Sex-Dependent Risk of Postoperative Delirium and Mediating Effects of Family Visits

May 27, 2026 updated by: Julian Rössler

Sex-Dependent Risk of Postoperative Delirium and Mediating Effects of Family Visits: A Prospective Observational Study

Postoperative delirium is a common and serious complication after surgery, affecting 10-40% of older patients undergoing non-cardiac procedures. It is characterized by sudden changes in attention, awareness, and thinking that fluctuate throughout the day. Delirium is associated with longer hospital stays, higher mortality, worse long-term brain function, and substantially increased healthcare costs. While several risk factors are known, it remains unclear whether a patient's sex independently influences the risk of developing postoperative delirium, as existing studies have produced conflicting results and were often not designed to specifically examine sex differences.Family visitation is a promising non-drug approach to preventing delirium. Studies in intensive care patients have shown that those who receive family visits have a significantly lower risk of developing delirium. However, it is unknown whether men and women receive different amounts of family visits after surgery, and whether any such difference could help explain sex-based disparities in delirium risk. Given that traditional gender roles in caregiving persist, women - who often serve as primary caregivers in their families - may receive fewer visits when they themselves become patients.This prospective observational study led by the University of Zurich will enroll 471 patients aged 65 years or older undergoing non-cardiac surgery lasting at least 2 hours under general or spinal anesthesia. The primary aim is to determine whether female patients have a higher risk of developing postoperative delirium within three days after surgery compared to male patients. Delirium will be assessed twice daily using the 4 A's Test (4AT), a validated and standardized screening tool. The secondary aim is to evaluate whether female patients receive fewer family visits than male patients and whether any difference in visitation mediates the sex-dependent delirium risk. Family visits will be recorded using an anonymous sign-in sheet placed in the patient's room. The study does not involve any experimental interventions; all patients receive standard clinical care. Participation is voluntary, and withdrawal is possible at any time without affecting medical treatment.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
471

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

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patients aged 65 and older who are having noncardiac surgery

Description

Inclusion Criteria:

  • Informed consent as documented by signature;
  • ≥65 years of age;
  • Scheduled non-cardiac surgery with expected surgery duration ≥ 2 hours;
  • Under either general or spinal anesthesia.

Exclusion Criteria:

  • Known drug or alcohol abuse;
  • Requirement for postoperative ventilation;
  • Current participation in another study with an investigational drug;
  • Inability to complete the study assessments.

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

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Female
Female patients aged 65 years or above with scheduled non-cardiac surgery with expected surgery duration ≥ 2 hours under either general or spinal anesthesia.
Male
Male patients aged 65 years or above with scheduled non-cardiac surgery with expected surgery duration ≥ 2 hours under either general or spinal anesthesia.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Postoperative Delirium
Time Frame: Starting on postoperative day (POD) 1 and continuing until POD 3, or discharge - whichever comes first.
The primary outcome is presence of delirium as assessed by the 4AT test. A 4AT score of 4 or above will be used for dichotomous assessment of the primary outcome presence of delirium. Participants will be assessed daily in the morning and the evening.
Starting on postoperative day (POD) 1 and continuing until POD 3, or discharge - whichever comes first.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Family Visits
Time Frame: Starting on postoperative day (POD) 1 and continuing until POD 3, or discharge - whichever comes first
The secondary outcome is hours spend being visited. Visits shall be self-reported by the visiting party. All visits regardless of relation to the participant (e.g., family, friends, or colleagues) shall be reported. Visits should be recorded in hourly intervals, regardless of the number of visitors present (e.g., two visitors for one hour, or one visitor for one hour, should counted as the same).
Starting on postoperative day (POD) 1 and continuing until POD 3, or discharge - whichever comes first

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Julian Rössler

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 5, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 25, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 25, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 31, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 1, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2025-02296

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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