Association between visitation restriction during the COVID-19 pandemic and delirium incidence among emergency admission patients: a single-center retrospective observational cohort study in Japan

Aim This study aimed to identify the association between total visitation restriction because of the coronavirus 2019 (COVID-19) pandemic and the incidence of delirium for emergency inpatients. Methods This was a single-center, retrospective, observational cohort study conducted at a tertiary critical care center in urban Kyoto, Japan. Adult emergency patients hospitalized between January 1, 2019, and June 30, 2020, were recruited. In response to the COVID-19 pandemic, the authors' hospital began restricted visitation on March 28, 2020. This study defined before visitation restriction as January 1, 2019, through March 31, 2020, and after visitation restriction as April 1, 2020, through June 30, 2020. We did not restrict emergency services, and there were no changes in the hospital's routine, except for visitation restrictions. The primary outcome was the incidence of delirium. The adjusted odds ratio (AOR) with 95% confidence interval (CI) for delirium incidence was calculated to compare the before and after visitation restriction periods, and the logistic model was used to adjust for seven variables: age, sex, ward type on admission, primary diagnosis, ventilator management, general anesthesia surgery, and dementia. Results Study participants were 6264 patients, median age 74 years (56-83), and 3303 men (52.7%). The total delirium incidence in entire research period was 2.5% (158 of 6264 patients), comprising 1.8% (95/5251) before visitation restriction and 6.2% (63/1013) after visitation restriction. The AOR for delirium incidence was 3.79 (95% CI, 2.70-5.31) after visitation restriction versus before visitation restriction. Subgroup analysis showed no apparent interaction for delirium incidence. Conclusion Visitation restriction was associated with an increased incidence of delirium in emergency inpatients.