Association between preoperative serum amyloid A levels and postoperative delirium in older adults undergoing hip surgery: a retrospective study.

Abstract

Background: Postoperative delirium (POD) is a common and serious complication in older adults. Prior studies have validated serum amyloid A (SAA) as a potential biomarker for various inflammatory conditions; however, its role in POD is poorly characterized. This study aimed to examine the association between preoperative SAA levels and the occurrence of POD.

Methods: This study comprised a retrospective review of the electronic medical records of patients aged 60 and older who underwent hip surgery between April 2022 and January 2024. Cognitive function was assessed using the Nursing Delirium Screening Scale (Nu-DESC), while diagnosis was confirmed by psychiatrists using the Confusion Assessment Method (CAM). The associations between POD occurrence and preoperative/postoperative SAA levels and other patient, anesthesia, and surgical factors were analyzed using logistic regression models.

Results: Of 731 patients, delirium occurred in 121 patients (16.6%) within the first five postoperative days (five-day POD). Preoperative SAA levels were significantly higher in the POD group (91.2 mg/L) than the non-POD group (6.6 mg/L) (P < 0.001). Logistic regression showed that preoperative SAA levels were independently associated with POD occurrence (odds ratio [OR]: 1.005, 95% CI: 1.002‒1.008; P < 0.001). Age (P < 0.001), height (P = 0.006), and preoperative albumin levels (P = 0.008) were also identified as significant factors influencing POD risk.

Conclusions: Elevated preoperative SAA levels were associated with an increased risk of five-day POD in older adults undergoing hip surgery. Further research is required to explore the clinical utility of SAA as a biomarker for predicting POD.