One in eight COVID-19 patients (12.7%) is likely to experience long term symptoms, a study from the Netherlands has reported, compared with just 8.7% of uninfected people followed over the same period during the research.
Using digital questionnaires, researchers collected data on the frequency of 23 symptoms commonly associated with COVID in an uninfected population and in people who had had a positive diagnosis, reports The BMJ.
The findings, published in The Lancet, found that 21.4% (381/1782) of adults who had had COVID experienced at least one new or severely increased symptom three to five months after infection when compared with before.
This compared with only 8.7% (361/4130) of uninfected people followed over the same period.
The core long COVID symptoms highlighted by the researchers include chest pain, difficulties breathing, pain when breathing, painful muscles, loss of taste and smell, tingling extremities, lump in throat, feeling hot and cold, heavy arms or legs, and general tiredness.
The questionnaire was sent out 24 times to the same people from March 2020 to August 2021. During this period people would have been infected with alpha or an earlier variant, and most people were unvaccinated.
More than 76 ,000 participants completed a total of 883,973 questionnaires; the average age of respondents was 54, and 61% were female. A group of 4,231 (5.5%) participants who had COVID were then matched to 8,462 controls who did not, taking into account sex, age, and the time of diagnosis.
Aranka Ballering, study author and a PhD candidate at the University of Groningen, Netherlands, said: “By looking at symptoms in an uninfected control group and in individuals both before and after SARS-CoV-2 infection, we were able to account for symptoms which may have been a result of non-infectious disease health aspects of the pandemic, such as stress caused by restrictions and uncertainty.
“Post-COVID-19 condition is an urgent problem with a mounting human toll. Understanding the core symptoms and the prevalence of post-COVID in the general population represents a major step forward for our ability to design studies that can ultimately inform successful healthcare responses to the long term symptoms the virus.”
The authors acknowledged some limitations to the study, including that it did not include an ethnically diverse population and that because of asymptomatic infection they may have underestimated the true prevalence of COVID-19. Additionally, some symptoms that have been highlighted as potentially relevant to long COVID, such as brain fog, were not considered during the study.
Study details
Persistence of somatic symptoms after COVID-19 in the Netherlands: an observational cohort study
Aranka Ballering, Sander van Zon, Tim Hartman, Judith Rosmalen.
Published in The Lancet on 6 August 2022
Summary
Background
Patients often report various symptoms after recovery from acute COVID-19. Previous studies on post-COVID-19 condition have not corrected for the prevalence and severity of these common symptoms before COVID-19 and in populations without SARS-CoV-2 infection. We aimed to analyse the nature, prevalence, and severity of long-term symptoms related to COVID-19, while correcting for symptoms present before SARS-CoV-2 infection and controlling for the symptom dynamics in the population without infection.
Methods
This study is based on data collected within Lifelines, a multidisciplinary, prospective, population-based, observational cohort study examining the health and health-related behaviours of people living in the north of the Netherlands. All Lifelines participants aged 18 or older received invitations to digital COVID-19 questionnaires. Longitudinal dynamics of 23 somatic symptoms surrounding COVID-19 diagnoses (due to SARS-CoV-2 alpha [B.1.1.7] variant or previous variants) were assessed using 24 repeated measurements between March 31, 2020, and Aug 2, 2021. Participants with COVID-19 (a positive SARS-CoV-2 test or a physician’s diagnosis of COVID-19) were matched by age, sex, and time to COVID-19-negative controls. We recorded symptom severity before and after COVID-19 in participants with COVID-19 and compared that with matched controls.
Findings
A total of 76,422 participants (mean age 53·7 years [SD 12·9], 46,329 [60·8%] were female) completed a total of 883,973 questionnaires. Of these, 4,231 (5·5%) participants had COVID-19 and were matched to 8,462 controls. Persistent symptoms in COVID-19-positive participants at 90–150 days after COVID-19 compared with before COVID-19 and compared with matched controls included chest pain, difficulties with breathing, pain when breathing, painful muscles, ageusia or anosmia, tingling extremities, lump in throat, feeling hot and cold alternately, heavy arms or legs, and general tiredness. In 12·7% of patients, these symptoms could be attributed to COVID-19, as 381 (21·4%) of 1,782 COVID-19-positive participants versus 361 (8·7%) of 4,130 COVID-19-negative controls had at least one of these core symptoms substantially increased to at least moderate severity at 90–150 days after COVID-19 diagnosis or matched timepoint.
Interpretation
To our knowledge, this is the first study to report the nature and prevalence of post-COVID-19 condition, while correcting for individual symptoms present before COVID-19 and the symptom dynamics in the population without SARS-CoV-2 infection during the pandemic. Further research that distinguishes potential mechanisms driving post-COVID-19-related symptomatology is required.
See more from MedicalBrief archives:
South African research sheds light on microclots’ role in long COVID
Health minister’s advisers recommend more research on long COVID after study
Long COVID impacts heart, lung and kidney – Scottish study
Long COVID can trigger type 2 diabetes in some – VA cohort study