Clinical Characteristics and Outcomes of Covid-19 Patients With Underlying Dementia: Results From a Large Multicenter Propensity-matched Brazilian Cohort Study

Abstract Background Although dementia has emerged as an important risk factor for severe SARS-CoV-2 infection, results on COVID-19-related complications and mortality are not consistent. We examined the clinical presentations and outcomes of COVID-19 in a multicentre cohort of in-hospital patients, comparing those with and without dementia. Methods This retrospective observational study comprises COVID-19 laboratory-confirmed patients aged ≥60 years admitted to 38 hospitals from 19 cities in Brazil. Data were obtained from electronic hospital records. A propensity score analysis was used to match patients with and without dementia (up to 3:1) according to age, sex, comorbidities, year and hospital of admission. Our primary outcome was in-hospital mortality. We also assessed admission to the intensive care unit (ICU), invasive mechanical ventilation (IMV), kidney replacement therapy (KRT), sepsis, nosocomial infection, and thromboembolic events. Results Among 8,947 eligible patients, 405 (4.5%) had a diagnosis of dementia and were matched with 1,151 patients without dementia. Compared to a group of similar demographics and comorbidities, patients with dementia presented a lower duration of symptoms (5.0 vs. 7.0 days; p<0.001) and frequency of dyspnoea, cough, myalgia, headache, ageusia, and anosmia. Fever and delirium were more frequent in patients with dementia than the control group. Patients with dementia also received more palliative care than the control group. Dementia was associated with lower admission (32.7% vs. 47.1%, p<0.001) and length of stay (7 vs. 9 days, p<0.026) in the ICU, frequency of sepsis (17% vs. 24%, p=0.005), KRT (6.4% vs. 13%, p<0.001), and IVM (4.6% vs. 9.8%, p=0.002). We did not find differences in hospital mortality among those with and without dementia. Conclusion Clinical manifestations of COVID-19 differ in older patients with and without dementia in the hospital, with delirium being highly prevalent among those with dementia. Our findings indicate that dementia alone might not explain higher short-term mortality after severe COVID-19. Clinicians should include other risk factors such as acute morbidity severity and baseline frailty when evaluating the prognosis of COVID-19 in the hospital.