Sepsis-associated delirium affects 43% of ICU patients, mechanical ventilation strongest risk factorRisk Factors Linked to Delirium in Patients with Sepsis
Intensive & critical care nursingPublished October 4, 2026Study authors: Hao Tian, Xie Haohao, Jia Donghui, Wang Hengyang, Niu Wenxiu, Sha Yuhan, Qi Ruirui, Zhang Lin, Zhang…PubMed ↗DOI ↗Editorial oversight: Dr. Lars van Dijk, PhD · Surgical, Procedural & Diagnostic
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Key Takeaway
Recognize SAD as common in ICU sepsis; screen high-risk patients, especially those on mechanical ventilation.
This meta-analysis examined the incidence of sepsis-associated delirium (SAD) and its associated risk factors in ICU patients, synthesizing data from 89,789 patients. The pooled incidence of SAD was 43% (95% CI 39%-47%).
The authors identified several high-evidence-strength risk factors, defined as those reported in at least 5 studies. These included higher APACHE II score, higher SOFA score, advanced age, elevated neuron-specific enolase, mechanical ventilation, elevated lactate, elevated S100beta protein, and cerebrovascular disease. Among these, mechanical ventilation showed the strongest association with SAD (OR 2.623).
Factors reported as protective, including history of surgery, total bilirubin, and peripheral perfusion index, were supported by limited evidence and the authors state these should be interpreted with caution. The review notes that associations for risk factors do not establish causality.
Adverse events, follow-up duration, and funding or conflicts of interest were not reported. The authors suggest that nurses should perform routine delirium screening in high-risk patients with sepsis and implement targeted interventions, including minimizing sedation, optimizing mechanical ventilation, and monitoring metabolic parameters such as blood glucose and lactate. Early mobilization and individualized care may be beneficial for patients at risk of SAD.
How this fits prior evidence
This meta-analysis quantifies SAD incidence and risk factors, extending prior sepsis coverage that has focused on treatment feasibility, biomarkers, and diagnostic tools. Prior coverage noted a feasibility study for meropenem versus piperacillin/tazobactam that did not establish superiority, and highlighted the gap between sepsis biomarker discovery and clinical deployment. This review similarly identifies candidate risk markers such as neuron-specific enolase and S100beta protein, but does not establish their clinical utility. It also aligns with prior emphasis on POCUS and evidence-mapping for bedside decision support, while providing no data on interventions to prevent or treat SAD.
A large meta-analysis of 89,789 patients in intensive care units looked at the incidence of sepsis-associated delirium (SAD). The study found that about 43% of these patients experienced delirium. Because the study is a meta-analysis, it provides a broad overview of existing data rather than a new clinical trial.
Several factors showed a strong link to a higher risk of delirium. These include advanced age, higher severity scores (APACHE II and SOFA), and the use of mechanical ventilation. Specifically, patients on mechanical ventilation were over twice as likely to develop delirium. Other factors linked to risk included elevated lactate levels and certain proteins like S100 beta and neuron-specific enolase.
Some factors, such as a history of surgery or specific blood levels, showed a potential protective effect, but the evidence for these is limited. Because these findings show associations rather than direct causes, they are intended to help healthcare teams identify high-risk patients. Doctors and nurses can use this information to provide more targeted monitoring and care for patients at risk.
What this means for you:
High-risk factors for sepsis-related delirium include advanced age and the use of mechanical ventilation.
Common questions
What are the main risk factors for delirium in patients with sepsis?
The study identified several factors with high evidence strength linked to delirium. These include advanced age, higher APACHE II and SOFA scores, mechanical ventilation, and higher levels of lactate, S100 beta protein, and neuron-specific enolase. Patients on mechanical ventilation were found to have a significantly higher risk of delirium.
How common is delirium in patients with sepsis?
The analysis of 89,789 patients in intensive care units found a pooled incidence of sepsis-associated delirium of approximately 43%. This means nearly half of the patients in the study experienced delirium during their stay.
Are there any factors that might protect patients from delirium?
The study noted some factors with limited evidence that might be associated with a lower risk of delirium, such as a history of surgery, total bilirubin, and peripheral perfusion index. However, because the evidence for these specific factors is limited, they should be interpreted with caution.
OBJECTIVES: To investigate the incidence and risk factors of sepsis-associated delirium (SAD) in ICU patients, with the goal of providing evidence for risk stratification and guiding ICU delirium management.
METHODS: The study protocol was registered at PROSPERO on August 2, 2025 (CRD420251118228). A systematic search was conducted across PubMed, Embase, Web of Science, Cochrane Library, CNKI, Wanfang, VIP, and CBM databases. The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS). Meta-analysis was performed using Stata software (version 18.0).
RESULTS: Fifty-two studies comprising 89,789 ICU patients were included. The pooled incidence of SAD was 43% (95% CI: 39%-47%). Seventeen significant factors were identified across 32 studies that reported risk factors. High-evidence-strength factors (≥5 studies) included higher APACHE II score, SOFA score, advanced age, neuron-specific enolase, mechanical ventilation, lactate, S100β protein, and cerebrovascular disease. Mechanical ventilation showed the strongest association with SAD (OR = 2.623). Other factors also identified in fewer studies. In contrast, history of surgery, total bilirubin, and peripheral perfusion index appeared to be protective factors, although supported by limited evidence and should be interpreted with caution.
CONCLUSION: This systematic review and meta-analysis demonstrated incidence of SAD was high in ICU patients and identified multiple associated risk factors. These findings support early risk identification and targeted nursing interventions. Future research should focus on standardized diagnosis and nurse-led prevention strategies.
IMPLICATIONS FOR CLINICAL PRACTICE: Nurses should perform routine delirium screening in high-risk patients with sepsis and implement targeted interventions, including minimizing sedation, optimizing mechanical ventilation, and monitoring metabolic parameters such as blood glucose and lactate. Early mobilization and individualized care may be beneficial for patients at risk of SAD.
