Depression, post-traumatic stress disorder, and functional disability in survivors of critical illness in the BRAIN-ICU study: a longitudinal cohort study

Abstract

Background: Critical illness is associated with cognitive impairment, but mental health and functional disabilities in survivors of intensive care are inadequately characterised. We aimed to assess associations of age and duration of delirium with mental health and functional disabilities in this group.

Methods: In this prospective, multicentre cohort study, we enrolled patients with respiratory failure or shock who were undergoing treatment in medical or surgical ICUs in Nashville, TN, USA. We obtained data for baseline demographics and in-hospital variables, and assessed survivors at 3 months and 12 months with measures of depression (Beck Depression Inventory II), post-traumatic stress disorder (PTSD, Post-Traumatic Stress Disorder Checklist-Event Specific Version), and functional disability (activities of daily living scales, Pfeffer Functional Activities Questionnaire, and Katz Activities of Daily Living Scale). We used linear and proportional odds logistic regression to assess the independent associations between age and duration of delirium with mental health and functional disabilities. This study is registered with ClinicalTrials.gov, number NCT00392795.

Findings: We enrolled 821 patients with a median age of 61 years (IQR 51-71), assessing 448 patients at 3 months and 382 patients at 12 months after discharge. At 3 months, 149 (37%) of 406 patients with available data reported at least mild depression, as did 116 (33%) of 347 patients at 12 months; this depression was mainly due to somatic rather than cognitive-affective symptoms. Depressive symptoms were common even among individuals without a history of depression (as reported by a proxy), occurring in 76 (30%) of 255 patients with data at 3 months and 62 (29%) of 217 individuals at 12 months. Only 7% of patients (27 of 415 at 3 months and 24 of 361 at 12 months) had symptoms consistent with post-traumatic distress disorder. Disabilities in basic activities of daily living (ADL) were present in 139 (32%) of 428 patients at 3 months and 102 (27%) of 374 at 12 months, as were disabilities in instrumental ADL in 108 (26%) of 422 individuals at 3 months and 87 (23%) of 372 at 12 months. Mental health and functional difficulties were prevalent in patients of all ages. Although old age was frequently associated with mental health problems and functional disabilities, we observed no consistent association between the presence of delirium and these outcomes.

Interpretation: Poor mental health and functional disability is common in patients treated in intensive-care units. Depression is five times more common than is post-traumatic distress disorder after critical illness and is driven by somatic symptoms, suggesting approaches targeting physical rather than cognitive causes could benefit patients leaving critical care.

Funding: National Institutes of Health AG027472 and the Geriatric Research, Education and Clinical Center (GRECC), Department of Veterans Affairs Medical Center, Tennessee Valley Healthcare System.

Figure. A Comparison of Mental Health and Functional Related Scores by Age at 3 and 12 Months

This figure displays scores on our 4 primary outcome measures separated by age group (≤49, 50-64, and ≥65 years): A) Beck Depression Inventory II (BDI-II), which assesses depressive symptoms; B) PTSD Checklist (PCL), which assesses symptoms of PTSD; C) Katz Activities of Daily Living (ADL), which assesses disability in activities of daily living; and D) Pfeffer Functional Activities Questionnaire (FAQ), which assesses disability in instrumental activities of daily living (IADLs). †Jittering was used to prevent overplotting of equivalent points at integer values.