Older COVID-19 patients who experience delirium in the hospital are at higher risk of increased functional disability and cognitive impairment in the 6 months after leaving the hospital, a new JAMA Network Open study suggests.
Sometimes mistaken for dementia, delirium is a striking change in mental status that leads to confusion and lack of awareness of the situation and environment.
COVID worsened risk factors for delirium
The Yale University–led study involved 311 patients aged 60 years and older being treated for COVID-19 at one of five hospitals in the Yale–New Haven Health System from June 2020 to June 2021, with telephone or videoconference follow-up through January 2022. Information on the patients' pre-COVID cognitive condition was derived from electronic health records.
The researchers assessed delirium using the Chart-based Delirium Identification Instrument and cognition with the Montreal Cognitive Assessment at 1, 3, and 6 months after hospital release. Disability was measured across 15 functional activities, including activities of daily living and mobility activities. The average patient age was 71.3 years, 52.4% were women, and more than one-third were of minority race.
"The COVID-19 pandemic amplified certain factors associated with increased risk of delirium," the researchers noted. "These include prolonged hospital stays, the administration of medications such as sedatives, social isolation resulting from infection control measures, immobility, and communication barriers between patients and health care practitioners arising from the use of personal protective equipment."
Delirium patients had more preexisting disabilities
Of the 311 adults with functional disability, 49 (15.8%) experienced in-hospital delirium, as did 31 (11.4%) of the 271 patients with impaired cognition. In-hospital delirium was tied to 32% greater functional disability (rate ratio [RR], 1.32) and more than double the risk of worse cognitive symptoms (odds ratio [OR], 2.48) in the 6 months after hospital release.
Patients who experienced delirium were more likely to have a history of greater functional and cognitive disability and were older than those who didn't have delirium in both the functional cohort (average age, 75.6 vs 70.5 years) and the cognition cohort (73.1 vs 70.2).
A greater proportion of patients with delirium in both cohorts were admitted to a stepdown (intermediate) unit or intensive care unit (ICU) and needed mechanical ventilation. Twenty-nine patients (9.3%) in the functional disability group were admitted to the ICU.
Before hospitalization, the unadjusted average number of disabilities among patients with delirium was 4.0, rising to 6.6 at 1 month after hospital release and falling slightly, to 5.3, at 6 months. In contrast, the average number of pre-hospitalization disabilities among patients without delirium was 1.8, climbing to 2.7 at 1 month and ebbing to 2.1 at 6 months.
A multivariable analysis showed that in-hospital delirium was linked to more disabilities in the 6 months after hospitalization (RR, 1.32).
Delirium prevention, rehab
Prehospitalization, the unadjusted proportion of cognitively impaired patients was 9.7% (3 of 31) among those with delirium, compared with 2.9% (7 of 240) among those without it. One month after hospital release, 12 patients with delirium (63.6%) reported cognitive problems, compared with 49 (22.6%) without the condition.
These findings suggest that after discharge from hospitalization for COVID-19, older adults who experience in-hospital delirium may need to be counseled, screened, and provided resources to mitigate their risk of long-term functional disability and cognitive impairment.
By 6 months, 8 patients with delirium (34.8%) had impaired cognition, compared with 43 (20.7%) without it. A multivariable analysis associated delirium with cognitive impairment 6 months after hospitalization (OR, 2.48).
"Delirium has been recognized as a severe complication of COVID-19 and has been linked to worse outcomes, including increased in-hospital mortality, ICU admission, length of stay, and in-hospital complications," the study authors wrote.
In addition to delirium-prevention measures such as adequate hydration and the use of visual and hearing aids, "these findings suggest that after discharge from hospitalization for COVID-19, older adults who experience in-hospital delirium may need to be counseled, screened, and provided resources to mitigate their risk of long-term functional disability and cognitive impairment," the authors concluded.
The team called for research into whether delirium-prevention strategies and cognitive screening in the hospital, as well as rehabilitation after release, can reduce the consequences of in-hospital delirium among older COVID-19 patients.
