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New research finds an association between COVID-19 mortality and neurological symptoms. yacobchuk/Getty Images
  • Some patients with COVID-19 have also developed neurological symptoms.
  • The researchers of the present observational study demonstrate the prevalence of these symptoms.
  • They find that these neurological symptoms have links with an increased risk of in-hospital mortality.

In new research, scientists have demonstrated the frequency of neurological issues related to hospitalized patients with COVID-19, and their association to the in-hospital risk of mortality.

The report, which appears in the journal JAMA Network Open, suggests that self-reported neurological issues, such as headaches and a loss of smell or taste, are highly prevalent.

The researchers discovered that the most common clinically observed neurological symptom was acute encephalopathy — which refers to general damage or disease that affects the structure or function of the brain.

The team also found an association between neurological issues and a higher risk of dying in the hospital due to COVID-19.

COVID-19 is a respiratory disease that primarily affects a person’s pulmonary system. However, researchers have also noted that the illness can affect many other organs and systems in a person’s body, including the brain.

Due to the novelty of SARS-CoV-2, which causes COVID-19 in people who contract the virus, experts do not fully understand the prevalence of neurological issues related to the disease.

Additionally, the relationship between neurological issues in COVID-19 patients and their risk of mortality is not known.

Dr. Sherry Chou is the lead author of the present study and associate professor of critical care medicine, neurology, and neurosurgery at the University of Pittsburgh School of Medicine. She commented, “very early on in the pandemic, it became apparent that a good number of people who were sick enough to be hospitalized also develop neurological problems.

“A year later, we are still fighting an unknown, invisible enemy and, like in any battle, we need intel — we have to learn as much as we can about the neurological impacts of COVID-19 in patients who are actively sick and in survivors.”

To help respond to this gap in the literature, Dr. Chou and her research team performed an interim analysis of patient data collected from two large global consortia, established to investigate the incidence, type, and outcomes of neurological manifestations among patients hospitalized with COVID-19.

They analyzed data from three cohorts involving a total of 3,744 patients.

The Global Consortium Study of Neurologic Dysfunction in COVID-19 conducted the first and second cohorts, from March to September 2020.

The first cohort included 3,055 patients hospitalized with COVID-19, including people with and without neurological symptoms. The second cohort involved 475 individuals hospitalized with COVID-19 who had confirmed neurological issues.

The European Academy of Neurology Neuro-COVID Registry conducted the third cohort between March and October 2020. This cohort involved 214 patients hospitalized with COVID-19 who had received a neurological consultation.

In the first cohort, which included COVID-19 patients with and without neurological issues, the researchers discovered that the most common clinically reported neurological sign was acute encephalopathy, which they found in 50% of patients.

The most common self-reported symptom was headache (38%), followed by loss of taste or smell (28%). The research team found similar results in the other two cohorts.

In the second cohort, which only included COVID-19 patients with confirmed neurological issues, the team found encephalopathy in 53% of these individuals. Additionally, 35% reported headaches, while 20% reported a loss of taste and smell.

In the third cohort, which included COVID-19 patients who had received a neurological consultation, the scientists found encephalopathy in 24% of them. Additionally, 27% reported experiencing headaches, while 23% reported a loss of taste or smell.

For Dr. Chou, “acute encephalopathy is by far the most common symptom that we see in the clinic. Those patients may be in an altered sensory state or have impaired consciousness, or they don’t feel like themselves and act confused, delirious, or agitated.”

After adjusting for confounding factors, the researchers also found that having neurological issues related to COVID-19 increased a patient’s risk of dying while in hospital by five-fold.

As a consequence, Dr. Chou and her coauthors suggest that “a formal neurological consultation may be warranted when doctors suspect neurological signs or symptoms among individuals testing positive for COVID-19.”

While the researchers demonstrate an association between neurological issues in patients with COVID-19 and an increased risk of in-hospital mortality, what may be accounting for this is not yet clear. With this in mind, scientists need to carry out more research to determine if these neurological issues are causing the increase in mortality.

For Dr. Chou, “many factors contribute to the risk of dying during acute hospitalization in COVID-19 patients, so we must be very careful in attributing something as ‘causal.’

“What we do know is that our finding holds true even after we take into account the effects of factors generally associated with higher death rates in COVID-19: older age, male versus female, race differences, ethnicity differences, and variations in death rates at different hospitals.

“What this means is that, if we take people of the same age, sex, race, ethnicity, and at the same hospital, those who have neurological manifestations with COVID-19 are still more likely to die during acute hospitalization.

“This naturally leads to the question: did their neurological manifestation cause death, either directly or indirectly? While this is possible, we need to do a dedicated study to answer this question with confidence.”

The team notes some limitations with their research. While it is the largest study looking at neurological issues in COVID-19 patients to date, it was conducted rapidly amid the first wave of the pandemic.

Consequently, the available data determined the sample size, rather than the team deciding the sample in advance. Additionally, both retrospective and prospective data capture took place, increasing the risk of bias.

Nonetheless, the study lays the groundwork for future research involving standardized protocols, which may be able to track patients with neurological issues after they leave the hospital.

For Dr. Chou, “even if we completely eradicate the pandemic, we are still talking about millions of survivors who need our help. It is important to find out what symptoms and health problems those patients are facing, and there is still plenty of work for years to come.”

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