Delirium in Patients with COVID-19 in Japan

OBJECTIVE: The incidence and clinical importance of delirium in coronavirus disease 2019 (COVID-19) have not yet been fully investigated. The present study reported the prevalence of delirium in patients with COVID-19 and identified the factors associated with delirium and mortality. METHODS: We performed an observational, retrospective study of patients diagnosed with COVID-19 at the Kinki-Chuo Chest Medical Center. Univariate and multivariate logistic regression analyses were used to explore delirium risk factors. PATIENTS: All consecutive patients diagnosed with COVID-19 at the Kinki-Chuo Chest Medical Center. RESULTS: We identified 600 patients [median age: 61.0 (interquartile range: 49.0-77.0) years old], of whom 61 (10.2%) developed delirium during their stay. Compared with patients without delirium, these patients were older (median age 84.0 vs. 56.0 years old, p<0.01) and had more comorbidities. Based on a multivariate analysis, age, dementia, severe disease, and lactate dehydrogenase (LDH) levels were independent risk factors for developing delirium. For every 1-year increase in age and 10-IU/L increase in LDH, the delirium risk increased by 10.8-12.0% and 4.6-5.7%, respectively. There were 15 (24.6%) in-hospital deaths in the group with delirium and 8 (1.6%) in the group without delirium (p<0.01). Delirium was associated with an increased mortality. CONCLUSION: Delirium in patients with COVID-19 is prevalent and associated with poor clinical outcomes in Japan. Despite difficulties with COVID-19 patient care during the pandemic, physicians should be aware of the risk of delirium and be trained in its optimal management.