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Cognitive sequelae in post-COVID-syndrome : a Danish-Swedish case-control study

Christensen, Johan Frederik Mebus Meyer ; Meyer, Rikke ; Holmqvist, Madlene LU ; Carlson, Katherine LU ; Palmqvist, Sebastian LU orcid ; Kahn, Fredrik LU and Jürgens, Gesche (2025) In Infectious Diseases p.1-14
Abstract

BACKGROUND: While patients with post-COVID syndrome (PCS) suffer from cognitive deficits few studies directly compare patients with PCS to subjects recovered after an infection with the 'Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)'.

OBJECTIVES: To investigate cognitive performance adjusting for age, increasing body-mass-index (BMI), smoking, years of education, gender and hospitalisation while infected in patients with PCS compared to controls fully recovered. Secondly, to stratify cognitive performance based on the SARS-CoV-2 virus strain (variant of concern 'VOC') causing the infection. Thirdly, to assess whether patients with PCS have increased levels of psychological distress and affected hand grip strength as... (More)

BACKGROUND: While patients with post-COVID syndrome (PCS) suffer from cognitive deficits few studies directly compare patients with PCS to subjects recovered after an infection with the 'Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)'.

OBJECTIVES: To investigate cognitive performance adjusting for age, increasing body-mass-index (BMI), smoking, years of education, gender and hospitalisation while infected in patients with PCS compared to controls fully recovered. Secondly, to stratify cognitive performance based on the SARS-CoV-2 virus strain (variant of concern 'VOC') causing the infection. Thirdly, to assess whether patients with PCS have increased levels of psychological distress and affected hand grip strength as both are associated with cognitive performance.

METHODS: A Danish-Swedish case-control study we recruited adult patients (18-75 years) with PCS from long-COVID outpatient clinics in Region Zealand Denmark and Skåne County Sweden. Participants had confirmed SARS-CoV-2 infection >12 weeks prior to inclusion and healthy control subjects had recovered completely. All study participants were exposed to cognitive tests, Kessler's psychological distress scale (K10) and tested with a hand-dynamometer.

RESULTS: Recruiting 181 cases and 155 control subjects, patients with PCS had reduced cognitive performance scores on all domains though hardly clinically significant. Reduced processing speed was impacted the most with patients infected early in the pandemic exhibiting greater deficits.

CONCLUSION: PCS was associated with reduced cognitive processing speed compared to fully recovered controls with those infected early in the pandemic having greater deficits. Psychological distress and hand grip strength were affected in patients with PCS, but not decisively associated with cognitive performance.

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; ; ; ; ; and
author collaboration
organization
publishing date
type
Contribution to journal
publication status
epub
subject
in
Infectious Diseases
pages
1 - 14
publisher
Taylor & Francis
external identifiers
  • pmid:40944707
ISSN
2374-4235
DOI
10.1080/23744235.2025.2551665
language
English
LU publication?
yes
id
563eaba1-d02c-4097-9115-26c4b8434942
date added to LUP
2025-09-22 08:48:27
date last changed
2025-09-22 12:24:31
@article{563eaba1-d02c-4097-9115-26c4b8434942,
  abstract     = {{<p>BACKGROUND: While patients with post-COVID syndrome (PCS) suffer from cognitive deficits few studies directly compare patients with PCS to subjects recovered after an infection with the 'Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)'.</p><p>OBJECTIVES: To investigate cognitive performance adjusting for age, increasing body-mass-index (BMI), smoking, years of education, gender and hospitalisation while infected in patients with PCS compared to controls fully recovered. Secondly, to stratify cognitive performance based on the SARS-CoV-2 virus strain (variant of concern 'VOC') causing the infection. Thirdly, to assess whether patients with PCS have increased levels of psychological distress and affected hand grip strength as both are associated with cognitive performance.</p><p>METHODS: A Danish-Swedish case-control study we recruited adult patients (18-75 years) with PCS from long-COVID outpatient clinics in Region Zealand Denmark and Skåne County Sweden. Participants had confirmed SARS-CoV-2 infection &gt;12 weeks prior to inclusion and healthy control subjects had recovered completely. All study participants were exposed to cognitive tests, Kessler's psychological distress scale (K10) and tested with a hand-dynamometer.</p><p>RESULTS: Recruiting 181 cases and 155 control subjects, patients with PCS had reduced cognitive performance scores on all domains though hardly clinically significant. Reduced processing speed was impacted the most with patients infected early in the pandemic exhibiting greater deficits.</p><p>CONCLUSION: PCS was associated with reduced cognitive processing speed compared to fully recovered controls with those infected early in the pandemic having greater deficits. Psychological distress and hand grip strength were affected in patients with PCS, but not decisively associated with cognitive performance.</p>}},
  author       = {{Christensen, Johan Frederik Mebus Meyer and Meyer, Rikke and Holmqvist, Madlene and Carlson, Katherine and Palmqvist, Sebastian and Kahn, Fredrik and Jürgens, Gesche}},
  issn         = {{2374-4235}},
  language     = {{eng}},
  month        = {{09}},
  pages        = {{1--14}},
  publisher    = {{Taylor & Francis}},
  series       = {{Infectious Diseases}},
  title        = {{Cognitive sequelae in post-COVID-syndrome : a Danish-Swedish case-control study}},
  url          = {{http://dx.doi.org/10.1080/23744235.2025.2551665}},
  doi          = {{10.1080/23744235.2025.2551665}},
  year         = {{2025}},
}