Classification and risk factors of Post COVID-19 condition: a longitudinal study in the Belgian population

Abstract Background Since the onset of the COVID-19 pandemic, most research has focused on the pathophysiology and management of the acute symptoms of COVID-19, yet some people tend to experience symptoms beyond the acute phase of infection, that is, Post COVID-19 condition (PCC). However, evidence on the prevalence of PCC, its symptoms, and mechanisms are still scarce. This study aimed to assess the distribution, patterns of symptoms, and associated factors of PCC in adult with confirmed COVID-19 infection in Belgium. Methods This is a longitudinal cohort study of Belgian adult population with recent COVID-19 infection confirmed via a molecular test and systematically recruited via national tracing call centers. A total of 5181 people were followed-up using online questionnaires at the time of their infection and 3 months later (from April 2021 to February 2022). Their physical, social and mental health was evaluated as well as their acute COVID-19 symptoms and persistent PCC symptoms. These different variables were self-reported. Results Half of the participants reported PCC (49.6%). The most frequent persistent symptoms 3 months after infection were fatigue (28%), headache (18%), and memory problems (12%). Women (OR = 1.67,CI95%=1.40-1.99), people with a lower level of education (OR = 1.23,CI95%=1.02-1.48), obese people (OR = 1.23,CI95%=1.02-1.48), people with chronic disease (OR = 1.97,CI95%=1.40-2.77), and people with a higher number of acute COVID-19 symptoms (OR = 2.56, CI95%=1.83-3.58) or hospitalised (OR = 2.19,CI95%=1.25-3.82) were more likely to report PCC. Finally, a latent class analysis on the 29 PCC symptoms highlighted 3 different classes of symptoms. Conclusions With the growing number of people infected with COVID-19, PCC is becoming an important public health issue. To allow people with PCC to recover, it is essential to have a multidisciplinary approach and to provide early post-acute physical and psychological rehabilitation interventions according to symptom patterns.


Introduction:
Covid-19 has been a pandemic for the past two years. From early on, it became obvious that some of the individuals surviving the infection continued to experience symptoms beyond the acute phase of the infection or else developed symptoms after the acute infection. Multiple terminologies describing this phenomenon started to appear with 'Long Covid' being a popular nomenclature. It soon became evident that Long Covid can affect almost all the body's systems with a plethora of associated symptoms, while new symptoms keep on emerging across time. These persistent symptoms are noted to act differently among different individuals, irrelevant whether they were previously healthy or previously suffering from any chronic disease/s. Indeed, while some experienced persistent symptoms for a couple of weeks, some had persistent symptoms for months. The variations in the severity of symptoms are another feature that became evident among Long Covid sufferers. The year 2021 saw the approval of different Covid-19 vaccines and the initiation of vaccination rollouts across Europe. As the vaccine population coverage progressed, it was anticipated that the lower viral infectivity rate will also decrease the occurrence of Long Covid-19 among the vaccinated as compared to the unvaccinated. Yet breakthrough Covid-19 infections still occurred along with the development of Long Covid-19 among vaccinated, especially as new variants emerged and immunity waned. Long Covid-19 is still a relatively new condition with unspecified pathophysiology and unknown long-term disability trajectory. Therefore, it is imperative that this condition is put into the spotlight to comprehend this pandora's box while trying to prevent its occurrence and the associated sequela. Aim: Considering the fluidly of this condition with speculations that Long Covid might be the new chronic disease of this decade, this workshop is set to provide a multidisciplinary platform for emerging evidence on Long Covid originating from across Europe. In fact, the presentations in this workshop will tackle various aspects pertaining to Long Covid. The first presentation will provide evidence on the different risk factors and symptoms of Long Covid. The second presentation will discuss the association of multimorbidity and socio-economic factors as risk factors of Long-Covid. The third presentation will bring forward the perspectives of those suffering from the condition and the need for an integration of health care targeting both Long Covid and chronic diseases. While the fourth presentation will discuss the burden of Long-Covid symptoms and its impact on the quality of life. Finally, the bidirectional relationship between Long Covid-19 and NCDs along with the required public health action will be discussed. This will be followed by a discussion between the presenters and the audience.

Key messages:
Long Covid-19 is a common occurrence among healthy and chronic diseases population alike with a plethora of contributing risk factors. An integrated healthcare plan is required to decrease the impact of Long Covid-19 on the population while simultaneously managing other underlying conditions and diseases.

Results:
Overall, 73% of respondents were estimated to have at least one persistent symptom associated with Covid-19 illness and, on average, they had 2.73 symptoms. However, there were some statistically significant across country differences in the presence and number of symptoms. Respondents who were employed were more likely to report at least one symptom (OR = 1.40) and those with higher levels of education were less likely to report any symptoms (OR = 0.67). Respondents with multimorbidity had an increased risk of experiencing an additional symptom (RR = 1.12) while respondents who were employed had a decreased risk of experiencing an additional symptom (RR = 0.85).

Discussion and conclusions:
Presence and number of persistent symptoms associated with Covid-19 illness was highly prevalent and varied significantly across European countries. Evidence from the present work underscores the need to target high-risk groups and those with multimorbidity to reduce long-term health consequences of Covid-19.

Introduction:
After COVID-19, many people continue to experience various symptoms for several weeks, even after a mild acute phase, and encounter difficulties when confronted with the healthcare system. Patient associations asked the Belgian Health Care Knowledge Centre to investigate the needs of these patients to improve their management.

Purpose of research:
An online quantitative survey was conducted in 2021 among Belgian patients with history of COVID-19; having/had persisting symptoms for at least 4 weeks. Alongside questions on symptoms, treatment and impact on employment, Health-Related Quality of Life (HRQoL) before and after COVID-19 was measured through the EQ-5D-5L. A regression analysis identified the factors associated with the impact of long COVID on HRQoL. The qualitative approach consisted in 33 interviews and forum discussions among 101 patients.
Results: 1320 patients completed the online survey, most were symptomatic for more than 3 months. The average EQ-5D-5L index score was 0.85(95%CI:0.83-0.86) before and 0.65(95%CI:0.63-0.66) after infection. Duration, number and type of symptoms of long COVID significantly impacted HRQoL. More than half of the patients were unable to work. Qualitative part identified lack of empathy of health professionals, of systematic diagnostic approach, of interdisciplinary coordination. Patients felt misunderstood and developed their own diagnostic or treatment strategies. They questioned the value of medicine and resorted to non-reimbursed alternative therapies.

Conclusions:
Long COVID has a significant impact on HRQoL and employment. Because of long COVID, patients were confronted, sometimes for the first time, with the imperfections of the health system. Better informing the health professionals on Long COVID patterns and management options, including reimbursement possibilities, and a comprehensive interdisciplinary assessment would give them the tools to respond to the needs of these patients.

Introduction:
Previous studies indicated that a significant share of COVID-19 patients experiences long lasting health complaints; a condition also referred to as ''long COVID''. In order to assess the long term burden of disease of COVID-19, including long COVID, information is needed on health symptoms, healthrelated quality of life and duration of symptoms of long COVID patients. Therefore, the aim of this study was to assess health symptoms and health-related quality of life of long COVID in the general population of the Netherlands.

Methods:
A total of 33,903 COVID-19 patients from the region South-Holland South (the Netherlands) whom tested positive between June 2020 and May 2021 at the municipal health services were invited to complete a web-based questionnaire on the presence, nature and consequences of long COVID and health-related quality of life, measured with the EQ-5D-5L.