≥15 (OR 3.73, 1.93 - 7.20, p<0.0001) are independent risk factors for POD. Elevated serum IL-6 and total bilirubin did not reach significance as risk factors. Based on our findings, a medical history of known hepatic pathology potentially increases a patient's risk for POD. However, our study did not implicate any specific biomarkers as predisposing risk factors for POD but rather their indicated summative hepatic influence in the form of a MELD score.