One in eight Dutch people have persistent symptoms after COVID-19

Picture: Jan van Hoek has Long COVID and participates in the study. A tilt table test will be used to examine how his body regulates blood pressure and blood circulation when posture changes. 

Large-scale data study 

The researchers used data of the Lifelines biobank to compare people’s symptoms before and after having COVID-19. They also compared these symptoms with the symptoms of people who did not fall ill in the same period. A unique, large-scale study was conducted into ‘Long COVID’ among the general population. The results were published today in leading scientific journal The Lancet (read the publication here). The research, in which Radboudumc also participated, was made possible by a subsidy from ZonMw (the Netherlands Organisation for Health Research and Development). 

Certain persistent complaints more common 

Comparing people who have had COVID-19 with those who have not experienced the disease shows that certain persistent symptoms are more common in the months following a COVID-19 infection. These symptoms include chest pain, loss of smell and taste, shortness of breath, fatigue, and muscle pain.  
 
Judith Rosmalen: ‘We looked at how many participants developed symptoms or whose symptoms got worse after COVID-19 compared to how they felt before infection. We also looked at participants who did not have a COVID-19 infection in the same period so that we could consider changes in symptoms due to other causes. For example, changes in symptoms due to seasons changing, people developing new diseases, or living conditions changing due to the pandemic and the restrictions. That is why data from the general population is indispensable.’ 

Search for causes of Long COVID

The follow-up research is focused on the causes of Long COVID. Based on the previously collected health data and materials from Lifelines, the team is investigating the risk factors for Long COVID. Lifelines offers the possibility to look for proteins in blood samples from participants that indicate organ damage or long-term inflammation caused by COVID-19. The researchers will also conduct extra tests on some of those with long-term symptoms.  
 
Judith Rosmalen: ‘In some of the Lifelines participants with Long COVID, we want to measure thyroid function, perform an exercise test, determine autonomic nervous system function, and perform several other diagnostic tests. We also want to carefully examine lung function. Thanks to Lifelines, we have the results of lung function tests from recent years. We can compare the tests of people with Long COVID with those from before they became ill, and find out whether COVID-19 is causing a deterioration in lung function, whom that has happened to, and whether it is precisely those people who have persistent symptoms.’ 

Consequences of Long COVID 

The team will also investigate to what extent people with Long COVID can still function, particularly at work. Rosmalen: ‘We are also asking what care people have received and how they have experienced it. The data will be used to develop care pathways to provide patients with the right care and to calculate the social costs, in terms of both medical costs and productivity loss.’  

Impact and importance of health data 

The Lifelines biobank has been collecting a wide range of health data from a large group of Dutch people for 15 years. At the end of March 2020, together with Lifelines, the UMCG and the University of Groningen started sending questionnaires to Lifelines participants.  
 
Rosmalen explains: ‘Weekly, and later monthly, thousands of people were asked about COVID-19, psychological symptoms, living and working conditions, and many other topics. These lists also included questions about 23 physical symptoms. Due to this repetition and the multiplicity of questions, we now have a globally unique collection of health data for this research into Long COVID.’ A total of 27 questionnaires have since been sent out, which have been completed by an average of 35,000 people. In total, there are more than 900,000 questionnaires providing detailed information about the health of the Dutch population before, during, and after COVID-19 but also about the consequences for their wellbeing and daily functioning. These data are relevant for policy and for better care. 

Lifelines COVID-19 research 

This large-scale COVID-19 study is an initiative of the UMCG, the University of Groningen, the Aletta Jacobs School of Public Health, and the Lifelines biobank. Due to the close cooperation in the Northern Netherlands, a lot of extra health data has been collected since the start of the pandemic. This study forms part of a larger project in which patients’ experiences with Long COVID are charted using questionnaires and in-depth interviews. The knowledge gained is being converted into care pathways for this group of patients.  
 
More information about this can be found at: ACTION – Naar betere zorg voor Long COVID (actioncovid.nl). 

More about Lifelines COVID-19 research can be found in this video: Professor Judith Rosmalen on Lifelines (LONG) COVID-19 data.