Preoperative Biofluid Biomarkers for Predicting Postoperative Neurocognitive Disorders in Older Adults: A Systematic...

Area of Science:

• Neuroscience
• Geriatric Medicine
• Biomarker Research

Background:

• Perioperative neurocognitive disorders (PNDs) are a significant concern in older adults undergoing surgery.
• Preoperative biofluid biomarkers, including those related to Alzheimer's disease (AD), neuronal injury, and inflammation, may aid in risk stratification for PNDs.
• Existing evidence on the predictive value of these biomarkers for PNDs beyond seven days requires comprehensive summarization.

Purpose of the Study:

• To summarize current evidence on the association between preoperative biofluid biomarkers and PNDs (specifically postoperative cognitive dysfunction, POCD) in surgical patients aged 60 years and older.
• To evaluate the potential utility of biomarkers reflecting neuronal injury, inflammation, and AD pathology in predicting long-term cognitive decline post-surgery.

Main Methods:

• Systematic literature search of six databases and three trial registries up to January 17, 2024.
• Inclusion of studies assessing preoperative biomarkers and cognitive decline beyond seven days post-surgery in participants aged ≥60 years.
• Exclusion of preclinical studies, intracranial surgery studies, and studies with participants younger than 60 years.
• Acceptance of a wide range of cognitive outcomes, including those termed POCD, due to heterogeneity in PND assessment.
• Pooled incidence of POCD was summarized using binary cognitive outcomes.

Main Results:

• Fifteen studies involving 2103 participants were included, exhibiting significant heterogeneity in cognitive outcome metrics and assessment timeframes.
• The pooled incidence of POCD was 23.4% at <3 months, 11.4% at 3 to <12 months, and 6.9% at ≥12 months postoperatively.
• Amyloid biomarkers showed the most promising results, with four out of five studies indicating that lower preoperative amyloid levels are associated with an increased risk of POCD.
• Other biomarkers like p-Tau181 and Neurofilament Light showed potential but were limited by small sample sizes and conflicting results.

Conclusions:

• Preoperative biofluid amyloid biomarkers demonstrate potential utility in predicting POCD, though current evidence is limited.
• Biomarkers such as p-Tau181 and Neurofilament Light may also be relevant, but further investigation is required.
• Standardized cognitive outcome metrics and consistent assessment timeframes are crucial for future studies to establish the prognostic value of these biomarkers for POCD.