The relationship between preoperative hypoalbuminemia and postoperative subsyndromal delirium in elderly hip fracture patients: a prospective study

Background This study aimed to assess the prevalence of preoperative hypoalbuminemia in patients with hip fractures at Honghui Hospital, Xi’an Jiaotong University, and to examine its associations with postoperative subsyndromal delirium (SSD) and postoperative discharge-status. Methods A prospective study was conducted at Honghui Hospital, Xi’an Jiaotong University, involving patients who underwent hip fracture surgery between October 2023 and March 2024. Data on demographics, comorbidities, preoperative serum albumin levels, SSD occurrence, and postoperative discharge status were also collected. Hypoalbuminemia was defined as serum albumin levels below 35 g/L. Results In total, 279 patients were included in the analysis. Hypoalbuminemia was observed in 60 patients (21.51%) and 114 patients (40.86%) exhibited postoperative SSD. Multivariate logistic regression analysis revealed that diabetes mellitus (OR = 2.93, p = 0.007), smoking (OR = 4.30, p = 0.033), and hypoalbuminemia (OR = 6.13, p < 0.001) were independently associated with an elevated risk of SSD. Furthermore, each one-point increase in MMSE score was independently associated with a 1.74 reduction in SSD risk ( p < 0.001). A threshold effect on the association between albumin levels and SSD was observed when serum albumin level was treated as a continuous variable ( p for likelihood test = 0.034). Among the 279 patients, 22 were admitted to the ICU; however, further statistical analysis was not conducted for the five patients with hypoalbuminemia who were admitted to the ICU due to low ICU occupancy. Conclusion Our study identified a 21.51% prevalence of preoperative hypoalbuminemia in elderly patients undergoing hip fracture surgery, which independently contributed to an increased risk of postoperative SSD. We recommend implementing preoperative interventions to correct hypoalbuminemia.