Clinical Characteristics and Outcomes of Covid-19 Patients With Underlying Dementia: Results From a Large Multicenter Propensity-matched Brazilian Cohort Study
Authors: Bicalho Maria Aparecida Camargos , Aliberti Márlon Juliano Romero , Delfino-Pereira Polianna , Chagas Victor Schulthais , Rosa Patryk Marques da Silva , Pires Magda Carvalho , Ramos Lucas Emanuel Ferreira , Bezerra Adriana Falangola Benjamin , Feres Ana Beatriz de Castro , Gomes Angélica Gomides dos Reis , Bhering Angelinda Rezende , Pessoa Bruno Porto , Silva Carla Thais Cândida Alves da , Cimini Christiane Corrêa Rodrigues , Carazai Daniela dos Reis , Ponce Daniela , Rios Danyelle Romana Alves , Manenti Euler , Anschau Fernando , Batista Joanna d'Arc Lyra , de Alvarenga Joice Coutinho , Viguini Julia Avancini , Zanellato Julia Mariot , Rugolo Juliana Machado , Ruschel Karen Brasil , Nascimento Leticia do , Menezes Luanna Silva Monteiro , de Oliveira Lucas Moyses Carvalho , de Castro Luís César , Nasi Luiz Antônio , Carneiro Marcelo , Ferreira Maria Angélica Pires , de Godoy Mariana Frizzo , Guimarães-Júnior Milton Henriques , Bonardi Naiara Patrícia Fagundes , de Oliveira Neimy Ramos , Ziegelmann Patricia Klarmann , Porto Paula Fonseca , Mendes Paulo Mascarenhas , Paraíso Pedro Gibson , Reis Priscilla Pereira dos , de Abreu Roger Mendes , Francisco Saionara Cristina , Araújo Silvia Ferreira , Avelino-Silva Thiago Junqueira , Suemoto Claudia Kimie , Marcolino Milena Soriano 
Published: October 2022

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.