Many long-haul COVID-19 patients suffer fatigue and cognitive impairments months after their initial COVID-19 diagnosis, according to new research published in the journal Brain, Behavior, and Immunity. The study, which analyzed data from tens of thousands of patients, also found that COVID-19 was associated with persistent inflammation.
A growing body of evidence indicates that patients who get sick with COVID-19 can suffer long-term physical and mental health consequences. These long-term effects are currently referred to as “post-COVID-19 syndrome” or “Long COVID.”
Roger S. McIntyre, the corresponding author of the new study, mainly researches the neurobiological causes of cognitive impairment in individuals with mood disorders, such as depression. But he has started to examine treatments for COVID-19 symptoms in the wake of the pandemic.
“Long COVID is common, persistent, and extremely debilitating,” said McIntyre, a professor at the University of Toronto and head of the Mood Disorders Psychopharmacology Unit at the University Health Network. “Many of the symptoms of long COVID overlap with symptoms of depression, which is the condition I primarily research and treat. We were interested in whether any of our treatments in psychiatry that help brain fog and fatigue could also help people with long COVID.”
McIntyre and his colleagues conducted a systematic review and meta-analysis of 81 studies that had a follow-up time of at least 12 weeks since a confirmed COVID-19 diagnosis. The studies included 56 prospective cohort studies, 14 cross-sectional studies, 10 retrospective cohort studies, and 1 retrospective case-control study.
The meta-analysis included fatigue data for 25,268 individuals and cognitive impairment data for 13,232 individuals. Fatigue was assessed with scientific questionnaires such as the Functional Assessment of Chronic Illness Therapy and the Fatigue Severity Scale. Cognitive impairment was assessed with a variety of validated diagnostic tools, including the Montreal Cognitive Assessment and the Telephone Interview for Cognitive Status.
McIntyre and his colleagues found that approximately a third of individuals (32%) experienced persistent fatigue, while slightly more than one in five individuals (22%) showed signs of sustained cognitive impairment.
An analysis of 14 studies that investigated inflammatory markers in COVID-19 patients revealed that a subset of individuals showed signs of systemic inflammation 12 or more weeks following diagnosis. Several studies noted an association between heightened inflammation and long COVID symptoms, “suggesting hyperinflammation is an amenable cause of fatigue and/or cognitive impairment,” the researchers said.
Furthermore, 34 studies investigated the functional consequences of post-COVID syndrome, including limitations related to physical activity and occupational status. Post-COVID syndrome was associated with “marked levels” of functional impairment, the researchers said. Approximately 16% to 28% reported being unable to partake in a sport or recreational activity. Between 8% to 39% reported disruption in their work life and between 29% to 47% of those who were employed prior to infection were unable to return to work.
“People should be aware that there are many post-acute complications of COVID-19, including post-COVID syndrome — which can be debilitating,” McIntyre told PsyPost. “If you have such symptoms, you should speak to a healthcare provider and make sure you are not experiencing some other disorder (e.g. major depressive disorder or a physical health condition).”
Fatigue and cognitive impairment were more common among women, older people, those with greater severity of acute illness, and those with pre-existing comorbidities. The researchers observed a lower incidence of fatigue and cognitive impairment among children compared to adults.
But there is still much we don’t know about post-COVID syndrome, including “who is most at risk, whether the vaccines protect against long COVID, whether variants make a difference, and whether it puts people at risk for other conditions,” McIntyre said. “Long COVID still has not been sufficiently characterized. We still need a single validated definition. We don’t know enough about how long these symptoms will go on for.”
The study, “Fatigue and cognitive impairment in Post-COVID-19 Syndrome: A systematic review and meta-analysis“, was authored by Felicia Ceban, Susan Ling, Leanna M.W. Lui, Yena Lee, Hartej Gill, Kayla M. Teopiz, Nelson B. Rodrigues, Mehala Subramaniapillai, Joshua D. Di Vincenzo, Bing Cao, Kangguang Lin, Rodrigo B. Mansur, Roger C. Ho, Joshua D. Rosenblat, Kamilla W. Miskowiak, Maj Vinberg, Vladimir Maletic, and Roger S. McIntyre.