Frailty and hyperactive delirium in hospitalized older patients with COVID-19: an insight from GeroCovid registry

Background: Delirium is an acute neuropsychiatric condition associated with unfavourable outcomes, frequent in older hospitalized people. In the context of the SARS-CoV-2 pandemic, few studies have specifically focused on the inflammatory status of older, frail patients with hyperactive delirium (HD) hospitalized for COVID-19. Aim: To identify biological correlates of HD at hospital admission and to assess the independent effect of delirium and physical frailty on in-hospital mortality. Methods: Data were retrospectively extracted by the multicenter registry GeroCovid Observational Study. Individuals aged ≥ 60 years were included if the information on the presence of HD, frailty based on the modified Fried criteria and inflammatory status had been collected. The risk of mortality was evaluated using a Kaplan-Meier estimator, according to frailty and delirium. Logistic and restricted cubic-spline regressions were employed to assess the relationship between inflammatory markers and HD. Results: Three-hundred-thirty-seven older adults were included in the analysis [mean age (SD) 77.1 (9.5) years, 50.1% females], and 11.5% presented with HD. A significant association of both PaO2/FiO2 ratio (p = 0.015) and serum lactate dehydrogenase (p = 0.04) with delirium was observed. By Cox multivariable regression, frail and non-frail patients with HD had a 4.42 and 2.85 higher mortality risk compared with non-frail, non-delirious patients. Conclusions: Hyperactive delirium at hospital admission is related with markers of lung failure among older adults, especially when physical frailty coexists. Delirium is associated with increased in-hospital mortality risk, which is doubled by the coexistence of physical frailty.