Older COVID-19 patients who experience delirium during their hospital stay may face a decline in functional and cognitive abilities in the months following their discharge, according to a recent study published in JAMA Network Open.

Delirium, often mistaken for dementia, is a sudden change in mental status characterized by confusion and a lack of awareness of one’s surroundings and situation. The study, led by Yale University, involved 311 patients aged 60 and above who were hospitalized for COVID-19 treatment at five hospitals within the Yale–New Haven Health System from June 2020 to June 2021. Follow-up assessments were conducted via telephone or videoconference until January 2022, with pre-COVID cognitive conditions obtained from electronic health records.

The researchers evaluated delirium using the Chart-based Delirium Identification Instrument and cognitive function with the Montreal Cognitive Assessment at 1, 3, and 6 months post-hospital discharge. Disability levels were assessed across various functional activities, including daily living tasks and mobility activities. The average age of the patients was 71.3 years, with over half being women and more than one-third belonging to minority groups.

The study highlighted that factors exacerbated by the COVID-19 pandemic, such as extended hospital stays, sedative use, social isolation due to infection control measures, immobility, and communication challenges arising from personal protective equipment usage, contributed to the increased risk of delirium.

Among the 311 adults with functional disability, 49 (15.8%) experienced in-hospital delirium, while 31 (11.4%) of the 271 patients with impaired cognition also had delirium during their hospitalization. In-hospital delirium was associated with a 32% higher functional disability rate (rate ratio [RR], 1.32) and more than double the risk of worsened cognitive symptoms (odds ratio [OR], 2.48) in the 6 months post-hospital discharge.

Patients who developed delirium were more likely to have a history of greater functional and cognitive disabilities and were older compared to those without delirium, both in the functional and cognition cohorts. A higher proportion of delirium patients in both groups were admitted to intermediate care units or ICUs and required mechanical ventilation. Prior to hospitalization, patients with delirium had an average of 4 preexisting disabilities.