Prevalence and prognostic value of Delirium as the initial presentation of COVID-19 in the elderly with dementia: An Italian retrospective study

Background: Delirium may be one of the presenting symptoms of COVID-19, complicating diagnosis and care of elderly patients with dementia. We aim to identify the prevalence and prognostic significance of delirium as the sole onset manifestation of COVID-19. Methods: This is a retrospective single-centre study based on review of medical charts, conducted during the outbreak peak (March 27-April 18, 2020) in a Lombard dementia facility, including 59 elderly subjects with dementia and laboratory-confirmed COVID-19. Findings: Of the 59 residents, 57 (96.6%) tested positive (mean age: 82.8; women: 66.7%). Comorbidities were present in all participants, with 18/57 (31.6%) having three or more concomitant diseases. Delirium-Onset COVID-19 (DOC) was observed in 21/57 (36.8%) subjects who were chiefly older (mean age: 85.4 y/o) and with multiple comorbidities. Eleven/21 DOC patients (52.4%) had hypoactive delirium, while hyperactive delirium occurred in ten/21 (47.6%). Lymphopenia was present in almost all subjects (median: 1.3 x 10(9)/L). Overall mortality rate was 24.6% (14/57) and dementia severity per se had no impact on short-term mortality due to COVID-19. DOC was strongly associated with higher mortality (p<0.001). Also, DOC and male gender were independently associated with increased risk of mortality (OR: 17.0, 95% CI: 2.8-102.7, p = 0.002 and 13.6, 95% CI: 2.3-79.2, p = 0.001 respectively). Interpretation: Delirium occurrence in the elderly with dementia may represent a prodromal phase of COVID-19, and thus deserves special attention, especially in the presence of lymphopenia. Hypoxia and a severe inflammatory state may develop subsequently. DOC cases have higher short-term mortality rate. (C) 2020 The Author(s). Published by Elsevier Ltd.