Prevalence and Risk Factors of Delirium Subtypes in the Surgical Intensive Care Unit: A Retrospective Study

Delirium is a frequent, yet often underdiagnosed, condition in intensive care units (ICUs), especially in postoperative patients. It has three subtypes: hyperactive, hypoactive and mixed, each with distinct clinical manifestations and outcomes. A deeper understanding of each subtype's prevalence and risk factors is essential for improving ICU patient care. This study aims to figure out the prevalence of each type of delirium and risk factors associated with each subtype of delirium.

This retrospective study included 4234 postoperative patients admitted to the surgical ICU between January 2017 and June 2019. Delirium was diagnosed using the Confusion Assessment Method for the ICU, and subtypes were determined using the RASS score. Multivariate logistic regression analysis was used to identify the risk factors associated with each delirium subtype. This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist.

The prevalence of delirium was 8.7%, with mixed delirium being the most common subtype (47.7%), followed by hypoactive delirium (40.3%) and hyperactive delirium (12.0%). Each subtype was linked to different risk factors: hypoactive delirium was correlated with shorter ICU stays and pH and O₂ imbalances, hyperactive delirium was associated with physical restraints and mixed delirium was linked to sedative medication and restraint use.

Among postoperative ICU patients, mixed delirium was the most prevalent subtype, followed by the hypoactive and hyperactive forms. Identifying the unique risk factors for each subtype highlights the need for targeted prevention and management approaches in ICU. Further research is warranted to investigate the underlying mechanisms and to develop effective interventions tailored to each delirium subtype.

This study is distinct from previous research in that it comparatively analysed the risk factors for delirium according to subtype. By distinguishing between the subtypes of delirium and identifying their incidence and risk factors, it is possible to enhance the overall understanding of delirium, particularly given that some of the known risk factors are more strongly associated with certain types of delirium. Identifying risk factors according to the type of delirium can facilitate the planning of proactive interventions based on risk factors. Furthermore, it can serve as a valuable resource for the development of tools for predicting different types of delirium to provide more tailored and evidence-based care for patients with delirium.

No patient or public contribution.