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COVID-19CORFUNCT05240742

CORona (COVID-19) Follow Up Study: Epidemiology, Pathophysiology, Prediction, and Communication

An observational study of COVID-19 and Long COVID, run by Maastricht University Medical Center at 1 site in Netherlands.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The CORFU study, funded by ZonMW, is a prospective, multiple, cohort study with a maximum follow-up of 24 months after COVID-19. Dutch COVID-19 patients from 7 existing prospective cohorts, aiming and designed to conduct COVID-19 research, will be included in this study. Read more about this study

Who is it for?
Ages 18 years and olderHealthy volunteers can take part
Conditions the study is for
COVID-19, Long COVID, Post COVID-19 Condition
How many people
4,291 participants
Where
1 siteNetherlands
Study dates
1 Oct 2021to 1 Nov 2024
Phase
Observational
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Study population: The study population consists of Dutch (former) COVID-19 patients and non-COVID-19 controls, who have been included in one of the cohorts and categorized in five subgroups: * Patients who suffered from (confirmed) COVID-19 and were admitted to the hospital ward. * Patient who suffered from (confirmed) COVID-19 and were admitted to the ICU. * Patients who suffered from (confirmed or suspected) COVID-19 at home. * Patients who suffered from (confirmed) COVID-19 and were in need of inpatient or outpatient rehabilitation after infection at home or in the hospital (ward and/or ICU). * Controls who did not suffer from (confirmed or suspected) COVID-19.

All 7 existing cohorts have specific inclusion and exclusion criteria.

For the CORFU study, in general, the criteria are:

Patients with proven or suspected COVID-19:

  • Confirmed (or suspected) COVID-19 - both home-isolated patients and patients who were admitted to the hospital ward and/or ICU;
  • Included in one of the seven cohorts from March 2020 onwards;
  • Aged 18 years or older;
  • Mastering the Dutch language sufficiently to answer the questionnaires;
  • Informed consent.

Controls who did not experience COVID-19:

  • Aged 18 years or older;
  • Mastering the Dutch language sufficiently to answer the questionnaires;
  • Informed consent.

There were no exclusion criteria.

Trial locations and contacts

1 site in 1 country.

Netherlands1 site

  • Maastricht University Medical Center+

    Maastricht, 6229HX

Other trials in Netherlands

About this study

Official title: Persistent Complaints After COVID-19: Epidemiology, Pathophysiology, Prediction, and Communication, the CORona Follow Up (CORFU) Study

The CORFU study, funded by ZonMW, is a prospective, multiple, cohort study with a maximum follow-up of 24 months after COVID-19. Dutch COVID-19 patients from 7 existing prospective cohorts, aiming and designed to conduct COVID-19 research, will be included in this study.

The CORFU study has 5 aims, divided into 4 work packages (WPs):

Read more
  1. To describe the nature, severity, pattern and duration of long COVID complaints up to a maximum of two years after infection and its relationship with quality of life (WP1);
  2. To describe the rehabilitation and corresponding activities for the treatment and improvement of complaints and quality of life (WP1);
  3. To describe the pathophysiological processes that cause long COVID complaints, and the role of vulnerability/resilience factors (WP2);
  4. To develop a prediction model for the persistence of complaints, with distinction between patients with and without pre-existing morbidity (WP3);
  5. To develop a patient platform prototype in which patients can digitally consult their answers and compare their answers with reference populations (WP4, in collaboration with the EuroQol foundation).

The 7 cohorts participating in the CORFU study are: POPCOrn, COVAS, ELVIS, MaastrICCht, DC\&TC, CAPACITY-COVID, and Adelante cohort.

(Clinical) baseline and follow-up data has been collected in these cohorts and will be used/aggregated to investigate CORFU study aims. In addition, questionnaires will be send to the (former) patients of the existing cohorts and patients will be asked about several domains such as persisting complaints and quality of life, at several moments, depending on when the patients have experienced COVID-19. Within this study a patient platform prototype will be developed, together with the EuroQol foundation, to be able to inform patients about the individual situation and course of disease.

Being tested
no intervention, the CORFU study conducts analyses based on data which has been prospectively collected (and aggregated when possible) in 7 existing cohorts
Keywords
Epidemiology, Pathophysiology, Prediction model, Patient platform
Medical subject headings
COVID-19, Post-Acute COVID-19 Syndrome

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • no intervention, the CORFU study conducts analyses based on data which has been prospectively collected (and aggregated when possible) in 7 existing cohortsOther

    Also called Integrated database

    (Clinical) baseline and follow-up data will be collected in the 7 existing cohorts. These data will be aggregated (when possible). The CORFU analyses will be conducted based on the aggregated data.

Study groups in NCT05240742
Study groupRoleWhat they receive
Dutch COVID-19 patientsThe study population consists of Dutch (former) COVID-19 patients who have been included in one of the cohorts and categorized in various subgroups: * Patients who suffered from (confirmed) COVID-19 and were admitted to the hospital ward. * Patient who suffered from (confirmed) COVID-19 and were admitted to the ICU. * Patients who suffered from (confirmed or suspected) COVID-19 at home. * Patients who suffered from (confirmed) COVID-19 and were in need of inpatient or outpatient rehabilitation after infection at home or in the hospital (ward and/or ICU).
Receives: Other: no intervention, the CORFU study conducts analyses based on data which has been prospectively collected (and aggregated when possible) in 7 existing cohorts
Dutch controls who did not experience COVID-19One of the cohorts, the POPCOrn cohort, is a community-based cohort which partly consists of controls who did not experience COVID-19
Receives: Other: no intervention, the CORFU study conducts analyses based on data which has been prospectively collected (and aggregated when possible) in 7 existing cohorts

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Prevalence of long COVID complaints (based on data from all 7 cohorts)

    Long COVID complaints include: exhaustion, respiratory complaints, and mental health complaints.

    Measured: 24 months follow-up after COVID-19

Secondary outcomes (7)

  1. (Health-related) Quality of life (measured in all 7 cohorts)

    Measured using the EuroQol - 5 Dimensions - 5 Levels (EQ-5D-5L) questionnaire. Based on the Dutch tariff, scores range between -0.446 (worst) and 1.000 (best).

    Measured: 3, 6, 12, 18 and 24 months follow-up after COVID-19

  2. Anxiety and depression (measured in all 7 cohorts)

    Measured using the Hospital Anxiety and Depression Scale (HADS) questionnaire. Scores for both the Anxiety and Depression subscales range from 0 (best) to 21 (worst). A total subscale score of >8 points indicates considerable symptoms of anxiety or depression.

    Measured: 3, 6, 12, 18 and 24 months follow-up after COVID-19

  3. Prevalence of thrombo-embolic complications (not measured in all 7 cohorts)

    Thrombo-embolic complications of interest are: acute pulmonary embolism, deep-vein thrombosis, ischemic stroke, myocardial infarction and systemic arterial embolism

    The diagnosis, and therefore, the prevalence of various thrombo-embolic complications will be measured based on a combination of cardiovascular and thrombosis and haemostasis biomarkers (such as troponin I, CK-MB, APTT, and D-dimer), radiologic imaging techniques (computed tomography pulmonary angiography (CTPA), compression ultrasonography (CUS), echocardiography, CT scan of the brain, and CT angiography of the carotid and intracerebral arteries), and electrocardiogram.

    Measured: Measured during COVID-19 hospitalization (baseline), 3, 12, 24 months follow-up after COVID-19

  4. Physical functioning (not measured in all 7 cohorts)

    Measured using the 6 minute walk test (6MWT). The distance covered over a time of 6 minutes is used as the outcome by which to compare changes in performance capacity. An increase in the distance walked indicates improvement in basic mobility. The 6MWT result will be reported as a percentage of the predicted Dutch reference value which is based on the patient's age, sex, length and weight. A score <82% of the predicted value is considered deviant.

    Measured: Measured during admission in the rehabilitation clinic (baseline), 3, 6, 12 months follow-up

  5. Prevalence of cardiovascular diseases (not measured in all 7 cohorts)

    Cardiovascular diseases of interest are: coronary artery disease, heart failure, myocardial fibrosis, myocarditis, pericarditis.

    The diagnosis, and therefore, the prevalence of various cardiovascular diseases will be measured based on a combination of radiologic imaging techniques (such as cardiac magnetic resonance, CT and echocardiography), cardial biomarkers (such as troponin and CK-MB), and electrocardiogram.

    Measured: Measured during COVID-19 hospitalization (baseline), 1 week, 1 month, and through study completion, an average of 2 years

  6. Prevalence of endothelium dysfunction (not measured in all 7 cohorts)

    Measured using several biomarkers (such as endothelin-1, coagulation and inflammatory cytokines).

    Measured: Measured during COVID-19 hospitalization (baseline), 3, 12 months after COVID-19

  7. Disease severity during intensive care unit stay (not measured in all 7 cohorts)

    Measured using the Sequential Organ Failure Assessment (SOFA) score which is based on the degree of dysfunction of six organ systems. For each organ system, scores range between 0 (best) to 4 (worst). A sum score per day at the intensive care unit can be calculated, which ranges between 0 (best) and 24 (worst).

    Measured: Measured on the day of admission with COVID-19 to the intensive care unit (baseline), followed by daily measurement until discharge, an average of 18 days

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted15 Feb 2022
  2. Study start1 Oct 2021
  3. Primary completion1 Jan 2024
  4. Study completion1 Nov 2024

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Prospective
Enrolment
4,291 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05240742
Sponsor's protocol ID
METC2021-2990
Acronym
CORFU
Status last verified
Nov 2024
First submitted
26 Nov 2021
Last updated
1 Oct 2025
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided

Publications

  • Bels JLM, van Kuijk SMJ, Ghossein-Doha C, Tijssen FH, van Gassel RJJ, Tas J, Collaborators M, Schnabel RM, Aries MJH, van de Poll MCG, Bergmans DCJJ, Meex SJR, van Mook WNKA, van der Horst ICC, van Bussel BCT. Decreased serial scores of severe organ failure assessments are associated with survival in mechanically ventilated patients; the prospective Maastricht Intensive Care COVID cohort. J Crit Care. 2021 Apr;62:38-45. doi: 10.1016/j.jcrc.2020.11.006. Epub 2020 Nov 17.

    PubMed 33246196

  • Dutch COVID & Thrombosis Coalition (DCTC). Early effects of unfractionated heparin on clinical and radiological signs and D-dimer levels in patients with COVID-19 associated pulmonary embolism: An observational cohort study. Thromb Res. 2021 Apr;200:130-132. doi: 10.1016/j.thromres.2021.01.023. Epub 2021 Feb 2. No abstract available.

    PubMed 33592531

  • Dutch COVID & Thrombosis Coalition; Kaptein FHJ, Stals MAM, Grootenboers M, Braken SJE, Burggraaf JLI, van Bussel BCT, Cannegieter SC, Ten Cate H, Endeman H, Gommers DAMPJ, van Guldener C, de Jonge E, Juffermans NP, Kant KM, Kevenaar ME, Koster S, Kroft LJM, Kruip MJHA, Leentjens J, Marechal C, Soei YL, Tjepkema L, Visser C, Klok FA, Huisman MV. Incidence of thrombotic complications and overall survival in hospitalized patients with COVID-19 in the second and first wave. Thromb Res. 2021 Mar;199:143-148. doi: 10.1016/j.thromres.2020.12.019. Epub 2020 Dec 30.

    PubMed 33535120

  • van Gassel RJJ, Bels JLM, Raafs A, van Bussel BCT, van de Poll MCG, Simons SO, van der Meer LWL, Gietema HA, Posthuma R, van Santen S. High Prevalence of Pulmonary Sequelae at 3 Months after Hospital Discharge in Mechanically Ventilated Survivors of COVID-19. Am J Respir Crit Care Med. 2021 Feb 1;203(3):371-374. doi: 10.1164/rccm.202010-3823LE. No abstract available.

    PubMed 33326353

  • Kruip MJHA, Cannegieter SC, Ten Cate H, van Gorp ECM, Juffermans NP, Klok FA, Maas C, Vonk-Noordegraaf A; Dutch COVID Thrombosis Coalition study group. Caging the dragon: Research approach to COVID-19-related thrombosis. Res Pract Thromb Haemost. 2021 Mar 8;5(2):278-290. doi: 10.1002/rth2.12470. eCollection 2021 Feb.

    PubMed 33733026

  • Leijte WT, Wagemaker NMM, van Kraaij TDA, de Kruif MD, Mostard GJM, Leers MPG, Mostard RLM, Buijs J, van Twist DJL. [Mortality and re-admission after hospitalization with COVID-19]. Ned Tijdschr Geneeskd. 2020 Nov 19;164:D5423. Dutch.

    PubMed 33332036

  • Long D, Haagsma JA, Janssen MF, Yfantopoulos JN, Lubetkin EI, Bonsel GJ. Health-related quality of life and mental well-being of healthy and diseased persons in 8 countries: Does stringency of government response against early COVID-19 matter? SSM Popul Health. 2021 Sep 1;15:100913. doi: 10.1016/j.ssmph.2021.100913. eCollection 2021 Sep.

    PubMed 34522763

  • Tas J, van Gassel RJJ, Heines SJH, Mulder MMG, Heijnen NFL, Acampo-de Jong MJ, Bels JLM, Bennis FC, Koelmann M, Groven RVM, Donkers MA, van Rosmalen F, Hermans BJM, Meex SJ, Mingels A, Bekers O, Savelkoul P, Oude Lashof AML, Wildberger J, Tijssen FH, Buhre W, Sels JEM, Ghossein-Doha C, Driessen RGH, Kubben PL, Janssen MLF, Nicolaes GAF, Strauch U, Geyik Z, Delnoij TSR, Walraven KHM, Stehouwer CD, Verbunt JAMCF, Van Mook WNKA, van Santen S, Schnabel RM, Aries MJH, van de Poll MCG, Bergmans D, van der Horst ICC, van Kuijk S, van Bussel BCT. Serial measurements in COVID-19-induced acute respiratory disease to unravel heterogeneity of the disease course: design of the Maastricht Intensive Care COVID cohort (MaastrICCht). BMJ Open. 2020 Sep 29;10(9):e040175. doi: 10.1136/bmjopen-2020-040175.

    PubMed 32994259

  • Wiertz CMH, Vints WAJ, Maas GJCM, Rasquin SMC, van Horn YY, Dremmen MPM, Hemmen B, Verbunt JA. COVID-19: Patient Characteristics in the First Phase of Postintensive Care Rehabilitation. Arch Rehabil Res Clin Transl. 2021 Jun;3(2):100108. doi: 10.1016/j.arrct.2021.100108. Epub 2021 Feb 4.

    PubMed 33558860

  • Klein DO, Waardenburg SF, Janssen EBNJ, Wintjens MSJN, Imkamp M, Heemskerk SCM, Birnie E, Bonsel GJ, Warle MC, Jacobs LMC, Hemmen B, Verbunt J, van Bussel BCT, van Santen S, Kietelaer BLJH, Jansen G, Klok FA, de Kruif MD, Vernooy K, Haagsma JA, Asselbergs FW, Linschoten M, Cals JWL, Ten Cate H, van der Horst ICC, Wilmes N; CAPACITY-COVID Collaborative Consortium; Ghossein-Doha C, van Kuijk SMJ. Two years and counting: a prospective cohort study on the scope and severity of post-COVID symptoms across diverse patient groups in the Netherlands-insights from the CORFU study. BMJ Open. 2025 Sep 11;15(9):e093639. doi: 10.1136/bmjopen-2024-093639.

    PubMed 40940063

  • Jacobs LMC, Wintjens MSJN, Nagy M, Willems L, Ten Cate H, Spronk HMH, van Kuijk SMJ, Ghossein-Doha C, Netea MG, Groh LA, van Petersen AS, Warle MC. Biomarkers of sustained systemic inflammation and microvascular dysfunction associated with post-COVID-19 condition symptoms at 24 months after SARS-CoV-2-infection. Front Immunol. 2023 Oct 5;14:1182182. doi: 10.3389/fimmu.2023.1182182. eCollection 2023.

    PubMed 37868959

  • Ghossein-Doha C, Wintjens MSJN, Janssen EBNJ, Klein D, Heemskerk SCM, Asselbergs FW, Birnie E, Bonsel GJ, van Bussel BCT, Cals JWL, Ten Cate H, Haagsma J, Hemmen B, van der Horst ICC, Kietselaer BLJH, Klok FA, de Kruif MD, Linschoten M, van Santen S, Vernooy K, Willems LH, Westerborg R, Warle M, van Kuijk SMJ. Prevalence, pathophysiology, prediction and health-related quality of life of long COVID: study protocol of the longitudinal multiple cohort CORona Follow Up (CORFU) study. BMJ Open. 2022 Nov 29;12(11):e065142. doi: 10.1136/bmjopen-2022-065142.

    PubMed 36446465

Questions about this trial

What is this clinical trial studying?

An observational study of COVID-19 and Long COVID, run by Maastricht University Medical Center at 1 site in Netherlands.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 1 Oct 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Netherlands. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Prevalence of long COVID complaints (based on data from all 7 cohorts) (time frame: 24 months follow-up after COVID-19). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05240742, which also lists 12 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Oct 2025; AzTrials last refreshed its copy on 7 Nov 2026.

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