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Neurological features and outcome in COVID-19: dementia can predict severe disease

Our take —

In this single-site retrospective study of 361 hospitalized COVID-19 patients during the early phase of the pandemic in Iran (March 2020), more than half of patients experienced at least one neurological symptom during the course of their illness and 31 (9%) had a major neurological complication. In age-adjusted analysis, history of dementia was associated with mortality. Neurological features and complications during COVID-19 are an important, yet understudied aspect of disease course, and larger prospective studies with long-term follow-up are needed to better understand their impacts.

Study design

Retrospective Cohort

Study population and setting

This retrospective cohort study at one tertiary care center (Imam Hossein Hospital) in Tehran, Iran evaluated neurological features of 361 adult patients (mean age: 62 years, 41% women) hospitalized with COVID-19 from March 5 to April 3, 2020. COVID-19 diagnosis was based on RT-PCR results or presentation suggestive of COVID-19 with known exposure to COVID-19 in the 14 days prior to symptom onset. Medical history, laboratory findings, and disease course details were collected from the medical record. Patients were classified as non-severe (mild or moderate disease) or severe (any of: respiratory distress, chest imaging with obvious lesion progression, respiratory failure, organ failure, requirement of mechanical ventilation, shock state). Neurological features were reviewed by two trained neurologists.

Summary of Main Findings

Of the 361 hospitalized patients, the initial symptom was neurological in 21 (6%) cases, whereas 186 (52%) had at least one neurological symptom during the course of disease, commonly including headache (30%), loss of taste/smell (19%), dizziness (15%) and altered mental status (11%). Compared to those with non-severe COVID-19, the 233 patients (66%) with severe disease more commonly presented with shortness of breath (31% vs. 18%) and altered mental status (8% vs. 2%), but less often with fever (25% vs. 44%). In age-adjusted analyses, patients with a history of dementia were more likely to develop severe COVID-19 (RR=1.28, 95% CI: 1.15-1.42). Overall, 31 (9%) patients had neurological complications at any point during COVID-19, including encephalopathy (n=11), seizures (n=10), ischemic stroke (n=8), intracerebral hemorrhage (n=4), subarachnoid hemorrhage (n=1), multiple sclerosis relapse (n=1), and Guillain-Barre syndrome (n=1), which were not seemingly associated with COVID-19 severity or other laboratory findings, but were associated with death.

Study Strengths

All neurological features were reviewed and confirmed by two neurologists. Patients or the families of deceased patients were additionally contacted by phone call 2-6 weeks after discharge to clarify disease history details, which likely helped improve data quality.


The sample of patients was small and duration of follow-up was inconsistent (2 to 6 weeks after discharge). Data for analysis were retrospectively reviewed and subject to data availability. Comparison of neurologic symptoms and comorbidities between severe and non-severe COVID-19 patients or their association with death were unadjusted and confounding likely explains some (if not most) of the observed differences. The only adjusted analysis presented was that of the association between dementia and death, but it was only adjusted for age and residual confounding due to other comorbidities or disease severity is likely.

Value added

This study adds modest evidence regarding the prevalence of neurologic symptoms in hospitalized COVID-19 patients.

This review was posted on: 4 February 2021