Reporting individual symptoms in postoperative delirium studies: Protocol for a systematic review

Research output: Contribution to conferencePosterpeer-review


Delirium is a nonspecific cerebral syndrome characterised by an acute and transient alteration in cognition and attention. This may affect memory, orientation, language and perception, which cannot be accounted for by pre-existing dementia. Delirium studies often report delirium as a dichotomous outcome, providing limited information into the potential phenotypes of delirium which are present within the population, and the symptom profiles patients are experiencing. Delirium is particularly common in patients who have undergone surgery. In this systematic review, we aim to identify studies of these populations which report and record symptoms of delirium individually, as well as whether they record delirium psychomotor subtype and severity.

This systematic review has been registered with Prospero: CRD42021236622
This systematic review will be conducted in accordance with PRISMA 2020 guidelines. We will search Medline, Embase and Web of Science for studies of any language and any publication date. An example of the search strategy is shown in Table 1. These studies will include only patients over the age of 18, and patients undergoing surgery of any type in hospital, who develop postoperative delirium, and report its individual symptoms. Only studies that report individual symptoms of delirium will be included. We will include all clinical trials, randomised controlled trials, observational studies, and qualitative studies including interventional design studies. Case reports, cases series, editorials, reviews, systematic reviews and animal studies will be excluded. Studies which include patients with pre-existing diagnosed dementia, pre-operative delirium, Wernicke’s encephalopathy, brain tumours, brain aneurysms, neurological disorders or studies involving alcohol abuse and withdrawal will also be excluded. Two independent, blinded, reviewers will assess abstracts and titles for eligibility.
Due to the nature of our research question, we anticipate a high number of studies to be included for full-text review. This stage will involve 8 fully-trained independent reviewers; each paper will be screened in duplicate, and quality-control methods conducted. Data will be extracted and quality appraised using the Newcastle Ottawa Scale, by two independent reviewers. Missing data will be addressed by contacting study authors in the first instance, but alternatively by noting the limitation or excluding the study, depending on the extent of the missing data. Our findings of how many studies report on individual delirium symptoms will be reported by a narrative synthesis.
Current methods of reporting delirium by dichotomous outcome or psychomotor subtype provide little information on the full clinical and biological profile of the patient. This is limiting knowledge of the potential delirium phenotypes. By reporting, discussing and comparing the differences in symptoms reported in delirium studies, we can highlight the importance of individuality in reports, alongside the spectrum of delirium presentations that occur. This would emphasise the importance of identifying subphenotypes of delirium, expanding knowledge of the condition and therefore progressing research into targeted treatments. This review should encourage the study of symptom profiles occurring in various populations, alongside predisposing and precipitating delirium risk factors.

Original languageEnglish
Publication statusPublished - 13 Jun 2022
EventAmerican Delirium Society - Indianapolis, Indianapolis, United States
Duration: 12 Jun 202214 Jun 2022


ConferenceAmerican Delirium Society
Abbreviated titleADS 2022
Country/TerritoryUnited States


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