Pre-existing Alzheimer’s and dementias associated to the chance of hospitalization for COVID-19

Alzheimer’s disease, dementia, and related cognitive disorders are the top risk factors for COVID-19, researchers found in an observational cohort study published in Brain, Behavior and Immunity.

The researchers tested the association of COVID-19 status with 974 diseases and 30 blood biomarkers using medical records of 389,620 subjects of European descent from the UK Biobank, a population-based prospective study that recruited more than 500,000 people aged 40 to 69 years between 2006 and 2010.

Individuals enrolled outside of England, who died prior to September 2019, or had a self-reported gender that does not match genetic information were not included. The researchers included COVID-19 laboratory test results from March 16 to May 18, 2020, associated with one of the remaining 389,620 patients.

The researchers analyzed the inpatient hospital records, cancer registry and death registry in the database, identified hospital stays and tests for COVID-19, and collected the 30 biomarkers from blood samples from the UK biobank cohort. They found that 1,091 of the 3,884 patients who tested for COVID-19 had tested positive at least once in the hospital.

The researchers found a link between COVID-19 and delirium, dementia, amnesia, and other cognitive disorders (P = 1.36 × 10-44, odds ratio) [OR]1.90; 95% confidence interval [CI]1.24-2.90 in combined samples; OR 2.06; 95% CI, 1.11-3.81 in men), dementia (P = 3.48 × 10-44; OR 2.16; 95% CI 1.36-3.42 in combined samples; OR 2.05 ; 95% CI 1.05–3.98 in men; OR 2.24; 95% CI 1.18–4.24 in women) and Alzheimer’s disease (P = 2.45 × 10–27; OR 2, 29; 95% CI 1.25–4.16 in combined samples; OR 2.40; 95% CI; 1.02–5.62 in men). Of the 992 patients with dementia in the cohort, 45 tested negative and 34 tested positive for COVID-19. Of the 509 patients with Alzheimer’s disease in the cohort, 25 tested negative and 20 positive for the coronavirus.

The patients who tested positive for COVID-19 also tended to be older (P = 0.024), more often male (P = 7.33 × 10-8), and had a higher body mass index (BMI) (P = 7.27 × 10-). 18) and smoked more frequently (P = 2.84 × 10-5) compared to the rest of the cohort, and they had a higher BMI (P = 3.9 × 10-3) and a higher tendency to be male (P. =) 3.2 × 10-3) than those who tested negative for COVID-19.

Limitations of the study included susceptibility to collider distortion due to the small sample size, the inability to provide additional information about certain symptoms or outcomes of subjects with COVID-19, and the inability to address the causal roles of risk factors.

“Based on our findings, cognitive disorders are likely risk comorbidities in older groups, and the associated susceptibility to severe COVID-19 isn’t just due to older age,” the researchers said. “Another possible explanation for finding that more people with mental disorders have COVID-19 is that they are at higher risk of viral infections due to their limited ability to be self-sufficient and their frequent interactions with health care providers. Collectively, these results should help stimulate COVID-19 research on the special needs of patients with these cognitive disorders. Given the different risks faced by elderly people of different styles, a more comprehensive strategy with precise approaches to primary prevention may be desirable during this and similar pandemics. ”

“Our results identified associations of a variety of pre-existing diseases and genetic variants as being associated with COVID-19,” the researchers said. “However, the actual causal effects of risk factors on susceptibility to COVID-19 are likely to vary based on genetic background, lifestyle, and social affiliation, and are likely to be more complicated than indicated on our population-level screening.”


Zhou J, Liu C, Sun Y, Huang W, Ye K. Cognitive Disorders Associated with Hospitalization for COVID-19: Results of an Observational Cohort Study [published online October 24, 2020]. Brain, behavior, immune. doi: 10.1016 / j.bbi.2020.10.019

This article originally appeared on Psychiatry Advisor

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