Association Between COVID-19 and Delirium Development in the General Medical Units at an Academic Medical Center

Evidence suggests that inpatients who develop delirium experience worse outcomes. Although there is reason to believe that COVID-positive patients may be at a higher risk for developing delirium, little is known about the association between COVID-19 and delirium among hospitalized patients outside the intensive care unit (ICU). This study aimed to examine (1) the independent association between COVID-19 infection and the development of delirium among all non-ICU patients and (2) the risk factors associated with developing delirium among patients admitted with COVID-19, with a special focus on presenting symptoms.

Using electronic health record (EHR) data of adults admitted to any general medical unit at a large academic medical center from July 2020 through February 2021, we used a cross-sectional multivariable logistic regression to estimate the associations, while adjusting for patients' sociodemographic, clinical characteristics, delirium-free length of stay, as well as time fixed effects.

Multivariable regression estimates applied to 20 509 patients hospitalized during the study period indicate that COVID-19-positive patients had 72% higher relative risk (odds ratio 1.72; 95% CI, 1.31 - 2.26; P < 0.001) of developing delirium than the COVID-19-negative patients. However, among the subset of patients admitted with COVID-19, having any COVID-19-specific symptoms was not associated with elevated odds of developing delirium compared to those who were asymptomatic, after controlling for potential confounders.

COVID-19 positivity was associated with higher odds of developing delirium among patients during their non-ICU hospitalization. These findings may be helpful in targeting the use of delirium prevention strategies among non-ICU patients.