Risk Factors for Postoperative Delirium in Elderly Patients Undergoing Major Non-Cardiac Surgery in Singapore

  • End date
    Dec 28, 2023
  • participants needed
  • sponsor
    National University Hospital, Singapore
Updated on 28 October 2022


The primary aim is to establish the risk factors, in particular the modifiable risk factors, for the development of POD in elderly patients undergoing major non-cardiac surgery in a tertiary hospital in Singapore.

The secondary aims are:

  1. To establish the incidence of POD in elderly patients in Singapore, including the proportions that develop hypoactive, hyperactive and mixed delirium, as well as dementia within a one-year follow-up period;
  2. To understand the timeline of the development and peak incidence of POD, from the post-anaesthesia care unit till 3 days postoperatively;
  3. To compare the utility and accuracy (sensitivity and specificity) of two simplified delirium detection tools, 3D CAM and NuDESC, against the gold standard DSM-5 criteria, in our population as a means for monitoring POD as standard of care in the future;
  4. To collect data for holistic evaluation of neurobehavioural and daily functioning status


Singapore's population is growing older and increasingly burdened with systemic disease. It is estimated that over 320 million people underwent surgery worldwide in 2010, with Asia being the fastest growing region. Elderly patients aged >65 years are presenting for surgery at an ever-increasing rate. In the United States, studies have estimated that approximately 53% of all surgical procedures are performed on patients over the age of 65. Projections estimate that approximately half of the population over the age of 65 will require surgery once in their lives.

We often hear from our elderly patients that they value their quality of life more than prolonging it. Therefore it is essential that we optimize the care in the perioperative period to allow patients to fully benefit from surgery, as this period profoundly impacts survival and quality of life of patients after surgery. There is a current focus on enhanced recovery after surgery (ERAS) where surgeons implement protocols such as improved analgesia, less invasive procedures and early mobilisation to encourage earlier discharge of post op patients. In the best practice guidelines for care of elderly surgical patients put forward by the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) and the American Geriatrics Society (AGS) published in 2012, anaesthesia plays a role in more than half of the 13 recommendations put forward.

One of these recommendations is to reduce postoperative delirium (POD). The anaesthetic agents we use is toxic to the brain, and deep anaesthesia causes POD, which is linked to increased hospital length of stay, increased 30-day mortality, and dementia. POD is one of the leading causes of why patients fall at home after surgery. Up to 10% will develop long-term neurocognitive deficits, which in turn diminish the quality of life and levy a tremendous socio-economic burden on family and care-givers, and shortens life. The topic of POD has dominated the anaesthesia literature in the last year, with both the US and European societies issuing best practice guidelines such as the Brain Health Initiative and the Safe Brain Initiative, as well as harmonization of the definitions of postoperative neurological outcomes with that used by neurologists in compliance with DSM-5 definitions to allow for collaborative solutions.

Awareness of POD remains poor amongst both doctors and the public. The reason for this is that POD requires specialized neurological testing and currently, there are no established biomarkers or monitors to detect it. Yet when patients are assessed for POD, it has been reported that it occurs in as many as 11-50% of patients undergoing major non-cardiac surgery. Studies have shown that up to 40% of POD is preventable. Anecdotally, POD is one of the leading reasons for in-hospital (blue letter) psychiatric referrals after surgery in NUHS, as delirious patients will refuse to comply with physiotherapy, medications and wound care, leading to delayed healing, infection and delayed discharge. Patients are not routinely assessed for POD, and can be discharged with it. Patients who are still delirious can end up with poor feeding and self-care, and even hurt themselves leading to rehospitalisation. In short, POD is a common yet under-diagnosed, and potentially preventable, complication of anaesthesia and surgery in the elderly that has significant long-term effects on the independence of patients after surgery and their quality of life.

Condition Postoperative Delirium
Treatment Neurocognitive tests and blood taking
Clinical Study IdentifierNCT04617210
SponsorNational University Hospital, Singapore
Last Modified on28 October 2022


Yes No Not Sure

Inclusion Criteria

Elderly patients aged 65 years and above
Undergoing major non-cardiac surgery, defined as surgery that is predicted to be at least 2 hours and requiring at least 1 day postoperative stay in the hospital
English, Chinese or Malay speaking

Exclusion Criteria

History of psychiatric disease
Unable to provide informed consent for surgery
An active history of substance abuse
Undergoing neurosurgical procedures
Undergoing emergency surgeries
Has a second surgery within 5 days of index surgery
Non-resident of Singapore
Severe hearing and/or speech impairment
Clear my responses

How to participate?

Step 1 Connect with a study center
What happens next?
  • You can expect the study team to contact you via email or phone in the next few days.
  • Sign up as volunteer  to help accelerate the development of new treatments and to get notified about similar trials.

You are contacting

Investigator Avatar

Primary Contact


Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

Learn more

If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

Learn more

Complete your scheduled study participation activities and then you are done. You may receive summary of study results if provided by the sponsor.

Learn more

Similar trials to consider


Not finding what you're looking for?

Every year hundreds of thousands of volunteers step forward to participate in research. Sign up as a volunteer and receive email notifications when clinical trials are posted in the medical category of interest to you.

Sign up as volunteer

user name

Added by • 



Reply by • Private

Lorem ipsum dolor sit amet consectetur, adipisicing elit. Ipsa vel nobis alias. Quae eveniet velit voluptate quo doloribus maxime et dicta in sequi, corporis quod. Ea, dolor eius? Dolore, vel!

  The passcode will expire in None.

No annotations made yet

Add a private note
  • abc Select a piece of text from the left.
  • Add notes visible only to you.
  • Send it to people through a passcode protected link.
Add a private note