Delirium in hospitalized older adults with COVID-19: a cross-sectional cohort study

Older adults are more likely to develop delirium with COVID-19 infection. This cross-sectional cohort study was designed to explore the risk factors of delirium in hospitalized older adults with COVID-19 and to evaluate whether delirium is an independent predictor of mortality in this cohort of patients.

Data were collected through a retrospective clinical chart review of patients aged 65 years or older who were admitted to St. James's Hospital between March 2020 and 2021 who tested positive for SARS-CoV-2 infection.

A total of 261 patients (2.8 % of total admissions 65 years or older) were included in this study. Patients who developed delirium were older (80.8 v. 75.8 years, p < 0.001), more likely to have pre-existing cognitive impairment (OR = 3.97 [95% CI 2.11-7.46], p < 0.001), and were more likely to be nursing home residents (OR = 12.32 [95% CI 2.54-59.62], p = 0.0018). Patients who developed delirium had a higher Clinical Frailty score (mean 5.31 v. 3.67, p < 0.001) and higher Charlson Co-morbidity index (mean 2.38 v. 1.82, p = .046). There was no significant association between in-hospital mortality and delirium in the patient cohort (p = 0.13). Delirium was associated with longer hospital stay (40.5 days v. 21 days, P = 0.001) and patients with delirium were more likely to be discharged to nursing homes or convalescence instead of home (OR = 8.46 [95% CI 3.60-19.88], p < 0.001).

Delirium is more likely to occur in COVID-19 patients with pre-existing risk factors for delirium, resulting in prolonged admission and functional decline requiring increased support for discharge.