Background
Previous research evaluating the prevalence and symptoms of post-COVID-19 either lacked a control group or did not compensate for the presence of somatic symptoms in the general population. Furthermore, these studies were unable to determine if somatic symptoms that were reported following a COVID-19 diagnosis existed prior to SARS-CoV-2 infection. Furthermore, because these were clinical investigations, the general public’s post-COVID-19 situations were ignored.
There is an urgent need for empirical evidence on the scope of the long-term repercussions of COVID-19 to influence the development of an adequate healthcare response because long-COVID may be the next impending public health catastrophe.
Study design
Researchers used information from Lifelines, an observational population-level cohort study comprising all COVID-19-related data of those living in the northern Netherlands, for the current investigation. To compare the intensity of symptoms before and after receiving a COVID-19 diagnosis, researchers matched test patients and controls 1:2 by gender, age, and time of completing questionnaires that indicated a diagnosis.
All of the adult Lifelines participants were asked to respond to a computerised COVID-19 survey by the researchers. They started collecting responses every week, then every two weeks starting in June 2020, but eventually this changed to every month.
Using 24 consecutive measurements between March 31, 2020, and August 2, 2021, the researchers used the data they had gathered to measure the longitudinal dynamics of 23 somatic symptoms among COVID-19 cases. They rated each of the 23 symptoms on a five-point Likert scale, where one represented how bothersome it was and five represented how uncomfortable it was. Researchers only deemed a symptom to be persistently present when it received a score of three (moderate score). The researchers then calculated a mean pre-COVID-19 score for each participant based on that symptom.
Population characteristics were given by the researchers as absolute numbers or, when appropriate, as averages with standard deviation (SD). Additionally, they used Q-Q plots and histograms to check the study data for normality. Finally, the researchers provided a moving average symptom report broken down further by gender and symptom for each person who tested positive for COVID-19.
Study results
Throughout the course of the trial, the response rate to digital COVID-19 surveys ranged from 28% to 49%. 883973 questionnaires were completed by a total of 76,422 study participants, who were 53.7 years old on average. The authors matched 8462 controls with 4231 COVID-19 diagnosed cases, of which more than 60% were female.
These people experienced a variety of symptoms in the 90 to 150 days after being diagnosed with COVID-19, including chest pain, painful breathing, breathing issues, muscle pain, anosmia, lumps in the throat, alternately hot and cold sensations, tingling in the extremities, heavy arms or legs, and fatigue. Only 12.7% of patients had these symptoms, which is interesting because even COVID-19-negative controls showed a significant rise (moderate intensity, i.e., score of 3) in at least one of these symptoms at the same time point.
It is interesting to note that while 56% of the experts believed that a headache was crucial to the case definition, only 39% of the experts thought that tingling extremities were a significant post-COVID-19 symptom. The current research revealed that although the headache was unrelated to COVID-19, tingling in the extremities was a fundamental symptom. The necessity for long-term cohort studies in the general population with pre-infection data and controls to identify the extent of the post-COVID-19 condition was made clear by these disparities.
Conclusions
Overall, the study’s findings suggested that one in eight SARS-CoV-2-infected people in the general community would experience post-COVID-19 symptoms. The authors claim that this is the first study to characterise the population-level symptom prevalence and severity in COVID-19 patients. They were successfully adjusted for each symptom that existed before to SARS-CoV-2 infection as well as the symptom dynamics reported by controls who were age- and sex-matched but had not contracted the virus during the same time period.
The study also looked at changes in these chronic COVID diseases brought on by seasonality and public health initiatives implemented during the epidemic. Most interestingly, the study showed that the symptoms that were most frequently reported were not those that were most unique for the post-COVID-19 state. In order to better guide the medical approach to protracted COVID, future investigations should delve deeper into the nature of the key symptoms highlighted in the current analysis.
Journal reference:
Aranka V Ballering, Sander K R van Zon, Tim C olde Hartman, Judith G M Rosmalen, for the Lifelines Corona Research Initiative*. (2022). Persistence of somatic symptoms after COVID-19 in the Netherlands: an observational cohort study. The Lancet. doi: https://doi.org/10.1016/S0140-6736(22)01214-4 https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(22)01214-4/fulltext