Evaluation of the Predictive Impact of Serum S100B and S100B Polymorphisms on Postoperative Cognitive Dysfunction and Delirium

March 29, 2026 updated by: Sait Bilgic, Ankara University

Investigation of the Predictive Effect of Serum S100B and S100B Polymorphisms on Postoperative Cognitive Dysfunction and Delirium in Patients Undergoing Surgery With Bispectral Index Monitoring

Postoperative cognitive disorders, including postoperative cognitive dysfunction (POCD) and postoperative delirium (POD), are common complications following surgery and anesthesia, particularly in vulnerable patient populations. These conditions are associated with increased morbidity, prolonged hospitalization, and higher healthcare costs. Early identification of patients at risk remains challenging, and reliable biomarkers are needed to improve perioperative risk stratification.

S100B protein has been proposed as a biomarker of neuronal injury and blood-brain barrier dysfunction. In addition, genetic variations in the S100B gene may influence individual susceptibility to postoperative cognitive impairment.

The aim of this prospective cohort study is to evaluate the association between perioperative serum S100B levels, S100B gene polymorphisms, and postoperative cognitive disorders. Furthermore, the predictive value of perioperative changes in S100B levels for postoperative cognitive dysfunction and delirium will be investigated.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Postoperative cognitive disorders, including postoperative cognitive dysfunction (POCD) and postoperative delirium (POD), are common complications associated with surgery and anesthesia. These conditions affect perception, memory, and learning abilities, and are associated with increased morbidity, prolonged hospital and intensive care unit stays, and higher healthcare costs. Although the exact mechanisms underlying these disorders are not fully understood, perioperative inflammatory processes and neuronal injury are considered key contributing factors.

In recent years, considerable research has focused on identifying reliable biomarkers for the early prediction of postoperative cognitive disorders. Among these, S100B protein has emerged as a promising marker of neuronal injury and blood-brain barrier dysfunction. In addition, single nucleotide polymorphisms (SNPs) in the S100B gene may influence individual susceptibility to cognitive impairment.

The aim of this study is to investigate the relationship between serum S100B levels, S100B gene polymorphisms, and postoperative cognitive disorders.

In this prospective study, preoperative cognitive function will be assessed using standardized cognitive tests. Blood samples will be collected preoperatively and within 30 minutes after surgery for the measurement of serum S100B levels. Cognitive assessment will be performed preoperatively and repeated at 1, 3, and 6 months after surgery. Patients will also be evaluated for postoperative delirium during the first 3 postoperative days.

The incidence of postoperative cognitive dysfunction and postoperative delirium will be recorded, and the association between S100B levels, genetic polymorphisms, and cognitive outcomes will be analyzed. The predictive value of these biomarkers for postoperative cognitive disorders will also be evaluated. Particular emphasis will be placed on the perioperative change in S100B levels (ΔS100B) as a potential predictor of postoperative cognitive outcomes.

Study Type

Observational

Enrollment (Actual)

137

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
    • Ankara
      • Ankara, Ankara, Turkey (Türkiye), 06000
        • Ankara University Faculty of Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

The study population consists of adult patients undergoing elective surgery under anesthesia who were prospectively enrolled. Patients were evaluated for postoperative cognitive dysfunction and postoperative delirium using standardized cognitive assessments. Perioperative blood samples were collected for the measurement of serum S100B levels and for the analysis of S100B gene polymorphisms. All participants were followed for cognitive outcomes up to 6 months after surgery.

Description

Inclusion Criteria:

  • Adult patients (≥18 years) undergoing elective surgery under anesthesia
  • Patients able to provide informed consent
  • Patients with sufficient cognitive function to complete cognitive assessments
  • Patients who agreed to participate in follow-up evaluations

Exclusion Criteria:

  • Patients with a history of neurological or psychiatric disorders affecting cognitive function
  • Patients with diagnosed dementia or severe cognitive impairment
  • Patients with inability to complete cognitive tests (e.g., severe visual, hearing, or language impairment)
  • Patients with alcohol or substance abuse
  • Patients undergoing emergency surgery
  • Patients with missing baseline cognitive assessment
  • Patients who refused participation or were lost to follow-up

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Surgical Patients
Patients undergoing surgery who were prospectively followed for postoperative delirium and postoperative cognitive dysfunction with serial cognitive assessments, serum S100B measurements, and S100B gene polymorphism analyses.
Other: Perioperative Assessment
Observational study with no assigned intervention. Patients were evaluated with perioperative blood sampling for S100B levels and genetic analysis, and were followed for postoperative cognitive outcomes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Postoperative Cognitive Dysfunction
Time Frame: 6 months after surgery
Postoperative cognitive dysfunction assessed using the Montreal Cognitive Assessment (MoCA). Cognitive assessment was performed preoperatively and repeated at 1, 3, and 6 months after surgery.
6 months after surgery

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Postoperative Delirium
Time Frame: Within the first 3 postoperative days
Incidence of postoperative delirium assessed during the first 3 postoperative days.
Within the first 3 postoperative days
Perioperative Serum S100B Levels
Time Frame: Preoperatively and within 30 minutes after surgery
Serum S100B protein levels measured in blood samples collected preoperatively and within 30 minutes after surgery.
Preoperatively and within 30 minutes after surgery
S100B Gene Polymorphisms
Time Frame: Preoperative period
Single nucleotide polymorphisms in the S100B gene analyzed from preoperative blood samples.
Preoperative period

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ankara University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 27, 2023

Primary Completion (Actual)

November 6, 2024

Study Completion (Actual)

November 6, 2024

Study Registration Dates

First Submitted

March 29, 2026

First Submitted That Met QC Criteria

March 29, 2026

First Posted (Actual)

April 3, 2026

Study Record Updates

Last Update Posted (Actual)

April 3, 2026

Last Update Submitted That Met QC Criteria

March 29, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • AU-ANES-MB-01

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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