Dual-threshold plasma Aβ oligomerization for postoperative delirium risk stratification

Area of Science:

• Geriatric Medicine
• Neuroscience
• Anesthesiology

Background:

• Postoperative delirium is a frequent complication in elderly surgical patients.
• Currently, there is a lack of simple blood tests to effectively identify patients at risk.
• Plasma amyloid-β oligomers (MDS-OAβ) show potential as indicators of neurodegenerative vulnerability.

Purpose of the Study:

• To evaluate the utility of preoperative plasma MDS-OAβ levels as a biomarker for predicting postoperative delirium in older adults.
• To assess the diagnostic accuracy and establish thresholds for MDS-OAβ in delirium risk stratification.
• To explore a dual-threshold strategy for managing delirium risk.

Main Methods:

• 101 patients aged 65 and older undergoing elective orthopedic surgery were enrolled.
• Preoperative blood samples were collected for MDS-OAβ quantification.
• Delirium was assessed daily using standardized scales (DRS-R-98 and DSM).
• Propensity-score matching was used to control for Alzheimer-type vulnerability factors.
• Logistic regression and ROC analyses determined discrimination and optimal thresholds.

Main Results:

• Preoperative MDS-OAβ concentrations were significantly higher in patients who developed delirium.
• MDS-OAβ demonstrated strong discrimination for delirium, with an AUC of 0.855 in the overall cohort.
• A dual-threshold approach effectively identified low-risk and high-risk patient groups.
• Similar discrimination was observed in a pooled postoperative dataset (AUC 0.884).

Conclusions:

• Preoperative plasma MDS-OAβ serves as a scalable biomarker for perioperative risk stratification of postoperative delirium in older adults.
• A dual-threshold strategy using MDS-OAβ can guide targeted prevention and monitoring.
• While low MDS-OAβ suggests lower risk, it does not rule out delirium; biomarker-guided stratification complements routine surveillance.