Delirium and Inflammation in Older Adults Hospitalized for COVID-19: A Cohort Study

Marie-France Forget,1 Sophie Del Degan,1 Julie Leblanc,1 Rita Tannous,1 Michaël Desjardins,2 Madeleine Durand,3,4 Thien Tuong Minh Vu,1,5 Quoc Dinh Nguyen,1,4 Philippe Desmarais1,5 1Department of Medicine, Division of Geriatrics, Centre Hospitalier de l’Université de Montréal, Montréal, Québec, Canada; 2Department of Medicine, Division of Infectious Disease, Centre Hospitalier de l’Université de Montréal, Montréal, Québec, Canada; 3Department of Medicine, Division of Internal Medicine, Centre Hospitalier de l’Université de Montréal, Montréal, Québec, Canada; 4Innovation Hub, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, Québec, Canada; 5Department of Neurosciences, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montréal, Québec, CanadaCorrespondence: Marie-France ForgetDepartment of Medicine, Division of Geriatrics, Centre Hospitalier de l’Université de Montréal, 1000 Rue Saint-Denis, Montréeal, Québec, H2X 0C1, CanadaTel + 1 514 890 8000Fax + 1-514-412-7953Email marie-france.forget@umontreal.caPurpose: The occurrence and predictors of delirium in older adults hospitalized for coronavirus disease 2019 (COVID-19) have not been well described. Highlighting the association with inflammatory markers may be useful for identifying delirium. This study aimed to determine the prevalence and incidence of delirium and explore its association with the C-reactive protein (CRP).Patients and Methods: This cohort study of adults aged 65 and older with a COVID-19 diagnosis took place at an academic healthcare institution between April and May 2020. COVID-19 was diagnosed by positive nasopharyngeal swab. Serum levels of CRP were collected as a marker of systemic inflammation. The primary outcome was the prevalence and incidence of delirium. Delirium was diagnosed primarily during a patient’s stay in hospital based on the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5). To ensure that no delirium diagnosis was missed during hospital stay, clinical records were reviewed by clinicians with geriatric medicine training for retrospective diagnoses.Results: A total of 127 patients aged 65 and older were hospitalized with a diagnosis of COVID-19. The median age was 82 years (IQR: 74– 88), with 54 (43%) females. Overall, delirium was present in 62 (49%) patients: manifestations of delirium were present on the first day of hospitalization in 53 of these cases (86%), while 9 cases (14%) developed delirium during hospitalization. After controlling for age and sex, the mean CRP value over the first 3 days since arrival was associated with a higher risk of delirium (OR 1.35; 95% CI: 1.01– 1.85) for every 50 mg/L increase.Conclusion: In this cohort of older adults hospitalized for COVID-19, delirium was highly prevalent. An early increase in CRP levels should raise suspicion about the occurrence of delirium and could improve its diagnosis.Keywords: delirium, COVID-19, SARS-CoV-2, older adult