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Two new studies describe long-COVID symptoms, with one finding that 53% of hospitalized COVID-19 patients still had cognitive impairment (“brain fog”) 13 months after infection, and another adding conditions such as hair loss and sexual dysfunction to the list of persistent symptoms among outpatients.
The first study, by University of Oslo researchers in Norway, was published yesterday in Open Forum Infectious Diseases. The team used four computer-based cognitive tests from the Cambridge Neuropsychological Test Automated Battery to assess 75 adult COVID-19 patients’ cognitive function 13 months after release from a single hospital. Included patients were, on average, 55.7 years old and were admitted to the hospital up to June 2020.
The four tests were delayed matching to sample (DMS) (testing short-term memory, visuospatial processing, learning, and attention), the One-touch Stockings of Cambridge (OTS) test (executive function), rapid visual-information processing (RVP) (sustained attention), and spatial working memory and strategy (SWM).
Rates of cognitive dysfunction were 25% on the DMS, 24% on the OTS, 21% on the RVP, and 14% on the SWM. Overall, 53% showed impairment on at least one of the four tests.
Severe COVID-19, as evidenced by the receipt of supplementary oxygen, was associated with a higher likelihood of impaired cognition on the DMS only (odds ratio [OR], 9.43; 95% confidence interval, 1.54 to 57.74). Adjusting for the presence of underlying diseases only slightly changed the ORs and didn’t affect the significance.
The researchers said there may be several reasons behind the impairments, including causes other than COVID-19. “It is possible that this could be explained by premorbid conditions, living in the epidemic, or psychological sequalae; however, this could not be determined in the present study,” they wrote. The findings “should be ascertained in larger studies and with even longer observation times.”
In the second study, published earlier this week in Nature Medicine, a team led by University of Birmingham researchers retrospectively mined a UK-based primary care database to determine if outpatients had any of 115 COVID-related symptoms lasting longer than 12 weeks, as well as the risk factors for having lingering symptoms.
The cohort included 486,149 adult COVID-19 survivors and 1,944,580 matched uninfected controls from January 2020 to April 2021, before the Omicron SARS-CoV-2 variant surge began.
A total of 56.6% of COVID-19 survivors tested positive in 2020, and 43.4% did so in 2021. Overall, 4.5% of survivors and 4.7% of controls had received at least one dose of COVID-19 vaccine before the index date. The most common vaccines received were Pfizer/BioNTech (2.8%) and AstraZeneca/Oxford (1.7%).
COVID-19 survivors were more likely than controls to report more than one symptom after 12 weeks from the index date (one symptom, 5.6% vs 4.7%; two symptoms, 3.6% vs 2.9%; and three or more, 4.9% vs 4.0%).
Sixty-two symptoms were significantly linked to long COVID, with the largest adjusted hazard ratios (aHRs) for loss of smell (aHR, 6.49), hair loss (3.99), sneezing (2.77), ejaculation difficulty (2.63), and reduced libido (2.36).
Among COVID-19 survivors, the risk factors for long COVID included female sex, younger age, non-White ethnicity, socioeconomic deprivation, smoking, obesity, and a wide range of underlying illnesses.
The most common associated underlying conditions were chronic obstructive pulmonary disease (aHR, 1.55), enlarged prostate (1.39), fibromyalgia (1.37), anxiety (1.35), erectile dysfunction (1.33), depression (1.31), migraine (1.26), multiple sclerosis (1.26), celiac disease (1.25), and learning disability (1.24).
The most common symptoms were loss of smell, shortness of breath, chest pain, fever, amnesia, apraxia (impaired ability to perform familiar movements or commands), bowel incontinence, erectile dysfunction, hallucinations, and swelling of the arms or legs.
“This research validates what patients have been telling clinicians and policy makers throughout the pandemic, that the symptoms of Long Covid are extremely broad and cannot be fully accounted for by other factors such as lifestyle risk factors or chronic health conditions,” senior author Shamil Haroon, MBChB, PhD, of the University of Birmingham, said in a university news release.
“The symptoms we identified should help clinicians and clinical guideline developers to improve the assessment of patients with long-term effects from Covid-19, and to subsequently consider how this symptom burden can be best managed,” he added.
The researchers called for research into the natural history of long COVID, characterization of persistent symptom clusters, and clinical outcomes. “Further research is also needed to understand the health and social impacts of these persistent symptoms, to support patients living with long-term sequelae and to develop targeted treatments,” they concluded.
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