COVID-19 outcomes among patients with dementia and age-matched controls who were hospitalized in 21 US health-care systems.

Introduction: COVID-19 had devastating impacts worldwide. However, most research examining the impact of dementia on COVID-19 outcomes has been conducted in Europe and Asia and has not examined dementia subtypes.

Methods: A retrospective analysis of electronic health record data from 21 US health-care systems examined relationships of all-cause dementia, Alzheimer's disease (AD), and vascular dementia with in-hospital mortality, intensive care unit (ICU) admission, and hospital stay duration.

Results: All-cause dementia, but not AD or vascular dementia independently, was associated with increased mortality risk, the inclusion of discharge to hospice as a mortality equivalent increased risk for mortality for all-cause dementia, and AD and vascular dementia. Patients with all-cause dementia and AD were less likely to be admitted to the ICU than patients without. Patients with any form of dementia had longer hospital stays than patients without.

Discussion: Dementia was associated with increased mortality or hospice discharge, decreased ICU admissions, and longer hospital stays.

Highlights: Only all-cause dementia was associated with increased mortality risk. This risk was lower than what has been published in previous research. Combining mortality and hospice discharge increased risk for all dementia subtypes. All-cause and Alzheimer's disease (AD) dementia were associated with decreased intensive care unit admissions. All-cause, vascular, and AD dementia were associated with longer hospital stays.