Association between preoperative anemia and postoperative delirium in elderly patients undergoing total hip arthroplasty with combined spinal-epidural anesthesia: A retrospective cohort study.

Background: The effect of preoperative anemia on postoperative delirium (POD) risk in elderly patients undergoing total hip arthroplasty (THA) with spinal-epidural anesthesia remains unclear. This study aimed to evaluate the association of preoperative anemia and its severity on POD occurrence in this population. Methods: This retrospective cohort study included 609 patients aged ≥ 65 years who underwent their first elective total THA with CSE between January 1, 2020, and December 31, 2024. Patients were stratified by preoperative anemia status using WHO criteria as hemoglobin < 13 g/dL males and < 12 g/dL females. Anemia severity was further stratified into mild or moderate-to-severe categories using a hemoglobin cutoff of 11 g/dL. Inverse probability of treatment weighting (IPTW) was employed to adjust for potential confounders. The primary outcome was the incidence of postoperative delirium. The secondary outcomes included in-hospital deep vein thrombosis, pulmonary infection, surgical site infection, and length of hospital stay (LOS). Results: The overall POD incidence was 4.5 % (24/538). Moderate-to -severe anemia was significantly associated with increased POD risk (odds ratio [OR] 3.29; 95 % confidence interval [CI], 1.21-8.96; Conclusions: Moderate-to-severe preoperative anemia was significantly associated with an increased risk of postoperative delirium in elderly patients undergoing THA with combined spinal-epidural anesthesia. Further prospective studies are warranted to evaluate the efficacy of specific interventions aimed at correcting preoperative anemia in this patient population.