Long-Term Self-Reported Cognitive Problems After Delirium in the Intensive Care Unit and the Effect of Systemic Inflammation

OBJECTIVES: To describe the association between intensive care unit (ICU) delirium and self-reported cognitive problems in 1-year ICU survivors, and investigate whether this association was altered by exposure to systemic inflammation during ICU stay.

DESIGN: Prospective cohort study.

SETTING: Dutch medical-surgical ICU.

PARTICIPANTS: One-year ICU survivors, admitted to the ICU ≥48 hours.

MEASUREMENTS: Self-reported cognitive problems were measured with the Cognitive Failures Questionnaire (CFQ). Cumulative exposure to systemic inflammation was based on all daily C-reactive protein (CRP) measurements during ICU stay, expressed as the area under the curve (AUC). Multivariable linear regression was conducted to evaluate the association between delirium and the CFQ. The effect of inflammation on the association between delirium and CFQ was assessed, comparing the effect estimate (B) of delirium and CFQ between models with and without inclusion of the AUC of CRP.

RESULTS: Among 567 1-year ICU survivors, the CFQ was completed by 363 subjects. Subjects with multiple days of delirium during ICU stay reported more self-reported cognitive problems (Badj = 5.10, 95% CI 1.01-9.20), whereas a single day delirium was not associated with higher CFQ scores (Badj = -0.72, 95% CI -5.75 to 4.31). Including the AUC of CRP did not change the association between delirium and the CFQ (ratio for a single and multiple days were respectively: 1.00, 95%CI 0.59-1.44 and 0.86, 95% CI 0.47-1.16).

CONCLUSION: Multiple days of delirium was associated with long-term self-reported cognitive problems. The cumulative exposure to systemic inflammation did not alter this association, suggesting that delirium in the context of little inflammation is also detrimental.