Delirium During Critical Illness and Subsequent Change of Treatment in Patients With Cancer: A Mediation Analysis*

Abstract

OBJECTIVES: To assess whether delirium during ICU stay is associated with subsequent change in treatment of cancer after discharge. DESIGN: Retrospective cohort study. SETTING: A 50-bed ICU in a dedicated cancer center. PATIENTS: Patients greater than or equal to 18 years old with a previous proposal of cancer treatment (chemotherapy, target therapy, hormone therapy, immunotherapy, radiotherapy, oncologic surgery, and bone marrow transplantation). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We considered delirium present if Confusion Assessment Method for the ICU was positive. We assessed the association between delirium and modification of the treatment after discharge. We also performed a mediation analysis to assess both the direct and indirect (i.e., mediated by the development of functional dependence after discharge) of delirium on modification of cancer treatment and whether the modification of cancer treatment was associated with mortality at 1 year. We included 1,134 patients, of whom, 189 (16.7%) had delirium. Delirium was associated with the change in cancer treatment (adjusted odds ratio [OR], 3.80; 95% CI, 2.72–5.35). The association between delirium in ICU and change of treatment was both direct and mediated by the development of functional dependence after discharge. The proportion of the total effect of delirium on change of treatment mediated by the development of functional dependence after discharge was 33.0% (95% CI, 21.7–46.0%). Change in treatment was associated with increased mortality at 1 year (adjusted OR, 2.68; 95% CI, 2.01–3.60). CONCLUSIONS: Patients who had delirium during ICU stay had a higher rate of modification of cancer treatment after discharge. The effect of delirium on change in cancer treatment was only partially mediated by the development of functional dependence after discharge. Change in cancer treatment was associated with increased 1-year mortality.

Changes in Cancer Therapy After ICU Admission: The Long Arm of Delirium*

“…At the same time, ICU researchers should feel compelled to examine whether ICU delirium changes management plans for other disease processes (e.g., coronary revascularization in patients with coronary artery disease, liver transplantation in patients with cirrhosis). The arm of ICU delirium is long, and based on the results of the study by Vizzacchi et al (8), we now know that it may reach into more aspects of ICU survivors’ lives than we previously thought.…”

“…Patients who experienced delirium were more likely to have worsening performance status (ECOG > 2) than patients without delirium. As sepsis is an important potential confounder in the study by Vizzacchi et al (8) (i.e., reluctance to resume cancer therapy in a patient recovering from sepsis), it is important that there was no difference in delirium occurrence in septic patients compared with nonseptic patients.…”

“…The study by Vizzacchi et al (8), published in this issue of Critical Care Medicine , is an important contribution for two reasons. First, it explores the association between ICU delirium and long-term mortality for an important and frequently encountered ICU patient population: patients with cancer.…”

“…While important work has been done to spread awareness of the long-term neuropsychiatric consequences of delirium, we suspect that few intensivists consider the potential effect of delirium on future cancer treatments. As the study by Vizzacchi et al (8) reveals, impact on cancer therapeutics is very much a matter of life and death. Based on these data, ICU clinicians should be motivated to redouble efforts to prevent delirium, especially among cancer patients.…”