Background: It is known that patients with COVID-19 are at high risk of developing delirium. The aim of the study was to compare the incidence of delirium between critically ill patients with and without a diagnosis of COVID-19.
Methods: This is a retrospective study conducted in a southern Brazilian hospital from March 2020 to January 2021. Patients were divided into two groups: the COVID-19 group consisted of patients with a diagnosis of COVID-19 confirmed by reverse transcription-polymerase chain reaction (RT-PCR) or serological tests who were admitted to specific ICUs. The non-COVID-19 group consisted of patients with other surgical and medical diagnoses who were admitted to non-COVID ICUs. All patients were evaluated daily using the Intensive Care Delirium Screening Checklist (ICDSC). The two cohorts were compared in terms of the diagnosis of delirium.
Results: Of the 649 patients who remained more than 48 h in the ICU, 523 were eligible for the study (COVID-19 group: 292, non-COVID-19 group: 231). There were 119 (22.7%) patients who had at least one episode of delirium, including 96 (32.9%) in the COVID-19 group and 23 (10.0%) in the non-COVID-19 group (odds ratio [OR] 4.42; 95% confidence interval [CI], 2.69 to 7.26; p < 0.001). Among patients mechanically ventilated for two days or more, the incidence of delirium did not differ between groups (COVID-19: 89/211, 42.1% vs non-COVID-19: 19/47, 40.4%; p = 0.82). Logistic regression showed that the duration of mechanical ventilation was the only independent factor associated with delirium (p = 0.001).
Conclusion: COVID-19 can be associated with a higher incidence of delirium among critically ill patients, but there was no difference in this incidence between groups when mechanical ventilation lasted two days or more.
Keywords: COVID-19; delirium; intensive care unit; mechanical ventilation.