Association Between Blood Urea Nitrogen and Delirium in Critically Ill Elderly Patients Without Kidney Diseases: A Retrospective Study and Mendelian Randomization Analysis
2025

Blood Urea Nitrogen and Delirium in Elderly ICU Patients

Sample size: 5867 publication 10 minutes Evidence: moderate

Author Information

Author(s): Yipeng Fang, Tang Xiaohong, Gao Ying, Xie Hui, Shen Yuehao, Peng Min, Liu Jie, Zhang Yunfei, Cui Yan, Xie Keliang

Primary Institution: Tianjin Medical University General Hospital

Hypothesis

This study investigates the association between blood urea nitrogen (BUN) levels and the risk of delirium in critically ill elderly patients without kidney disease.

Conclusion

Elevated BUN may be a risk factor for delirium in critically ill elderly patients without renal dysfunction, potentially influenced by midazolam exposure.

Supporting Evidence

  • Delirium incidence among elderly patients in ICUs can reach up to 87%.
  • Each 1 mmol/L increase in BUN upon admission raises the risk of delirium by 18%.
  • Patients with BUN levels exceeding 23 mg/dL have significantly higher odds of developing delirium.

Takeaway

High levels of a substance called blood urea nitrogen (BUN) can make older patients in the hospital more likely to get confused or delirious, especially if they haven't taken a certain medicine called midazolam.

Methodology

A retrospective analysis using data from the MIMIC‐IV database, with logistic regression and Mendelian randomization to assess the relationship between BUN and delirium.

Potential Biases

Potential confounding factors may affect the accuracy of the findings.

Limitations

The study is retrospective and may be influenced by confounding factors; the generalizability is limited due to the single-center design.

Participant Demographics

Elderly patients (age ≥ 65 years) admitted to the ICU, with a majority being Caucasian.

Statistical Information

P-Value

p<0.001

Confidence Interval

95% CI 1.01–1.02 for BUN increase and delirium odds

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1111/cns.70201

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