Delirium, a long-recognized occurrence in hospitalized patients, is often considered temporary. But what happens to cognitive function after a patient leaves the ICU (intensive care unit)? In a new study published in the New England Journal of Medicine on Oct. 3, the BRAIN-ICU Study investigators identified that those patients who developed in-hospital delirium had worse cognitive functioning for at least a year after discharge.
The study included adults with respiratory failure or shock in the medical or surgical ICU, who were evaluated for in-hospital delirium, and received global cognition and executive function assessments at 3 and 12 months after discharge with the use of the Repeatable Battery for the Assessment of Neuropsychological Status and the Trail Making Test, Part B.
There were 821 patients enrolled, 6 percent of whom had cognitive impairment at baseline; delirium developed in 74 percent during the hospital stay. At 3 months, 40 percent of patients had global cognition scores similar to scores for patients with moderate traumatic brain injury and 26 percent had scores similar to patients with mild Alzheimer's disease.
These deficits were seen in both older and younger patients, and persisted after a year with 34 percent and 24 percent of patients with scores similar to those of patients with moderate traumatic brain injury mild Alzheimer's disease, respectively, according to the paper. The investigators also reported that a longer duration of delirium was independently associated with worse global cognition at 3 and 12 months (P=0.001 and P=0.04, respectively) and worse executive function at 3 and 12 months (P=0.004 and P=0.007, respectively).
“In this multicenter, prospective cohort study involving a diverse population of patients in general medical and surgical ICUs, we found that one out of four patients had cognitive impairment 12 months after critical illness that was similar in severity to that of patients with mild Alzheimer's disease, and one out of three had impairment typically associated with moderate traumatic brain injury,” the authors concluded.
Stay tuned for a full story on this study in an upcoming issue of Neurology Today. For now, browse our archives on in-hospital delirium: http://bit.ly/1e4lstG.