Neurodegenerative diseases that cause dementia increase the risk of severity and death Covid-19. In patients with Alzheimer’s disease These risks are three times as high and can be increased six times if they are older than 80 years.
The results were backed up by a study by researchers of the University of São Paulo (USP) It’s from Butantane Institute in partnership with colleagues Federal University of Rio de Janeiro (UFRJ).
The results of the FAPESP-sponsored study were described in an article published in the journal on Wednesday the 21st Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.
“We found that all causes of dementia are risk factors for increased severity and death from Covid-19 and that these risks are more pronounced in patients with Alzheimer’s disease,” says Sérgio FAPESP Agency, Sérgio Verjovski, professor at the USP Institute Chemistry and project coordinator.
Dementia had previously been identified as a risk factor for Covid-19 along with other comorbidities such as cardiovascular and respiratory diseases, high blood pressure, diabetes, obesity and cancer. One reason is age: Patients with dementia are on average older and mostly live in the care of other people at home or in nursing homes, which increases the risk of infection and transmission of the virus.
However, it has not yet been studied whether patients with neurodegenerative diseases that cause dementia, such as Alzheimer’s and Parkinson’s, are more infected are at a higher risk of developing severe forms and dying from Covid-19, and whether age increases these dangers .
To clarify these doubts, the researchers looked at the number of positive diagnoses, hospitalizations and deaths from Covid-19 in a cohort of 12,863 patients over 65 with positive or negative test data for the coronavirus registered between March and August 2020 at the UK Biobank – clinical database of approximately 500,000 patients, followed by the UK healthcare system since 2006.
Of that total, 1,167 were diagnosed with Covid-19. In order to consider age as a risk factor, they were divided into three age groups: 66 to 74, 75 to 79 and 80 years or older.
“Some of the benefits of using the clinical data from this bank are that they are detailed, meaning they record all pre-existing illnesses and the patients who tested positive or negative who were hospitalized and who died as a result of COVID-19 , Show. This allows us to assess the risk factors associated with infection, severity and death from the disease, including all causes of dementia, especially Alzheimer’s and Parkinson’s, ”explains Verjovski.
The results of the statistical analyzes showed that all causes of dementia – and Alzheimer’s disease in particular – were risk factors for the severity and death of hospital patients, regardless of age.
Alzheimer’s disease in particular did not increase the risk of hospitalization compared to chronic comorbidities. However, after hospitalization, patients with this disease were three times more likely to develop severe illness or die of Covid-19 than patients without neurodegenerative disease. In patients affected by the disease and older than 80 years of age, these risks were six times higher compared to less elderly patients, the researchers found.
“There is an as yet unidentified factor that increases the predisposition of patients in this condition to develop into a more severe condition and die from the effects of Covid-19,” said Verjovski.
“The results of our work show that it is necessary to pay special attention to these patients when admitting them,” he says.
One explanation for the observed results is that chronic inflammatory conditions or defective immune responses caused by aging of the immune system (immunosensitivity) can increase susceptibility and decrease the ability of these patients to respond effectively to infections.
Another hypothesis is the change in the permeability of the blood-brain barrier caused by Alzheimer’s disease, which can allow an increase in central nervous system infection
Recent studies have shown that SARS-CoV-2 can penetrate the central nervous system through the olfactory mucosa and that the presence of the virus in this region leads to a local immune and inflammatory response.
Other studies have reported the presence of the new coronavirus in the brain stem, which includes the primary cardiovascular system and the center of breath control, increasing the possibility that central nervous system infection in patients with Covid may mediate respiratory and cardiovascular problems or worsen -19.
“We now intend to carry out genomic analyzes of these patients, also available from the UK Biobank, to determine which genes are mutated and which may be associated with an increased risk of people with Alzheimer’s disease developing into serious diseases and Covid -19 die, “says Verjovski.
The item Dementia is an age-independent risk factor for severity and death in patients with COVID-19 (DOI: 0.1002 / al. 12352), by Ana C. Tahira, Sergio Verjovski-Almeida and Sergio T. Ferreira, can be read in the journal Alzheimer & Demenz.