Delirium is a presenting symptom of COVID-19 in frail, older adults: a cohort study of 322 hospitalised and 535 community-based older adults

Zazzara, M. B.; Penfold, R. S.; Roberts, A. L.; Lee, K.; Dooley, H.; Sudre, C. H.; Welch, C.; Bowyer, R. C. E.; Visconti, A.; Mangino, M.; Freydin, M. B.; El-Sayed Moustafa, J. S.; Small, K.; Murray, B.; Modat, M.; Wolf, J.; Ourselin, S.; Martin, F. C.; Steves, C. J.; Ni Lochlainn, M.

Background: Frailty, increased vulnerability to physiological stressors, is associated with adverse outcomes. COVID-19 exhibits a more severe disease course in older, co-morbid adults. Awareness of atypical presentations is critical to facilitate early identification. Objective: To assess how frailty affects presenting COVID-19 symptoms in older adults. Design: Observational cohort study of hospitalised older patients and self-report data for community-based older adults. Setting: Admissions to St Thomas' Hospital, London with laboratory-confirmed COVID-19. Community-based data for 535 older adults using the COVID Symptom Study mobile application. Subjects: Hospital cohort: patients aged 65 and over (n=322); unscheduled hospital admission between March 1st, 2020 - May 5th, 2020; COVID-19 confirmed by RT-PCR of nasopharyngeal swab. Community-based cohort: participants aged 65 and over enrolled in the COVID Symptom Study (n=535); reported test-positive for COVID-19 from March 24th (application launch)- May 8th, 2020. Methods: Multivariate logistic regression analysis performed on age-matched samples from hospital and community-based cohorts to ascertain association of frailty with symptoms of confirmed COVID-19. Results: Hospital cohort: significantly higher prevalence of delirium in the frail sample, with no difference in fever or cough. Community-based cohort: significantly higher prevalence of probable delirium in frailer, older adults, and fatigue and shortness of breath. Conclusions: This is the first study demonstrating higher prevalence of delirium as a COVID-19 symptom in older adults with frailty compared to other older adults. This emphasises need for systematic frailty assessment and screening for delirium in acutely ill older patients in hospital and community settings. Clinicians should suspect COVID-19 in frail adults with delirium.