IntroductionDelirium is associated with impaired outcome, but it is unclear whether this relationship is limited to in-hospital outcomes and whether this relationship is independent of the severity of underlying conditions. The aim of this study was to investigate the association between delirium in the intensive care unit (ICU) and long-term mortality, self-reported health-related quality of life (HRQoL), and self-reported problems with cognitive functioning in survivors of critical illness, taking severity of illness at baseline and throughout ICU stay into account.MethodsA prospective cohort study was conducted. We included patients who survived an ICU stay of at least a day; exclusions were neurocritical care patients and patients who sustained deep sedation during the entire ICU stay. Delirium was assessed twice daily with the Confusion Assessment Method for the ICU (CAM-ICU) and additionally, patients who received haloperidol were considered delirious. Twelve months after ICU admission, data on mortality were obtained and HRQoL and cognitive functioning were measured with the European Quality of Life – Six dimensions self-classifier (EQ-6D). Regression analyses were used to assess the associations between delirium and the outcome measures adjusted for gender, type of admission, the Acute Physiology And Chronic Health Evaluation IV (APACHE IV) score, and the cumulative Sequential Organ Failure Assessment (SOFA) score throughout ICU stay.ResultsOf 1101 survivors of critical illness, 412 persons (37%) had been delirious during ICU stay, and 198 (18%) died within twelve months. When correcting for confounders, no significant association between delirium and long-term mortality was found (hazard ratio: 1.26; 95% confidence interval (CI) 0.93 to 1.71). In multivariable analysis, delirium was not associated with HRQoL either (regression coefficient: -0.04; 95% CI -0.10 to 0.01). Yet, delirium remained associated with mild and severe problems with cognitive functioning in multivariable analysis (odds ratios: 2.41; 95% CI 1.57 to 3.69 and 3.10; 95% CI 1.10 to 8.74, respectively).ConclusionsIn this group of survivors of critical illness, delirium during ICU stay was not associated with long-term mortality or HRQoL after adjusting for confounding, including severity of illness throughout ICU stay. In contrast, delirium appears to be an independent risk factor for long-term self-reported problems with cognitive functioning.

The results of most studies of the studies reviewed suggest that critical illness and ICU treatment are associated with long-term cognitive impairment. Due to the complexity of defining cognitive impairment, it is difficult to standardize definitions and to reach consensus on how to categorize neurocognitive dysfunction. Therefore, the magnitude of the problem is uncertain.

Although symptoms of anxiety, depression, and posttraumatic stress disorder were found to be common 1 year after critical illness, the occurrence of delirium during ICU stay did not increase the risk of these long-term mental health problems.

Exposure to medication with anticholinergic properties, as defined by the Anticholinergic Drug Scale, does not increase the probability of delirium onset in patients who are awake and not delirious in the ICU.

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 selfreported cognitive problems (Badj = 5.10, 95% CI 1.01-9.20), whereas a single day delirium was not associated with higher CFQ scores (Badj = À0.72, 95% CI À5.75 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. J Am Geriatr Soc 65:786-791, 2017.